Vaccines Have Serious Side Effects

The Revised Authoritative Guide To Vaccine Legal Exemptions

Comprehensive, authoritative information about vaccine exemptions you can trust, from Alan Phillips, J.D., a leading vaccine rights attorney with years of experience helping clients throughout the U.S. legally avoid vaccines in a wide variety of vaccine-refusal settings. Critical details for parents, students, immigrants, healthcare employees, military personnel and contractors, agencies, attorneys and clientsvirtually anyone concerned with legally avoiding vaccines in the United States. This Guide provides and explains: Important background information about the legal system; How state and federal statutes, regulations, constitutions and legal precedent interact to define the boundaries of your legal exemption rights; How to deal with local authorities and to avoid mistakes that cost others their exemption; Where legal technicalities and practical reality differand what to do about it; Read more here...

The Revised Authoritative Guide To Vaccine Legal Exemptions Summary

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Vaccinia As A Cancer Vaccine

The experience with vaccinia in the eradication of smallpox led to research into its use as an antitumor vaccine. Vaccinia was engineered to express tumor antigens and serve as a cancer vaccine. The size of the potential transgene that can be put into the vaccinia vector allows for flexibility in engineering, such that immune enhancing genes and antigenetic genes can be recombined into the genome. The immunostimulatory effects and efficient transcriptional machinery of the virus were utilized to create various cancer vaccine vectors (Table 2). Recently, a phase I clinical trial of vaccinia expressing prostate specific antigen (PSA) in prostate cancer patients was published. In this trial the Wyeth strain virus was delivered intradermally every 4 wk for three doses without producing significant systemic toxicities. A cutaneous reaction, consistent with viral replication was seen in all patients treated with the virus at a dose of 2.65 x 107 pfu. Several patients developed T-cell immune...

Selection of KLH Conjugate Plus QS21 Vaccines

We have explored a variety of approaches for increasing the antibody response against carbohydrate and peptide cancer antigens, including the use of different immunological adjuvants (12,60-65), chemical modification of gangliosides to make them more immunogenic (66-69), and conjugation to various immunogenic carrier proteins (60,70). The conclusion from these studies is that the use of a carrier protein plus an immunological adjuvant is the optimal approach. The optimal immunological adjuvant in each case was one or more purified saponin fractions (QS-21 or GPI-0100) obtained from the bark of Quillaja saponaria (65,71). The optimal carrier protein was in each case KLH. This approach (covalent attachment of the carbohydrate to KLH and administration mixed with QS-21 or GPI-0100) has proved optimal for antibody induction in mice and cancer patients for each of the antigens in Table 1, except for sLea, which has not been tested yet. The role of carrier protein in these conjugate...

Organization and content of dna vaccines

Theoretically, administration of multiple plasmids containing genes for cooperating proteins is possible and easy to perform. However, considering the low efficiency of transfection, the chance of being colocalized to ensure optimal cooperation is very small. Thus, innovative methods for incorporating more than one therapeutic gene into a single plasmid became essential for optimizing DNA vaccines. Several approaches to solve this problem have been proposed. The simplest method is cloning of an additional expression cassette (promoter-gene-polyA) into the vector, although caution has to be exercised to avoid cross-promoter silencing (see Fig. 2B M. Sektas, personal communication). Along this line bidirectional promoters have been used allowing the unilateral expression of two transgenic proteins HbsAg and HbcAg (80 see Fig. 2D). and IL-1P have been constructed and were functional (84), but the real power of this approach was demonstrated in the combination of HIV-1 gp120 and...

Mechanisms of dna vaccineinduced immunity

The ability to sneak in to an organism without inciting a strong immune response makes plasmid DNA unique among vaccines. In fact, complete adaptive immunity specific to plasmid DNA has not been reported. Importantly, although plasmid DNA is quickly deposited in myocytes and APCs (10), there is a several-hour time gap between injection of DNA vaccine and the appearance of encoded antigen. This might have major consequences for the ability of DNA vaccines to prime naive T cells. The amount of antigen produced in vivo after DNA inoculation is in the picogram to nanogram range (3). Equivalent amount of antigen introduced in vivo in the form of protein would probably be processed by macrophages without inducing an adaptive response, resulting in the impression that the antigen was either ignored or tolerized. These observations suggest that the plasmid itself may function as a powerful immunomodulator (Fig. 3). Receptor-mediated activation of monocytes is the most likely mechanism of...

Rotavirus Vaccine and intussusception

After over 9 months of apparently successful use of the vaccine in the USA, on 16 July 1999 the CDC reported that between 1 Sept 1998 and 7 July 1999, according to the Vaccine Adverse Event Reporting System (VAERS), a passive system operated by FDA and CDC, 15 cases of intussusception had occurred following vaccination with RRV-TV (CDC 1999b). It was estimated that 1.8 million doses of RRV-TV had been distributed and that 1.5 million doses had been given. Although the number of intussusception cases reported was within the expected value (considering a New York State background rate of 51 per 100 000 infants

Bacterial Extracts in Cancer Vaccines

This early work has led to the development of many of the modern immune adjuvants currently in clinical trials with cancer vaccines. Furthermore, the nonspecific approach used by Coley and others is still being investigated. For example, the therapeutic efficacy of bacille Calmette-Guerin (BCG) against superficial bladder cancer has been correlated with the secretion of Th1 cytokines and chemokines (reviewed in ref. 12). Additionally, an immunostimulant prepared from heat-killed Mycobacterium vaccae, SRL 172, has shown some benefit in human malignancies (13-16).

The Current Generation of Vaccines

The problem of intussusception from the rhesus vaccine changed the way that the next generation of rotavirus vaccines would have to be tested. The rhesus vaccine had demonstrated that live oral vaccines could be highly effective and protect children against severe rotavirus diarrhea. However, new vaccines also had to jump the hurdle of safety and demonstrate greater safety than Rotashield. While trials of several thousand children were adequate to demonstrate vaccine efficacy, trials exceeding 60,000 children would be required to demonstrate safety if the risk of intussusception were about 1 event per 5000 vaccines. Both GlaxoSmithKline and Merck proceeded to develop alternative live oral vaccines. The GSK vaccine, called Rotarix , was based on a single strain of rota-virus derived from a patient and attenuated by multiple passaging in cell culture. The vaccine comes as a lyophilized powder that is reconstituted with a buffer and administered orally in a 2 dose schedule. The Merck...

The Effect of Conjugated Pneumococcal Vaccines on Different Forms of Pneumococcal Disease

Altogether 6 randomized controlled trials have been published to date on the efficacy of PCV for individual healthy infants (Table 12.2) four of these were primarily designed to provide information on PCV efficacy effectiveness against invasive pneumococcal disease (IPD) (Lucero et al., 2004 Black et al., 2000 Klugman et al., 2003 O'Brien et al., 2003 Cutts et al., 2005) and two for acute otitis media (Eskola et al., 2001 Kilpi et al., 2003 Prymula et al., 2005). As expected from the experience with conjugated Hib vaccines, the PCV efficacy against IPD is high, even in HIV-positive children, when a 4 or 3-dose schedule is used. Of the randomized controlled trials studying the effect of PCV on pneumonia, only the Gambian (Cutts et al., 2005) and the Philippine trials (Lucero et al., 2005) have pneumonia as their primary endpoint. Access to care, case definitions of both clinical and radiological pneumonia and care practices have varied across trials, which may partly explain the...

Targeting Genetic Vaccines

One of the most common cellular localization sequences used for targeting an antigen fusion partner to the MHC class I pathway is ubiquitin. Ubiquitin marks proteins for degradation by the proteosome into small peptides which are then transported to the endoplasmic reticulum for loading onto MHC class I molecules. Addition of ubiquitin to plasmid fusion constructs usually increases CTL responses at the cost of humoral responses (91-95). However, in one study, a ubiquitin fusion construct demonstrated a decrease in humoral response whereas CTL response remained unchanged (96). Further examination of ubiquitin fusion constructs will be required for generalization of this strategy. Calreticulin (CRT) is a particularly interesting candidate for cancer vaccines because it has both MHC class I targeting capacity and antiangiogenesis properties (the ability to inhibit blood vessel growth to the site of a tumor) (97-166). Addition of CRT to fusion constructs has shown to exhibit notable...

Ntroduction of Pneumococcal Vaccines into National Vaccination Programs

The Pnc polysaccharide vaccine is recommended for use in risk groups, including children above 2 years of age in most rich countries (Fedson et al., 2004 Pebody et al., 2005). How well the target groups are being reached is unclear as most countries do not have adequately functioning vaccine registries which could be linked to disease specific registries to understand the association between PPV vaccine coverage and age-specific effectiveness of PPV. Presently very few countries have introduced PCV universally into their national vaccination program. First was the United States in the year 2000. This decision was backed up by favorable cost-effectivess predictions (Lieu et al., 2000). The first European country to introduce PCV on universal basis was Luxembourg in year 2004 (Pebody et al., 2005). Most other rich countries have recommendations for the use of PCV in risk groups only, the cost of which is covered either by the state or insurance. The reason for this selective approach is...

Tomorrows Genetic Vaccines

This ideal genetic vaccine formulation has already been described as having the following properties (1) low dose frequency, (2) low cost, (3) effective immune response, (4) high reproducibility, (5) pharmaceutical acceptability, and (6) a high safety profile (134). However, effective immune response, by definition, requires a strong elicitation of the immune system, a process which is currently believed to be intimately tied to danger signals (77). It is reasonable then to question whether effective genetic vaccines will have this high safety profile until our limited understanding of adjuvancy is substantially increased. One indication of this challenge is apparent in FDA clinical trials for conventional adjuvants. With approx 80 yr having passed since the first usage of alum in humans, there are still no additional FDA approved adjuvants. This could be the result of crude adjuvancy and low toxicity being mutually exclusive traits. In the short term, mastering the intricate balance...

Tuberculin Mantoux testing and BCG vaccination

A tuberculin (Mantoux) test should be performed prior to BCG vaccination in all individuals over 6 months of age. (It is read at 48-72 hours.) If area of induration 5-10 mm typical of past BCG vaccination The BCG vaccination should be given if reaction 5 mm induration. BCG recommended for others at increased risk (and where value of BCG vaccine uncertain), e.g. health care workers, travellers 5 years with significant exposure

Vaccines for lymphomas 21 Idiotype Based Protein Vaccines for Follicular BCell Lymphoma

Kwak, Levy, and coworkers at Stanford University pioneered the vaccination of patients with B-cell lymphoma with Id protein derived from the patients' tumors (16,17). In their first report of nine treated patients with low-grade follicular lymphoma primarily at first remission after chemotherapy, each patient received a series of subcutaneous injections of autologous Id protein that had been conjugated to an immunogenic carrier protein, keyhole limpet hemocyanin (KLH). Id-specific humoral and or cellular immune responses developed in seven of nine immunized patients. Tumor regression was observed in two patients who had measurable disease (16). In these patients, it was subsequently shown that cell-mediated cytolytic immune responses might be an important determinant of vaccine efficacy (18). In their follow-up study, 41 patients received a series of injections with vaccines consisting of Id protein coupled to KLH and emulsified in an immunological adjuvant, either incomplete adjuvant...

Vaccines for multiple myeloma

A part of the lysate antigens and that there were shared tumor antigens among patients. No killing of autologous peripheral blood mononuclear cells (PBMCs), purified B cells, or Epstein-Barr virus-transformed B-cell lines was observed. Consistent with our results, a recent study also showed that myeloma bone marrow-derived T cells, after ex vivo stimulation with autologous tumor-loaded DCs, could kill autologous myeloma cells, but not nonmyeloma cells in the bone marrow, myeloma cell lines, DCs loaded with Id protein, or allogeneic myeloma cells (71). Collectively, these data demonstrate that CTLs induced by tumor lysate-pulsed DCs specifically kill autologous tumor cells, but not normal PBMCs or B cells, and provide a rationale for vaccination with tumor cell-pulsed DCs in myeloma patients.

Tumorassociated antigen vaccines

Many shared TAAs have been identified in ovarian and breast cancer patients (see Table 4). The list of potential antigens includes cell-surface proteins that are overexpressed and released in the circulation by the cancer cells (MUC-1, HER-2 neu, CEA, CA-125, Ep-Cam), overexpressed genes (p53), specific or aberrantly glycosylated carcinoma-associated proteins (Sialyl-Tn, Tn, Globo H, Lewisy Ly ), and proteins whose expression is largely restricted to tumors (cancer testis antigens- NY-ESO-1, MAGE proteins). In breast cancer, the expression of HER-2 neu, MAGE-A, and Ep-CAM predicts clinical outcome and tumor behavior (33-35). Targeting proteins that are necessary for metastasis or tumor growth are attractive for vaccine development as this ensures the

General Regulatory Issues Related to Tumor Vaccines

Just as it is important to find novel approaches for cancer therapy, it is also important that these tumor vaccine products are developed to best reveal their therapeutic potential. The role of the product reviewer is to ensure that patients are receiving a product that is safe, pure, and potent at all stages of development. A safe, pure, and potent product is most likely to be produced if there is quality and consistency in both the testing and manufacture of the product. Although the standards outlined as Good Manufacturing Practices (GMPs) will not be achieved before licensure, many of the principles should be applied to product testing and manufacturing at all stages of product development. Consistent production of tumor vaccine products, particularly multiantigen preparations, autologous tumor cell lysates, and cellular vaccines is critical in order to verify and confirm any promising activities observed at the early stages of the clinical trial. Prior to a product sponsor's...

Tumor Vaccine Specific Regulatory Issues

As mentioned earlier, this section is focused on three broad classes of tumor vaccines (a) cellular tumor vaccines, (b) multiantigen preparations and tumor lysates, and (c) recombinant or purified proteins and peptides. This section will discuss regulatory issues specific to products in each of these product classes. For each tumor vaccine discussed we will provide a description, examples, current clinical applications, and some of the regulatory issues unique to that vaccine product. This is not meant to be an inclusive discussion, but an attempt will be made to cover many of the types of products currently being investigated. 2.2.1. Cellular Tumor Vaccines Cellular tumor vaccines are composed of autologous or allogeneic tumor cells, tumor-specific lymphocytes, and antigen-presenting cells (APCs). These cells can be used alone or in combination with other types of tumor vaccines. They can also be administered with adjuvant or cytokines to enhance their potential as a vaccine product....

Live Attenuated Varicella Vaccine

Varicella-zoster virus (VZV) is the etiologic agent of varicella and zoster. Varicella is the primary infection, and zoster is due to reactivation of latent VZV acquired during chickenpox. Each disease is characterized by a macu-lopapular and vesicular skin eruption, which in varicella is generalized, and in zoster is unilateral and usually localized. Varicella is often mild and uncomplicated in otherwise healthy children, but it may unpredictably be associated with significant morbidity and even mortality. In the United States, in the pre-vaccine era, there were about 100 annual deaths from varicella and 11,000 hospitalizations 1 . Most deaths from varicella occurred in individuals who were healthy before contracting varicella. The risk of developing zoster is increased in the immunocompromised and the elderly, and zoster may be severe but is rarely fatal. Live Attenuated Varicella Vaccine Background A live attenuated varicella vaccine, the Oka strain, was developed in Japan in the...

Vaccine Strategies for HDV

If the immune response explanation of the genetic changes discussed above is correct, we could conclude that the stimulation of a potent immune response, which is inferred by the 27 week sequence changes in the animals that recovered from HDV infection, could be achieved by vaccination and that this response could clear the virus. Analysis of antibody responses to HDAg in patients and experimentally infected woodchucks indicated an immun-odominant domain between amino acids 52 and 93 (Bergmann et al. 1989 Wang et al. 1990). A preliminary report (Bergmann et al. 1993) described a vaccine strategy in which woodchucks were vaccinated with three HDAg peptides conjugated individually to keyhole limpet hemocyanin. Vaccinated woodchucks were challenged with a woodchuck-adapted HDV pool. All animals became infected with HDV, based on the ability to detect HDV RNA in serum (Bergmann et al. 1993). However, preliminary analysis of viral RNA levels suggested that viremia was lower and of shorter...

Adenovirus use in cancer vaccine strategies

With so much known about Ad biology, it was a natural step to use recombinant Ad for vaccination purposes. As a first example, E1- Ad vectors have been engineered that express genes encoding epitopes (or whole proteins) derived from a number of pathogens, including (but not limited to) malaria, bovine herpesvirus (type 1), foot-and-mouth disease virus (FMDV), measles virus, and HIV (human immunodeficiency virus) (5-7). Vaccination with these Ad vectors has shown positive efficacy in preventing viral infection upon challenge with each of the respective viruses. The potential benefits provided by the use of Ad vectors as vaccines for the prevention of viral illnesses coincide with simultaneous efforts to use Ad vectors to vaccinate against various types of cancer. The first use of Ad against cancer occurred shortly after its discovery in 1953. In this experiment, concentrated wild-type Ad were intravenously administered into subjects affected by cervical cancer. The hypothesis was that...

Patients With Cancer Can Be Immunized With Class II Peptide Based Vaccines

GM-CSF is a recruitment and maturation factor for skin dendritic cells (DCs), Langerhans cells (LCs), and theoretically may allow more efficient presentation of peptide epitopes than standard adjuvants such as IFA. Six HLA-A2 patients with HER-2 neu-overexpressing cancers received six monthly vaccinations with 500 g of HER-2 neu peptide, p369-377, and mixed with 100 g of GM-CSF. The patients had either stage III or IV breast or ovarian cancer. Immune responses to the p369-377 were examined using an IFN-y ELIspot assay. Prior to vaccination, the median precursor frequency, defined as precursors 106 PBMC, to p369-377 was not detectable. Following vaccination, HER-2 neu peptide-specific precursors developed to p369-377 in just two of four evaluable subjects. The responses were short-lived and not detectable at 5 mo after the final vaccination. Immunocompetence was evident as patients had detectable T-cell responses to tetanus toxoid and influenza. These results...

TF Tn and sTn Vaccines

Patients with various epithelial cancers have been immunized with unclustered TF-KLH and sTn-KLH vaccines plus various adjuvants (84,85). High-titer IgM and IgG antibodies against TF and sTn antigens resulted. In our hands the majority of the reactivity was against antigenic epitopes present in the vaccine that were not present on naturally expressed mucins (porcine or ovine submaxillary mucins PSM or OSM ) or tumor cells (84,86). Based on previous studies with Tn antigen (87), Kurosaka and Nakada et al. hypothesized that MLS102, a monoclonal antibody against sTn, might preferentially recognize clusters ((c)) of sTn (88). Studies with monoclonal antibody B72.3 and with sera raised against TF-KLH and sTn-KLH conjugate vaccines in mice and in patients resulted in the same conclusion (41,84,86). The availability of synthetic TF, Tn, and sTn clusters consisting of three epitopes covalently linked to three consecutive serines or threonines has permitted proof of this hypothesis. In both...

Peptide vaccine strategies

Over the last decade, at least 20 HLA class I-restricted peptide epitopes have been defined from multiple melanoma differentiation and cancer-testis antigens. They are reviewed in ref. 15. Peptide vaccine trials have been conducted with individual or multiple peptides in patients with stage IV disease in aqueous solution or using different adjuvants, with different cytokines, or via DNA plasmid delivery. Some trials have already been conducted in high-risk resected patients, which would appear to be an optimal population for conducting cancer vaccine trials. Significant controversy exists, however, over the optimal surrogate immune end point to measure in peptide vaccine trials, appropriate dose, the duration of treatment, and scheduling. The first tumor antigen recognized by T cells that was cloned was MAGE-1, a member of a multigene family dubbed a cancer-testis antigen because it was found to be encoded normally in the germline but expressed only in tumor tissue, testis, and...

Rotavirus features relevant to vaccine development

Rotaviruses are 70 nm in diameter, non-enveloped and possess a distinctive double-shelled outer capsid. Within the inner shell is a third layer, the core, which contains the viral genome comprised of 11 segments of double-stranded (ds)RNA. During coinfection with different rotavirus strains, the segmented genomes readily undergo genetic reassortment. With regard to vaccine development, the two outer capsid proteins, VP4 and VP7, deserve special attention (Kapikian & Chanock 1996). VP7, a glycoprotein, comprises one of two major neutralization antigens located on the outer capsid and is encoded by RNA segment 7, 8 or 9 (depending on strain). The other outer capsid protein, VP4, is encoded by RNA segment 4 it protrudes from the outer capsid in the form of60 spikes. Antibodies to both VP7 and VP4 are independently associated with protection against illness in various animal models. Serotypes are characteristically determined by VP7, but a VP4 serotyping scheme has also been developed...

Multiple chaperone vaccines

If individual chaperone protein vaccines are effective against tumors, would one vaccine containing numerous chaperone protein family members be better The perceived advantages would be the probability of increasing the overall number of peptides available for antigen presentation because of multiple chaperone proteins, as well as the odds of increasing peptide diversity if members of the different chaperone families tend to escort distinct sets of peptides. Although their utilization has been suggested (74), part of the reason that such multichaperone vaccines are not commonplace lies in the difficulty of purifying sufficient quantities of multiple chaperones from a single source. Though such schemes are available (75,76), they are time consuming and generate numerous protein fractions requiring analysis prior to vaccine preparation. Our group set out to find a method that might enhance the rapid purification of multiple chaperones while keeping the workload and turnaround time...

VSV Gene Therapy and Vaccines

The generally low seroprevalence of VSV antibodies in the general population and genetic malleability indicated that VSV could be an attractive vector to develop new vaccines (26). VSV elicits strong humoral and cellular immune responses in vivo and naturally infects at mucosal surfaces (89-91). As mentioned, a major observation also included that VSV were found to accommodate large gene inserts and multiple genes in their genomes (88). Thus, it wasn't long before a variety of foreign viral glycoproteins were cloned into VSV vectors for the purpose of developing novel vaccines (89,92,93). Early studies involved placing the hemagglutinin (HA) or neuraminidase (NA) of influenza virus into VSV as extra genes. High-level expression of the heterologous products were obtained and animals inoculated with these VSV vectors were protected against lethal doses of influenza virus (88,89). Substitution of the VSV G protein with influenza virus HA was also found to function well and to exhibit...

Heat Shock Proteins As Vaccine Vehicles

In the killing, in an antigen-specific manner, of tumor cells and virus-infected cells. This dichotomy in antigen presentation theoretically excluded the presentation of an exogenous antigen in the MHC I molecules. However, in some conditions, APC are able to present exogenous antigen in the context of the MHC I molecules to CD8+ T cells, a process called antigen cross-presentation (Heath and Carbone, 2001 Yewdell et al., 1999). It is thought that antigens have to be taken up via endocytic receptors to be efficiently cross-presented in vivo (Arnold-Schild et al., 1999 Castellino et al., 2000 Singh-Jasuja et al., 2000 Wassenberg et al., 1999). This process allowed to propose new vaccine strategies based on the targeting of endocytic receptors selectively expressed by DC. Several studies were focused on identifying vector proteins exhibiting DC-targeting properties and able to mediate cross-presentation of vaccine antigens associated or coupled to the vehicle. The outer membrane protein...

Toxicity of DNPModified Autologous Vaccine

In most patients, the toxicity was limited to the reaction at the vaccine injection site. All patients developed pruritic papules that progressed to pustules, sometimes with small ulcerations, that resolved into small white or pink scars. The intensity of the local reactions was ameliorated by reducing the dose of bacille Calmette-Gu rin (BCG). As expected, about one-third of patients developed nausea, sometimes with vomiting, following administration of cyclophosphamide, but systemic toxicity caused by the vaccine was uncommon Less than 5 of patients noted fever or chills following vaccine administration, and no patient experienced a decrease in performance status. One patient developed generalized urticaria 15 min after injection of her fourth dose of DNP-vaccine this was treated with an antihistamime and resolved in 5 d without sequelae. Three patients developed erythema around their lymphadenectomy sites following vaccine administration, which was asymptomatic and spontaneously...

The need for a rotavirus vaccine

Since the golden age of viral gastroenteritis commenced in the early 1970s, many viruses have been implicated as etiological agents of diarrhoeal illnesses. However, rotaviruses reign as the number one cause of severe diarrhoeal disease worldwide, surpassing the enteric adenoviruses, astroviruses, caliciviruses and bacterial agents. Thus, the need for a rotavirus vaccine is clear and compelling, with the goal being the prevention of severe rotavirus diarrhoea during the first two years of life when the consequences of such illnesses are most serious.

Plant Derived Injectable and Edible Vaccines

The immune system of humans and animals reacts against viral and bacterial pathogens by producing antibodies that are specific for certain proteins of these pathogens (immunogenic proteins). Antibodies are able to recognise these proteins, attach to them and thus initiate the destruction of the pathogenic organism. To avoid an outbreak of a known disease among human or animal populations, vaccination can be used as a precaution. Conventional vaccines usually consist of a killed or weakened form of the targeted pathogen and are usually administered by injection. The subsequent immune response will secure immunity against the disease for a defined period of time. Vaccines are currently produced by infecting human or animal cells in appropriate culture media. Modern biotechnological methods, especially genetic modification, provide powerful possibilities for the development of new strategies for vaccine production. GM plants may serve as biofactories producing vaccines free from any...

Methods Of Dna Vaccine Delivery 31 Electroporation

Studies on the delivery of TAA antigens using electroporation have yielded promising results. Mendiratta et al. reported vaccination using electroporation with both plasmid encoded human GP100 and mouse TPR2 antigen elicited complete protection from melanoma challenge (21). Lohr et al. demonstrated that introduction of plasmid encoding IL-2 and IL-12 (inflammatory cytokine signals) by electroporation at tumor sites caused transduction and inhibition of murine melanoma without the systemic cytokine levels experienced after adenoviral gene transfer (22). Further investigations have shown that electroporation can be used to facilitate the discovery of novel antigen encoded plasmid constructs. For example, Kalat et al. used electroporation methods to optimize tyrosinase related protein-2 antigens to elicit CD8+ responses and inhibition of melanoma growth in two challenge models (23). This same group later demonstrated that electroporation was capable of inducing immune responses...

Recombinant viral vaccines

As a means to increase antigen processing and expression in APCs and improve the expression of costimulatory molecules, recombinant viral-based vaccines have been developed. The pox virus family has been most commonly used (vaccinia, fowlpox) but others such as adenovirus have been used. Genes encoding TAAs are genetically recom-bined to the virus and then administered. The virus serves as a vector, infecting cells including APCs the passenger gene is then transcribed and translated into a full-length protein, then cleaved into smaller peptides (9-10 amino acids in length for major histocompatibility complex MHC class I, 13-15 amino acids for MHC class II presentation) and then presented on the cell surface in the context of appropriate costimulatory molecules to activate both CD4 and CD8 T cells (13). Phase I clinical trials have been completed for both vaccinia-CEA (14,15) and ALVAC-CEA (16). These trials both demonstrated significant generation of CEA-specific cytotoxic T...

Future development of recombinant pox virus vaccines

The future development of recombinant pox virus vaccines holds considerable promise for cancer management. Virtually all of the clinical studies described above have been carried out in patients with relatively advanced cancers. These patients most likely have subtle but depressed immune responses, which have been exhibited in two ways (a) via downregulation of the Z chain of the T-cell receptor and (b) in the cytokine profile of T cells obtained from advanced cancer patients (type 2 profile) compared with a type 1 profile from healthy individuals. Thus, the full potential of these vaccines has yet to be defined. The advantage of diversified prime and boost protocols employing pox virus recombinants has now been demonstrated preclinically and in the clinic. It is not known, Modification of tumor-associated immunodominant epitopes such as those of gp100 and CEA have been shown to enhance immune responses in vitro (75) and in patients (7678). The use of recombinant pox viruses...

Dendritic Cell Based Vaccines for BCell Lymphoma

DCs are the most potent APCs and are ideally suited to serve as natural adjuvants for purposes of vaccination and immunotherapy for cancers (30,31). Methods have been developed to obtain substantial numbers of DCs from proliferating CD34+ progenitors in bone marrow and peripheral blood, as well as from nonproliferating precursor cells, such as CD14+ monocytes, in human blood (32-34). Induction of antitumor immune responses by injection of antigen-loaded DCs has been extensively studied in animals. First, it was found that injection of DC-enriched preparations pulsed with tumor lysates (35,36) could protect na ve animals from subsequent lethal tumor challenge. Next, it was shown that administration of density gradient-purified splenic DCs pulsed either with soluble tumor protein antigen expressed by a B-cell lymphoma (37) or with synthetic MHC class I-restricted peptides derived from tumor antigens (38,39) induced protective antitumor immunity. Thus, it was evident that ex vivo...

Cytokine Modified Tumor Cell Vaccines

Antitumor vaccination with irradiated autologous cancer cells, transfected ex vivo to express cytokine genes was exemplified by the use of GM-CSF gene modified cancer cell delivery (86,99). Promising initial preclinical studies with an antitumor vaccine comprised of irradiated autologous GM-CSF secreting-Dunning rat prostate carcinoma cells led to a clinical trial in which eight patients with prostate cancer were treated with autologous GM-CSF secreting, irradiated tumor cell vaccines prepared by ex vivo retroviral transduc-tion of surgically harvested cells (100). Insufficient cells were obtained from three other patients. Indeed, the major limitation of this approach was the poor prostate cancer cell recovery and growth from clinical specimens. Side effects were minimal and localized to the site of injection. The treatment resulted in DC and macrophage infiltration at the injection site. They also found activation of T- and B-cells against prostate cancer antigens, representing both...

Advantages of Vaccines That Induce Antibodies Over Vaccines Designed to Augment TLymphocyte Immunity

The concept of a vaccine that consistently augments T-lymphocyte immunity against cancer cells is exciting and offers enormous potential for clinical benefit. However, demonstration that this has been achieved has proven to be more difficult than initially appreciated, for a variety of reasons 3. Augmentation of T-cell responses by vaccination in humans is more difficult to induce than augmentation of B-cell responses and has yet to be clearly achieved and confirmed in a majority of vaccinated patients against any tumor antigen. 4. Vaccine design depends on the immune response desired. There are hundreds of available approaches or combinations of approaches to inducing T-cell immunity. These include immunization with peptides or proteins with various adjuvants, dendritic cells pulsed with or transduced to express particular antigens, viruses or bacteria transduced to express antigens, and DNA or RNA vaccines. In each case these vaccines could include approaches to augmenting cytokine...

Future Vaccines in the Pipeline

It is unlikely that vaccines produced by these two multinationals will be able to satisfy the global need for rotavirus vaccines at an affordable cost. A number of other candidate vaccines are in the pipeline and all are likely to be produced by emerging manufacturers in the developing world. In China, a rotavirus vaccine based on a single strain of lamb rotavirus and produced by the Lanzhou Institute of Biological Products has been licensed and is currently being sold. The efficacy of this vaccine has never been clearly established and a second generation of vaccine based upon reassortant strains of this vaccine is in development. The vaccine is unlikely to be sold outside of China. Neonatal strains of rotavirus are being developed by groups in Australia and India. Newborns have been infected with rotavirus strains in neonatal units in many countries. These neonatal strains are genetically unusual because they can replicate in infants despite the presence of high titers of maternal...

Idiotype Based Protein Vaccines for Myeloma

In our second series of the study, immunization was performed by subcutaneous or intradermal injection of Id protein and GM-CSF (73). Five patients with IgG myeloma were treated, and an Id-specific type-1 T-cell response developed in all of them. The response involved both CD8+ and CD4+ subsets and was mainly MHC class I restricted. There was a transient rise in B cells producing IgM anti-idiotypic antibodies in all patients. One patient had a clinical response, defined by a significant decrease in serum Id protein (from 20 g L to 7 g L) and normalization of serum Ig levels, which lasted for more than 1 yr after commencement of immunization. Although these studies involved a limited number of patients, the results clearly indicated that Id protein vaccination, especially in combination with GM-CSF, was able to induce specific anti-Id cellular and humoral immune responses, which were occasionally accompanied by a clinical response in treated patients. Other clinical settings for...

Use of autologous or allogeneic vaccines

One question in the development of whole-cell vaccines is whether autologous or allogeneic vaccine should be used. Although autologous (and thus personalized vaccines) are appealing, they are difficult to produce. The small size of many tumor specimens obtained by biopsy can make it difficult to obtain sufficient cells for therapy, especially when multiple immunizations are part of the clinical protocol. In some instances, it is possible to propagate tumor cells in vitro to increase the number of cells available, but prolonged cell culture may radically alter the characteristics of the tumor-cells if dominant clones outgrow the other cells present in the tumor sample. More practical has been the development of allogeneic tumor cell banks, although significant regulatory requirements that include detailed characterization of the cellular product and assays to detect adventitious agents remain a challenge. Although allogeneic tumors would not be expected to directly prime immune...

Vaccines for Acute Myeloid Leukemia AML

AML cells can be made into cell vaccines for the disease. A strategy that has been extensively pursued is the differentiation or maturation of leukemia cells into DCs, which reflects the knowledge of DC development from primitive myeloid cells (32-34). A representative study by Choudhury and coworkers (113) demonstrated that the cytokine combination of GM-CSF and IL-4 together with CD40L or TNF-a induced primary AML cells from 18 of 19 patients to differentiate into DC-like cells that were able to An alternative method is direct gene transfer of immunomodulators into AML cells as a means of improving their immunogenicity. These could be the costimulatory molecules and IL-12, which can facilitate T-cell priming cytokines such as GM-CSF and IL-2, which trigger inflammation and recruit high numbers of professional APCs to the vaccination site or GM-CSF, IL-4, and CD40L, which promote differentiation and maturation of leukemia cells into effective APCs (105). In murine models of AML,...

Le and Globo H Vaccines

The development of Ley and Globo H vaccines was previously limited by the lack of sufficient quantities of antigen for vaccine construction and testing. Over the last 6 yr, Dr. Samuel Danishefsky in our group has successfully synthesized both antigens (76-78). We have immunized groups of mice with Globo H-ceramide plus or minus adjuvants QS-21 and Salmonella Minnesota mutant R595, and with Globo H covalently attached to KLH or bovine serum albumin (BSA) plus immunological adjuvants QS-21 or GPI-0100. The highest antibody titers against both synthetic antigen and MCF7 cells expressing Globo H were induced by the Globo H-KLH plus QS-21 vaccine (77). The antibody titer induced against synthetic Globo H was 1 120,000 by ELISA, the titer induced against MCF7 was 1 320, and potent complement-mediated cytotoxicity was seen as well. Ley-BSA and Ley-KLH vaccines have also been tested in the mouse. High-titer antibody responses have resulted against the synthetic epitope of Ley and against...

Dendritic cell vaccines

Dendritic cell vaccines for colon cancer have generally been loaded with MAGE (a cancer antigen) or CEA. In one study, MAGE was expressed by one-third of colon cancers (48). In a larger study, MAGE expression was exclusive to the tumor tissue with at least one of the 10 MAGE antigens tested being present on 70 of the 80 samples and MAGE-3 expression was associated with increased metastatic potential (49). Clinical studies are ongoing using MAGE as a vaccine target in GI cancers. In one, Sadanaga et al. demonstrated the feasibility and safety of treating GI cancer patients with MAGE-3-pulsed autologous dendritic cells. Four of eight patients developed CTL responses and tumor markers decreased in seven patients (50). Minor regressions were seen in three patients, making this an extremely promising approach for the future. Fong and colleagues (51) administered Flt-3-ligand-mobilized dendritic cells loaded with the modified CEA peptide CEA610D to patients with CEA-expressing malignancies...

The Goal for Rotavirus Vaccines

The goal for rotavirus vaccines remains the prevention of rotavirus diarrhea in children worldwide. In each country, this goal should be measurable within several years of the vaccine's introduction and will differ in the developed and developing world. In industrialized countries, a rotavirus vaccine program should decrease hospitalizations and clinic visits for diarrhea in children by 30-50 within 2-3 years of the vaccine's introduction. This would lead to substantial economic savings in hospital and clinic care as well as social costs - such as savings from parents' loss of work to care for sick children. In developing countries, the economic benefits will be dwarfed by improvements in child survival, especially from diar-rheal deaths. Monitoring the impact of a rotavirus vaccine should be straightforward since severe disease can be monitored in hospitalized patients, the diagnosis from fecal specimens is cheap and easy, and infection presents uniquely as diarrhea, and the impact...

Summary and challenges to vaccines for lung cancer

Lung cancers, like other malignancies, can escape immune recognition by downregulation of HLA class I molecules. Administration of IFN-gamma has been shown to upregulate HLA class I on NSCLC and thus may be a useful adjunct (37). Fas-ligand (Fas-L), frequently detected in lung carcinoma cell lines and resected tumors, can cause apoptosis of T cells. In fact, lung carcinoma cells were capable of killing the Fas-sensitive human T-cell line Jurkat in coculture experiments (65). Inhibiting Fas-L expression by tumors might therefore be a useful adjunct to immunotherapies. The tumor antigen RCAS1, positive in 47 of NSCLC specimens (and up to 80 of adenocarcinomas), induces apoptosis in immune cells bearing the RCAS1 receptor (66). Interference with its activity might improve the activity of lung cancer immunotherapy. Lung cancers may negatively regulate DC differentiation and this observation supports the use of ex vivo-generated DCs in vaccine strategies (67). Lung cancer cell lines...

Other uses of rcc vaccines

Vaccine-Primed Lymph Node Cells Lymph nodes that drain malignancies or sites of tumor vaccination presumably harbor preeffector cells that can be activated and expanded ex vivo using anti-CD3 antibody and low concentrations of IL-2. In an early-phase clinical trial, 12 patients with metastatic RCC were treated with vaccine-primed lymph node (VPLN) cells and high-dose bolus IL-2 (44). There were two complete and two partial responses. In a similar study, 20 patients with metastatic RCC were treated. The therapy was well tolerated and there was one partial response. These feasibility studies prompted the initiation of a phase II trial using VPLN cells plus IL-2 for RCC (45). Vaccines consisted of autologous tumor cells irradiated and admixed with Tice bacille Calmette-Guerin (BCG). Seven days after vaccine administration, the VPLN cells were harvested from the draining lymph nodes and activated using anti-CD3 and IL-2. These cells were then adoptively transferred with high-dose...

Alphavirus Used In Cancer Vaccines

Alphavirus vectors have frequently been applied for vaccine production. In this context, recombinant particles as well as naked nucleic acids have been applied. The proof of concept was originally demonstrated for viral surface proteins known for their potential immunogenicity and capability to induce cytotoxic T-cell (CTL) responses and protection against challenges with lethal viruses (20). Moreover, immunization against tumor challenges has resulted in some promising observations (Table 1). For instance, injection of RNA from an SFV vector expressing bacterial P-galactosidase into mice provided protection against tumor challenges (21). Administration of recombinant SFV particles expressing the P1A gene resulted in protection against P185 tumor challenges in mice (22). The human papilloma virus (HPV) E6 and E7 oncoproteins have been

Was there an epidemic of intussusception because of vaccine use

Our initial doubts about the overall risk of this vaccine arose from evaluation of published data from CDC which failed to reveal a striking increase in the overall number of cases of intussusception that would have been anticipated from the extremely high odds ratios, noted above, that were presented for the first week following vaccination. For example, CDC reported the occurrence of three cases of intussusception in 9802 vaccinees in a California managed care study, which translated to an overall incidence of 30 cases per 100 000 over an unspecified period of time. However, because one of the three cases occurred during the first week after vaccination, CDC reported that the incidence of intussusception was 314 per 100 000 individuals during that period (CDC 1999b). However, the overall risk of the vaccine in this large cohort of children was not presented. Similarly, in a Minnesota study, five cases were reported in recipients of 53 479 doses, an incidence of 9 per 100 000 doses...

DNA vaccines against tuberculosis

DNA plasmids encoding Mycobacterium tuberculosis antigen 85 (Ag85) were tested as vaccines in animal models. Ag85 DNA induced relevant immune responses (i.e. T helper (Th) cells, Th1 cytokines and cytotoxic T lymphocytes) and was protective in mouse and guinea pig models of mycobacterial disease. Therefore, DNA vaccination holds promise as an effective means of preventing tuberculosis in humans. Furthermore, this technique is amenable to identifying the protective antigens of M. tuberculosis. Tuberculosis causes more deaths ( 3 million per year) than any other disease caused by a single pathogen, despite the widespread availability of a tuberculosis vaccine. The lack of overall effectiveness of this vaccine, which is a live attenuated form of Mycobacterium bovis termed Bacillus Calmette Guerin (BCG), makes it imperative that a more effective vaccine be developed. To this end, research is active in several areas, including experimental tuberculosis vaccines based on subunit...

Vaccination Past Present and Future

In 1300, vaccines were not available, and Siena did not have the choice of preventing the plague. Only recently has mankind managed to partially control infectious diseases thanks to the discovery and development of antibiotics and vaccines. The new technologies to develop vaccines available today have the power to achieve even much more spectacular results in the fight against infectious diseases. Genomics, Proteomics and Vaccines edited by Guido Grandi 2004 John Wiley & Sons, Ltd ISBN 0 470 85616 5 1.2 Vaccination the past A more successful approach came in 1796 with Edward Jenner, an English physician. During his practice in the countryside, he had noticed that farmers exposed to infected materials from cows did not develop the disease but acquired immunity to smallpox. Jenner decided to use the less dangerous material derived from the bovine (vaccinus) lesions to 'vaccinate' a boy (James Phipps) and showed that he was immune to a subsequent challenge with smallpox. The scientific...

Tumor Antigens And Cancer Vaccines

Prior to the identification of specific TSA and TAA sequences, tumor antigens were provided from tumor cells, either as lysates or as irradiated cell lines derived from either autologous or allogeneic tumors. The perception is that good anecdotal and phase I II studies have never translated into positive randomized trials. However, there are two positive randomized vaccine trials, one for colorectal cancer and the other for renal, both published in the Lancet (Jocham et al., 2004 Vermorken et al., 1999). Vaccines made from autologous tissue are procedure vaccines as opposed to product vaccines. An alternative to autologous vaccines is the use of established allogeneic cell lines which express shared antigens. Concerns about HLA matching do not appear to be a negative concern as preclinical models show that allogeneic cell lines are often better than autologous presumably because allo represents a danger signal and is more likely to break tolerance. There are several allogeneic cell...

Cytokinemodified tumor vaccines

The ability of bacterial products to elicit inflammatory cytokines underlies the antitumor activity observed with the administration of bacterial extracts as immunologic adjuvants. The ability of locally delivered BCG or recombinant cytokines to enhance antigen-specific immunity led to the testing of cytokine-secreting tumor vaccines as a strategy for delivering relevant tumor antigens in the context of immune-activating cytokines. A number of cytokines, including IL-2 (76-80), IL-4 (81-83), TNF (84-86), IFN-y(87-89), IFN-a (90), MCP-1 (91), G-CSF (granulocyte colony-stimulating factor) (92), IL-7 (93-96), IL-12 (97-100), Flt-3 ligand (101,102), and GM-CSF (granulocyte-macrophage colony-stimulating factor) (83) have been tested in preclinical gene transfer studies and or clinical trials (summarized in Table 3). This discussion will focus on the use of IL-12, Flt-3 ligand, and GM-CSF gene transfer, because the mechanisms by which tumor cells that secrete these cytokines activate...

The Different Pneumococcal Structures and Vaccines Directed Against Them

The first documented vaccines against Streptococcus pneumoniae used either the whole bacterial cell or the capsular polysaccharides (Wright et al., 1914) as the starting point. During the 1970's and 1980's more purified forms of the multivalent polysaccharide vaccines (PPV) were tested against a wide array of pneumococcal infections, but with disappointingly little success in young children (Fedson et al., 2004). In second generation of pneumococcal vaccines, the capsular polysaccharide is linked via a chemical conjugation process to a carrier protein such as an outer membrane protein of Neisseria meningitidis, tetanus or diphtheria toxoid, or a 37 kD protein of Haemophilus influenzae, thus making the polysaccharide antigen T-cell dependent. These vaccines induce immunological memory at an early stage, i.e. before 2 years of age, unlike the PPVs which are poorly immunogenic for most pneumococcal serotypes at this stage (Eskola et al., 2004). Pneumococci have several surface proteins...

Examples of Vaccines Produced in Plants

Several strategies to produce effective vaccines in plants have been developed. One of them makes use of a plant virus, harbouring the gene for a protein of a human virus. After infection of a plant with this GM plant virus, the human virus protein is produced and can be isolated, purified and used as a vaccine. Indeed, animals, when vaccinated, developed antibodies that would react with the human virus. Vaccines for the human immunodeficiency virus (HIV) and the human rhino virus (HRV) have been developed following this method. In potatoes, an orally active vaccine against cholera has been developed. Cholera-causing bacteria produce two types of toxin proteins but only one of them is toxic for humans. The harmless protein can therefore be used to induce immunity. A part of this protein was produced in potatoes after introducing a gene fragment coding for the toxin. Mice that were fed with the GM potatoes, were found to produce antibodies that would neutralise the activity of both...

Patients With Cancer Can Be Immunized With Class I Peptide Based Vaccines

Clinical trials performed vaccinating cancer patients with class I binding peptides derived from a variety of tumor antigens have demonstrated that patients can be immunized to boost immunity to self-tumor antigens. Peptide-based vaccines offer an excellent model for assessing the ability to immunize by measuring immunity generated with assays that can specifically measure class I T-cell responses. Lee et al. (13) used MHC tetramer flow cytometry to evaluate in vivo response to vaccination with gp100209_217 and tyrosinase368-376 peptides in 44 HLA-A2 patients with advanced-stage melanoma. Tetramer assays performed before, during, and following the period of vaccination demonstrated appearance of gp100-specific T cells as early as 4 wk, i.e., after two vaccinations. At 18 wk at least 20 of CD8+ T cells were specific for gp100209-217 in four of six patients. Overall, 37 of 42 patients developed an immune response to gp100209-217 following vaccination as measured by MHC tetramer assay....

The Overall Protective Effect of Pneumococcal Vaccines

Pneumococcal disease can be prevented by a) the direct protective effect of the vaccine on vaccinated individuals (both PPV and PCV) and or b) an indirect protective effect via reduced transmission of the pathogen to susceptible, nonvacci-nated individuals (PCV only, since the mucosal protection provided by PPV is insignificant). The public health benefit arising from both is enforced by the reduction of the incidence of vaccine preventable strains resistant to antimicrobials. Also, the unexpected finding from the Gambian study that the 9-valent PCV prevented 16 of the overall, all-cause mortality in the study children (Cutts et al., 2005), makes the vaccine a very powerful tool both against childhood morbidity and mortality globally.

Unresolved issues regarding rotavirus vaccine and intussusception

The CDC data regarding the clustering of cases particularly during the first week after the first dose of vaccine are significant and important, and this needs to be studied further. However, the key question that has even greater public health importance and which has not been answered satisfactorily relates to the attributable risk, if any, of RRV-TV among the one million infants who were vaccinated. How many cases of intussusception did the RRV-TV vaccine cause in excess of the background baseline incidence of 51 cases per 100 000 (or 1 per 1961 infants) during the first year of life Surprisingly, it is still not known whether an 'epidemic' of intussusception occurred in the USA following the administration of RRV-TV to one quarter of the US birth cohort, or whether there was a decrease in the number of cases. This is a major, as yet unanswered, question for both developed and developing countries where in the former (for example the USA), over 500 000 infants and young children...

Role of primeboost for polyepitope vaccines

Polyvalent vaccines are being developed to induce broad CTL responses against multiple tumor antigens and epitopes restricted by more than one major histocompatibility complex (MHC) class I molecule. Poly-epitope vaccines aiming to induce such polyvalent responses have been tested in combination with the heterologous prime-boost approach. Instead of engineering single epitopes or antigens into heterologous vectors, poly-epitope and or poly-protein expressing constructs have been used to drive the expansion of several CTL specificities. It has been shown that a string-of-beads assembly of known epitopes into artificial new poly-epitope genes can lead to simultaneous priming of CTLs with a range of specificities (12). However, we and others have shown that, during the boosting step, competition of CTLs around the APCs is a major factor in reducing the breadth of a primed response (4,13). By simultaneously monitoring CTLs of several different specificities ex vivo we have shown that...

Minigenes Based Polyepitope Vaccines

Revealing the molecular mechanism of MHC peptide recognition by aP T-cell receptors (TCRs) (104) allowed the identification of a large number of immunogenic epitopes (105). Synthetic peptide combinatorial libraries proved to be a powerful tool for screening millions of peptide candidates, thus greatly speeding up discovery of new immunogenic epitopes (106), with immediate consequences for the design of vaccines. Numerous immunogenic epitopes have now been identified in many potential targets of vaccination ranging from important clinical pathogens, such as HIV, to antigens from a wide variety of tumors. Instead of using the entire coding region of an antigen in plasmid DNA, only a single epitope or several epitopes with known immunogenicity can be sequentially arranged into a single polypeptide, thus forming a string of epitopes. This so-called minigene or minimal-epitope approach takes advantage of the fact that plasmid DNA-encoded antigenic peptides can be loaded onto MHC class I...

Vaccine Draining LN T Cells

LNs draining a site of vaccine inoculation are an enriched source of T lymphocytes that have been sensitized to tumor antigens. Preclinical kinetic studies have clearly demonstrated that the optimal number of preeffector T cells is present between 6 and 14 d with subsequent waning of activity. These findings recommend a strategy of placing a tumor vaccine in a region that is uninvolved with tumor so that newly sensitized T cells can be obtained by removal of the vaccine draining LNs at the peak of the reaction. In an initial study of VDLN cells, subjects with metastatic melanoma or RCC were treated. Irradiated autologous tumor cells admixed with bacille Calmette-Guerin (BCG) was used as a vaccine and 7 d later draining LNs were removed. The T cells were stimulated with immobilized anti-CD3 (OKT3) for 2 d followed by culture in IL-2 to reach a mean treatment dose of 8.4 x 1010 cells. These activation conditions generated a mixture of CD4 and CD8 that demonstrated specific release of...

Genetic Vaccines for Cancer Therapy

A primary focus of current research on genetic vaccination is the development of strategies to activate nonresponsive antigen specific T-cells. The first consideration of any tumor therapy is the choice of cancer antigen in a genetic construct. Much effort has been devoted to the optimization of TAAs, and this work is described in detail elsewhere (11,12). Despite this optimization and the large number of genetic vaccine clinical trials for cancera, DNA vaccination in humans has not elicited as potent immune responses as observed in smaller animal models. For example, eliciting an immune response with intramuscular (im) naked DNA vaccination (plasmid DNA with no delivery vehicle) requires as much as 5mg of plasmid DNA in nonhuman primates (13), but only 50 to 300 g in mice (4). Although high doses of plasmid are generally well tolerated in humans (14), the need for additional technologies to boost the effectiveness of genetic vaccines is apparent. One of the earliest advances in DNA...

Conclusions on Vaccination Studies

It is difficult to assess and to compare the studies, particularly because the monitoring after immunization and after challenge is described insufficiently in some studies and the sensitivity of the tests to measure HDV viremia is not comparable. Together these results allow us, however, to conclude that immunization against HDV with conventional vaccines is not possible. Neither a good humoral nor a weak Th-cell immune response is sufficient to protect from HDV superinfection. Immunizations with vaccinia virus or DNA expressing HDAg were at least able to modulate the course of infection. In general, these approaches are known to induce a CTL response, which maybe essential for protection. In further studies HDV vaccination schemes should be optimized to enhance the cellular immune response, e.g., by using different combinations of DNA vaccines with woodchuck cytokine (Lohrengel et al. 1998, 2000). This approach has been shown to enhance the cellular immune response to other...

Adjuvants for tumor vaccines

Regardless of the model for T-cell activation, because tumors express self molecules, to which the immune system may be tolerant, and because the tumor environment may contain immunosuppressive molecules such as interleukin-10 (IL-10) and TGF-P, additional danger signals will be needed to properly activate the immune response. The most frequent manipulation to tumor cell vaccines is irradiation to render them unable to propagate in the recipient of the vaccine. Although irradiation causes primarily apoptosis, it can also cause necrosis, which can activate these danger signals. Alternatively, these danger signals signals could be provided by immunological adjuvants such as inflammatory bacteria or bacterial cell-wall products. The two most developed whole-cell vaccines, CanVaxin and autologous colon cancer cells (Oncovax ), are administered with bacille Calmette-Guerin (BCG). The complexity of the manipulations necessary to achieve an immune response were highlighted by the earlier...

Prospects for tuberculosis vaccine development

The data presented here and elsewhere (Huygen et al 1996) demonstrate Ag85A DNA vaccination against tuberculosis in animal models. DNA encoding hsp65 and the 38kDa antigen of M. tuberculosis have also been shown to confer protection (Tascon et al 1996, Zhu et al 1997). These data suggest that there may be several protective antigens in M. tuberculosis and that a combination of DNA plasmids encoding discrete antigens should be investigated. But which antigens There are likely to be several thousand proteins expressed by M. tuberculosis, thereby greatly complicating the determination of those that are protective against disease. One potential means of identifying these proteins is by taking advantage of the DNA vaccine technology itself. Johnston and colleagues recently showed that pools of many thousand different plasmids each containing a fragment of the genome of a pathogen (in this case Mycoplasmapulmonis) could be used to vaccinate and protect mice from challenge (Barry et al...

Rhesus Tetravalent Vaccine Rotashield

The rhesus tetravalent rotavirus vaccine became the next major candidate for development. The monovalent rhesus vaccine suffered the same variable efficacy in field trials, as the original RIT borne vaccine, so a tetravalent vaccine was developed. This vaccine was based upon the assumption that animal strains that shared no neutralization epitopes with human strains would need to carry genes encoding these key neutralization targets - principally the VP7 genes of the most common rotavirus strains. Reassortant strains were developed that were composed of 10 genes with the attenuation properties from the parent rhesus vaccine strain and a single gene encoding the VP7 capsid protein from each of the 4 serotypes of rota-virus in common circulation. In clinical trials, this tetravalent vaccine was significantly more effective than it monovalent predecessor. In 1998, this vaccine, developed at the National Institutes of Health by Dr. A. Kapikian and prepared by Wyeth Lederle as RotaShield,...

Other rotavirus vaccines

A presentation on rotavirus vaccines would not be complete if it did not consider the prospects for other rotavirus vaccines that may fill the void left by the withdrawal of the rhesus rotavirus-based vaccine. Table 2 summarizes the status of the various rotavirus vaccines that have been evaluated in efficacy trials in infants and young children. Evaluation of monovalent bovine or rhesus rotavirus vaccine has been discontinued because of the variable efficacy of these immunogens. The quadrivalent WC3 bovine rotavirus-based reassortant vaccine with G1, G2, G3 and P1A 8 specificity is undergoing active field testing. A quadrivalent UK bovine rotavirus-based reassortant vaccine with G1, G2, G3 and G4 specificity is 'on hold' pending developments with its counterpart rhesus rotavirus tetravalent vaccine. A monovalent attenuated human rotavirus G1 vaccine is under active clinical evaluation. As shown in Table 3, various other vaccine candidates have been evaluated in phase 1 safety and...

Clinical trials of chaperone protein vaccines

Antigenics Inc. (New York, NY) has developed a clinical GRP94 gp96 vaccine termed HSPPC-96, or Oncophage (102). Data generated from clinical trials evaluating HSPPC-96 Oncophage against a variety of cancers have been reported at recent American Society of Clinical Oncology (ASCO) and American Association of Cancer Research (AACR) conferences. The major limiting factor for producing Oncophage from a patient's tumor is the ability to purify enough GRP94 gp96 from the autologous tissue. Oncophage is manufactured in a 10-h process from autologous tumors. The minimum tissue required to produce enough vaccine for a course of treatment is between 1 and 3 g, and patients have been immunized either subcutaneously or intradermally weekly for 4 wk and then every two to four weeks for another three to five vaccinations. In the reported trials, HSPPC-96 vaccine consisted of 2.5, 5, 10, 25, 50, or 100 g of purified GRP94 gp96. Generally, adequate protein was purified to complete the vaccination...

Vaccines for Chronic Myeloid Leukemia CML

In CML, more than 90 of patients express the 210-kDa chimeric fusion proteins bcr2 abl2 or bcr3 abl2. Because bcr abl chimeric protein is expressed only in CML cells, not in normal cells, the fusion sequence may act as a potential target for a T-cell-mediated immune response to CML. Within the fusion region of the bcr3 abl2 protein, different peptides have been identified that bind to HLA-A2, -A3, -A11, and -B8 (133,134). As CML DCs share a common progeny with leukemia cells, bcr abl is constitutively expressed in these cells (135). The finding by Yasukawa and coworkers (136) that bcr abl fusion protein-derived, peptide-specific CD4+ T-cell clones were able to augment colony formation by CML cells in a bcr abl type-specific and HLA class II-restricted manner without addition of exogenous antigen suggests that CML cells can naturally process and present endogenous bcr abl fusion protein to CD4+ T cells. Their subsequent study confirmed this finding (137). Thus, leukemia-derived DCs can...

Prevention and Control Measures 91 Vaccine

A number of strategies have been used for the development of both Lassa and Ebola virus vaccines (Baize et al., 2001 Fisher-Hoch and McCormick, 2004 Sullivan et al., 2000). One novel approach involving immunisation with a DNA priming vaccine followed by a booster immunisation containing recombinant adeno-virus expressing glycoprotein was associated with the development of both humoral and cellular immunity against Ebola virus in Cynomolgus monkeys (Sullivan et al., 2000). Recently, the threat of bioterrorism using VHF agents has underpinned renewed impetus and enthusiasm for the development of effective vaccines (Baize, 2005 Jones et al., 2005 Peters, 2005).

Polyvalent Vaccines

The basis for emphasis on polyvalent vaccines is tumor cell heterogeneity, heterogeneity of the human immune response, and the correlation between overall antibody titer against tumor cells and effector mechanisms such as complement-dependent cytotoxicity (CDC) or antibody-dependent cell-mediated cytotoxicity (ADCC). For example, using a series of 14 tumor cell lines and MAbs against three gangliosides, we have shown that significant cell-surface reactivity analyzed by flow cytometry and CDC increased from two to eight of the cell lines using one of three MAbs to all 14 of the cell lines when the three MAbs were pooled. The median CDC increased fourfold with the pool of MAbs compared to the best single MAb (14).

Tumor Cell Vaccines

As is the case with other solid tumors, lung cancer by themselves may be poorly immunogenic, but can become potent vaccines if modified to increase their immunoge-nicity. For example, modification of lung cancers with the the costimulatory molecule CD80 results in a greater ability to active CTL in vitro (53). In a phase I II trial for patients with stage IV or relapsed NSCLC, an allogeneic, irradiated lung adenocarcinoma cell line transfected with CD80 and human leukocyte antigen (HLA)-A1 or -A2 was administered subcutaneously to 12 patients (54). There was one partial response and three with stable disease lasting 7-12+ mo. Three of these patients also showed significant increases (44-to 267-fold) in tumor-specific CD8 CTLs, measured by interferon (IFN)-gamma ELISPOT assay. Nemunaitis and colleagues (55) performed a phase I II study of autologous lung cancers modified with an adenoviral vector encoding granulocyte-macrophage colony-stimulating factor (GM-CSF) (GVAX). A challenge for...

Vaccination Studies

HDV superinfection of HBV carrier patients is a severe disease therefore, a vaccine would be important to prevent patients from HDV superinfection. The woodchuck is a good model to test vaccine candidates. The immune response after vaccination can be assessed as far as possible in these outbred animals and the induction of protection can be investigated. Different strategies have been followed to induce a protective immune response against HDV superinfection. Synthetic peptides, incomplete or complete HDAg expressed in E. coli, yeast, or baculovirus, vaccinia virus expressing the small or the large HDAg, and DNA immunization by gene gun have been studied. Table 1 gives an overview of the vaccination studies. Considering the fact that HDAg is a nucleoprotein, one might hypothesize that HDV protein may induce a strong cellular rather than a humoral immune response and, therefore, could be used as a vaccine. It has been shown for several viral infections, including influenza A virus,...

Vaccination

If all other measures are unsuccessful or impossible to apply, the use of animals protected by vaccination may be considered. If vaccination is unavoidable, one should in the first place consider whether it might be sufficient to vaccinate the female breeding animals only, as passive immunization through maternal antibodies in most cases must be considered as less interfering with research than active immunization of the experimental animal. Apart from this, it is easier and cheaper. In this way, pneumonia due to B. bronchiseptica may be almost totally eliminated from breeding colonies of guinea pigs, although the agent still persists in the colony.233 Vaccination of the experimental animals has been used against Sendai virus pneumonia,234,235,236 ectromelia,237 mycoplasmosis,238,239 and the various effects of infection with cytomegalovirus.240 Especially for larger laboratory animals, such as pigs, this is a common way of dealing with infectious problems.241 However, in regard to...

The Earliest Vaccine

To date, all of the vaccines against rotavirus that have entered clinical trials have been live attenuated rotavirus strains that have been administered orally with buffers. Attenuation has been achieved either through the repeated passaging of human rotavirus strains or the natural attenuation of animal strains administered to humans. The first candidate rotavirus vaccine was a bovine strain of rotavirus, RIT 4237 prepared by SmithKline Rixensart, that was administered to infants just before the winter rotavirus season. The unexpected high efficacy of this animal strain to protect infants in Finland against rotavirus diarrhea, often in the absence of a measurable immune response, provided the motivation to pursue this line of research. However, the variable efficacy of this vaccine in subsequent trials in other settings led to the demise of this program.

AntiId DNA Vaccines

Our anti-Id antibody, 1A7 mimicking GD2, induced both Ab3 and Ab1' humoral responses in injected small animals (54), primates (38), as well as melanoma patients (55). However, presumed cellular responses could not be detected in the injected patients. Various plasmid constructs have been reported to invoke combined humoral and cellular immune responses in injected hosts against the transgene product. To investigate the induction of cellular immune responses we constructed two plasmids expressing 1A7 scFv for use as vaccines. One of the plasmids expressed the VH-Ln-VL format of scFv, whereas the other expressed the VL-Ln-VH format (56). Following intramuscular injection of mice, the plasmids were detectable in the injected tissues for at least 3 mo and the injected plasmids actively transcribed the scFv of 1A7 at the injected site. A single intramuscular immunization of mice with either of the plasmids in phosphate-buffered saline induced humoral immune responses against 1A7 as well as...

Peptide vaccines

Tumors express peptides, often oncogenes, that are unique to the malignant cells. Typically, these proteins are mutated forms of the native protein. Though variation in the specific mutations seen would make immunologic targeting difficult across a patient population, several oncogenes share significant homology among patients. For example, K-ras commonly is mutated in codon 12 and could serve as a potential target for vaccine development. Several investigators are testing this hypothesis in patients. The methods include obtaining an individual patient's tumor and determining the presence or absence of particular oncogene mutation. If present, patients are then treated with a vaccine that targets the mutated section of the protein. The obvious advantage of this approach is that because normal cells do not express the mutated gene, very little systemic toxicity would be expected. However, as with all molecularly targeted therapies, tumor heterogeneity could result in escape for those...

Vaccinations

A travel medicine consultation is an opportunity to check and complete routinely recommended immunizations such as tetanus diphtheria, pneumococcal, influenza, and hepatitis B vaccination. It has to be kept in mind that the southern hemisphere influenza season is from April to September, while in the tropics influenza can occur all year long. Additional immunizations have to be considered according to travel style, duration, and destination. Open immunization questions usually require the consultation of a specialized institution (see links). Further details on this issue can be seen in the chapter on vaccinations in this book.

And Vaccines

Tumor Antigens and Cancer Vaccines IX. Tumor Antigens as Surrogate Markers and Targets for Therapy and Vaccines There are a large number of tumor antigens, which may either be specific to the tumor or inappropriately expressed or processed (tumor-associated antigen, TAA). Over the last few years, hundreds of new TAAs have been identified. Some of these represent good targets for both passive (antibody based) and active (vaccine based) therapies. Antibody treatments targeted on tumor-specific antigens, such as Herceptin and Cetuximab, have been effective in clinical trials and are now licensed. In addition, TAAs act as good surrogate markers for use in both the diagnosis and assessment of treatment in cancer patients. 2007 Elsevier Inc. The immune system evolved to protect the host against infection. However, its role in surveillance of cancer is more controversial. The identification of tumor-specific antigens (TSAs) or tumor-associated antigens (TAAs) and...

Vaccines

It suggests a possible role for these vectors as vehicles for prophylactic or therapeutic vaccines. For example, one study demonstrated that a recombinant AAV vector expressing a secreted HSV-2 gB led to the activation of gB-specific CTL, which were most likely activated via cross-presentation of the secreted protein by DC (195). In contrast, mice injected intramuscularly with an AAV vector expressing ovalbumin developed a robust humoral response to the transgene product but only a minimal ovalbumin-specific CTL response (199). In rhesus macaques, a single-dose, intramuscular administration of an AAV vector expressing the simian immunodeficiency virus (SIV) major structural genes resulted in long-term CD8 +, antigen-specific CTL responses against multiple SIV protein epitopes that were similar to responses observed in monkeys directly infected with pathogenic SIV. Neutralizing antibody responses were also robust and persisted for more than 1 year. More recent studies have begun to...

Ad Vaccine Carriers

The strong humoral and cellular immune response to the expressed transgene suggests that adenovirus vectors may be effective as vaccines for infectious diseases and cancer. It is possible that there is an inflammatory response to Ad capsids or to residual Ad gene expression that enhances the immune response over that obtained by expression from a plasmid vector. Alternatively, the ability of Ad to directly infect dendritic cells in vivo (78,149) and express the antigen gene may result in antigen presentation by the class I pathway. Examples of exploiting the cellular antitransgene response include eliciting a cellular immune response to tumor antigens as discussed earlier. This property may also be useful in elimination of virus-infected cells (150-152) or malaria (153). It is clear that antigens expressed by Ad also elicit a strong humoral immunity that can be used to block initial infection by viruses (154,155). In the context that most humans have been infected by wild-type...

Ganglioside Vaccines

We have been refining our ability to induce antibodies against GM2 in melanoma patients for 15 yr, since it was first demonstrated that patients immunized with irradiated melanoma cells occasionally produced antibodies against GM2, and that vaccines containing purified GM2 could be more immunogenic than vaccines containing tumor cells expressing GM2 (72). Initially GM2 adherent to bacille Calmette-Guerin (BCG) was selected as optimal, inducing immunoglobulin M (IgM) antibody responses in 85 of patients. Antibody responses are defined here as an ELISA titer of 1 40 or greater (or at least eightfold above baseline) confirmed by reactivity against cancer cells by immune thin-layer chromatography or flow cytometry. Though these antibodies and monoclonal antibodies against GM2 were only able to kill 25 of melanoma cell lines by CDC, patients with natural or vaccine-induced antibodies had significantly longer disease-free and overall survival (11). This was the basis for a randomized trial...

Michael A Morse MD Timothy M Clay PhD and H Kim Lyerly MD

Destruction Development of Cancer Vaccines Challenges to Cancer Vaccines References harnessing these observations, it has been possible to design vaccines with the necessary ingredients for activating tumor antigen-specific immune responses in vivo. A model of antitumor immunity that only includes cytolytic T cells is of course too simplistic. First, the activity of CTL is modified by positive influences from CD4+ helper T cells and negative influences from regulatory and suppressor T cells. Second, non-MHC-restricted tumor killing by NK cells may also be important for tumors that escape recognition by downregulation of MHC. Third, the other arm of the immune system, humoral or antibody-mediated immunity, may play an important role. Indeed, in some vaccine strategies, outcome correlates most with antibody titer. Fourth, cytokines and chemokines, elaborated by both immune effectors and tumors, may dramatically modify the activity of cellular components of the immune response. CD4+...

Prospects for prevention and control

Given the immense disease burden of viral agents of gastroenteritis, our research must be directed toward prevention and control of the resulting disease. For the endemic agents of children, vaccines provide the most likely approach toward prevention. Rotavirus represents the most important virus in this group, and vaccines against rotavirus have already been under development and testing for 15 years (Bresee et al 1999). The enteric adenoviruses and astrovirus pose another challenge, since the disease they cause is less common than rotavirus diarrhoea, and most studies indicate that gastroenteritis associated with astrovirus is less severe than that caused by rotavirus (Pang et al 2000). Consequently, efforts to push for a vaccine would require more data documenting that there was enough severe or fatal disease or hospital or health care costs to justify the massive investment required. For the epidemic diseases, other challenges remain. The caliciviruses pose the greatest epidemic...

The HIVspecific cellular immune response

Various therapeutic vaccine strategies have been developed during the last few years and mostly tested in SIV-infected rhesus macaques aiming at inducing an SIV-specific CTL response that may alter the natural course of disease. Recently, a promising approach was published by Lu and his group who reported on a vaccine trial using autologous dendritic cells in SIV-infected rhesus macaques that were pulsed with inactivated SIV (73). In contrast to the unvaccinated control group, monkeys that were vaccinated showed a dramatic decrease in the viral load, and the development of anti-SIV-directed humoral and cellular immune responses. Meanwhile, a pilot trial has been initiated in a cohort of 18 HIV-infected antiretroviral-naive patients with stable viral load. The patients were vaccinated with autologous monocyte-derived dendritic cells that were pulsed with inactivated autologous virus. During the following 112 days, a median decrease of 80 of the viral load was observed and maintained...

Characteristics of Class I Peptides

Epitopes recognized by CD8+ T cells are, in general, peptides of 8-10 amino acids in length anchored at each end within the major groove of MHC class I molecules. As a consequence, class I molecules exhibit more amino acid sequence specificity based on these anchoring residues, than class II molecules, which may be more promiscuous in the binding of peptides. Most investigators have focused on defining class I epitopes for human leukocyte antigen (HLA)-A2 molecules (Table 1). Most likely the interest in HLA-A2 is fueled by the increased prevalence of this allele in many human populations. However, as early studies of peptide-based vaccines have shown that cancer patients can be immunized against a variety of tumor antigens, more studies are focusing on HLA-A alleles other than A2 as well as HLA-B motifs. The frequency of common HLA-B alleles is shown in Table 2. A potential problem in the development of CTL epitope-based vaccines is the large degree of MHC polymorphism and the need...

Identification of Class I Peptides

Once a class I specific peptide has been identified, one must determine whether that peptide can be used to generate T cells capable of responding to and lysing HLA-matched tumor that expresses the antigen of interest. These studies may be performed by using peptide to sensitize T cells in vitro. However, in vitro propagation of human lymphocytes is labor intensive and operator dependent. In addition, establishing T-cell lines using lymphocytes derived from patients with cancer may be made more difficult due to potential inherent defects in the T-cell response in tumor-bearing hosts. For these reasons, another approach has been developed to rapidly evaluate the utility of predicted class I epitopes, active immunization of HLA-A2 transgenic mice. Vaccinating mice with class I peptides allows a more robust immune response to be generated to a particular tumor antigen than the response found endogenously in cancer-bearing patients. Moreover, initiating in vitro culture with a robust...

New Generation Control Tools

Successful elimination will therefore require further R&D investment. In 2003, the NIH Director established a Roadmap for the development of new therapies (www.nih.gov roadmap). Although primarily intended for disease in the industrialized world, this also affords an opportunity to target the NTDs (Hotez, 2004b). In addition, the Bill and Melinda Gates Foundation has made significant investments in the development of new generation vaccines for NTDs including leishmaniasis and hookworm, and new drugs for African sleeping sickness, leishmaniasis, Chagas disease (www.gatesfoundation.org) (Hotez, 2001 Hotez et al., 2005). These new tools could become urgently needed in the face of emerging drug resistance. We might be facing once-in-a-lifetime opportunities to forever eliminate humankind's most ancient scourges. Never has the time been so propitious for ending centuries of neglect.

Health Issues Affecting Lgbt Populations

Of those health problems related directly to sexual behavior, HIV is currently the one most closely identified with the gay community, though it was foreshadowed by hepatitis B. The clinical and epidemiological evidence that hepatitis B was prevalent among gay men resulted in landmark hepatitis B vaccine trials in New York City in the late 70's and early 80's (Dienstag, et al., 1982 Stevens and Taylor, 1986 Szmuness, et al., 1980 Szmuness, et al., 1981). Ironically, an epidemiological study tracking the incidence of gay hepatitis B among gay men in three gay urban areas (San Francisco, New York, and Amsterdam) provided some of the earliest evidence about the emergence and progression of HIV (Hessol, et al., 1994 Van Griensven, et al., 1993). HIV has profoundly affected the LGBT community, both in terms of the unprecedented loss of community members and in terms of the community mobilization and institution-building it engendered. Despite advances in treatment and a broad-based change...

From The Laboratory To The Clinic Oncolytic Herpes Simplex Viruses Appear Safe In Trials But Just How Effective Will

Clinical trials have also commenced using NV1020 to treat colon cancer that has spread to the liver and has not responded to prior chemotherapy (NLM identifier NCT00012155 www.clinicaltrials.gov). This study, which is no longer recruiting patients, is a dose escalating protocol designed to evaluate the safety, tolerability, and antitumor activity of a single intrahepatic arterial injection of NV1020. Although this virus replicates more robustly than 7134.5 null strains, it is substantially more virulent, presumably because it produces the 7134.5 gene product, and is unsuitable for use in the CNS. As this strain is non-neuroinvasive and cannot gain entry into the CNS, it may be useful in treating non-CNS tumors that are refractory to traditional therapies. Extensive prior study of R7020, the parent of NV1020, as a putative vaccine strain demonstrated its safety for non-CNS administration to rabbits, rodents, and nonhuman primates (61,62). However, one must not lose sight of the fact...

HHV6 cellular receptor

CD46, also designated membrane cofactor protein, is a type-1 glycoprotein expressed on the surface of all nucleated human cells examined to date (Liszewski et al., 1991 Seya et al., 1995). It is a member of a family of glycoproteins that act as regulators of complement activation (RCA). Their physiological function is essential because it prevents the spontaneous activation of complement on autologous cells. Interestingly, CD46 has also been identified as a primate-specific cellular receptor for other viruses, including vaccine strains of measles virus (MV) (Dorig et al., 1993 Naniche et al., 1993). Multiple isoforms of CD46 display MV receptor function (Manchester et al., 1994). However, the relevance of CD46 for the entry of clinical isolates of MV is controversial (Buckland and Wild, 1997 Sakata et al.,

Ebola and Marburg Fever

Marburg virus was first described in 1967 when an outbreak of VHF occurred in laboratory workers simultaneously in Marburg, Frankfurt and Belgrade. These workers were subsequently shown to have been infected from African green monkeys imported from Uganda for polio vaccine manufacture. Of the 31 infected lab workers, 7 died (all of whom belonged to the sub group with primary infections).

Treatment in the Adjuvant Setting

The basis for emphasis on vaccination in the adjuvant setting is best demonstrated in preclinical models. The syngeneic murine tumor models involving EL4 lymphoma are particularly informative in terms of trial design (9). EL4 lymphoma naturally expresses GD2 ganglioside, which is recognized by MAb 3F8. Vaccines containing GD2 covalently conjugated to keyhole limpet hemocyanine (KLH) and mixed with immunological adjuvant QS21 are optimal for vaccination against GD2. Relatively higher levels of MAb administered 2 or 4 d after intravenous tumor challenge or moderate titers induced by vaccination that were present by day 4 after tumor challenge were able to eradicate disease in most mice. If MAb administration was deferred until day 7 or 10 after iv challenge, little or no benefit could be demonstrated. If the number of cells in the EL4 challenge was decreased, giving a longer window of opportunity, the vaccinations could be initiated after tumor challenge and good protection seen (9)....

Conclusions And Future Prospects

Vaccination against tumor challenges has also been frequently explored. Therapeutic effects have been seen after intratumoral injections in various animal models. The recent description of SIN vectors homing naturally to tumor tissue is a new and intriguing finding. This tumor targeting capability can be achieved in alphavirus vectors by introduction of target sequences into envelope genes or by the inclusion of virus particles into liposomes. This liposomal protection, furthermore, avoids host immune responses and, therefore, allows repeated vector applications. Engineering of novel, less cytotoxic vectors that lead to prolonged host cell survival will be beneficial for gene therapeutic approaches that base on the expression of immunostimulatory proteins. The current challenge of alphavirus vector production for future clinical trials is the development of vectors, host cell lines and technologies compatible with GMP standards.

Governmental Laboratories

Federal, state, and local government agencies, such as health departments, operate laboratories or contract with commercial laboratories for testing related to diagnosis, regulatory compliance, investigations, and environmental monitoring. Since the early 1800s, governmental laboratories have performed testing that led to the identification of outbreaks of diphtheria, cholera, smallpox, and typhoid fever. During the 20th century, these laboratories, in conjunction with academic laboratories, helped develop vaccines and contributed to the detection of polio, rubella, measles, and whooping cough. The response to West Nile fever in the United States and the release of viable Bacillus anthracis in 2001 required these laboratories to develop procedures quickly for diagnosis and identification of agents that they had not previously encountered. Governmental laboratories are key to the recognition of new and emerging infectious diseases and are vital to surveillance efforts.

Implications for tuberculosis control

It is among the indigenous population, given the difficulties with adherence with preventive therapy and the frequency of tuberculosis developing as a result of recent infection, that a vaccine, were an effective compound available, would be particularly useful (Orme 1997).

Genetically Engineering Rna Viruses And

The advent of genetic engineering facilitated the manipulation of DNA viruses such as phage viruses, insect viruses, and then mammalian viruses including vaccinia virus and adenovirus (2-4,72). This allowed virus genetics to be performed and even new vaccine and gene therapy concepts to be developed. In the mid 1990s it was reported that adenovirus lacking the E1B-55k gene could replicate in tumor cells lacking functional p53 (6). This event has encouraged a number of studies aimed at improving the oncolytic activity of a variety of DNA viruses through genetic engineering (10,14). However, the ability to genetically manipulate RNA viruses proved a little more difficult because a DNA copy of the entire RNA genome was first required. The development of retroviruses as gene therapy vectors then progressed. Retroviruses are single-stranded RNA viruses that contain a core structural protein (gag) an RNA-dependent RNA polymerase (pol), and viral envelope (env) (73). Usually, some of these...

DTH and Helper TCell Mediated Immunity

Generation of helper T cells has been evaluated by in vitro T-cell proliferation assays. Splenocytes isolated from non-tumor-bearing mice immunized with 3H1 were stimulated in the presence of 3H1, as well as the nominal antigen CEA. No stimulation was observed with splenocytes from naive mice and at least three to four immunizations were needed to detect the stimulation (14). Peripheral blood mononuclear cells (PBMC) isolated from cynomolgus monkeys showed T-cell stimulation in the presence of the anti-Id antibody 11D10. No stimulation could be observed using isotype-matched antibodies (68). Increased T-cell proliferation, following anti-Id vaccination, has been also observed in cancer patients (21,22,24,29,50,58,67,69). In the clinical trial of postsurgical colorectal cancer patients (70), using the anti-Id antibody 3H1, 3H1 consistently generated potent anti-CEA cellular responses detected by the T-cell proliferation assays.

Nondefective Replication Competent Adenoviral Vectors

Provided that the total length of the recombinant DNA molecule does not exceed about 105 of wild type (Bett et al., 1993), DNA can be inserted at several sites in the adenovirus chromosome to create a nondefective recombinant (see Fig. 2). Such vectors have been used to express foreign proteins in many studies, particularly for vaccine development studies where the ability of the virus to replicate postadministration may be advantageous. In addition to the commonly used serotypes 2 and 5, adenoviruses of other subgroups such as Ad4 and Ad7 have been used for protein expression (Imler, 1995). A property of nondefective vectors that may be useful in some situations is their ability to shut off host cell macro-molecular synthesis. This effectively enriches the expression of a recombinant protein regulated by late viral transcriptional and translational elements.

Paramyxoviruses Measles virus and Newcastle Disease Virus

Measles virus (MV) and Newcastle Disease virus (NDV) are members of the negative single-stranded RNA paramyxoviridae family (120). MV is a member of genus Morbillivirus whereas NDV is a member of the Rubulovirus genus that comprises mumps virus. These family members encode 6 to 7 covalently linked genes from a 15-to 16-kb genome and are enveloped viruses (83). In the case of MV, the hemagglutinin (H) attachment protein binds to one of two cellular receptors, CD46 or the signaling activation molecule. CD46 is frequently overexpressed on cancer cells (20). Given that other replicating RNA viruses were becoming noted for their oncolytic effects, it was decided to evaluate whether derivatives of the Edmonston-B-strain of measles virus (MV-Ed), which are live attenuated vaccines that have been effectively used for over 30 yr, exhibited similar properties. Indeed, intratumoral and intravenous inoculation of MV-Ed was found to induce the regression of human lymphoma in xenographed models...

The Mechanism of Immunity

Studies of the natural history of rotavirus in Australia, Mexico and India all confirm that first infections with rotavirus can lead to good immunity against subsequent disease. While first infections are often symptomatic and associated with much viral shedding and a robust immune response, subsequent infections are usually asymptomatic or lead to very mild disease with little shedding but a boost in immunity. Mexican children are frequently infected and 20 of children followed for the first 2 years of life have 5 documented infections evidenced by four fold rises in their antibody titers. The fact that a child gets only one symptomatic infection implies that this infection can protect the child against symptoms from infections with the other common serotypes. The strategy to develop vaccines has therefore been to work with live, attenuated strains of rotavirus that can mimic the immune response of natural infection without causing disease. The mechanism of immunity to rotavirus has...

Prime and boost with pox viruses

A number of investigators have now demonstrated the advantage of priming with vaccinia recombinants and boosting with immunogens such as recombinant protein, peptide, or recombinant fowlpox or avipox vectors to enhance immune responses in cancer vaccine models (27,33-35). The experimental studies that involved priming with recombinant vaccinia and boosting with recombinant avipox also demonstrated that the host immune response to the transgene increased with continued booster vaccinations (27). It has now been demonstrated through both preclinical studies (27,33,36) and recent clinical studies (37,38) that optimal generation of specific T-cell responses can be achieved employing a heterologous prime-and-boost strategy. This has been demonstrated using a primary vaccination with a recombinant vaccinia virus expressing human CEA (designated rV-CEA) and a boost or multiple booster vaccinations with recombinant Induction of CEA-SpecificT-Cell Responses in Patients Vaccinated with rV-C E A...

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