Immunohistological Studies

The Revised Authoritative Guide To Vaccine Legal Exemptions

Vaccines Have Serious Side Effects

Get Instant Access

We also studied the immunohistology of lesions that were undergoing rejection after vaccine therapy in a group of seven patients, compared with a group of six untreated melanoma patients, and other control subjects, including a patient who had a DETOX-induced granuloma at the site of injection, which allowed us to compare the rejection site

Fig. 3. Immunohistology of a melanoma lesion undergoing rejection after treatment with allogeneic lysates after staining with specific monoclonal antibodies to cluster determinants. (A) CD8+ T cells, (B) CD4+ T cells, (C) Macrophages, (D) HLA class I antigens (w6/32), (E) HLA class II antigens. Note the predominance of CD4+ T cells over CD8+ T cells in the lesion, the peripheral and perivascular distribution of T cells in general, and the predominance of macrophages over all. HLA class I molecules (by beta-2 microglobulin staining) were present in all 11 lesions examined from six patients, whereas HLA class II molecules were absent from the tumor in the same lesions. CD4+ T cells and macrophages were HLA class II positive, however. (Original magnification: A and B x250; C, D, E x125.)

Fig. 3. Immunohistology of a melanoma lesion undergoing rejection after treatment with allogeneic lysates after staining with specific monoclonal antibodies to cluster determinants. (A) CD8+ T cells, (B) CD4+ T cells, (C) Macrophages, (D) HLA class I antigens (w6/32), (E) HLA class II antigens. Note the predominance of CD4+ T cells over CD8+ T cells in the lesion, the peripheral and perivascular distribution of T cells in general, and the predominance of macrophages over all. HLA class I molecules (by beta-2 microglobulin staining) were present in all 11 lesions examined from six patients, whereas HLA class II molecules were absent from the tumor in the same lesions. CD4+ T cells and macrophages were HLA class II positive, however. (Original magnification: A and B x250; C, D, E x125.)

with a classical delayed-type hypersensitivity (DTH) reaction (Mitchell MS et al., unpublished data). It was interesting that, contrary to our expectations, the predominant cell in all of the sites of rejection was the monocyte-macrophage, identified with anti-CD11c (Leu M5), anti-class I and II antigens, and usually anti-CD4. CD4+ T cells and CD8+ T cells were present at the periphery of the tumor and perivascularly, with CD4+ cells predominating 3:1 or 3:2 (Fig. 3).

To our pathologist, the lesions most resembled a DTH reaction although the granuloma was far more intense in its representation of T cells and macrophages. HLA class I molecules (identified with monoclonal antibody w6/32 against beta2 microglobulin) were present on the tumor in all specimens undergoing rejection, and in all control melanoma specimens. In this study, performed in the early 1990s, we did not attempt to study the loss of specific HLA class I alleles from the tumor (20,21), and so cannot rule out downregulation of specific molecules even though HLA class I molecules in general were present. In contrast, HLA class II molecules (identified with monoclonal antibody L227) were absent from the tumor in all 11 specimens from seven patients whose lesions were regressing after treatment with melanoma lysates. However, HLA class II molecules were present on the tumor (3+ staining intensity) in specimens from 7 of 11 untreated melanoma patients, and 5 of 6 patients who had received other types of immunotherapy 2-3 mo earlier. Whether the loss of HLA class II molecules makes tumor cells somehow more vulnerable to immunological attack, and their presence confers resistance, or alternatively whether class II molecules are lost as a consequence of immuno-logical attack are interesting open questions. In favor of the first set of premises, the inverse correlation of HLA class II expression on melanoma and sensitivity to immunotherapy is consistent with the findings of Ferrone and coworkers, who emphasized that primary melanomas that expressed HLA class II molecules had a poorer prognosis than those with absent HLA class II (22).

Despite the association of clinical response with rises in precursors of CTLs, a direct cytotoxic role of either CD4+ or CD8+ T cells was not supported by these observations. Rather, a more indirect role is suggested, perhaps involving cytokines or chemokines released by the T cells.

6.4. Schema of Immune Response to Allogeneic Lysates

We suggest that allogeneic lysates are taken up by dendritic antigen-presenting cells in the dermis after injection, and then processed and presented in self-HLA-class I and -class II context to CD8+ and CD4+ T cells, respectively. The addition of alloantigens, far from preempting the immune response to weaker tumor-associated antigens, may well augment the response, by eliciting additional T-cell help, in the form of cytokines such as IL-2, from alloreactive T helper cells. The additional cytokines from the alloreactive T cells may augment CD4+ and CD8+ T-cell activity against the tumor, in some cases leading to its destruction if all other elements enabling response are present, such as adequate representation of HLA molecules and tumor epitopes on the tumor cells, and lack of antagonism of T cells by cytokines released from or elicited by the tumor. This schema, which is illustrated in Fig. 4, was presented previously in a similar form after our data from early trials were first analyzed (23).

Fig. 4. Schema of the mechanism by which allogeneic lysate vaccines may immunize against a tumor. Uptake and processing of the lysates by dendritic cells after injection may lead to the production of CD4+ and CD8+ T cells directed against the tumor. Presentation of exogenous epitopes by HLA class II molecules to CD4+ cells and by HLA class I molecules to CD8+ T cells (cross-priming) have both been demonstrated. Alloantigens may augment T-cell help to CD4+ and CD8+ T cells, through stimulation of alloreactive T cells to produce cytokines, in addition to those produced by tumor-specific T cells immunized by tumor antigens. Thus, alloimmunization may be beneficial to immunity directed at the tumor.

Fig. 4. Schema of the mechanism by which allogeneic lysate vaccines may immunize against a tumor. Uptake and processing of the lysates by dendritic cells after injection may lead to the production of CD4+ and CD8+ T cells directed against the tumor. Presentation of exogenous epitopes by HLA class II molecules to CD4+ cells and by HLA class I molecules to CD8+ T cells (cross-priming) have both been demonstrated. Alloantigens may augment T-cell help to CD4+ and CD8+ T cells, through stimulation of alloreactive T cells to produce cytokines, in addition to those produced by tumor-specific T cells immunized by tumor antigens. Thus, alloimmunization may be beneficial to immunity directed at the tumor.

Was this article helpful?

0 0
How To Bolster Your Immune System

How To Bolster Your Immune System

All Natural Immune Boosters Proven To Fight Infection, Disease And More. Discover A Natural, Safe Effective Way To Boost Your Immune System Using Ingredients From Your Kitchen Cupboard. The only common sense, no holds barred guide to hit the market today no gimmicks, no pills, just old fashioned common sense remedies to cure colds, influenza, viral infections and more.

Get My Free Audio Book


Post a comment