Practical Classification of Immunity

A generation ago, it was common at certain times of the year for grade-school classrooms to be nearly empty, due to several infectious "childhood diseases," including measles, mumps, rubella, and chicken pox. However, each child usually suffered each illness only once, thanks to naturally acquired active immunity. This form of immunity develops after a primary immune response and is a response to exposure to a live pathogen and development of symptoms.

Today, most children in developed countries do not contract measles, mumps, or rubella because they develop another type of active immunity, produced in response to receiving a preparation called a vaccine. A vaccine contains an antigen that can stimulate a primary immune response against a particular disease-causing agent, but does not produce the severe symptoms of that disease.

A vaccine might contain bacteria or viruses that have been killed or attenuated (weakened) so that they cannot cause a serious infection, or it may contain a toxoid, which is a toxin from an infectious organism that has been chemically altered to destroy its dangerous effects. A vaccine may even consist of a single glycoprotein or similar large molecule from the pathogen's surface, which may be sufficient evidence of a foreign antigen to alert the immune system. A vaccine causes a person to develop artificially acquired active immunity.

Vaccines of the future may consist of plant foods genetically manipulated to produce antigens that evoke an immune response against a human pathogen. The first such vaccine tested consisted of raw potato that manufactures a bacterial toxin that causes diarrhea in mice. A week after mice ate the potato vaccine, their blood contained antibodies to the toxin. Because raw potato isn't particularly appetizing, future plant-based vaccines (for humans) may be delivered in bananas — certainly an easier way to immunize infants than the traditional injection route.

Vaccines stimulate active immunity against a variety of diseases, including typhoid fever, cholera, whooping cough, diphtheria, tetanus, polio, chicken pox, measles (rubeola), German measles (rubella), mumps, influenza, hepatitis B, and bacterial pneumonia. Vaccines have virtually eliminated smallpox from the world and greatly diminished the number of cases of poliomyelitis and infection by Haemophilus influenzae type B, which causes meningitis in preschool children. Unfortunately, distribution of vaccines is not equitable worldwide. Many thousands of people living in underdeveloped countries die of infectious diseases for which vaccines are widely available in other nations.

Viruses whose genetic material rapidly mutates present a great challenge to vaccine development because their surfaces, which serve as antigens, change. It is a little like fighting an enemy who is constantly changing disguises. For this reason, pharmaceutical companies must develop a new vaccine against influenza each year. HIV is particularly changeable, which has severely hampered efforts to produce a vaccine.

Shier-Butler-Lewis: IV. Transport 16. Lymphatic System and © The McGraw-Hill

Human Anatomy and Immunity Companies, 2001

Physiology, Ninth Edition

Antigen

Antigen receptor

Receptor-antigen

Cytokines from helper T cell

Antigen

Antigen receptor

Receptor-antigen

Cytokines from helper T cell

Cognitive Conceptualization

Plasma cell (antibody-secreting cell)

Memory cell (dormant cell)

Plasma cell (antibody-secreting cell)

Memory cell (dormant cell)

Plasma cell (antibody-secreting cell)

Memory cell (dormant cell)

Plasma cell (antibody-secreting cell)

Memory cell (dormant cell)

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