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If you reflect on what you've learned about the immune system, you may recall that there are really 2 types of lymphocytes, B-cells and T-cells.
· The B-type makes circulating antibodies. The B-type is made in lymph nodes and bone marrow.
· The T-type lymphocyte kills foreign cells on contact or helps by releasing chemicals that assist in killing invaders. T-cells recognize the surface proteins on other cells and when they come in contact with an intruder, the invading cells are killed. These lymphocytes are made in a gland at the base of the neck, called the thymus. Production of T-cells can be reactivated at any time, if a foreign antigen is presented. T-cells also play a role in the rejection of transplanted tissue and in fighting cancer.
1. Why would the body not be adequately protected if it only had the B or T-cell immune system? Why does it need BOTH types of immune responses?
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In addition to the body's natural defenses, vaccines may be administered to boost the body's immunity and prevent disease. For many diseases, the vaccine contains the infection, but it is weakened. The goal in vaccine manufacturing is to make the infectious organism weak enough so that it won't cause the disease but strong enough so that it will activate the body's immune system.
Once the immune system is activated by the disease agent, antibodies are created to fight the disease. The antibodies are "programmed" specifically to fight that particular infectious agent. The original antibodies that are generated in response to a vaccination eventually go away, but the immune system has a "memory".
After a vaccination, if the disease agent that was vaccinated against enters the body, new antibodies are immediately created using the "programming" from the old vaccine. The new antibodies are specifically developed to destroy the specific disease agent that has entered the body.
2. Make a list of diseases for which there are vaccines. Make one list for humans and one for animals. Make another list of diseases for which there are NO vaccines, categorizing the list, once again, by human and animal diseases.
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3. Research some of the human vaccines you have listed. Indicate how often the vaccination has to be repeated and any other interesting information you find out about different vaccines. Be sure to write down the websites or books you use to find your information (document your sources).
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Activity #2: Immune System - Q/A