THE MAKING OF A VACCINE: Whenever a disease-causing micro-organism enters the body, the immune system mounts a defense, producing proteins to fight off the foreign substance. Vaccines stimulate the body's immune system by introducing a weakened form of a particular germ or virus, making the body think it is being invaded by a foreign organism. If a person who has been vaccinated is later exposed to the virus, he or she will be protected because the body already has the necessary antibodies to ward off infection.
HOW DOES THE BODY PROTECT ITSELF? The human immune system is a network of immune cells produced in the bone marrow from stem cells. The immune cells circulate through the body in the blood, or are stored in the lymph nodes located at various spots in the body. Some immune cells are more general, patrolling the body and clearing away dead cells, viruses and bacteria. Other cells are activated only by a single substance (called an antigen), such as a particular protein on the surface of the virus. These are called T-cells. When T-cells detect the presence of an antigen, they multiply to combat the invading virus.
The The American Mathematical Association of America, and the Institute for Operations Research and the Management Sciences contributed to the information contained in the TV portion of this report.