1. Aim: How does your body become immune (resistant) to disease?

2. Bioterrorism Fatal hemorrhagic smallpox in a twelve-year-old girl, 1970s, Bangladesh. A genetically - engineered strain of smallpox might produce unusual symptoms such as these. Here, the eyes are filled with blood, and blood blisters form in the mouth and inside the body. How can we protect ourselves? vaccines Today there is mounting concern about the threat of a bioterrorist attack using smallpox -- so much concern that in October 2001 the American government decided to order enough vaccines to protect every U.S. citizen. Smallpox has a fearsome reputation, having killed more people in history than any other infectious disease.

3. What is a vaccine? A vaccine is a dose of a pathogen or part of a pathogen that has been disabled or destroyed so it is no longer harmful, but it still has the antigens present. These antigens trigger an immune response Weakened Pathogen Antigen Antibody

4. How was the first Vaccine developed? English physician Edward Jenner developed an inoculation against smallpox in 1796. Knowing that milkmaids who had been exposed to cowpox, a relatively mild affliction, didn't come down with smallpox, Jenner intentionally infected an eight-year-old boy with cowpox. Two months later he infected the boy again, this time with smallpox. As Jenner expected, the child didn't come down with the disease -- he was immune.

5. Vaccines depend on the “memory” of the immune system. The first response is relatively slow and weak because time is needed for enough WBCs to form and defeat the pathogen. The second response to the same pathogen triggers a quicker and stronger response. ** After the first response, the immune system “remembers” specific pathogens by leaving behind WBCs that protect the body for years (memory cells).

6. How do scientists make vaccines? http://www.pbs.org/wgbh/nova/bioterror/vaccines.html 1)Obtain pathogen 2)Treat pathogen to kill or weaken it. 3)Inject altered pathogen (vaccine) into organism. 4)Body responds to antigens by making antibodies & having WBCs attack invader. 5) Some WBCs specific for this pathogen remain in the body to protect the organism from future attacks.

7. What happens when you get invaded by the real pathogen? Some white blood cells specific for this pathogen (called Memory Cells) are already present and will multiply quickly and destroy the invader before it has the chance to cause the disease. Memory Cells

8. What is immunity? The ability of a person who once had a disease to be protected from getting the same disease again.

9. Immune response Antibody Concentration Time First exposure Second exposure Interval between exposures Vaccine Real Pathogen

10. Vaccines 3 min

11. Active vs. Passive immunity Active Immunity You make your own antibodies to fight the pathogen Long lasting Passive Immunity You get antibodies from a different organism, you don’t make your own antibodies Short lasting

12. How are these two types of immunity different?