1.  You are playing football. You take a swing pass, elude two defenders, but then are tackled just shy of the goal line. For a muscle review, think about how having a slightly different muscle fiber composition might have made the difference on this play. For now though, imagine you get up and find that a small splinter has pierced your hand. Describe what begins to happen in the area of the wound to protect you from infection as you head back to the huddle.

2.  Early in this century, patients with syphilis were often treated by heating them up in special chambers. What natural response to infection is this similar to? Why might this represent a defense rather than just a symptom? What is the evidence for this?

3.  The protein lactoferrin binds iron and is found within the mammalian female reproductive tract. What might be the value of such a protein here?

4.  What are the four defining characteristics of the immune system? What component or components of the system give it each of these characteristics?

5.  Imagine that you are exposed to a pathogen (e.g., flu or chicken pox virus) and your immune system mounts a response to it. How is it that the system can respond to the very particular characteristics of a given virus strain? Are the specific cells which respond to this threat pre-existing or do they adapt to recognize the viral antigen in adulthood? Relate your answer to clonal selection.

6.  Think about the molecular details of the response to a specific antigen such as the viruses referred to in the last question. What is it about the antibody molecule (IgG) that creates such extraordinary variability?

7.  Now imagine your system is exposed to chicken pox a second time. How does the response this time around differ from the first exposure? What is the different nature of the response primarily due to? What if, instead of the very slow mutating chicken pox virus, you were exposed to the very quickly mutating flu virus? How might a second exposure to this virus differ from a second exposure to the chicken pox virus? (is the flu virus the same virus when you see it the second time?) How do these two examples relate to vaccination and how effective a vaccination might be?

8.  Allergies are mystifying. We mount a vigorous and even sometimes fatal response to a protein or other antigen that cannot hurt us. Thinking about things like hayfever, which type of antibodies are most important for these responses and what might be the reason this response exists?

9.  We have two basic types of specialized immune system cells. What are these two types? Compare the two in terms of origins, functions, and modes of action.

10.  Some persons are genetically immune to HIV infection. What explains this immunity and what does it tell us about the way HIV gains entrance into immune cells?

11.  Related to the last question: what two features of the HIV virus and HIV infection make it so difficult for both the immune system and clinicians to prevent progression to AIDS?