There are two different but not necessarily exlusive theories of what triggers an immune reaction: the self/non-self theory and the danger or damage theory. How do these two theories differ in terms of how they do or do not explain our response to the commensal microbes that reside in our guts?

Using complete sentences, compare and contrast the of the innate and adaptive immune systems with the following considerations: What are each system’s functions? Which cells are involved in each? What outcomes occur afteractivation?

Describe how the principle of herd immunity works to protect unvaccinated individuals. What characteristics of the pathogen or of the host do you think would most impact the degree to which this principle begins to take hold?

Once the antigen presenting cell delivers the message about the identity of the specific pathogen to the adaptive immune system, what is the mechanism of lymphocyte activation to make sure lymphocytes target that specific pathogen or toxin (Specificity)? Why does this process create a slow response during the first exposure of a pathogen?

What is Herd Immunity and what is its Immunological and public health significance?

Johnny has just been infected and needs your help in letting him know how his body is fighting the infection. To do so, describe how the innate and adaptive immune systems work together. You should address the following: 1. define adaptive and innate immunity; 2. Describe the role of natural killer cells (how do they work); 3. what are antigen presenting cells and what is their function, what are MHCs?; 4. describe the role of the complement system; 5. what is the role of interferons?; 6. How do helper T cells, cytotoxic T cells and B lymphocytes work make sure you address adaptive immunity memory?; 7. Define HIV, which cells do they attack and why do some individuals develop persistent lymphadenopathy (swollen or enlarged lymph nodes)?