$1.$ Explain why the second time you encounter an organism only your memory cells

respond. Is this advantageous to you and why?

$2.$ Explain the difference between the two ways that alloreactive T cells can be

stimulated in an acute transplant rejection $($what$$s happening?$)$

$3.$ Describe the ways that normal gut flora can benefit the human host

$4.$ Explain original antigenic sin and how it can be detrimental to our secondary

immune response

$5.$ What is the most effective type of vaccine and the preferred mode of entry?

Why?

$6.$ Explain why a different influenza vaccine is necessary every year. How is this

different from the development of pandemic versions? Please include in your

answer the terms antigenic shift and antigenic drift.

$7.$ Explain several issues we have with HIV vaccine development. Why haven$$t we

been able to produce a successful vaccine?

$8.$ What is different about a type IV hypersensitivity reaction versus the other three

types?

$9.$ Explain why women who show no disease symptoms themselves can pass on

inheritable immunodeficiencies their sons, whereas their daughters seem to be

unaffected. Would a disease with this pattern of inheritance be caused by a

recessive or a dominant allele?