MHC Diversity and Antigen Presentation Pathways

For Immunology Chapter 8 Day 2

1. List two ways that MHC molecules exhibit diversity at an individual level.
2. List two ways that MHC molecules exhibit diversity at a population level.
3. Explain the difference in purpose of displaying self-peptides in MHC molecules in primary lymphoid organs vs. secondary lymphoid organs.
4. Viral antigens are often displayed within MHC class I molecules, so several types of viruses block MHC class I antigen presentation. In what way can this strategy backfire?
5. What types of cells express MHC I molecules? What types of cells express MHC II molecules?  What does cross-presentation mean?
6. How and why are the expression levels of MHC molecules regulated?
7. Compare and contrast the “determinant-selection model” and the “holes-in-the-repertoire model” that describe the ways in which MHC alleles carried by an individual may make that individual more or less likely to be resistant/susceptible to specific pathogens?
8. Tasmanian devils are on the verge of extinction. The current bottleneck in population size has allowed a transmissible tumor to spread within the population.  How?
9. Draw a detailed picture of the pathway in which a cell presents antigens via the endogenous (MHC I) pathway.
10. Draw a detailed picture of the pathway in which a cell presents antigens via the exogenous (MHC II) pathway.
11. Cd1 is a noncanonical MHC molecule that displays lipids rather than peptides. Describe the MHC/lipid interactions and point out how this is different than the MHC/peptide interactions we reviewed in the previous day’s discussion.