Antigen Recognition

Question 1

What T cell is for extracellular pathogens?

Answer 1

CD4

Question 2

What T cell is for intracellular pathogens?

Answer 2

CD8

*kills virus in cell by inducing apoptosis, so virus won’t spread

Question 3

What MHC receptor treats vesicles (extra or intracellular vesicles)?

Answer 3

MHC 2

Question 4

What MHC receptor treats pathogens in cytosol?

Answer 4

MHC 1

Question 5

For cytosolic pathogens, what is the process in which we get the peptide on the cell surface?

Answer 5

Peptide from pathogen gets broken down with proteasome, and the fragments go to ER via TAP. In the ER, it combines with the MHC 1 receptor and gets sent to cell surface.

Question 6

What kind of cells have to have HLA 1?

Answer 6

Any nucleated cell that can be infected by virus. So basically every cell in body except RBC!

Question 7

What cells do we want to turn on CD4 cells?

Answer 7

Phagocytic cells - macrophages, dendritic cells, and B-cells

these also have HLA 2!

Question 8

In order to prevent the MHC 2 from binding to self peptide, what does the body do?

Answer 8

Bind invariant chain in peptide binding groove.
Once the complex binds with a vesicle after exiting the ER, the chain gets chopped up and a little piece remains called CLIP. CLIP gets removed via HLA-DM.

Question 9

How do you maximize peptide presentation on MHC molecules?

Answer 9

Polygenic (many genes) & Polymorphic (many shapes)

Question 10

How are we able to present a large number of peptides to activate our T cells?

Answer 10

1) Polygenism
2) Polymorphism
3) Anchor residues