Antigen Presentation

Question 1

What are the three human genes for Class I MHC proteins? What chromosome are they on?

Answer 1

HLA-A, B, and C

Chromosome 6

Question 2

What molecule does each class I HLA protein pair with to make a complete class I MHC molecule?

Answer 2

Beta-2 microglobulin

Question 3

What chromosome are Class II MHC molecules encoded on?

Answer 3

6

Question 4

What is the correct AA peptide length presented by class I MHC?

Answer 4

~9 AA’s

Question 5

What are the 3 main steps in class I MHC display?

Answer 5

1. Generation of peptide by proteasome
2. Transport of peptide to ER
3. Binding of peptide to groove of MHC I molecule

Question 6

What cell type do Class II MHC molecules present peptides to?

Answer 6

Helper T cells

Question 7

What two proteins make up class II MHC molecule? What do they bind to?

Answer 7

Alpha and beta chains

Bind to invariant chain

Question 8

What fills the MHC II molecule to prevent it from picking up other peptides?

Answer 8

Invariant chain

Question 9

Where are class II MHC molecules loaded with peptides?

Answer 9

Within endosomes

Question 10

What cellular protein in endosome catalyzes release of invariant chain?

Answer 10

HLA-DM

Question 11

What cell types do Class I MHC molecules present to?

Answer 11

Killer T cells (cytotoxic T cells)

Question 12

Name the three types of APCs.

Answer 12

1. Dendritic cels
2. Macrophages
3. Activated B cells

Question 13

Where do dendritic cells take up position? What cells do they activate to initiate immune response?

Answer 13

Beneath barriers of epithelial cells

Virgin T cells

Question 14

What two kinds of signals activate dendritic cells?

Answer 14

1. Cytokines from other immune cells like neutrophils and macrophages.
2. Cellular receptors which recognize molecular patterns of a broad invader class - Toll-like receptors (TLRs)

Question 15

What TLR is used to sense LPS - component of bacterial cell walls?

Answer 15

TLR-4

Question 16

What TLRs are located in walls of phago-lysosome and are alerted to viral or bacterial proteins?

Answer 16

TLR 7 and 9

Question 17

What co-stimulatory protein do traveling dendritic cells produce?

Answer 17

B7 proteins

Question 18

Why do B-cells have an advantage over other APCs?

Answer 18

They can concentrate Ag for presentation

Question 19

If a pathogen is encountered a second time, what APCs can get the adaptive immune system going quickly by concentrating small amts of Ag for presentation?

Answer 19

Memory B-cells

Question 20

What is the non-classical molecule found in the immune system called? What is it paired with? What is it designed to bind?

Answer 20

CD1 molecules - resembles class I MHC molecules

Paired with beta-2 microglobulin

Binds lipids