L2 - MHC

Question 1

What does MHC do?

Answer 1

Binds peptides and displays them to T cells

Question 2

What needs to happen to antigens for T cells to recognise them?

Answer 2

Be broken into peptides and displayed in association with MHC

Question 3

What cells display MHC class I?

Answer 3

All nucleated cells in the body

Question 4

What cells display MHC class II?

Answer 4

Antigen presenting cells (macrophages, dendritic cells, B cells)

Question 5

What T cell co-receptor binds MHC class I?

Answer 5

CD8

Question 6

What T cell co-receptor binds MHC class II?

Answer 6

CD4

Question 7

What is the role of MHC class I? What cell does it present peptides to?

Answer 7

Shows peptides made within the cell to Tc cells; lets them know if the cell is infected

Question 8

What is the role of MHC class II? What cell does it present peptides to?

Answer 8

Shows peptides from outside the cell to Th cells; alerts them to extracellular invaders

Question 9

What types of peptides can MHC class I bind?

Where are the anchoring residues situated?

Answer 9

Short peptides (8-10 AAs)

Anchored at ends

Question 10

What types of peptides can MHC class II bind?

Where are the anchoring residues situated?

Answer 10

Longer peptides (13-22 AAs)

Anchored at the base of the groove, peptide is free to overhang at the ends

Question 11

What segments are MHC class I genes separated into?

Answer 11

Human leukocyte associate (HLA) A, B, and C

Question 12

What segments are MHC class II genes separated into?

Answer 12

DP, DQ, and DR

Question 13

What is the inheritance pattern of MHC genes?

Answer 13

They are inherited co-dominantly; both from each parent are used

Question 14

What makes MHC similar to an ID card?

Answer 14

There are lots of different alleles and allele combinations in the population, and a person can have any combination of haplotypes

Question 15

What pathway does MHC class I use to load and present peptides?

Answer 15

Endogenous pathway

Question 16

What pathway does MHC class II use to load and present peptides?

Answer 16

Exogenous pathway

Question 17

What types of protein are loaded into MHC class I in the endogenous pathway?

Answer 17

Damaged or incorrectly translated proteins

Question 18

What are the stages of the endogenous pathway of MHC peptide presentation (4)?

Answer 18

1. Proteins are broken down by proteasome
2. Tap1 and 2 transporters take to ER
3. Bind to MHC class I groove
4. Put in vesicles and sent to surface

Proteasome, Tap, bind, vesicle

Question 19

What are the names of the specific transporters that take endogenous peptides to the ER in MHC class I presentation?

Answer 19

Tap1 and Tap2

Question 20

What are the stages of the exogenous pathway of MHC peptide presentation (5)?

Answer 20

1. Invariant chain (CLIP) binds to MHC groove in ER
2. MHC enters endosome with exogenous peptide
3. Endosome enzymes break apart protein
4. HLA-DM protein removes CLIP
5. Peptide takes its place

Invariant, endosome, enzyme, HLA-DM, peptide

Question 21

What is used as a place holder in the exogenous pathway of MHC peptide presentation?

Answer 21

Invariant chain (CLIP)

Question 22

What removes the invariant chain in the exogenous pathway of MHC peptide presentation?

Answer 22

HLA-DM