Major Histocompatibility Complex

Question 1

MHC Class I Composition

Answer 1

Alpha chain with three domains: 1, 2, and 3.

Beta-2-microglobulin not encoded by the MHC gene

Question 2

MHC Class II Composition

Answer 2

Alpha chain with two domains: 1, 2
Beta chain with two domains: 1, 2
Both encoded by MHC locus

Question 3

MHC Class I Peptide Binding Groove

Answer 3

Recognizes anchor residues of peptides 8-10 amino acids long

Has closed ends

Question 4

MHC Class II Binding Groove

Answer 4

Recognizes anchor residues of peptides 13-35 (or longer) amino acids long
Has open ends

Question 5

MHC Class I presentation pathway presents _____ antigens

Answer 5

intracellular

Question 6

MHC Class II presentation pathway presents ______ antigens

Answer 6

extracellular

Question 7

TAP transporter

Answer 7

TAP-1 and TAP-2

Move degraded peptides into the lumen of the ER to load onto MHC Class I molecules

Question 8

Peptide-loading Complex

Answer 8

Loads peptides brought in via TAP-1/2 onto newly synthesized MHC class I molecules

Question 9

Failure of peptide loading onto MHC Class I molecules leads to ____

Answer 9

degradation, deficiency of TAP can lead to deficiency of MHC Class I molecules

Question 10

Invariant chain

Answer 10

Loaded onto newly synthesized MHC Class II molecules to prevent other peptides from binding

Question 11

CLIP

Answer 11

Short remnant of the invariant chain; cleaved within cytosolic vesicles to prevent other peptides from binding

Question 12

HLD-DM

Answer 12

Removes the CLIP after vacuole associates with phagolysosome so that pathogen peptide can be bound

Question 13

Lack of invariant chain leads to ______

Answer 13

inability to distinguish between intra and extracellular pathogens

Question 14

Cells that express MHC Class I Molecules

Answer 14

ALL nucleated cells (very low density on neuronal cells)

Question 15

Cells the express MHC Class II Molecules

Answer 15

antigen presenting cells (dendritic cells, macrophages, and B cells) and thymic epithelial cells

Question 16

CD4 cells only recognize ____

Answer 16

MHC Class II molecules

Question 17

CD8 cells only recognize ____

Answer 17

MHC Class I molecules

Question 18

polygeny

Answer 18

multiple loci that encode structurally similar and functionally identical proteins

Question 19

polymorphism

Answer 19

two or more forms of a given gene (alleles) in a population

Question 20

Minimum number of MHC class I isoforms

Answer 20

3, if the individual is homozygous at each locus (HLA-A, HLA-B, and HLA-C)

Question 21

Minimum number of MHC Class II isoforms

Answer 21

3, if the individual is homozygous (HLA-DP, HLA-DR, HLA-DQ)

Question 22

Maximum number of MHC Class I isoforms

Answer 22

6

Question 23

Maximum number of MHC Class II isoforms

Answer 23

16