L15 and L16 - Cell-Mediated Immunity

Question 1

MHC Class I

Answer 1

• binds peptides 8-9 residues in length
• closed-ended binding cleft
• encoded by A, B, and C genes of HLA

Question 2

MHC Class II

Answer 2

• binds peptides that are 13-20 residues in length
• open-ended binding site
• encoded by DP, DQ, and DR genes of HLA

Question 3

superantigens

Answer 3

exogenous antigens produced by Gram+ bacteria that aberrantly activate T-cells by binding to both MHC II and the TCR

Question 4

TAP1/2

Answer 4

enzymes responsible for transporting small peptides into the ER lumen

Question 5

DM

Answer 5

protein encoded in HLA; responsible for catalyzing the release of CLIP and loading of peptide onto MHC II

Question 6

CLIP

Answer 6

portion of invariant chain that binds to the antigen-binding site of MHC in order to prevent aberrant loading

Question 7

T-cell activation

Answer 7

Cytoplasmic portions of CD3 and ζ components of TCR have ITAMs that are phosphorylated. Binding of MHC/peptide complex brings CD4/CD8 in close proximity to ITAMs. CD4/CD8 have cytoplasmic domains that interact with Lck, a tyrosine kinase. Phosphorylation of ITAMs provides a docking site for ZAP-70, a tyrosine kinase, which is phosphorylated and activated by Lck. ZAP-70 activates a signalling cascade.

Question 8

AIRE

Answer 8

protein responsible for the expression of peripheral self-antigen in the thymus during the process of T-cell maturation

Question 9

bare lymphocyte syndrome

Answer 9

disease characterized by a genetic mutation in CIITA, a transcription factor controlling expression of MHC II; individuals thus lack CD4 T-cells

Question 10

autoimmune polyglandular syndrome (APS-1)

Answer 10

genetic disorder characterized by lack of AIRE; patients thus suffer from autoimmunity

Question 11

enzymes responsible for transporting small peptides into the ER lumen

Answer 11

TAP1/2

Question 12

protein encoded in HLA; responsible for catalyzing the release of CLIP and loading of peptide onto MHC II

Answer 12

DM

Question 13

portion of invariant chain that binds to the antigen-binding site of MHC in order to prevent aberrant loading

Answer 13

CLIP

Question 14

protein responsible for the expression of peripheral self-antigen in the thymus during the process of T-cell maturation

Answer 14

AIRE

Question 15

disease characterized by a genetic mutation in CIITA, a transcription factor controlling expression of MHC II; individuals thus lack CD4 T-cells

Answer 15

bare lymphocyte syndrome

Question 16

genetic disorder characterized by lack of AIRE; patients thus suffer from autoimmunity

Answer 16

autoimmune polyglandular syndrome (APS-1)