Lecture # 12 MHC Restriction Recap Antigen Processing and Presentation - Class I

Question 1

MHC and applications to transplantation

Answer 1

Slight differences in MHC from donor to acceptor causes allergy.

Question 2

Super antigens

Answer 2

Bind to the outside of the MHC/TCR VB3 NOT VIA MHC1; Polyclonal activation of VB3+ T Cells; cytokine storm (cause toxic shock syndrome) and deletion of T Cells; recognize by T cells without being processed into peptide;

Question 3

JITT #5 Q# 1; From the class I deficiency study, Tatiana and Alexander had normal delayed type hypersensitivity response to tuberculin and candida (fungal organism) Why do you think this is?

Answer 3

1) Candida and Tuberculin are fungal and bacterial respectively, both are extracellular pathogens
2) We know that MHC I is deficient, MHC II must be at work
3) MHC II specifically works against extracellular pathogens

Question 4

MHC I combats which type of pathogen?

Answer 4

Viral

Question 5

MHC II combats which type of pathogen?

Answer 5

extracellular

Question 6

Why is deficiency such a big deal when we are considering CD8+ and CD4+?

Answer 6

Because if we are deficient in an MHC, then there is no CD8+ or CD4+ development!!! Low levels of T Cells!!

Question 7

What type of peptides do CD4 T cells recognize?

Answer 7

CD4+ cells recognize bacterial peptides in the context of MHC II

Question 8

Antigen processing

Answer 8

refers to the generation of peptides from an intact antigen that involves modification of naive protein

Question 9

Antigen presentation

Answer 9

refers to the display of the peptide at the cell surface by MHC molecules to T cells

Question 10

In what region do peptides recognized by CD8+ T Cells originate from?

Answer 10

Pathogen peptides are from the cytosolic compartment

Question 11

In what region do peptides recognized by CD4+ T Cells originate from?

Answer 11

Pathogen peptides are from the endosomal/vesicular compartment

Question 12

Cross Presentation pathway (Class I )

Answer 12

Exogenous antigens from a dying virus infected cell that is phagocytosed by a DC can be transported to the cytosol

Question 13

Class II pathway

Answer 13

BCR mediated endocytosis, peptides are presented; MHC II expression and CD4+ effectors

Question 14

What types of peptides can APC express?

Answer 14

Professional APCs present pathogens to both CD4+ and CD8+

Question 15

Which type of MHC presentation is TAP specific for?

Answer 15

MHC class I presentation

Question 16

How do peptides from the cytosol get into the ER to be loaded to MHC Class I molecules?

Answer 16

By TAP

Question 17

Proteosome

Answer 17

large protease complex that degrades cytosolic proteins

Question 18

What are the two types of proteosomes?

Answer 18

Constitutive proteosome and immunoporteosome

Question 19

Constitutive proteosome

Answer 19

alpha and beta subunits induced to become the immunoproteosome by interferon gamma

Question 20

Immunoproteosome

Answer 20

LMP2, MECL-1, LMP7 subunits

Question 21

PA28

Answer 21

compound that binds to ends of inducible proteosome, opens up the ends and increases the rate at which peptides are releases. induced by interferon gamma

Question 22

ERAP

Answer 22

chops peptides more to produce a peptide that better fits to MHC go to slide 22right now

Question 23

Viral Evasins

Answer 23

degrade class I or bind to TAP and inhibit peptide loading