Antigen Presentation and Processing

Question 1

Immunological Synapse

Answer 1

MHC on APC -- TCR/CD3
CD80/86 on APC -- CD28 on T cell 
ICAM-1 on APC -- LFA-1 on T cell 
LFA-3 on APC -- CD2 on T cell
CD4 or CD8 co-receptor on T cell  → MHC

Question 2

what protein transports peptides into RER to be loaded into MHC

Answer 2

TAP

Question 3

what protein trims/edits peptide before putting into MHC

Answer 3

ERAP

Question 4

what protein(s) ensure proper folding of the MHC class I alpha chain

Answer 4

ERp57 (disulfide bonds) and Calnexin

Question 5

which protein allows for association of MHC complex w/ TAP

Answer 5

tapasin

Also may help with loading peptide

Question 6

how are peptides from virus infected cells presented on class I MHC molecules

Answer 6

distinct 20S proteasome induced by IFN gamma and TNF a.

Degrades and presents viral proteins on cell surface.

Question 7

endocytic pathway - 2 ways

Answer 7

phagocytosis or receptor mediated internalization

Question 8

assembly of class II MHC molecules

Answer 8

in RER -
MHC Class II + Invariant chain for stabilization –>
in endosome - digest invariant chain = CLIP, antigenic peptide replaces CLIP with help of non-classical MHC (HLA-DM) (regulated by HLA-DO)

Question 9

how to treat mhc Class II deficiency (Vs mhc class I)

Answer 9

Class II can do stem cell transplant - cannot with MHC Class I because those are on all cells, not just immune cells

Question 10

MHC is on what chromosome

Answer 10

6

Question 11

B2-microglobulin (MHC class I) is on what chromosome

Answer 11

15

Question 12

how to constitutive proteasome to immunoproteasome

Answer 12

ifn alpha or beta

Question 13

what cells are required to activate Th0

Answer 13

dendritic cells

Question 14

all t cells need two instructional signals to become activated =

Answer 14

1 - TCR-antigen on MHC

2- costimulatory (CD80/86 on APC to CD28 on T cell)

Question 15

cytotoxic t cell effect once activated

Answer 15

1 - IFNg and TNFa – inflammatory t cell recruitment and M1 macrophage activation
2 - binding to death receptor (Fas), release of perforin
3- granzymes

Question 16

tab/tbp on what chromosome

Answer 16

6 w/ MHC molecules

Question 17

steps to present on Class I mhc

Answer 17

1. Endogenous antigen degraded by proteasome
2. Peptide transported to RER by TAP
3. Class I MHC a-chain binds calnexin and ERp57
4. Then bind b2-mg
5. Calnexin goes away
6. Tapasin and Calreticulin bind
7. MHC captures peptide
8. Class I MHC-peptide transported from RER to golgi to Plasma membrane

Question 18

steps to present on Class II mhc

Answer 18

1. Class II MHC a and b chains bind invariant chain- blocking binding of endogenous antigen
2. MHC complex routed through golgi to endocytic pathway compartments
3. Invariant chain degraded leaving CLIP segment
4. Exogenous antigen taken up, degraded, routed to endocytic compartments
5. HLA-DM (and inhibited by DO) mediate exchange of CLIP for antigenic peptide
6. Class II MHC-peptide transported to plasma membrane