Lecture 8 Flashcards Preview

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Flashcards in Lecture 8 Deck (24)
1

How many signals do T cells need to get activated? Name them.

1. TCR-peptide+MHC
2. Costimulation: CD28-B7
3. Cytokine

2

How do dendritic cells change with PAMP binding?

↑MHC 1 AND2
↑B7 = costimulatory molecule
Change chemokine receptors to move toward lymph node for T/B cell stimulation
From phagocytosis role --> processing machine

3

Do APCs always express costimulatory molecules?

NO - must undergo maturation to express these
DC & macrophages ↑costim molecules after binding PAMPs, getting proinflam cytokines of CD40-CD40L
B cells must be induced by T cells via CD40-CD40L

4

Do all T cells require co-stimulation?

NO
Naive - always
Memory - sometimes
Effector - no

5

What are plasmacytoid DCs?

Innate immunity
Make a lot of type IFNs when activated

6

What are fDCs?

@ secondary lymph organs
Not - MHC restricted
Display antigen to B cells

7

What are CD8+ DC cells?

DC cells that can express MHC1

8

Which has higher precursor frequency: pathogens or non-self MHC?

Non-self MHC = higher precursor frequency

9

For MHC2, which chains are MHC encoded - alpha or beta?

BOTH

10

For MHC1, which chains are MHC encoded? Alpha or beta2 microglobuin?

Alpha aka the heavy chain ONLY

11

What are superantigens?

Creates peptide non-specific TCR/MHC interactions
General T cell activation - cytokines aren't antigen specific = non-specific inflammation

12

What 5 molecules are critical for MHC1 antigen processing?

1. Chaperones = calnexin, calreticulin
2. Tapasin - holds MHC 1 near TAP
3. TAP brings in peptides
4. Proteosome - unique to MHC1!
5. ERAAP - customizes peptides for the specific MHC

13

Describe the proteosome used for MHC1 peptide presentation.

20s core
Alpha & beta subunits = proteolytic
C term creates peptides that are more likely to bind MHC 1 molecules
Fxn upregulated by IFN gamma
- + PA28 cap to speed up peptide production

14

What is the source of protein antigens for MHC 1 vs 2?

1: Sometime phagosomes but usually proteins in the cytosol
2: Endosomal/lysosomal proteins internalized from extracellular environment

15

What is cross priming?

CD8 DCs!!!!!
The ability of APCs to present on MHC1s
TAP dependent
B/C NEED COSTIM

16

What is alloreactivity?

Reaction to non-self MHC
Think of transplant
MHCa + MHCa - identical match vs small DNA differences due to polymorphisms

17

Which viruses block peptide entry into the ER to evade immune response?

Herpes simplex 1
Human cytomegalovirus
Bovine herpes

18

Which viruses retain MHC1 in the ER to evade immune response?

Adenovirus
Human cytomegalovirus
Murine " "

19

Which viruses degrade MHC 1 to evade immune response?

Human cytomegalovirus
Murine gamma herpes

20

What virus binds MHC 1 at cell surface to evade immune response?

Murine cytomegalovirus

21

How can you increase avidity?

Tetramer of MHC-peptide with TCR

22

Why would you have a MHC2 deficiency? What is the net effect?

Lacking TFs
NO CD4 cells
EX: Coeliac

23

Why would you have a MHC1 deficiency? What is the net effect?

TAP mutation
Beta2 microglobulin mutation
NO CD8 cells

24

Why do we care about peptide anchor residues?

Predict which peptides will bind well to particular MHC alleles
- Vaccination
- Looking for antigen-specific T cells
- Tumor immunology