8. Antigen Processing and Presentation II (Snippets) Flashcards Preview

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Flashcards in 8. Antigen Processing and Presentation II (Snippets) Deck (50)
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1

what are the three signals to activate naive lymphocytes to specific effector?

1. antigen receptor (TCR-peptide/MHC)
2. costimulation (CD28/B7)
3. Cytokines (lead to specific effector functions)

2

central dovma of adaptive immunity?

Phenotypic changes to the DC = 'loss of DC adhesiveness" and means that the chemokine receptors change when the DC becomes stimulated and moves out of the epithelium. They become lymp node-attracted at this point, which is based on the changes to the type of chemokine receptors expressed. Important for stimulation of both CD4 and CD8 cells

phenotypic changes to the DC:
- increase class II and class I
- upregulate B7
- change chemokine receptors
- go from a phagocytic phenotype to a processing machine

3

Th1 cells do what?

macrophage activation: destruction of phagocytosed microbe

4

Th-all, esp TFH cells do what? (T-follicular helper)

B cell antibody secretion: antibody binding to microbe

5

CD8 cells do what?

kill antigen-expressing infected cells

6

dendritic cells do what?

APCs only

7

macrophages do what?

APCs when activated by T cells or PAMPA; otherwise they clean things up

8

B cells do what?

present BCR-binding antigens to antigen-specific T cells

9

when do DCs express Class II MHC?

constitutive, but increases as mature

10

when do macrophages express Class II MHC?

low; induced by IFN-gamma

11

when do B cells express Class II MHC?

constitutively, augmented by cytokines

12

costimulation (eg B7) is inducible how in DCs?

by PAMPS, pro-inflamm cytokines, and CD40-40L

13

costimulation (eg B7) is inducible how in macrophages?

by PAMPs, proinflamm cytokines, CD40-40L

14

costimulation (eg B7) is inducible how in B cells?

by T cells (CD40-40L) and antigen

15

what is the principle function of DCs?

initiation of naive T cell responses to protein (CD4 and CD8)

16

what is the principle function of macrophages?

induction and effector phases of CMI

17

what is the principle function of B cells?

present antigen to antigen-specific CD4 helpers

18

naive and some memory T cells require cosimulation (eg B7) - what about effector T cells?

do not require costimulation, only the ag/MHC recognition

19

plasmacytoid DC?

part of the innate immune system making large amounts of Type I IFNs upon activation (hopefully can take care of pathogen without adaptive immunity)

20

MHC restriction?

TCR recognizes the peptide/MHC complex

21

T cells respond vigorously to APC bearing non-self MHC alleles, in the so called _____ response (the bane of transplantation surgeons)

allogenic/allo response

22

Class I and Class II genes are very polymorphic - each allele will bind what?

a particular set of peptides, which in turn will activate different clones of antigen-specific T cells

23

what part of the Class I MHC is MHC encoded?

only H chain

24

peptides that bind class I MHCs are generated where?

the cytosol

25

Class I molecs are upregulated during infection via what?

cytokines, exp gamma IFN

26

class II molecs are expressed by which cells?

B cells, DCs, macrophages, and thymic epithelium

27

peptides that bind class II MHC are generated where?

lysosomes

28

Class II MHC are upregulated during infection via what?

cytokines, esp gamma IFN

29

Treg cells do what?

dampen immune response

30

Th2 cells do what?

involved in defense of epithelia/mucosae, against extracellular parasites