T cell receptor and MHC

Question 1

primary fn of T cells

Answer 1

monitor intracellular env of host cell

Question 2

TCR is (soluble/transmembrane)? What modification does it have?

Answer 2

transmembrane, glycosylated

Question 3

CD3

Answer 3

• after antigen binds to TCR, CD3 transcribes signal

- cell becomes activated

Question 4

what do aB TCRs recognize?

Answer 4

short peptides generated from antigenic proteins presented by MHC on cell surface

Question 5

strand with most variability in MHC Class I

Answer 5

a1 and a1

Question 6

strand with most variability in MHC Class II

Answer 6

B1

Question 7

a chain of MHC class II

Answer 7

monomorphic

Question 8

can MHC bind multiple peptides?

Answer 8

yes - if they share similar sequences

Question 9

cross-reactive recognition can explain

Answer 9

alloreactivity

Question 10

what happens with peptide-dominant or MHC-dominant binding of TCR?

Answer 10

• TCR can bind to non-self MHC in peptide dominant
• TCR can bind wrong peptide in MHC dominant
• responds as if normal

Question 11

on what cells is MHC I expressed

Answer 11

nucleated cells

Question 12

on what cells is MHC II expressed

Answer 12

professional antigen presenting cells

-subset of hematopoietic and thymic stromal cells

Question 13

CD4 and CD8 interact with (variable/non-variable) regions of MHC

Answer 13

non-variable

Question 14

CD4 and CD8 act as co-receptors on T cells and increase _____ sensitivity for peptide MHC

Answer 14

aBTCR

Question 15

expression of MHC is

Answer 15

codominant

Question 16

MHC haplotype

Answer 16

complete set of alleles within an animal’s MHC

Question 17

are divergent MHC haplotypes good or bad

Answer 17

good - allow presentation of more peptides -> more protection

Question 18

2 reasons for diversity of MHC

Answer 18

• polymorphism - allelic variation

- polygeny - several different MHC genes (w/ similar fn)

Question 19

relative risk = 1

Answer 19

no increased risk with trait

Question 20

relative risk > 1

Answer 20

association between allele and disease

Question 21

relative risk =

Answer 21

RR = allele in individuals with disease / allele in individuals w/out disease

Question 22

MHC I presents what kind of pathogen

Answer 22

cytosolic

NOT extracellular

Question 23

MHC II presents what kinds of pathogen

Answer 23

intravesicular (macrophage), extracellular (B cell)

NOT cytoplasmic

Question 24

what happens when MHC I presents a cytosolic pathogen

Answer 24

cell death

Question 25

what happens wheh MHC II presents an intravesicular pathogen on a macrophage

Answer 25

macrophage is activated to kill

Question 26

what happens when MHC II presents extracellular pathogens and toxins on a B cell

Answer 26

B cell is activated, secretes Ih to eliminate extracell bacteria/toxins

Question 27

how does MHC I process antigen

Answer 27

• peptide is ubi -> fragmented in proteaome
• peptide binds TAP in ER
• goes to lumen in ER
• finds MHC I bidning groove, displaces self peptide
• MHC I:peptide goes to cell surface

Question 28

how does MHC II process antigen

Answer 28

• antigen ingested -> phagolysosome, degraded by proteases
• peptides go to endosomal compartments
• find binding groove of MHC II, displace CLIP
• MHC II:peptide go to cell surface

Question 29

bridge between TCR and MHC, stimulate high percentage of T cells bearing V genes

Answer 29

superantigens

Question 30

what don’t need to be presented by MHC to be antigenic

Answer 30

superantigens

Question 31

TSS causes overproduction of

Answer 31

IL2, IL4, IL1, TNF-a