T Cell Receptor Flashcards Preview

Immunology > T Cell Receptor > Flashcards

Flashcards in T Cell Receptor Deck (20):
1

What is the function of MHC?

Monitor IC environments by presenting short peptide fragments on surface of cell to T cell to either signal response against foreign protein

2

How do you get diversity of TCR? (5)

1. recombination of VDJ segments
2. recombination of different number of gene segments
3. imprecise joining by RAG
4. P and N nucleotide addition by TdT
5. Assembly of different combos of rearranged TCR chains (alpha/beta or delta/gamma)

3

Does TCR have affinity maturation?

No, because it doesn't have somatic hypermutation

4

What do cytosolic peptides bind to? What are they presented to? What is the effect on presenting cell?

-binds MHC class I, present to CD8, and causes cell death

5

What do intravesciular pathogens bind to? What are they presented to? What is the effect on presenting cell?

-binds MHC class II, presents to CD4, and activates the APC to kill intravesicular bacteria and parasites

6

What do extracellular pathogens and toxins bind to? What are they presented to? What is the effect on presenting cell?

-binds MHC class II, presents to CD4, activates B cells to secrete IG to eliminate EC pathogen

7

Is this affinity of TCR for Ag weak or strong compared to Ab?

weak

8

What region of the MHC protein do CD4 and CD8 recognize?

constant region, can interact with any MHC class II or class I protein respectively

9

What does gamma-delta TCR recognize?

3D shape of MHC molecule or Ag, not dependent on peptide held by MHC

10

How do superantigens work?

-recognizes outside constant regions of TCR and MHC to bind both in a nonspecific manner
-increases frequency of T cell response from 1 in 10^4 to 10^5 to 1 in 4 to 20 to get huge cytokine release

11

Does superantigen have any specificity?

-has specificity for certain VB segments, increases susceptibility for certain people

12

What HLA types make up class I MHC? class II?

for class I, HLA-A, HLA-B, HLA-C (homodimer)
for class II, HLA-D (heterodimer)

13

Where does the diversity come from for class I MHC? Class II?

for class I, diversity comes from number of alleles (6) since it's a homodimer
for class II, diversity comes from heterodimer arrangments

14

Which class of MHC is expressed on all nucleated cells?

MHC class I

15

What class of MHC is expressed on APCs?

MHC class II to allow interact with CD4 T cells so it can secrete cytokines to help B cells

16

What is the structure of MHC class I? Which subunits make up the binding groove?

-alpha 1, 2, 3 (transmembrane), beta 2
-alpha 1 and 2 make up binding groove

17

What is the structure of MHC class II? Which subunits make up the binding groove?

-alpha 1, 2 (transmembrane), beta 1, 2 (transmembrane)
-alpha 1 and beta 1 make up the binding groove

18

Which MHC class has a closed off binding groove that fits smaller peptides only?

class I

19

Which class of MHC do extracellular pathogens present from?

class II

20

What is the processing pathway for IC pathogens?

-pathogen in cytosol degraded in proteasome to peptides
-transported into ER where they bind MHC previously held by chaperones, and are exported to cell surface