Immunology Lecture 8.

Question 1

What type of killing do cytokines do?

Answer 1

slow killing

Question 2

What does fast killing?

Answer 2

perforin

Question 3

CD28

Answer 3

receptor on T cells for the B7 co-stimulatory molecules (critical role in activation and proliferation of T cells after they first encounter antigen)

Question 4

CTLA-4

Answer 4

high-affinity receptor for B7 molecules on T cells - critical role in SHUTTING OFF t cell response

Question 5

B7

Answer 5

major T cell co-stimulatory molecules - bind to CD28 and CTLA-4

Question 6

CD3

Answer 6

part of the TCR (Tcell receptor) complex - escorts the TCR to cell membrane and helps with signal transduction

Question 7

What is the difference between TCR and immunoglobulin genes?

Answer 7

no somatic mutation of TCR genes

Question 8

Which has more diversity? TCR or immunoglobulin? Why?

Answer 8

TCR - more junctional diversity

Question 9

What is the difference in recognition by immunoglobulin and TCR?

Answer 9

anitbodies recognize surface structures (proteins, carbs, lipids), TCR recognizes short peptide fragments

Question 10

Why do antibodies have stronger affinity than TCR/MHC?

Answer 10

somatic mutation makes it stronger

Question 11

How do the subunits of MHC class I and II differ?

Answer 11

class I: alpha 1,2,3 and beta 2 (to help stabilize) class II: alpha 1 and 2 and beta 1 and 2 (longer peptides that are more specific)

Question 12

What is required for delivery of signal to T cell?

Answer 12

recognition of both MHC and peptide, and CD3 to deliver signal. can also have non self MHC class II which will respond as self MHC presenting foreign antigen

Question 13

What binds CD4?

Answer 13

MHC class II

Question 14

What binds CD8?

Answer 14

MHC class I

Question 15

How do gamma/delta TCR receptors differ from alpha/beta?

Answer 15

they are more similar to NK receptors because they can recognize MHC or antigen by themselves

Question 16

What is the MHC haplotype?

Answer 16

one MHC allele from each parent - expressed codominantly, 3 different genes on each allele (can have 6 different MHC genes) - more homogeneity, more susceptible to disease

Question 17

How can you tell if an allele has an association with a disease?

Answer 17

Relative risk (>1 = association)

Question 18

How is antigen processed by MHC class I?

Answer 18

newly synthesized proteins are ubiquinated, then fragmented into peptides by the proteasome, —> peptides attach to TAP protein in membrane of ER —> complex moves into lumen, peptide is placed in binding groove of MHC class I, then complex goes to cell surface

Question 19

How is antigen processed by MHC class II?

Answer 19

ingested antigen taken into phagolysosome and fragmented by proteases —> peptides move to endosomal compartments and placed in binding groove of MHC class II, displacing CLIP, then complex is carried to surface

Question 20

What is CLIP?

Answer 20

classII associated invariant chain peptide: binds MHC class II groove to prevent the binding of self-peptide fragments

Question 21

What is a super antigen?

Answer 21

high stimulation of T cells with certain v genes (causes toxic shock, sepsis) - no antigen needed - causes bridge between TCR and MHC