MHC

Question 1

What is the main function of T- cells?

Answer 1

protect body against intracellular pathogens + to activate macrophages and B cells

Question 2

True or False: T cells require activation before functioning as effector cells

Answer 2

TRUE

Question 3

How are T cells activated?

Answer 3

through APCs like:

• Dendritic cells
• Macrophages
• B cells

Question 4

How do T cells and APCs interact and become activated?

Answer 4

TCRs on T cells bind to proteins on APCs called MHC molecules

Question 5

What were MHC’s discovered as?

Answer 5

locus of genes responsible for graft rejection

Question 6

What are the 2 possible outcomes to a skin graft from 1 animal to another?

Answer 6

1. the graft will survive and function
2. the graft will be rejected (recognized as foreign by MHC)

Question 7

When will grafts in animals survive? when will they be rejected?

Answer 7

grafts exchanged between INBRED animals survive

grafts exchanged between OUTBRED WILL NOTTTT- rejected

Question 8

What controls graft rejection or survival?

Answer 8

MHC molecules!

Question 9

MHC class 1

Answer 9

has receptors for ENDOgenous antigens found on most NUCLEATED cells

Question 10

MHC class 2

Answer 10

has receptors for EXOgenous antigens found ONLY on APCs

Question 11

MHC class 3

Answer 11

a mixed group of PROTEINS

including complement components of innate immunity

does not participate in antigen presentation!!

Question 12

Which MHC class is highly polymorphic?

Answer 12

MHC class 1 (1a, 1b, 1c) are polymorphic

some MHC class II are polymorphic but not all

Question 13

MHC class 1d

Answer 13

less polymorphic than 1a, 1b, 1c

located outside the MHC, on a dif chromosome

Question 14

How many MHC class 1a in…
Mice:
Rats:
Humans:
Dogs:
Cattle:
Pigs:

Answer 14

Mice: 30
Rats: 60
Humans: 20
Cattle: 14
Pigs: 11

** NOT ALL ARE FUNCTIONAL

Question 15

Which MHC class 1a are functional in humans?

Answer 15

A, B and C are functional

the rest are PSEUDOGENES

Question 16

What does a complete MHC class 2 region contain?

Which ones are found in primates?

Answer 16

3 paired loci

In primates: DPA, DPB, DQA, DQB, DRA, DRB

the A and B are alpha and beta chains

** some are polymorphic

Question 17

Where were MHC molecules originally found?

Answer 17

on WBCs

Question 18

What is the MHC of mice called? Rats?

Answer 18

Mice: H-2

Rats: RT1

Question 19

How are MHC genes expressed?

Answer 19

CO-DOMINANTLY

Question 20

Each individual has ______ MHC I genes

Answer 20

6

A, B, and C

6 dif class I antigens

Question 21

When MHC class genes give more diversity?

Answer 21

MHC class II

because different alpha and beta chains may pair to give distinct products

Question 22

Within a family, what are the chances that 2 of the offspring might share the same MHC type?

Answer 22

1 and 4 chances between siblings

Question 23

What is a haplotype?

Answer 23

a set of MHC alleles present on a chromosome

Question 24

Where are MHC I NOT found?

Answer 24

NOT FOUND on RBCs, gametes, neurons, or trophoblast

Question 25

Which MHC class presents PEPTIDE antigens to CD8+ T lymphocytes

Answer 25

MHC I presents to peptide antigens to CD8+ T cells (cytotoxic t cells)

Question 26

MHC II molecules present to?

Answer 26

CD4+ T lymphocytes (T helper cells)

Question 27

What is required for stable expression of MHC class I?

Answer 27

3 things:

1. alpha cain (a1, a2, a3)
2. B2 microglobulin
3. a bound peptide

Question 28

What makes up the antigen binding groove in MHC 1 molecules?

Answer 28

the extracellular domain makes up the antigen binding groove

Question 29

What is the most variable part of the MHC class I molecule?

Answer 29

the antigen binding groove

Question 30

Where do CD8+ T cells bind to on MHC1 molecules?

Answer 30

binds to the non variable a3 domain

Question 31

What peptides do MHC I molecules accommodate?

Answer 31

peptides of 8-10 AA

Question 32

What makes up the peptide binding groove in MHC II?

Answer 32

alpha 1 and beta 1 and parts of there appropriate chains