Major histocompatibility complex

Question 1

what activates the adaptive immune response?

Answer 1

recognition of antigens by T and B cells

Question 2

the primary adaptive response results in what?

Answer 2

a large pool of cells specific to the antigen. These cells are effector cells and memory cells.

Question 3

what happens in the secondary immune response when there is a secondary infection?

Answer 3

the specific memory cells divide rapidly forming effector cells and memory cells. This response is faster and greater

Question 4

what are the antigen receptors on B cells?

Answer 4

form of the immunoglobulin that the particular B cell is programmed to make

Question 5

can antigen receptors on B cells recognise antigens in their normal unprocessed form?

Answer 5

yes

Question 6

what are the antigen receptors on T cells?

Answer 6

T cell receptor that only recognises protein fragments of antigens expressed on our own cell surfaces (processed)

Question 7

can antigen receptors on T cells recognise antigens in their normal unprocessed form?

Answer 7

no
only recognises protein fragments of antigens expressed on our own cell surfaces (processed)

Question 8

2 ways in which antigens that derive from pathogens can end up on the surface of host cells

Answer 8

Pathogens that replicate within host cells
Antigen presenting cells resulted from endocytosis or phagocytosis

Question 9

major histocompatibility complex molecules are also referred to as what?

Answer 9

human leucocyte antigens HLA

Question 10

what do major histocompatibility complex molecules do?

Answer 10

Deliver and present pathogen derived peptides to the cell surface where they can be recognised by T cells

Question 11

T cells recognise a combination of MHC and what?

Answer 11

small antigen peptide fragments

Question 12

are major histocompatibility complex molecules specific?

Answer 12

no
they can present a range of antigen peptides (not specific)

Question 13

where are class 1 MHC molecules expressed?

Answer 13

on all nucleating cells including leucocytes (mark self cells)

Question 14

what do class 1 MHC molecules do?

Answer 14

Present antigen peptides to cytotoxic T cells

Question 15

name 3 class 1 MHC molecules

Answer 15

HLA-A
HLA-B
HLA-C

Question 16

where are class 2 MHC molecules expressed?

Answer 16

only on leucocytes that present antigen to T cells e.g. monocytes

Question 17

what do class 2 MHC molecules do?

Answer 17

Present antigen peptides to helper T cells

Question 18

name 3 class 2 MHC molecules

Answer 18

HLA-DP
HLA-DQ
HLA-DR

Question 19

Any individual only expresses how many forms of each MHC protein?

Answer 19

two forms of each protein
e.g. HLA-A: A23 and A7

One inherited from mother, the other from the father

Question 20

do siblings have the same MHC makeup?

Answer 20

not necessarily

Question 21

explain 2 clinical implications of MHC

Answer 21

1. Tissue grafting e.g. transplants need to have similar MHC makeup
2. Certain HLA types are linked to certain diseases

Question 22

what is the structure of class 1 MHC proteins?

Answer 22

transmembrane alpha chain (3 molecules) covalently bonded to a beta micro-globulin (1 molecule)

Question 23

what is the structure of class 2 MHC proteins?

Answer 23

2 transmembrane chains: a chain and b chain

Question 24

in the structure of MHC proteins The two domains closest to the membrane resemble what?

Answer 24

immunoglobulin domains

Question 25

where does the antigenic peptide bind through H bonding to MHC proteins?

Answer 25

long groove created by the 2 domains furthest from the membrane folding together