HLA and antigen presenting

Question 1

MHC 1 has how many transmembrane domains

Answer 1

1 domain that is split into 3 heavy chains

Question 2

MHC2 has how many transmembrane domains

Answer 2

2 domains that are equally split into chains

Question 3

what does MHC 1 also have

Answer 3

b2 micro-globulin

Question 4

what protein makes the peptide binding groove

Answer 4

alpha helices

Question 5

what supports the peptide binding groove

Answer 5

beta helices

Question 6

which MHC complex can fit longer peptides in their groove

Answer 6

MHC2

Question 7

the MHC complex are closely

Answer 7

linked genes on chromosome 6

Question 8

what are the genes that make up the MHC called

Answer 8

HLA

Question 9

class 1 and 2…

Answer 9

encode in separate regions

Question 10

the genes of MHC are

Answer 10

stable and do not undergo somatic changes

Question 11

How many HLA class 1 genes are expressed and what are they

Answer 11

6 expressed
HLA-A,B,C, E,F,G,

Question 12

what are the classical class 1 regions

Answer 12

HLA-A
HLA-B
HLA-C

Question 13

MHC 1 classical class 1 are on

Answer 13

all nucleated cells

Question 14

what are the classical class 1 involved in

Answer 14

fighting infections, tumors and rejecting transplanted tissue

Question 15

what is the job of classical class 1 genes

Answer 15

present cytosolic peptides to CD8 + T CELLS

Question 16

How many HLA class 2 molecules are there

Answer 16

5

Question 17

how many MHC2 classical class 2 molecules and what are they

Answer 17

3
- HLA-DR
-HLA-DQ
- HLA-DP

Question 18

what is the job of HLA classical class 2 molecules

Answer 18

present peptides from extracellular microorganisms to CD4+T cells which activate adaptive immune system

Question 19

what makes HLA 2 classical class different from 1

Answer 19

primarily expressed on antigen presenting cells ( dendritic cells, b cells)

Question 20

HLA is inherited as

Answer 20

haplotypes

Question 21

entire… from each parent

Answer 21

MHC

Question 22

….is rare and no…

Answer 22

recombination
gene rearrangement

Question 23

what type of expression is the HLA

Answer 23

co-dominant expression

Question 24

MHC is highly

Answer 24

polymorphic

Question 25

why is MHC polymorphic

Answer 25

amino acids substitutions in domains that bind peptide and interact with TCR

Question 26

in what domains are the substitutions mainly occuring for class 1

Answer 26

Alpha one and two domains ( they are polymorphic)

Question 27

in what domains are the substitutions mainly occuring for class 2 DR

Answer 27

only Beta one is polymorphic

Question 28

one benefit from MHC polymorphism

Answer 28

-more peptides allow stronger immunity to more pathogens

Question 29

what are three non benefits of MHC polymorphism

Answer 29

-rejection of transplanted organs - disease association - drug hypersensitivity

Question 30

What are the steps of class 1 peptide loading ( look at graph)

Answer 30

-the class 1 heavy chain is stabalized by calnexin until B2 binds -calnexin is released and class 1 heavy chain and beta 2 form peptide loading complex with TAP etc is the peptide binding groove is held open - a peptide is delivered by tap ( goes through proteasome and makes it into the peptide binding groove) of the class 1 heavy chain forming a mature MHC class 1 molecule - class 1 molecule dissociates from peptide-loading complex and is released from the Endoplasmic reticulum

Question 31

what are the steps for MHC class 2 peptide loading

Answer 31

- antigen is taking up and is in a endosome - acidification activates the proteases that degrage the antigen into peptide fragments - the vesicles with the peptide fuse with a vessicle that has the MHC class 2 molecule - once in the ER it binds to the Invarient chain which prevents the peptide binding groove to be open -the invarient chain is cleaved and the CLIP fragment remains in the groove - HLA-DM then enters and facilitated the release of CLIP allowing peptides to bind

Question 32

what part of the cells are both MHC complexes brought into

Answer 32

endoreticulum

Question 33

what makes up the TCR complex

Answer 33

- t cell receptor and CD3 proteins

Question 34

what are the function of CD3 proteins

Answer 34

transmit signals to cell after TCR binds peptide/MHC

Question 35

TCR makes...

Answer 35

contact with both peptide and MHC

Question 36

TCR recognizes

Answer 36

amino acid side chain

Question 37

what two things add specificity

Answer 37

CD4 and CD8

Question 38

CD4 binds to

Answer 38

beta 2 domain and releases interleukins to drive immune response

Question 39

CD8 binds to

Answer 39

alpha 3 domain and lyse the infected or transformed cell