Quiz 4 part 3

Question 1

MHC genes are in a cluster of closely linked genes on chromosome ____

in humans, this is the….

Answer 1

6
HLA complex (human leukocyte antigen complex)

Question 2

do HLA genes rearrange?

Answer 2

NO
instead, HLA genes exhibit high genetic polymorphism and gene families

Question 3

which is more compact — the class 2 region or the class 1 region? what does this imply?

Answer 3

the class 2 region is more compact than the class 1 region.

this implies that there is a very small probability of crossover for the class 2 region (too close together)

Question 4

how many MHC class 1 isotypes are there?

Answer 4

6

Question 5

what are the 6 class 1 MHC isotypes?

Answer 5

HLA-A
HLA-B
HLA-C
HLA-E
HLA-G
HLA-F

Question 6

Which MHC class 1 isotypes present to CD8+ T cells and are also ligands for NK cells?

Answer 6

HLA-A
HLA-B
HLA-C

Question 7

Which MHC Class 1 isotypes are ONLY NK cell ligands (dont present to T cells)

Answer 7

HLA-E
HLA-G

Question 8

what is the function of HLA-F

Answer 8

HLA-F is a chaperone that transports HLA molecules that have lost peptide

Question 9

in MHC class 1, which locus’s have the greatest number of allotypes (most variation)

Answer 9

HLA-A
HLA-B
HLA-C

Question 10

there are _____ MHC class 2 isotypes
name them

Answer 10

5
HLA-DP
HLA-DQ
HLA-DR
HLA-DM
HLA-DO

Question 11

Which MHC class 2 isotypes present to CD4+ T cells?

Answer 11

HLA-DP
HLA-DQ
HLA-DR

Question 12

Which MHC Class 2 isotypes regulate loading onto other MHC Class 2 molecules?

Answer 12

HLA-DM
HLA-DO

Question 13

which can develop MORE combinations — MHC Class 1 or MHC class 2?

Answer 13

class 2 because it is a DIMER. there is variation in both the alpha chain and beta chain

Question 14

In MHC class 2, which has more diversity – B chains or A chains?

Answer 14

B chains

Question 15

of the MHC class 1 isotypes, which are HIGHLY polymorphic?

Answer 15

HLA-A
HLA-B
HLA-C

Question 16

MHC class 1 diversifies where?

Answer 16

in the binding pocket

Question 17

MHC Class 2 diversifies where?

Answer 17

in the beta chain

Question 18

does MHC class 1 or MHC class 2 only diversify on 1 side of the protein?

Answer 18

class 2 bc it only diversifies in the beta chain

Question 19

what is the optimum size of peptide for MHC class 1

Answer 19

9mer

Question 20

what binds to HLA-A

Answer 20

HIV reverse transcriptase

Question 21

what binds to HLA-B

Answer 21

influenza A nucleoprotein

Question 22

which has a stricter consensus for binding peptides – MHC class 1 or MHC class 2

Answer 22

MHC class 1 is more strict – must be certain size

Question 23

in order to bond to MHC, the T cell has to recognize….

Answer 23

TWO THINGS

The peptide bound to MHC AND
MHC molecule itself

Question 24

why would a t cell receptor ever not be able to recognize an MHC molecule?

Answer 24

bc isotypes exist (ie: HLA-A, HLA-B)

Question 25

“response to an antigen is restricted by the HLA isotype.” what is the term for this?

Answer 25

MHC class restriction

Question 26

in organ transplantation, what does it mean when they’re “finding a match”

Answer 26

they’re trying to match HLA type

Question 27

Why is it an advantage to have multiple MHC genes and genetic polymorphism?

Answer 27

a greater number of pathogen-derived peptides can be presented

Question 28

how are MHC genes inherited?

Answer 28

as a haplotype — from a single parent

Question 29

those with more divergent haplotypes have ____ advantage

similarly, _____zygous have an advantage over ____zygous

Answer 29

greater

heterozygous have an advantage over homozygous

Question 30

Non self MHC molecules are recognized by….

Answer 30

alloreactive T cells