MHC (Exam 1)

Question 1

What is the term for MHC in humans

Answer 1

HLA

human lymphocyte antigens

Question 2

How does MHC play a role in susceptibility to disease and autoimmunity

Answer 2

MHC expressed by an individual partly determines their response to an antigen

Question 3

What is the nomenclature for class 1 HLA

Answer 3

A B C

Question 4

Where will class 1 HLA bind

Answer 4

cytotoxic T cells

Question 5

What is the nomenclature for class 2 HLA

Answer 5

Dp, Dq, Dr

Question 6

Where will class 2 HLA bind

Answer 6

Th cells

Question 7

What chromosomes are all 3 classes of HLA found on

Answer 7

6

Question 8

What class of HLA is nonclassical

Answer 8

class 3

Question 9

What is the gene expression of HLA

Answer 9

codominant

Question 10

What does it mean that the gene expression is codominant

Answer 10

both parental copies expressed together

Question 11

What is the main function of HLA

Answer 11

bind antigenic peptides and present them to T cells

Question 12

What type of antigens do HLA class 1 present and what cell do they present to

Answer 12

endogenous (viral) antigens

Tc cells

Question 13

What type of antigens do HLA class 2 present and what cell do they present to

Answer 13

exogenous (bacterial) antigens

Th cells

Question 14

What will happen if a T cell cannot recognize MHC

Answer 14

will die in the thymus

Question 15

Where is class 1 HLA expressed

Answer 15

every nucleated cell

Question 16

What is class 1 HLA composed of

Answer 16

3 alpha chains and a beta 2 microglobulin

Question 17

What does Class 1 HLA bind

Answer 17

short peptides approximately 8-10 aa in length

Question 18

Where does the antigen bind on class I HLA

Answer 18

A1-A2 domains in its cleft

Question 19

What allows for the highly polymorphic nature of Class 1 HLA

Answer 19

several different alleles

Question 20

What is the function of beta 2 microglobulin in class 1 HLA

Answer 20

required for proper folding

Question 21

Without Beta 2 microglobulin what occurs

Answer 21

no class 1 expression, protein folds over on itself and doesn’t bind to proteins

Question 22

Where are class 2 HLA expressed

Answer 22

antigen presenting cells

Question 23

What are the antigen presenting cells that express class 2 HLA

Answer 23

macrophages
B cells
dendritic cells

Question 24

Do macrophages, B cells, and dendritic cells have class 1 HLA

Answer 24

yes. they are nucleated

Question 25

What are class 2 HLA composed of

Answer 25

an alpha and a beta chain

Question 26

How big are the peptides that bind to class 2 HLA

Answer 26

12-15aa in length

Question 27

Where does antigen bind to class 2 HLA

Answer 27

cleft between alpha 1 and beta 1 chains

Question 28

What alleles are many autoimmune diseases associated with

Answer 28

Dr

Question 29

What is the water affinity for the transmembrane regions of class 1 and 2 HLA

Answer 29

hydrophobic

Question 30

What is antigen processing

Answer 30

process by which peptides get loaded into the HLA and presented to Tc or Th cells

Question 31

What are the two different types of peptides in antigens

Answer 31

endogenous | exogenous

Question 32

Where do endogenous peptides bind

Answer 32

class I HLA

Question 33

Where do exogenous peptides bine

Answer 33

class II HLA

Question 34

What is the function of proteosomes

Answer 34

degrade larger viral proteins into small peptides

Question 35

HLA molecules are in the ER and peptides are in the cytoplasm how do the HLA molecules get loaded

Answer 35

Tap 1 and Tap 2

Question 36

What does TAP stand for

Answer 36

Transporter for Antigen processing

Question 37

What is Tap

Answer 37

molecular tunnel that shuttles peptides from cytoplasm into the ER

Question 38

HLA class 1 antigen are in the ER. How do they make it to the cell surface to present to Tc cells

Answer 38

vesicular transport through the golgi to the surface

Question 39

What type of protein will enter a proteosome

Answer 39

ubiquitinated protein

Question 40

What is essential to keep class I MHC folded properly

Answer 40

chaperones and peptides within the binding groove

Question 41

What two things are required in order for endogenous antigen to be presented

Answer 41

TAP and B2

Question 42

What is the process by which Class 1 MHC will present endogenous antigen

Answer 42

ubiquinated protein sent to proteosome where it will be degraded. Peptides sent through TAP to the ER Peptides replace self antigen on class I MHC. MHC with antigen goes through vesicular transport to be expressed on cell surface

Question 43

What will be seen with TAP deficiency

Answer 43

class 1 MHC deficiency. Susceptible to viral infections

Question 44

What will class 1 MHC present in an infected and healthy individual to cause an immune response

Answer 44

infected: viral antigen healthy: self antigen

Question 45

Why can't class 2 MHC bind peptides in the ER

Answer 45

because it is bound to an invariant chain

Question 46

What is the function of the invariant chain in exogenous antigen processing

Answer 46

prevents the binding of endogenous antigen. Ensures that only class 1 will present endogenous antigens

Question 47

What is the function of HLA-DM

Answer 47

pulls out the clip to free up peptide binding groove for the antigen

Question 48

Describe the process in which class 2 MHC will express exogenous antigen

Answer 48

vesicle with class 2 MHC with its invariant chain will fuse with a phagolysosome Acid chews up most of the invariant chain leaving a CLIP piece in place CLIP has higher affinity for HLA-DM and will bind to HLA-DM leaving a free peptide groove for antigen to bind Fuses to cytoplasmic membrane

Question 49

What class of MHC will APCs express

Answer 49

both class 1 and class 2

Question 50

What is the purpose of cross priming

Answer 50

puts Th and Tc cells in closer proximity allowing Tc cells to become stronger killers due to access of cytokines from Th cells

Question 51

What is the process of cross-priming

Answer 51

dendritic cell will engulf the entire viral infected cell: presents the viral antigen on class 1 MHC and both class 2 MHC. Th recognizes class 2 MHC and releases IL-2 which will act on Tc to make it a better killer

Question 52

On what type of cell will cross priming occur

Answer 52

dendritic cells

Question 53

Which HLA class is more suscpetible to disease

Answer 53

class 2

Question 54

What type of HLA deficiency would be more severe

Answer 54

class 2 as the entire immune response would be lost as you cannot present to Th cells

Question 55

What is the factor that can increase the risk of diseases associated with HLA

Answer 55

inbreeding

Question 56

How does inbreeding affect HLA

Answer 56

reduces heterogeneity in HLA type causing diseases to be more prevalent in these populations

Question 57

What can IFN gamma and TNF increase expression of

Answer 57

class 2 MHC

Question 58

How can IFN gamma and TNF increases expression of class 2 MHC

Answer 58

induces the formation of specific transcription factors that bind to promotors of MHC genes

Question 59

What affect can CMV proteins have on MHC class 1 complex

Answer 59

binds to beta 2 microglobulin preventing the proper assembly of class 1 mhc

Question 60

How might viruses affect the expression of MHC and how is this combatted

Answer 60

mask expression of MHC combatted by NK cells

Question 61

What are the names of MHC class 1

Answer 61

HLA-A HLA-B HLA-C

Question 62

What are the names of MHC class 2

Answer 62

HLA-DP HLA-DQ HLA-DR

Question 63

Where are MHC class 1 found

Answer 63

all nucleated cells

Question 64

Where are MHC class 2 found

Answer 64

antigen presenting cells

Question 65

What recognizes MHC class 1

Answer 65

CD8 cells

Question 66

What recognizes MHC class 2

Answer 66

CD4 cells

Question 67

What peptides are bound to MHC class 1

Answer 67

endogenous

Question 68

What peptides are bound to MHC class 2

Answer 68

exogenous

Question 69

What is the function of MHC class 1

Answer 69

elimination of viral cells by Tc cells

Question 70

What is the function of MHC class 2

Answer 70

elimination of extracellular organisms

Question 71

Does MHC class 1 use an invariant chain

Answer 71

No

Question 72

Does MHC class 2 use an invariant chain

Answer 72

yes

Question 73

Does MHC class 1 use Beta 2 microglobulin TAP

Answer 73

yes

Question 74

Does MHC class 2 use Beta 2 microglobulin TAP

Answer 74

no