Mhc Molecules & Antigen Presentation

Front 1

When is the adaptive immune response initiated?

Back 1

When lymphocytes recognize antigens

Front 2

What must APCs do to activate T-cells?

Back 2

break down antigen to peptides and present it on MHC molecules in SECONDARY LYMPHOID TISSUES

Front 3

What is the function of MHC molecules? Where are they expressed?

Back 3

Present PEPTIDE fragments to helper and cytotoxic T cells. expressed on all somatic cells

Front 4

T\F MHC molecules are constituitively located on cell surfaces?

Back 4

false, MHC molecules must be bound to an antigen before they are on the cell surface

Front 5

What do T cell Receptors bind to?

Back 5

MHC+antigen

Front 6

T\F MHC molecule binding groove are specific for a single peptide fragment?

Back 6

False

Front 7

Compare the structures of MHCI vs MHCII molecules?

Back 7

MHCI=One variable α chain and one NON-variable β chain

MHCII=Variable α and β chains

Front 8

Compare the cells that expresss the different MHC molecules?

Back 8

All nucleated cells=MHCI

APC's=MHC II

Front 9

What are the different cells that MHC's are used to present to and where are the peptides take up from?

Back 9

MHCI= express ENDOGENOUS peptides to Cytotoxic T lymphocytes

MHCII=take up EXOGENOUS peptides and display them to T helper cells

Front 10

What CD marker can bind to MHC II molecules?

Back 10

CD4(T helper cells)

Front 11

What is a function of the MHCI cells?

Back 11

All nucleated cells use these to express endogenous peptide to CTL when they have iINTRACELLULAR PATHOGENS or TUMOR PEPTIDES

Front 12

What CD marker can MHC II cells bind to?

Back 12

CD8=cytotoxic T lymphocyte

Front 13

Which chromosome is the MHC allele located on?

Back 13

Chromosome 6

Front 14

What are the 3 genes in each MHC class?

Back 14

MHCI:HLA-A\B\C
MHCII: HLA-DP\DQ\DR

Front 15

Why is the MHC locus considered to be polymorphic and polygenic?

Back 15

Polygenic because each class contains three genes

Polymorphic because the genes all have multiple alleles

Front 16

What is a MHC haplotype?

Back 16

it is the specific combonation of alleles for the genes present on the chromosome 6 MHC locus

Front 17

Why are MHC molecules usually inherited as a set?

Back 17

Because recombination at the MHC locus is really low

Front 18

Why do MHC I molecules have 6 different molecules?

Back 18

Because each person has 2 alleles for each of the 3 genes

Front 19

Why do MHC II molecules have more than 6 different molecules?

Back 19

Because each MHC molecule can have variable α and β units

Front 20

What types of MHCs do APC's express?

Back 20

Both MHCI and MHCII

Front 21

What types of MHC's do all nucleated cells express/?

Back 21

All MHC I coding regions

Front 22

Why do individuals have such variety of antigens their T cells can respond to?

Back 22

Because of variation in MHC alleles and because of the non-specificity of the peptide binding of MHC's

Front 23

Which MHC gene gives people susceptibility to malaria?

Back 23

HLA-B53

Front 24

What determines if Grafts are rejected by the immune system?

Back 24

When MHC molecules in individual don't match donor tissue: Histocompatible vs histoincompatible

Front 25

What are the 2 pathways for presentation?

Back 25

MHCI=cytosolic
and MHCII molecules=endocytic pathway

Front 26

What are the steps of the cytosolic pathway?

Back 26

Antigen is broken down in CYTOSOL by proteosome and peptides are tranported to RER by TAP transporter. MHCI made in RER and associated with peptide then transported to the membrane

Front 27

What is the functional deficiency of a person with TAP deficiency?

Back 27

Cytotoxic T cell function is dimished because no MHCI presentation, causing decreased cell mediated immune response

Front 28

What are the steps of MHC II presentation?

Back 28

Lysosomal degredation of antigen
Synthesis of MHCII+invariant chain(Ii) in RER
Transport of MHCII+invariant to endolysome
Removal and degredation of Ii
Loading of exogenous peptide by DM
Transport to membrane

Front 29

What is cross presentation of exogenous antigen? What does this allow?

Back 29

usually presented by MHCII but APCs can present exogenous with MHCI. Allows cells to capture viruses or infected cells and generate CTLs to those infected cells

Front 30

What types of MHC's do all nucleated cells express/?

Back 30

All MHC I coding regions

Front 31

Why do individuals have such variety of antigens their T cells can respond to?

Back 31

Because of variation in MHC alleles and because of the non-specificity of the peptide binding of MHC's

Front 32

Which MHC gene gives people susceptibility to malaria?

Back 32

HLA-B53

Front 33

What determines if Grafts are rejected by the immune system?

Back 33

When MHC molecules in individual don't match donor tissue: Histocompatible vs histoincompatible

Front 34

What are the 2 pathways for presentation?

Back 34

MHCI=cytosolic
and MHCII molecules=endocytic pathway

Front 35

What types of MHC's do all nucleated cells express/?

Back 35

All MHC I coding regions

Front 36

Why do individuals have such variety of antigens their T cells can respond to?

Back 36

Because of variation in MHC alleles and because of the non-specificity of the peptide binding of MHC's

Front 37

Which MHC gene gives people susceptibility to malaria?

Back 37

HLA-B53

Front 38

What determines if Grafts are rejected by the immune system?

Back 38

When MHC molecules in individual don't match donor tissue: Histocompatible vs histoincompatible

Front 39

What are the 2 pathways for presentation?

Back 39

MHCI=cytosolic
and MHCII molecules=endocytic pathway

Front 40

What are the steps of the cytosolic pathway?

Back 40

Antigen is broken down in CYTOSOL by proteosome and peptides are tranported to RER by TAP transporter. MHCI made in RER and associated with peptide then transported to the membrane

Front 41

What is the functional deficiency of a person with TAP deficiency?

Back 41

Cytotoxic T cell function is dimished because no MHCI presentation, causing decreased cell mediated immune response

Front 42

What are the steps of MHC II presentation?

Back 42

Lysosomal degredation of antigen
Synthesis of MHCII+invariant chain(Ii) in RER
Transport of MHCII+invariant to endolysome
Removal and degredation of Ii
Loading of exogenous peptide by DM
Transport to membrane

Front 43

What is cross presentation of exogenous antigen? What does this allow?

Back 43

usually presented by MHCII but APCs can present exogenous with MHCI. Allows cells to capture viruses or infected cells and generate CTLs to those infected cells