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24 Cards in this Set
- Front
- Back
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What do T lymphocytes recognize?
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these only recognize peptide fragments from protein antigens displayed in MHC complexes
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What do MHC's need before they can be displayed on a cells surface?
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these requires a peptide to be bound in their cleft before they are displayed
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What types of things can an MHC molecule bind?
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it can only bind peptides- but they may be self or non self- it doesnt matter
between 8-20 AA's in length a single binding groove can bind many different peptide fragments |
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What makes up Class 1 MHC's?
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these have one variable alpha chain, and one NON variable B2 chain.
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What expresses Class 1 MHC's?
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All nucleated cells
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What do class 1 MHC's bind?
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these bind endogenous peptides, and displays them to CTL's (cytotoxic T cells)
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What do Class 2 MHC's bind?
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these bind Exogenous peptides, and displays them to T helper Cells
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What makes up class 2 MHC's? what expresses them?
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these have both a variable alpha and beta chains.
expressed by APC's |
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What CD binds Class 2 MHC?
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CD4 (helper t cells- mhc 2 is from APCs)
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What CD binds Class 1 MHC?
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CD8 (cytotoxic t- cells, cuz Class 1 is from all nucleated cells)
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What are the 3 genes for class 1 MHCs?
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HLA-A, HLA-B, HLA-C
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What are the 3 genes for class 2 MHCs?
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HLA-Dp, HLA-DQ, HLA-DR
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What chromosomes are MHC's located on?
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chromosome 6
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How many alleles for each MHC do you posses?
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max of 2
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How many types of class 1 MHC's exist?
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6 types
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How many types of class 2 MHC's exist?
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greater than 6, there is some variability in the alpha and beta chains
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How does MHC expression influence response?
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different MHC expressions can influence the repertorie of antigens that T-cells can respond to.
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When does most graft rejection occur?
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when MHC molecules are not properly matched
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What pathway is used to present endogenous antigens? what cells?
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The cytosolic pathway- this is used by MHC 1 cells to present to CD8+ cells.
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What pathway is used to present exogenous antigens? what cells?
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APC's use the endocytotoic pathway to display them in MHC 2, presenting to helper T-cells (CD 4+)
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What is the cytosolic pathway steps?
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Breakdown stuff in cytosol by proteosomes
transport of peptides into RER by TAP transporter. make class 1 MHC in RER, then binds protein. Presentation to CTL (CD8+) |
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What happens in TAP deficiency?
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cells are unable to present to CD8+ cells with their MHC 1's.
reduced response to intracellular microbes and tumor cells |
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What are the steps of the endocytic pathway?
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Lysosomal degradation of endocytosed materal.
synthesis of class 2 MHC + Invariant chain in RER. (this invariant chain fits in the MHC's cleft) Fusion of MHC2+Li to endolysosomes w/ junk in them. FUSION! degradation and removal of Li, then puts the virus junk in the MHC's cleft. Present! |
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What cells can cross present Exogenous antigens in MHC class 1s?
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Dendritic cells can present to CTLs sometimes
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