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24 Cards in this Set
- Front
- Back
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What are the most polymorphic genes in the genome?
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MHC
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Size of peptide binding cleft for Class I MHC molecule
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8-11 amino acid residues
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Size of peptide binding cleft for Class II MHC molecule
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10-30 amino acid residues
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Components of fully assembled class I MHC molecule
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alpha chain, beta2 chain, bound antigenic peptide (stable expression requires all 3 components)
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True or false: multiple peptides compete with one another for binding to the single binding site of each MHC molecule.
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True
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How many different MHC molecules can an individual have?
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Up to 26 (6 class I and 10-20 class II)
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True or false: The association of antigenic peptides and MHC molecules has a very fast off-rate.
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False: slow off-rate
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True or false: MHC molecules can discriminate between self and foreign antigens.
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False: MHC molecules display both self and foreign antigens. T-cells survey these displayed peptides for the presence of foreign antigen.
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What is the theory behind why there is so much polymorphism in the MHC genes?
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The presence of multiple MHC alleles provides an evolutionary advantage for the entire population.
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Where is TAP gene located?
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Chromosome 6, within class II MHC.
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Function of TAP
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Transporter protein that moves cytosolic peptides into the ER, where the peptides can associate with Class I MHC molecules.
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Location of proteasome gene
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chromosome 6, within class II MHC cluster
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Function of proteasome
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degrade cytosolic proteins into peptides that are subsequently presented by class I MHC molecules
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Location of HLA-DM genes
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chromosome 6, within class II MHC cluster (HLA-DMA and HLA-DMB)
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Function of HLA-DM protein
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peptide binding to class II MHC molecules
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Proteins encoded in class III region of MHC
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TNF, LT-alpha, LT-beta, heat shock proteins
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Location of HLA-G gene
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Class I region of MHC
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Function of HLA-G protein
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Class IB; antigen recognition by NK cells
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Location of HLA-H gene
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Class I region of MHC
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Function of HLA-H protein
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Class IB; iron metabolism; no known immune system function
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Gene conversion
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A portion of the sequence of one gene is replaced with a portion of another gene without a reciporcal recombination event; responsible for the extraordinary polymorphism of MHC molecules
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5 cytokines that increase Class I MHC expression
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IFN-alpha, INF-beta, IFN-gamma, TNF, LT
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Principal cytokine involved in stimulating class II MHC expression
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IFN-gamma
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CIITA
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class II transcription activator; synthesized in response to IFN-gamma
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