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12 Cards in this Set
- Front
- Back
What are histocompatibility antigens?
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The antigens primarily responsible for the rejection of tissues, cells, or organs from genetically dissimilar donors. MAJOR Histocompatability Complex is a group of genes on chrom 6 and will encode surface proteins that are critical for the immune response and the body's ability to discriminate self from non self.
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What is the role of MHC genes?
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To present peptide to T-cells
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Describe Class I MHC molecules
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-A,B,C genes (proteins)
-On ALL nucleated cells -Dimer, MHC heavy chain -beta 2 microglobulin -binds 7-15 aa |
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How do these MHC molecules work?
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There's a binding pocket ontop of the cell, and in that pocket is a little peptide. The T-cell that comes in contact with this cell sees the peptide in the binding pocket of the MHC molecule and recognizes it. (T cell only recognizes a few peptides from that virus)
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Describe Class II MHC molecules
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-DP, DQ, DR genes (alpha and beta for each one)
-on Antigen Presenting Cells (dendritic cells, B lymphocytes, macrophages) -more important in the initial activation of T cells |
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What is an allele
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one of several alternate forms of a gene at a single locus that controls a particular characteristic; each MHC gene has several alleles in the human population
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How do we inherit these HLA genes?
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from mother and father, on chromosome 6. Get a whole block of these genes from each of your parents.
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What is the Beta-2 Microglobulin?
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on MHC Class I
-involved in transport of MHC+ peptide to the surface and stable expression |
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What do CD8+ T cells recognize?
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These are the killer cells. They recognize a foreign peptide on a surface of a cell in a Class I MHC molecule ( on all nucleated cells). This makes sense since we want the killer cell to be able to recognize any virus-infected cell.
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What do CD4+ T cells recognize?
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These are the regulator cells. They will recognize a peptide on the surface of a cell with Class II MHC molecules (on APC cells, on lymphoid tissues). Once activated, it can help out CD8+
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What is Relative Risk?
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the chance an individual with the disease-associated HLA antigen has of developing the disease compared with an individual who lacks the antigen. ie if you have a certain HLA allele, you're more likely to have a certain disease. The higher the RR, the most likely you have that disease if you have that allele.
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What is the rold of MHC in Organ/tissue graft rejection?
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recognition of non-self MHC by recipient T-cells is the major initiating factor for allograft rejection. To minimize rejection, donor and recipient are matched for MHC genes. Less mismatches, greater chance of survival.
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