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17 Cards in this Set
- Front
- Back
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What are the two cells that link the innate immune system to the adaptive ammune system?
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1) NK cells
2) γδ T cells |
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What is the difference between γδ T cells and αβ T cells?
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derived from same precursors 1)but do not undergo positive and negative selection
2)limited TCR diversity |
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What are the three things that γδ cells can do after recognizing phosphoantigens ? (P-Antigens)
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1) circulate directly to infected tissues
2) kill infected cell 3) become APC to migrate to 2* lymphoid tissue and precent P-Ag to αβ T cell |
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What γδ cells recognize phosphoantigens?
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Vγ9:Vδ2
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What γδ cells are found in the gut and what do they do?
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get activated by stress cells that produce MIC
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What is the 2 general features of the γδ T cell populations?
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different populations in different tissues
express distinct and limited receptors |
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What is an NK cell?
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no TCR/BCR gene rearrangements
express CD56 and other components in common with T cells |
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What are the types of receptors on the NK cells?
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NKG2D on all cell s
leptin like receptors Ig gene family receptors |
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How do NK cells discriminate healthy cells from infected cells?
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healthy cells have reduced MHC Class I
-MHC class I inhibits NK cell |
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What are two things that can cause an NK cell to become activated?
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1) MIC receptor on infected cell
2) lack of MHC I on infected cell |
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What monitors the HLA expression?
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HLA E which binds the leader sequence of class I molecules and inhibits the NK cell
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What is a KIR?
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killer cell inhibitory receptor that detects loss of expression of an HLA
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What is the missing self hypothesis?
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missing or defective MHC CLass I cause NK cells to not be tolerant to cell and infect own cell
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What are some broad classes of inhibitory receptors for MHC Class I?
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1) CD 94: NK2GA HLA A, B, C
2) KIR2DL - some HLAs 3) LILRB1 - all HLA 1 |
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What is the steps in the development of an NK cell>?
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1) common NK/T cell precursor
2) express CD94:NKG2A then KIR 3) if non of KIRs react with MHC Class I self it is retained 4) if some do react with self MHC Class 1 the expression is turned off of CD94:NKG2A |
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How do CD4 and CD 9 cells protect against mycobacterial infection?
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infected cell expresses CD1 from antigen on class 2
TCR recognizes it |
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What is the CD1d?
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isoform of CD1 that is expressed by epithelial cells
they present this to NKT cells |
