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19 Cards in this Set
- Front
- Back
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What is clonal selection?
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Ag specific activation results in expansion (clones expressing TCR of same specificity) of rare specific T-cells-> can be Th1 or Th2
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How does activation & expansion affect CD4 & CD8 T-cells?
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CD4 T-cells differentiate into cytokine producing Th1 or Th2 cells. CD8 cytotoxic T-cells become more effective
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What are memory cells?
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Retain TCR specificity but becme quiescent & survive longer. Maybe CD4 Th1, Th2, or Cd8 CTL. Upon re-exposure to Ag they are more rapidly activated-> stronger secondary response.
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What is the fcn of gamma/delta TCR?
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Assoc w/ mucosal tissues & may be involved in immunity in the gut & other mucus membranes
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What are the roles of cytokines produced by T-cells?
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Mediate immune actication, deactivate, inflammation, fever,wound healing, hematopoiesis, & other effector fcn. Specific only to their receptors
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What are the charac of cytokines?
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Small glycoproteins, not antigen specific, receptor specificity, produced by many cell types (mostly b y activated macro & T-cells), act on many cell types (autocrine, paracrine, endocrine)
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What are the Th1 cytokines? General fcn?
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IL-2 & IFN-gamma. Cell mediated immunity
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What is the mech & fcn of IL-2?
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Cell prolif: MHCII+Ag-> bind CD4 TRC on Th1-> IL2-> stim prolif (of Th1, Th2, CTL, NK, & B-cells)
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Wha tis the mech & fcn of IFN-gamma?
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Activation of macros, inc MHC expression on APC, , promotes Th1 differentiation, Inhib Th2 cells
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What are the Th2 cytokines?
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IL4, IL5, & IL10
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What is the fcn of IL4 & 5?
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Favor Ab production: B-cell proliferation & differentiation, Th2 maturation, modulate Ig class switching, & inhibition of Th1 cells & macro activation
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What is the fcn of IL10?
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Deactivation of macros & inhibition of T-cells
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What is the diff b/w Th1 & Th2?
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Th1 favors cell mediated immunity & Th2 favors Ab synthesis
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Describe the IL2 receptor.
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Beta/gamma chains are normally expressed on resting cell-> moderate affinty & low level prolif. w/ immune activation alpha cahin is synthesized-> makes it a high affinity receptor & high prolif via jak/STAT signaling
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What are superantigens?
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Nonspecifically stim T-cells by binding to ext parts of the TCR & MHC-> cause APC & T-cells to interact nonspecifically-> inflammation-> damage host tissue
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What are Th17 cells?
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Produce IL17-> inflammation. Assoc w/ immune mediated pathology
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What cytokines downreg T-cell fcns?
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IL4 (Th1), IL10 (T-cell & macros), IFN-gamma (Th2), & TGF-beta (t-cell)
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What are the inflamm mediators produced by macrophages? Other mediators.
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TNF-alpha, IL1, IL6, IL8. TGF-beta, IL12, &IL-18.
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Fcn of TGF-beta, IL12, & IL18.
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TGF-beta is (-) reg of T-cells & macros, enhances wound healins, & Ig switching (IgA). IL12 & IL18 enhance cytotoxicity. IL12 promotes Th1 maturation. IL18 stim IFN-gamma production
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