Lec 6 coscey

Lec 6 coscey - increases IL2 secretion 100 fold...

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Lec 6: T cell activation: costimulation and peripheral T cell tolerance What happens to T cells after leave thymus: Naïve T cells: thymus blood spleen; HEV&lymphnodes APCs; activated vs not (start over) T cell circulate in bloodstream, spleen, and lymph nodes APCS: Dendrtic Cells (strongest activators of naïve T cells; B cells weak) -DCs good APC b/c: express both MHC I/II; start in the right place (tissues); end in the right place (lymph node) immature DCs highly efficient at taking up AGs in tissues mature DCs (after maturation & migration) present Ags to T cells in lymph node *express costimulatory molecules (b7) (upregulated after activation of PAMPs) -pick up Ag at sites of infection bring to regionional lymph nodes or spleen -undergo “maturation” to become potent APCs (mature DC: high MHC + B7) CD28 signaling stabilizes IL2 & activates NFkB + AB-1
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Unformatted text preview: increases IL2 secretion 100 fold Costimulatory signal necessary: ensure that tissue specific self peptides do not activate T cells-prevent auto immunity by anergy (prevent T cells from being activated by self Ags not in thymus) (negative selection not perfect) T cell:-Signal 1 & 2 activation; Signal 1 activation-Signal 1 only anergy; signal 1 & 2 none (tolerance) Experiment: signal 2 evidence = Anti HA CD4 Tcell X HA pancreas T cel l {+ DC + HA no response} Naïve T cells require 2 signals to be activated: TCR + CD 28 Anergy= mechanism of ensuring tolerance to peripheral Ag not expressed in thymus Down Regulation of T cell activation: CTLA 4 (blocks costim by competing for B7 molec & sending inhib signals instead of active (CD28)) (puts on the breaks) + Fas (induce apoptosis in activated T cells) (rid unwanted T)...
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This note was uploaded on 04/04/2008 for the course MCB 150 taught by Professor Coscey during the Spring '08 term at Berkeley.

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Lec 6 coscey - increases IL2 secretion 100 fold...

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