MICR 360 Lecture 22: MICR 360 8:2
22 Dec 2018
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Document Summary
B cell act: b cell precursor rearranges ig genes, immature b bound to self ag removed from repertoire via -ve selection, mature b migrates to 2ndary lymphoid organs. + bound to foreign ag is act: memory or plasma b cell act. Initiated by bcr binding to ag then ab-ag complex taken into cell. B cell presents ag to helper t act b cell which prolif + diff into plasma or memory b cell. Signal 1: recognition phase: ag binds memb ab . Iga/igb heterodimer induces intra signaling cascade to incr mhc ii + b7, ag-ab internalized by r mediated endocytosis and ag degraded + presented on mhc ii. Ag recognition induces expression of t cell effector molecules which act b cell. Signal 2: b7-cd28 provides necessary costimulatory signal to act th cell. Cd40l on th interacts w cd40 on b cell, cd40 ligation induces nf-kb transcription factor act + expression of cytokine rs on b cell.
