PHGY 313 Lecture Notes - Lecture 14: B Cell, Antigen, Cytosol
24 May 2016
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Phgy 313-lect14: adaptive immunity 1 b cell development and god. Class i for intracellular antigens, class ii for extracellular antigens. Class i: presents cytosolic pathogens and cross-presentation of exogenous antigens, degraded in cytosol (retrotranslocation for exogenous, presented to cd8 t cells, effects: cell death, presenting cell activates cd8 t cell. Class ii: presents intravesicular pathogens and extracellular pathogens/toxins, degraded in endocytic vesicles (low ph, presented to cd4 t cells, effects: activation to kill intravesicular pathogens, activation of b cell (secrete abs) Cross-presentation: dead macrophage is engulfed retrotranslation antigens escape into cytosol of apc can get into normal route of mhc1 (proteososme degradation pathway, apcs have ability to present antigens via mhci and mhcii. Key feature is an immunoglobulin (specific cell-surface receptor) B cells recognize antigens in its native form; cannot recognize ag inside the cell!! Humoral immunity: antibody-mediated clearance of ec pathogens, b cells = enhanced by cd4+ th1 and th2 cell help.
