BLG 307 Lecture Notes - Phagocytosis, Antibody, Phagosome
Document Summary
Dendritic cells central function is antigen presentation migrant lifestyle various phenotypes various effects. Intro rapid immune response is important across epithelial barriers difficult because: low ag conc. low tcr affinity/ few tcr"s are specific for ag. ***apc"s reside at interface between host and environment bring antigens to lymphoid organs. Obstacles to recognizing dc importance very rare in tissue. Several varieties, changing phenotypes difficult to purify in vitro vs. in vivo alters patterns of differentiation. Dc structure / life cycle can be found at basal level of epithelium few cell bodies, but numerous projections. Mhcii localized intracellularly: dc progenitors from bone marrow and circulate in bloodstream take residence in non-lymphoid sites, immature dc"s / langerhans cells differentiated for optimal ag uptake. Mhcii extracellular: veiled cells return to lymphoid organs, mature dc"s reside in t-cell areas of lymph nodes and spleen stimulate t-cells. Immature dc"s: specialized for ag capture & processing: lots of vesicular mhcii, macropinocytosis low affinity/high capacity process.
