91401 Lecture Notes - Lecture 4: B-Cell Receptor, B Cell, Antibody
Document Summary
The b cell receptor (bcr: comprised of two components: -antibody -ig and ig(cid:533, signalling occurs through ig and ig(cid:533) complex only. 2nd and 3rd signals: t cells activate b cells: t cell provides: 1) cd40 ligation 2) cytokines; activation of b cells by cytokines and cd40 ligation; initiation of germinal center reaction. Fine tuning the immune response: somatic hypermutation and affinity maturation somatic hypermutation. Introduction of point mutations into rearranged vl& vh genes caused by an enzyme called activation-induced (cytidine) deaminase or aid": c region unaffected affinity maturation, b cells with bcrs that have increased antigen affinity are selected for survival. The germinal centre (gc): b cell activation and differentiation: mass of leukocytes that form within the lymph nodes during infection, primarily composed of proliferating (and differentiating) b cells. B cells in the immune response activated b cells travel to the dark zone of the. Gc and proliferate(clonal expansion) fine tuning the bcr: dark zone b cells(called.
