B cell activation in a secondary lymphoid follicle

BAFF-R: B cell-activating factor of the tumor necrosis factor family receptor; BCR: B cell receptor; CB: centroblast B cell; CC: centrocyte B cell; CD: cluster of differentiation; CD40L: CD40 ligand; CSR: class-switch recombination; CXCL13: chemokine cytosine-X-cytosine motif chemokine ligand 13; CXCR5: chemokine receptor cysteine-X-cysteine motif receptor 5; FDC: follicular dendritic cell; ICOS: inducible T cell costimulator; ICOSL: inducible T cell costimulator ligand; IL-21: interleukin-21; IL-21R: interleukin-21 receptor; MHC II: major histocompatibility complex II; SHM: somatic hypermutation; SLAM: signaling lymphocyte activation molecule; TCR: T cell receptor; Tfh: T follicular helper.