Five Human Mature B Cell Subsets

International audienceSecondary lymphoid organs display B lymphocytes at distinct stages of differentiation as a consequence of ongoing antigenic stimulation. In order to understand the molecular mechanisms which regulate B cell differentiation from virgin B cells to either memory B cells or plasma cells, it is important to isolate B cells at different stages during immune responses in vivo. The working model (Fig. 1) is based on many in vivo experiments on the microenvironments of B cell activations (1–3). It predicts 5 mature B cell stages. Bm1 (mature B cell subsets 1) represents virgin B cells; Bm2 ligand selected B cells (4), Bm3 germinal center centroblasts, Bm4 centrocytes and Bm5 memory B cells. Here we report on the identification and isolation of these B cell subsets from human tonsils