Divide and conquer: the importance of cell division in regulating B-cell responses.

Proliferation is an essential characteristic of clonal selection and is required for the expansion of antigen reactive clones leading to the development of antibody of different isotypes and memory cells. New data for mouse and human B cells point to an important role for division in regulating isotype class and in optimizing development of protective immunity by the regulated entry of cells to the plasma cell lineage.