Normal plasma cell development. Functional V(D)J rearrangements of IgH and IgL genes in pre-B cells in the BM generate an immature B cell that expresses a functional Ig on the cell surface, which then exits the BM as a virgin (mature) B cell, and homes to the secondary lymphoid tissues. Early in the immune response productive interaction with antigen stimulates formation of a lymphoblast which differentiates into a short-lived nonswitched (IgM), or switched (IgG, IgA, IgE, or IgD) PC. Later in the primary response or in a secondary response, the lymphoblast generated by productive interaction with antigen enters a germinal center, where it undergoes somatic hypermuation of its IgH and IgL genes, and antigen selection of cells with high affinity Ig receptor. A germinal center plasmablast that undergoes productive IgH switch recombination typically homes to the BM where it differentiates into a long-lived plasma cell (cf. myeloma cell).