The generation of memory B cells.
Immunization leads to the generation of antibody forming cells (AFC) and secondary B cells which differ substantially from primary B cells. Based on the function of the progeny of enriched precursor cell populations, naive progenitors of memory B cells have been separated from primary AFC precursors. Precursors of memory cells: (1) require multiple antigenic stimulations to generate antibody responses which are prolonged, of increased magnitude, and generated with rapid kinetics; (2) have the capacity to form germinal centers; (3) accumulate somatic mutations; (4) display repertoire similarities with secondary B cells; and (5) can be stimulated with cross-reactive antigens. The primary AFC precursors responded with characteristic primary responses.