On plasma cell longevity or brevity.

The seemingly long half-life of antibody-producing plasma cells demonstrated by antigen-binding (ELISA type of) assays as compared with the short-livedness of neutralizing and protective antibody-producing plasma cells is explained here by the heterogeneity and multiple crossreactive antibodies detected by ELISA-type assays. While DNP-specific B cell frequencies are about 10(-2) that of virus, serotype-specific B cell frequencies are about 10(-5)-10(-6). Therefore, the seemingly long-lived multiple low-affinity crossreactive antibody-producing plasma cells represent a collective of little if any biological or evolutionary relevance. The plasma cells producing high-affinity protective, neutralizing antibodies (>10(9) M(-1)) in mice are short-lived and therefore continued antibody production is dependent on antigen exposure from within (immune complexes and persistence of infections) or from without by epidemiologically circulating infectious agents, or by revaccinations.