The effects of antigen dose and adjuvant on the antibody response; amplification of restricted B cell clones.

Anti-DNP antibody production in inbred strain 2 guinea pigs immunized with chemically defined DNP-oligolysines was enhanced by increasing the antigen dose or employing more potent adjuvants. However, the increase in antibody titer was not accompanied by an increase in antibody heterogeneity. Only a small number of anti-DNP antibody-producing B lymphocyte clones were triggered to produce antibody, regardless of the antigen dose or the adjuvant used for immunization or the resulting specific antibody titer. This restricted response occurred despirte the capacity of these animals to synthesize a large number of distinct anti-DNP antibodies and of DNP-oligolysines to bind all these antibodies. These observations are inconsistent with the hypothesis that adjuvant and increased antigen dose enhance antibody titer by recruitment of more diverse precursor B cells (clonal recruitment), but support the hypothesis that adjuvant and increased antigen dose act by enhancing the expansion of a restricted few B lymphocyte clones (clonal expansion).