Studies on B-cell memory. IV. Effects of lipopolysaccharide on primary and secondary antibody responses to T-independent type-2 (TI-2) antigen in mice.

Effects of LPS on primary and secondary antibody responses to typical TI-2 antigens were investigated in mice. Simultaneous injection of LPS with a TI-2 antigen showed only little adjuvant effect on the following primary antibody response to the antigen. In contrast, either a single or multiple injections of LPS, prior to the immunization with a TI-2 antigen, significantly augmented the following primary antibody response to the antigen. LPS, however, inhibited the development of B-cell memory to a TI-2 antigen when administered together with the antigen. Moreover, an injection of LPS in mice, which had strong IgM and IgG B-cell memories to a TI-2 antigen, caused disappearance or profound reduction of the memories. The results suggest that LPS produced by gram-negative bacteria exerts inhibitory effects on the development and continuation of B-cell memory to bacterial infections.