Cross-stimulation of monoclonal antibodies in anamnestic responses.

Immunization of BALB/c mice with Group A streptococcal vaccines leads to the induction of high levels of monoclonal antibody populations. Subsequent immunization of these mice with Group A-variant streptococcal vaccines induces a significant level of monoclonal antibody of A-variant antigen specificity revealed by labeled group A-variant polysaccharide. During these course Av and Av' immunizations, the monoclonal Group A-specific antibodies were also restimulated to levels usually higher than the variant-specific antibodies. With two exceptions, these homogeneous antibody populations were not cross-reactive in vitro with the related antigen. Such cross-stimulation of monoclonal antibodies was interpreted as a function of particular membrane properties of the Ig receptor-bearing memory cells which, for restimulation, would only require the structurally closely related antigen which serves as a backbone to the original antigen, and not necessarily the exact fit of the homologous immunodominant group.