The generation of memory cells. V. Preferential priming of IgG1 B memory cells by immunization with antigen IgG2 antibody complexes.

We have studied the effects of priming mice with complexes of dinitrophenylated (DNP)-haemocyanin (KLH) and anti-DNP antibody on the generation of DNP-specific B memory cells producing IgG1 or IgG2 antibodies. Immunization with DNP-KLH alone (with or without adjuvant) induced roughly equal proportions of IgG1 and IgG2 memory cells, at all times after priming. In sharp contrast, immunization with DNP-KLH polyclonal anti-DNP antibody complexes induced 80%--90% IgG1 memory cells, especially early after priming. Further studies using conventional and hybridoma anti-DNP antibodies showed that this effect was induced by complexes containing IgG2 antibodies, and not by those made with IgG1 antibodies. The latter induced roughly equal proportions of IgG1 and IgG2 memory cells. Priming for preferential IgG1 memory was not induced by complexes made with (Fab')2 fragments of IgG2a antibody, nor was it seen in T cell-deprived mice immunized with antigen IgG2a complexes. The mechanisms involved in this phenomenon are unknown, but presumably reflect the well established capacity of immune complexes to concentrate in lymphoid follicles, which seem to be sites of B memory-cell generation.