GENERATION OF MEMORY CELLS .2. GENERATION OF B MEMORY CELLS WITH PREFORMED ANTIGEN-ANTIBODY COMPLEXES

Abstract

Mice were immunized with preformed complexes of dinitrophenylated [keyhole limpet] hemocyanin (DNP-KLH) and anti-DNP or anti-KLH antibodies, and subsequently assayed for the generation of B [bone marrow derived] memory (BM) cells. Complexes formed at equivalence or in slight antigen excess were far more effective than antigen alone in generating memory: as little as 100 ng DNP-KLH-anti-DNP produced substantial B cell priming. Anti-carrier and anti-hapten antibodies were equally effective. Complexes generated memory more rapidly than antigen alone, and the adjuvant effect was not simply due to aggregation of the antigen. Optimal priming by complexes required the integrity of the Fc portion of the antibody: F(ab'')2 antibody fragments were less effective. The capacity of complexes to prime BM cells was abrogated by depriving mice of C3 [3rd component of complement]. C3 was also required for localization of complexes within splenic lymphoid follicles; complexes made with F(ab'')2 localized in follicles, but less efficiently than those made with intact antibody. The generation of BM cells probably involves the C3-dependent localization of antigen-antibody complexes within lymphoid follicles. Germinal centers are probably the birthplace of BM cells.