Immune responses in vitro: VI. Cell interactions in the development of primary IgM, IgG and IgA plaque-forming cell responses in vitro

Abstract

Cell interaction requirements for generation of primary IgM, IgG and IgA responses to heterologous erythrocytes in mouse spleen cell cultures have been investigated. Interactions among antigen, macrophages, “helper” thymus-derived cells and precursors of antibody-producing cells are required and are facilitated by incubation of cultures on a rocking platform. Macrophages are required in the cultures for 48 hr for generation of optimal IgM, IgG and IgA responses. Intact erythrocyte antigen is necessary for 48 hr for development of optimal IgM responses, and for 72 hr for optimal IgG and IgA responses. Precursors of IgM antibody-producing cells appear to be “activated” by 48 hr incubation; precursors of IgG and IgA antibody-producing cells appear to be “activated” by 72 hr. These “activated” precursor cells can subsequently undergo final cycles of cell division and differentiate into mature antibody producing cells when incubated stationary in the presence of very few macrophages and in the absence of intact erythrocyte antigen.