Ontogeny of the antibody-forming cell line in mice. III. The generation of mature anti-sheep red blood cell-specific B cells is antigen-dependent.

A role for antigen in the generation of fully mature splenic type B cells has been shown. In adoptive transfer experiments, cells from bone marrow or fetal liver required a longer period to give an anti-sheep red blood cell plaque-forming cell (PFC) response than those from spleen. This delay was not overcome by allowing the cells a 7-day sojourn in the irradiated host before antigen challenge. A two-stage protocol was designed in which the in vivo generation of fully mature cells could be measured by their ability to give PFC in lipopolysaccharide-stimulated cultures in vitro. These experiments showed that a critical factor which influences the final differentiation of bone marrow or fetal liver cells into mature, splenic type B cells is exposure to antigen.