Role of antigen-binding B lymphocytes in the formation of antigen-dependent nonspecific immunoglobulin-forming cells.

A role for antigen-binding B cells in the induction of antigen-dependent B cells producing antigen-nonspecific immunoglobulins (nIFC) is analyzed. An in vitro immune response system was used; sheep red blood cells were employed as the antigen. It is shown that cocultivation of antigen-binding B cells with resting naive splenocytes in the presence of homologous antigen resulted not only in an increase in the number of antibody-forming cells (AFC), but also in a sharp increase in nIFC. Cocultivation of G0 splenocytes with primed B cells depleted for antigen-binding cells did not affect AFC induction, and only slightly augmented the number of nIFC. It is suggested that some of the nIFC appearing after antigenic stimulation arise from resting B lymphocytes in response (direct or indirect) to nonspecific B-cell factor(s).