The role of recombinant IL-2 and IL-1 in murine B cell differentiation.

This study was undertaken to compare and assess the relative contribution by IL-2 and IL-1 to the maturation into antibody-forming cells (AFC) of normal, mitogen-activated, proliferating B cells. Antigen affinity-enriched B cells were cultured under conditions at which T cells and macrophages are limiting. B cells were induced to proliferate upon stimulation with lipopolysaccharide (LPS), but not to mature into AFC. Maturation into AFC of LPS-stimulated B cells required the presence of recombinant interleukin-2 (IL-2). B cells stimulated with IL-2 alone were neither induced to proliferate nor to differentiate into AFC. Recombinant interleukin-1 (IL-1), in the presence of LPS, failed to induce the B cells to differentiate into AFC. However, IL-1 strongly synergized with IL-2 in further enhancing the AFC response. Although it has been known for some time that IL-2 and IL-1 contribute to the B cell response, our results indicate that these lymphokines primarily control the maturation of proliferating B cells into AFC.