Carrageenan stimulates populations of mouse “B” cells mostly nonoverlapping with those stimulated with LPS or dextran sulfate

Mouse spleen cells have been stimulated in vitro with three different mitogens: lipopolysaccharide, dextran sulfate, and ι-carrageenan. After removal of the blast cells by either filtration through Sephadex G-10, uv illumination following the incorporation of bromodeoxyuridine, or separation by density gradient centrifugation, the remaining cells are only poorly restimulated with the mitogen used in the first culture, yet they are significantly restimulated with the other two mitogens. Furthermore, in irradiated, bone-marrow-reconstituted mice, the kinetics of reappearance of a mitogenic reactivity are different for the three mitogens tested. Thus, LPS, dextran sulfate, and carrageenan seem to act on subpopulations of “B” cells which are mostly nonoverlapping.