The Polyclonal B Cell Activator Dextran-Sulphate Induces Formation of Colony Stimulating Activity

Abstract

The effect of dextran-sulfate (DS), a polyclonal activator known to stimulate immature murine B[bone marrow-derived]-cells, was assayed in a culture system allowing the growth of myeloid cells. DS induced the production of a myeloid colony stimulating factor (CSF) by cells from spleen and bone marrow. Nylonwool purified mouse spleen cells, enriched for T[thymus-derived]-cells, showed a diminished CSF production in response to DS; CSF production in response to Con A [concanavalin A] was increased. DS induced CSF in spleen and bone marrow cells from nude mice. Removal of macrophages did not affect CSF production. The CSF induced was non-dialysable and no small MW or lipoprotein inhibitors could be demonstrated. DS probably activates cells other than T cells or macrophages (possibly B cells or null cells) to produce a myeloid stem cell stimulating substance. Interactions between lymphoid and myeloid cells may take place during differentiation.