Abstract
Suramin, a drug against trypanosomiasis and onchocerciasis, stimulates in vitro mouse B-lymphocytes to transform into blastcells, to incorporate3H-thymidine and to go into mitosis. Thymus cells (hydro-cortisone-sensitive or resistant) do not respond whereas cells from homozygous nude mice are stimulated. The large majority of the blastcells have surface immunoglobulins, and the proportion of c cells with intracellular immunoglobulin increases during the course of the cultures.