Mouse B cells do not proliferate in human interleukin 2

By pre-activation with a monoclonal anti-IgM antibody coupled to Sepharose, either in the absence or presence of low doses of lipopolysaccharide, mouse B cell populations were rendered responsive to recombinant DNA derived human interleukin 2 (IL 2). However, if the B cell populations were subjected to separation based on their buoyant density before pre-activation, only low but not high buoyant density cells became responsive to IL 2. Both cell populations subsequent to anti-IgM pre-activation were equally responsive to a Sephadex G-100 fraction of supernatants from rat spleen cells stimulated with concanavalin A. Furthermore, the differences in the IL 2 titration curves on T and B cell populations indicate that only a subpopulation of cells are responding to IL 2 in the B cell populations. In B cell populations that did respond to IL 2, a population of Thy-1.2-positive cells appeared. The proportion of IL 2-responsive T cells needed to give a significant signal when admixed with nonresponding B cell populations was quantitated to be less than 1%.