Subpopulations of mouse spleen lymphocytes. I. Dissociation between the reactivities to different "non-specific" mitogens.

Fractionation on bovine serum albumin (BSA) continuous gradients or passage through anti-immunoglobulin-coated (RaMIg) columns were used to separate the populations of mouse spleen cells which react against mitogens specific for B ( lipopolysaccharide (LPS)) or T cells (concanavalin A (Con A) or phytohaemagglutinin (PHA)). These manipulations could distinguish the subsets of T cells reacting toward PHA or Con A. Fractionation on BSA gradients yielded two fractions, one light and the other dense, with high reactivity toward Con A; the cells reactive to LPS were concentrated in a fraction located between these two fractions, whereas the response to PHA was distributed irregularly throughout the gradient, without any apparent correlation with the response against Con A. Lymphocytes eluted from the RaMIg columns did not react to LPS, showed increased reactivity to PHA and decreased response to Con A, as compared to the unfractionated cells.