2-Mercaptoethanol-dependent lipopolysaccharide-responsive B cells in nylon-wool-fractionated spleen cell preparations.

The ability of lipopolysaccharide (LPS) to influence lymphocyte mitogen responsiveness to 2-mercaptoethanol (2-ME) was investigated. 2-ME was mitogenic for splenocytes only when fetal bovine serum lots containing elevated endotoxin levels were used to supplement (5%) the culture medium. 2-ME did not stimulate mitosis of nylon-wool-fractionated splenocytes (NWSC); however, 2-ME induced significant proliferation in the NWSC cell preparations when endotoxin-deficient culture medium was supplemented with doses of LPS which alone did not stimulate significant proliferation. The sIg+ and Thy-1-/Lyt-1- fractions of NWSC, which represented less than 5% of the cells in the 'T-cell preparations', were almost completely dependent on 2-ME for proliferation in response to LPS stimulation. These data indicate that nylon-wool-fractionated preparations contain splenic B cells that incorporate significant amounts of [3H]thymidine when stimulated with LPS and 2-ME.