B and T lymphocyte colony formation in agar: 2-Mercaptoethanol-activated albumin can substitute for 2-mercaptoethanol

The effect of 2-mercaptoethanol (2-ME) activated albumin (MaSF) on mouse B lymphocyte colony (BLC) formation and on human phytohemagglutinin (PHA)-induced T lymphocyte colony formation (TLC) formation in semisolid agar medium was studied. MaSF was found to stimulate colony formation comparable to the stimulation obtained with 2-ME. MaSF could not substitute for serum in any of the agar culture systems. BLC formation stimulated by MaSF was obtained with spleen cells from athymic nude mice and nonadherent spleen and lymph node cells of normal mice suggesting a direct effect of MaSF on the colony-forming B cell without interference with T cells or macrophages. The results suggest that the stimulatory effect of 2-ME in the BLC and TLC agar systems is mediated by 2-ME-activated albumin present in the culture medium.