The in vitro immune response to a T-independent antigen. I. The effect of macrophages and 2-mercaptoethanol.

The in vitro immune response of murine spleen cells to the T cell-independent antigen, 2,4-dinitrophenyl-beta-alanyl-glycyl-glycyl-N(2-aminoethyl)carbamyl-methylated Ficoll (DAGG-Ficoll), requires the presence of macrophages, or 24-hr culture supernates from peritoneal cells. Complete reconstitution of the response by supernates, however, is dependent on the addition of 2-mercapto-ethanol. Antigen is required to fully express the in vitro immune response, but is not required in cultures of peritoneal cells in order to obtain active supernates. Active supernates can be obtained from allogeneic or syngeneic peritoneal cell cultures. The enhancing effects of 2-mercaptoethanol and peritoneal cell supernates appear to be synergistic nonspecific events directed toward lymphocyte activation and differentiation.