Macrophage requirement for the in vitro response to TNP Ficoll: a thymic independent antigen.

The in vitro antibody-forming cell response of mouse spleen cells to the thymic independent synthetic polymer, TNP-Ficoll, was found to require the presence of either macrophages or 2-mercaptoethanol. The TNP-Ficoll response and that to the thymic dependent antigen, sheep erythrocytes, demonstrated the same degree of macrophage dependence. However, macrophage-depleted spleen cells which did not produce plaque-forming cells responded normally to T and B cell mitogens. Comparison of the antibody-forming cell response of macrophage-depleted spleen cells in the presence and absence of 2-mercaptoethanol indicated that either macrophages function 10 to 100 times more efficiently in its presence or that 2-mercaptoethanol partially replaces the function of macrophages.