In accordance with the present invention, the immunoregulatory activity of low doses of P4N was investigated. Unlike previously described antitumor drugs, low dose P4N, in doses of about 1 to 10 mg/kg, or at concentrations of about 10 to 100 nM, was surprisingly found to contribute to humoral immunity by raising the titers and activities of autoantibodies against GRP78 and F1F0 ATP synthase on the surface of CT26 cells, and inducing B cell proliferation and differentiation of plasma cells. Methods for inducing B cell proliferation, inducing BAFF stimulated B cell proliferation, and suppressing or inhibition growth of a neoplasia are provided.
