Tumor promoting agent induces lymphocyte mitogenic factor.

Human peripheral mononuclear cells treated with tumor promoting agent, 12-O-tetradecanoyl phorbol 13-acetate (TPA), released a soluble lymphocyte mitogenic factor (MF). The MF was found to be a protein capable of eliciting a proliferative response in normal human lymphocytes within 40-46 hours. The MF was detected in the culture supernatant fluid as early as 12 hours after TPA treatment and reached maximum at 48 hours. The biochemical characterization of MF is under active investigation.