THF-gamma 2, a synthetic thymic hormone, increases effectiveness of combined chemotherapy and immunotherapy against RPC-5 murine plasmacytoma.

The effect of a synthetic thymic hormone, THF-gamma 2, on the anti-tumor activity of spleen cells was studied in mice immunized against the RPC-5 tumor. Following two courses of the THF-gamma 2 treatment, the mean RPC-5 specific cytotoxic response of immune spleen cells was significantly increased when compared to normal cells (P less than 0.001) and to untreated immune spleen cells (P less than 0.04). In addition, THF-gamma 2 treatment improved the competence of immune spleen cells in adoptive immunotherapy (AIT) when performed in combination with chemotherapy by melphalan. Recipients of spleen cells from THF-gamma 2 treated mice showed a 35% increase in survival when compared to AIT with immune cells alone. The results suggest that THF-gamma 2 treatment of donors for AIT might be applicable to cancer therapy in humans.