Effects of BCG and Cyclophosphamide on the Spontaneous and Antibody-Dependent Cell-Mediated Cytotoxicity of Peritoneal and Spleen Lymphocytes of ACI/N Rats

: The effects of BCG and cyclophosphamide on the antibody-dependent cell-mediated cytotoxicity (ADCC) and natural killer (NK) activity of spleen and peritoneal lymphocytes were serially examined after treatment. The changes of ADCC and NK activity were different in peritoneal and spleen lymphocytes according to the route and timing of administration. The decrease of NK activity induced by cyclophosphamide is not marked, and the degree of decrease depends on the timing of cyclophosphamide administration. The ADCC and NK activity of peritoneal lymphocytes after intravenous BCG administration were elevated 7 days after treatment, but the NK activity of spleen lymphocytes was decreased. On the other hand, the NK activities of peritoneal and spleen lymphocytes were elevated in rats given intraperitoneal BCG. Spleen lymphocytes and peritoneal lymphocytes from rats given intravenous BCG suppressed tumor growth in the Winn test during the early tumor-bearing stage. The spleen lymphocytes with low NK activity in rats given intravenous BCG strongly suppressed the NK activity of normal spleen lymphocytes.