Phagocytic and natural killer cytotoxic responses of murine transitional cell carcinoma to postsurgical immunochemotherapy

Postsurgical immunochemotherapy with Corynebacterium parvum (CP) and cis-diamminedichloroplatinum (II) (CDDP) was evaluated in mice with transitional cell carcinoma (MBT-2). C3H/He mice were transplanted subcutaneously in the hind limb with 5 x 10⁵ tumor cells. Ten to 14 days later when the tumor reached a diameter of five to seven mm., it was surgically removed. Mice were then randomized into four groups to receive a total of three treatments on days 1, 3 and 5 after surgery: 1) saline (control group); 2) CP, 250 μg. into the surgical site; 3) CDDP, 5 μg./gm. body weight intraperitoneally; and 4) combined CP and CDDP. Recurrence of tumor occurred in 70%, 52%, 55% and 28% of mice receiving surgery only, CP, CDDP, and combined CP and CDDP respectively. In the second part of the experiment, phagocytic activity using chemiluminescence assay and natural killer (NK) activity using chromium-51 release assay were determined with cells from the peritoneum, spleen and inguinal lymph nodes. CP or CDDP alone enhanced the phagocytic and NK activity. The most significant enhancement was obtained with cells from the inguinal lymph nodes of mice receiving combined CP and CDDP, the group with the lowest tumor recurrence. These results suggest that combination of CP and CDDP may be useful in control of postsurgical recurrence of bladder cancer.