LECTIN-ACTIVATED KILLER-CELLS RAPIDLY INDUCED BY POKEWEED MITOGEN CONJUGATED BEADS AND THEIR IN-VIVO ANTITUMOR EFFECTS

Pokeweed mitogen (PWM) was found to induce rapidly killer cells in human peripheral blood mononuclear cells (PBMC). To avoid PWM contamination in infused lymphocytes, PBMC were stimulated with PWM-coated beads, CMC-1, One hour of stimulation with CMC-1 led to distinct cytotoxic activity in PBMC at 7 h, this reaching a peak at 23 h in the following in vitro culture. The cytotoxic activity and target cell spectrum of CMC-1-activated killer (PWM-AK) cells were similar to those of lymphokine-activated killer (LAK) cells, the precursor cells of PWM-AK cells, as are those of LAK cells which are also low-density lymphocytes. The in vivo antitumor effects of PWM-AK cells were examined in nude mice with peritoneal carcinomatosis generated by the human colon cancer cell line, RPMI 4788. The intraperitoneal (i.p.) injection of PWM-AK cells immediately after stimulation with CMC-1 significantly prolonged the survival of tumor-bearing mice, suggesting that these cells could be of value for clinical cancer therapy.