THERAPEUTIC EFFECT OF ACTIVATED HUMAN MACROPHAGES ON A HUMAN TUMOR LINE GROWING IN NUDE-MICE

Human peritoneal macrophages were collected from dialysis bags of rena l patients on Continuous Ambulatory Peritoneal Dialysis (CAPD), during an inflammation-free period. The macrophage suspension was cultured i n presence of bacterial lipopolysaccharide (LPS) and phorbol myristate acetate (TPA). The cultured macrophages were tested for therapeutic e ffectiveness against a human tumor-cell line, RC43, implanted subcutan eously in NMRI nude mice. The macrophages were injected around the tum or starting from the 14th day after inoculation, when the tumor growth was already detectable (mean tumor size 7 mm). Three injections of ma crophages on days 14, 18 and 21 induced hemorrhagic patches at the tum or site and almost complete regression of the tumor. One injection of macrophages cultured either in presence of LPS + TPA or of LPS + TPA PGE2 resulted in marked slow-down of the tumor growth. Injection of e ither TNF-alpha (4000 U/mouse) or of PGE2 (150 ng/mouse) given at the site of the palpable small tumor had no effect. Macrophages cultured i n medium or in medium supplied with either TPA, LPS or TPA + LPS, were not effective in nude mice bearing large (16 to 19 mm) tumors. The re sults obtained suggest that activated human macrophages might be thera peutically effective at certain stages of human cancer.