Immunotoxicology studies on lead: effects of exposure on tumor growth and cell-mediated tumor immunity after syngeneic or allogeneic stimulation.
Chronic exposure of C57BL/6 mice to lead acetate in the drinking water enhanced the growth of primary Moloney sarcoma virus (MSV)-induced tumors. Regression of MSV-induced tumors was not prevented by lead exposure and lead-treated animals were more resistant to late sarcoma development following primary tumor regression. The primary cell-mediated cytotoxic response in the spleen or lymph nodes of MSV-tumor bearing mice was significantly augmented by lead exposure. This augmentation appeared to reflect the increased antigenic stimulation resulting from the enhanced primary tumor growth in lead-exposed animals. Using an allogeneic tumor model, under conditions of similar antigenic stimulation, little effect of lead on T cell-mediated cytotoxicity was observed. On the other hand, macrophage phagocytic activity was significantly depressed in lead-exposed mice. Coupled with a decrease in the total number of macrophages recovered from lead-exposed mice, the results suggested significant impairment of macrophages function by lead. The influence of lead-induced macrophage dysfunction on tumor growth is discussed.
D000818:Animals; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D004306:Dose-Response Relationship, Immunologic; D007111:Immunity, Cellular / Q000187:drug effects*; D007854:Lead / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL / Q000276:immunology; D008811:Mice, Inbred DBA / Q000276:immunology; D008979:Moloney murine leukemia virus / Q000276:immunology; D009374:Neoplasms, Experimental / Q000473:pathology; D012509:Sarcoma / Q000473:pathology*; D013601:T-Lymphocytes / Q000276:immunology
D007854:Lead