title: Down-regulation of interleukin 1 production by macrophages of sarcoma-bearing mice.
abstract: Peritoneal macrophages from mice bearing a transplantable methylcholanthrene-induced sarcoma produced progressively less IL 1 as tumor burden increased. The loss of activity was not explained by the production of any inhibitor of the mouse thymocyte comitogen bioassay. Immune precipitation with a polyclonal antibody confirmed the decline in IL 1 appearance. Although tumor-bearing animals lost approximately 17% of their carcass mass, the reduced production of IL 1 was not satisfactorily explained by coexistent malnutrition, since similarly depleted non-tumor-bearing mice were capable of producing IL 1. In addition to an altered IL 1 production by macrophages of tumor-bearing mice, SDS-polyacrylamide gel electrophoresis and autoradiography revealed that the pattern of secretory protein synthesis from LPS-stimulated and unstimulated peritoneal macrophages differed between tumor-bearing and control animals. Administration of LPS to tumor-bearing mice early after tumor transplantation resulted in reduced tumor growth and prevented the down-regulation of in vitro IL 1 production by peritoneal macrophages. These findings demonstrate a specific defect in IL 1 production associated with increasing tumor burden. Further studies are required to determine whether this defect in IL 1 synthesis contributes to the increased tumor growth.
mesh_terms: D000818:Animals; D001835:Body Weight; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D007375:Interleukin-1 / Q000096:biosynthesis* / Q000172:deficiency / Q000235:genetics; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D009368:Neoplasm Transplantation; D012513:Sarcoma, Experimental / Q000378:metabolism* / Q000473:pathology
chemical_list: D007375:Interleukin-1; D008070:Lipopolysaccharides