An endotoxin-induced serum factor that causes necrosis of tumors.
In studying "hemorrhagic necrosis" of tumors produced by endotoxin, it was found that the serum of bacillus Calmette--Guerin (BCG)-infected mice treated with endotoxin contains a substance (tumor necrosis factor; TNF) which mimics the tumor necrotic action of endotoxin itself. TNF-positive serum is as effective as endotoxin itself in causing necrosis of the sarcoma Meth A and other transplanted tumors. A variety of tests indicate that TNF is not residual endotoxin, but a factor released from host cells, probably macrophages, by endotoxin. Corynebacteria and Zymosan, which like BCG induce hyperplasia of the reticulo-endothelial system, can substitute for BCG in priming mice for release of TNF by endotoxin. TNF is toxic in vitro for two neoplastic cell lines; it is not toxic for mouse embryo cultures. We propose that TNF mediates endotoxin-induced tumor necrosis, and that it may be responsible for the suppression of transformed cells by activated macrophages.
D000276:Adjuvants, Immunologic; D000818:Animals; D001500:BCG Vaccine; D004305:Dose-Response Relationship, Drug; D004731:Endotoxins / Q000494:pharmacology / Q000627:therapeutic use*; D007167:Immunotherapy; D007942:Leukemia, Experimental / Q000276:immunology / Q000628:therapy; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D009164:Mycobacterium Infections / Q000276:immunology; D009163:Mycobacterium bovis / Q000276:immunology*; D009336:Necrosis; D012513:Sarcoma, Experimental / Q000276:immunology* / Q000628:therapy; D013997:Time Factors
D000276:Adjuvants, Immunologic; D001500:BCG Vaccine; D004731:Endotoxins