Tumor necrosis factor and its induction by bacterial endotoxins.

Using suitable immunomodulators (Corynebacterium parvum vaccine, Zymosan or muramyl dipeptide), lipopolysaccharides (LPS) from various members of the family Enterobacteriaceae (Escherichia, Salmonella, Serratia, Shigella) were tested on rabbits in relation to the production of tumor necrosis factor (TNF). TNF was determined by means of the serum titration of L-929 cell cultures in the presence of Actinomycin D, this with resulting titres of 3.2 x 10(3) to 5.1 x 10(4) IU TNF/ml. Analogous titres were noted after the action of denatured LPS (ie LPS subjected to alkaline hydrolysis or H2O2).