Stimulation of RNA Synthesis in L-929 Cells by Rabbit Tumor Necrosis Factor 1

Summary BCG or Corynebacterium par-vum primed rabbits injected with endotoxin contained a serum substance called tumor necrosis factor (TNF) that killed transformed mouse L-929 cells but not secondary normal mouse embryo fibroblasts. L-929 cells treated with TNF showed a six-fold stimulation of RNA synthesis that reached a maximum at approximately the same time as they started to die. Non-sensitive normal mouse embryo fibroblasts as well as TNF resistant L-929 cells did not show this large stimulation of RNA synthesis. When actinomycin D was employed to inhibit RNA synthesis, in the presence of TNF, a synergistic effect on killing of the transformed cells occurred.