Induction of tumor necrosis factor by macrophage colony-stimulating factor in vivo

The effect of human urinary colony-stimulating factor (CSF-1) on the production of tumor necrosis factor (TNF) in vivo was assessed. Purified CSF-1 was administered i.v. to rabbits 4 days prior to injection with lipopolysaccharide (LPS). TNF in the serum prepared from rabbits bled 90 min after LPS injection was measured using cytotoxicity assays employing mouse L929 cells and antirabbit TNF monoclonal antibody. The results indicated that CSF-1 was able to induce the production of TNF in vivo and had a synergistic effect with Propionibacterium acnes.