Production of tumor necrosis factor in unprimed mice: mechanism of endotoxin-mediated tumor necrosis.

Tumor necrosis factor (TNF) was detected in the sera of normal mice, unprimed by reticuloendothelial system (RES) stimulators, when such mice were injected with lipopolysaccharide (LPS). Amounts of TNF were approximately 200-fold less than those found in Corynebacterium parvum-primed mice. No TNF activity was detected in the sera of mice not administered LPS. TNF induction in unprimed mice was refractory to repeated administration of endotoxin, thus exhibiting a tolerance phenomenon. TNF produced in unprimed mice eluted similarly to Mycobacterium bovis, strain BCG-primed TNF on Sephacryl S-200 and DEAE Sephacel columns and was neutralized by rabbit antisera raised to partially purified BCG-primed TNF. When BALB/c mice having 7-day old subcutaneous Meth A tumor implants were administered TNF antiserum, endotoxin-induced hemorrhagic necrosis was largely prevented. These findings strongly suggest that endotoxin-induced hemorrhagic necrosis of tumors is mediated through TNF production and action.