Tumor necrosis factor's cytotoxic activity is signaled by the p55 TNF receptor

Tumor necrosis factor (TNF), a potent cytokine produced primarily by activated macrophages, elicits a large number of biological effects, including hemorrhagic necrosis of transplanted tumors, cytotoxicity, a role in endotoxic shock, and inflammatory, immunoregulatory, proliferative, and antiviral responses. These cellular responses are mediated by the binding of TNF to specific cell surface receptors. Two distinct TNF receptors (TNFRs) of approximately 55 kd (TNF-R1, p55) and 75 kd (TNF-R2, p70 or p75) have been identified, and human and mouse cDNAs corresponding to both receptor types have been characterized.