Characterization of the in vitro and in vivo species preference of human and murine tumor necrosis factor-alpha.

The species preference of human and murine tumor necrosis factor-alpha (TNF-alpha) was evaluated in human and murine systems for cytotoxic/cytostatic effects and receptor binding in vitro and murine systems for toxicity and antitumor activity in vivo. The in vitro cytotoxic/cytostatic effects of both species TNF-alpha on human and murine cell lines as well as the receptor binding studies using 125I-labeled recombinant human TNF-alpha demonstrated homologous species preferences. Species preference of TNF-alpha was also apparent in toxicity studies with BALB/c nu/nu and CB6F1 mice, and antitumor responses of CB6F1 mice to s.c. Meth A sarcoma implants. Moreover the growth of Meth A sarcoma implanted i.p. was not inhibited by either human or murine TNF-alpha. These results are discussed in view of the potential for underestimation of the biological potency of TNF-alpha from heterologous sources.