Improvement of cytotoxicity of tumor necrosis factor (TNF) by increase in basicity of its N-terminal region.

Two new recombinant TNFs (named rTNF-Scw1 and -Scw2) with higher basicity than conventional recombinant human TNF-alpha (rTNF-alpha) in the N-terminal region were constructed. Their sequences were constructed based on those of partially purified cytotoxic factors from the culture supernatant of acute monocytic leukemia cells THP-1, which unlike rTNF-alpha are cytotoxic to T24 bladder carcinoma cells in vitro. These new rTNF-Ss showed a broader cytotoxicity to tumor cells than rTNF-alpha. This increase in the basicity of the N-terminal region over that of conventional TNF significantly increased the cytotoxicity on tumor cells in vivo as well as in vitro.