Efficient production of human tumour necrosis factor in Escherichia coli

Abstract Human tumour necrosis factor (TNF) cDNA was isolated from a cDNA library prepared using TNF mRNA from human alveolar macrophages. Using the cDNA, various expression plasmids were constructed and their TNF producibility was examined in Escherichia coli . The best transformants produced a TNF polypeptide in a yield of about 20% of cellular proteins. The purified TNF polypeptide was lacking a methionine residue at the N-terminus, and possessed the expected physical and chemical properties and the biological activities characteristic of TNF.