TNFα causes cytolysis and cytostasis of many tumor cell lines in vitro. It also enhances phagocytosis and cytotoxicity in neutrophilic granulocytes and modulates the expression of many other proteins. Cells expressing CD4 secrete TNFα while CD8 cells secrete little or no TNF-alpha. rHu TNFα, produced in E. coli is a single, non-glycosylated, polypeptide chain that contains 158 amino acids and has a molecular mass of 17.48 kDa.