Abstract
Summary The effect of monoclonal antibodies against the 55-and 75-kDa (p 55 and p 75) tumour necrosis factor (TNF) receptors on two tumour necrosis factor alpha (TNF α) induced responses was studied in rheumatoid synovial fibroblasts (RSF) in vitro. This provided functional evidence for the expression of both receptor types, which was confirmed by substantial inhibition of 125ITNFα binding to RSF by both antibodies. TNFα stimulation of prostanoid production was found to be a function of ligand binding to both receptor types, wheras the stimulation of cellular glycolysis was largely mediated via the p55 receptor. Thus, we showed that RSF express both types of TNF receptor and functional studies showed that stimulation of each receptor results in both similar and dissimilar cellular responses.