Prostaglandin production by rheumatoid synovial cells: stimulation by a factor from human mononuclear Cells

Human peripheral blood mononuclear cells (lymphocyte-monocyte) in culture release a solube factor which can stimulate, up to 200-fold, production of prostaglandin E2 by isolated, adherent, rheumatoid synovial cells. Production of the factor by the mononuclear cells is enhanced by phytohemagglutinin. This factor is similar in apparent mol vt (10,000-20,000) to that which also stimulates collagenase production by the same cells.