Elevation of PMN cytosolic free calcium and locomotion stimulated by novel peptides from IL-1-treated human synovial cell cultures

Treatment of human synovial cell cultures with human recombinant interleukin 1 (IL-1) results in the appearance of activity in the supernatant which stimulates human polymorphonuclear neutrophils (PMNs), as assessed by increased chemokinesis and elevation of intracellular free calcium concentration. IL-1 (or related cytokines) were unable to stimulate these responses. This activity chromatographed as a single peak on C 8 reversed-phase HPLC and subsequent size exclusion HPLC revealed two peaks of chemokinetic activity with apparent molecular masses of ≈ 13kDa and 6kDa. Fractions containing the higher molecular mass material also elevated PMN cytosolic free calcium. The local production of such factors may mediate IL-1-induced PMN accumulation in vivo.