Release of Neutral Protease and β-Glucuronidase from Human Neutrophils in the Presence of Cartilage Treated with Various Immunologic Reactants

Abstract

Abstract Human neutrophils were studied for their capacity to release cartilage proteoglycan matrix-degrading neutral protease in the presence of rabbit ear cartilage treated with various immunologic reactants. Extracellular discharge of neutral protease and β-glucuronidase from purified neutrophils was provoked by cell contact with cartilage treated with heat-aggregated immunoglobulin G but not normal immunoglobulin G. Neutrophils were incubated also with cartilage treated with both heat-aggregated immunoglobulin G and rheumatoid serum, rheumatoid synovial fluid, or cryoprecipitates from rheumatoid synovial fluid. The greatest amount of lysosomal enzyme release occurred when neutrophils interacted with cartilage that had been treated with both heat-aggregated immunoglobulin G and either rheumatoid synovial fluid or cryoprecipitates from rheumatoid synovial fluid. Methyl prednisolone sodium succinate, triamcinolone acetonide, vinblastine, and colchicine reduced the immunologic discharge of granule enzymes from human neutrophils. Normal serum and synovial fluid inhibited markedly the activity but not the release of neutrophilic neutral protease. Rheumatoid serum and synovial fluid also inhibited neutral protease activity but to a lesser extent. These studies indicate that human neutrophils are capable of releasing cartilage degrading neutral protease during cell contact with immobilized immunologic reactants and that certain anti-arthritic drugs can inhibit the immunologic release of this neutral protease.