Proteolytic Enzymes Modulate Preformed, Fixed Immunocomplexes and the Process of Immunocomplex-Formation In Vitro

Abstract Circulating and tissue bound immunocomplexes (IC) are involved in the pathogenesis of many chronic inflammatory and autoimmune diseases. In vivo and in vitro studies show that proteolytic enzymes can influence the amount of circulating IC. Using a sandwich-ELISA system we investigated the action mechanism of low dose proteases/protease combinations on solid phase fixed IC. We found that papain modulates preformed, fixed IC most effectively. In contrast, the effects of trypsin and especially bromelain were poor. We further investigated whether proteases also modulate IC during their formation. We found that bromelain and papain dose-dependently decreased the rate of IC-formation whereas the trypsin curve showed a biphasic course. Among the enzyme mixtures the combination bromelain/trypsin was most effectively indicating a possible synergistic effect between these proteases. The influence of enzymes on IC-formation occurred in a lower concentration range than the modulation of preformed IC. Further...