INVITRO MACROPHAGE CHEMOTACTIC GENERATION FROM SERUM IMMUNOGLOBULIN-G BY NEUTROPHIL NEUTRAL SERYL PROTEASE

Abstract

A neutral protease with a MW of about 14,000 was separated at acid pH from rabbit neutrophils and then partially purified by elution on DEAE-Sephadex, DM[carboxy methyl]-Sephadex and Sephadex G-75 in that order. This enzyme was inactivated by DFP phenylmethyl sulphonylfluoride (PMSF), soybean trypsin inhibitor (SBTI) or elastatinal, suggesting a seryl protease resembling elastase, but it failed to digest elastin-orcein. The enzyme seemed different from histonase of rabbit neutrophils because of its Hb (3HHb)-degrading ability and of inactivation by heparin. The protease generated in vitro macrophage chemotactic activity from guinea pig serum Ig[immunoglobulin]G. This chemotactic factor had a MW similar to that of IgG and its chemotactic generation was accompanied by release of dialysable peptide(s). No generation of macrophage chemotactic activity from IgG was induced in vitro by elastase from pig pancreas or by neutral thiol protease from rabbit neutrophils.