Limited Cleavage of Human Immunoglobulins by Elastase of Human Neutrophil Polymorphonuclear Granulocytes. Possible Modulator of Immune Complex Disease

Abstract

Human polymorphonuclear lysosomal granules contain a neutral protease which is capable of digesting human immunoglobulins. The protease is located in the azurophil granules and enzymatically cleaves IgG, producing a Fab-like piece which is recoverable. The Fc-like fragment is not crystallized. The Fab-like fragment competes effectively for ligands formed by native antibody from which the fragments were produced.