Phagocytosis of aged human neutrophils by macrophages is mediated by a novel 'charge-sensitive'recognition mechanism

Abstract

The removal of neutrophils and their histotoxic contents from the inflamed site is a prerequisite for resolution of tissue injury, and a point at which factors critical to the pathogenesis of chronic inflammation may act. Engulfment of intact, senescent neutrophils by macrophages represents an important neutrophil disposal process. In this study the mechanism by which human monocyte-derived macrophages (MΦ) recognized and ingested human neutrophils that had been aged in culture was studied using an in vitro phagocytic assay. Inhibition of MΦ receptors for Ig Fc and the opsonic complement fragments C3b and iC3b with MAbs to MΦ FcR, CR1, CR3, and CR4 had no effect on recognition, and the patte..