POLYMORPHONUCLEAR NEUTROPHILS RELEASE S-35 LABELED PROTEOGLYCANS INTOCARTILAGE DURING FRUSTRATED PHAGOCYTOSIS

Rabbit peritoneal polymorphonuclear neutrophils (PMN), incubated in me dium containing [S-35]sulphate, incorporated S-35 into proteoglycan an d protein fractions. Approximately 46% of the S-35-labelled macromolec ules associated with the PMN cells after 1 h of incubation were recove red in a cytoplasmic granule extract, the majority being present in az urophil granules. Analysis of the azurophil granule fraction showed th at approximately 90% of the S-35-labeIled macromolecules were proteogl ycans. When challenged with heat-aggregated rabbit gamma-globulin in t he presence of cytochalasin B and cGMP, PMN were induced to release gr anular enzymes but did not release S-35-labelled proteoglycans into th e incubation medium. When incubated with articular cartilage slices, P MN released their granule S-35-labelled proteoglycan into the medium a nd into the cartilage matrix. Granule enzymes and S-35-labelled granul e proteoglycan were extracted from the cartilage tissue after incubati on and S-35-labelled macromolecules were detected in the cartilage tis sue by autoradiography.