PARTICIPATION OF MONOCYTES IN GLOMERULONEPHRITIS IN ACUTE SERUM SICKNESS OF RABBIT

Abstract

Acute serum sickness in the rabbit was studied with special reference to the role of monocytes in the inflammatory process in the glomerulus. Macrophages were the major factor in producing glomerular hypercellularity in acute serum sickness. Proliferation of intrinsic glomerular cells or accumulation of polymorphonuclear leukocytes (PMN) was minimal. Ultrastructural characteristics of these phagocytic cells were described. Macrophages engulfed various inflammatory products such as fibrin and cell debris in the glomerular capillary. Colloidal C administered at the active inflammatory stage was phagocytized most often by macrophages, less by mesangial cells, and was not seen in endothelial or epithelial cells or PMN. The selective ingestion of the C particles by these macrophages made it possible to differentiate them from glomerular cells. The macrophages were probably derived from neither endothelial nor mesangial cells, but were of monocytic origin. Monocytic cells probably participated in glomerular inflammation, but also contributed to the repair of glomerular injuries through their active role for phagocytosis.