Enhancement of glomerular immune complex deposition by a circulating polycation.

Abstract

Polycations bind to and neutralize glomerular polyanions. The effect of the polycation polyethyleneimine (PEI) on glomerular deposition of preformed immune complexes was examined. Bovine serum albumin (BSA)-anti-BSA immune complexes made in 40 times antigen excess were administered following i.v. injection of PEI. Glomerular localization of immune deposits was assessed by quantitative immunofluorescence and EM and compared to controls receiving diluent without PEI followed by the same dose in immune complexes. In rats receiving PEI, deposits were localized within the glomerular basement membrane of all peripheral capillary walls and in the mesangium. In controls, deposits localized exclusively within the mesangium in smaller amounts than after PEI. Neutralization of glomerular polyanion by a circulating polycation enhances the deposition and alters the distribution of immune comlexes in glomeruli.