Localization of receptors for activated complement on visceral epithelial cells of the human renal glomerulus

Receptors for activated C3 have recently been demonstrated to be present in glomeruli of normal human kidneys. In the present communication, the precise location of these receptors within the renal corpuscle was studied with scanning electron microscopy. By this technique, the glomerular complement receptor (GCR) was found to be located on the visceral epithelial cell of the renal corpusle. This epithelial cell location was confirmed by comparison of in vitro GCR activity with the location of immunoglobulin and C3 deposited in vivo. Renal tissues in which Ig and C3 had been deposited in vivo diffusely in subepithelial loci had no in vitro GCR activity. Renal biopsies not showing Ig or C3 deposition or biopsies with Ig and C3 in the mesangium retained GCR activity. These results further confirm an important role for GCR in the trapping and deposition of C3 in some forms of immunologically mediated renal disease.