A Receptor for Activated C3 in the Normal and Abnormal Human Renal Glomerular Capillary Wall

Abstract

Abstract Most immunologically mediated renal disease results from the deposition of antigen-antibody-complement complexes within the glomerular capillary wall, yet the cause of this selective deposition is unknown. It has been shown by Gelfand, Frank, and Green that a tissue-bound receptor for activated C3 (C3b) is found in the normal human renal glomerular capillary wall. This receptor binds SRBC coated with IgM and anti-SRBC antibody and complement. The glomerular C receptor is specific for C3b, because EA coated with purified guinea pig or human C1, C14, C142 or C1423d are not bound. In this report we demonstrate the receptor for C3b located in the luminal surface of the capillary wall of the normal human renal glomerulus. We have also examined abnormal human kidneys harboring either immunologically or non-immunologically mediated lesions for the presence of C3b receptor, and the results were correlated with in vivo deposition of immunoglobulins and C3. As expected, there was a striking inverse relationship between in vivo C3 and Ig deposition and the C3b binding capacity in vitro.