抄録
The studies were carried out using frozen sections of renal specimens. Glomerular C3b-receptor (C3b-GR) activity (C3b-GRA) was semiquantitatively determined by enumerating C3-coated erythrocytes bound per unit of glomerulas. 1) a) C3b-GRA was enhanced by pretreatment with neuraminidase. b) C3b-GRA was diminished by pretreatment with protamine, whereas it was restored by treatment with heparin after protamine-pretreatment. c) C3b-GRA was more markedly diminished by treatment with protamine after neuraminidase-pretreatment rather than by protamine alonepretreatment. These results suggest that C3b-GR has many characteristics of negatively charged substances which are different from sialic acid. 2) a) In mesangial proliferative glomerulonephritis, C3b-GRA tended to decrease in the patients with diminished renal function and advanced histological changes, but was nearly normal in those with mild abnormalities. b) In membranous glomerulonephritis (MN), C3b-GRA markedly decreased in 75% of the patients, and the decrease in C3b-GRA appeared to be in connection with immune deposits and histological changes of membrane. c) In MN, C3b-GRA markedly decreased in the patients with nephrotic syndrome (NS), whereas C3b-GRA was normal in the patients without NS, suggesting the loss of C3b-GR as glomerular polyanion in MN with NS. d) In contrast to MN with NS, C3b-GRA was normal in minimal change NS. In minimal change NS, C3b-GRA was markedly diminished by protamine-treatment and the decrease in glomerular polyanion was shown with colloidal iron stain. These results suggest that the changes of glomerular polyanion may be different in quality between MN and minimal change NS. On the basis of these data, a role of C3b-GR in glomerulonephritis was discussed in connection with glomerular immune clearance.
