Complement receptor binding of C3b-coated cells treated with C3b inactivator, beta 1H globulin and trypsin.
Treatment of 125I-C3b bound to EAC1423b with C3b inactivator (C3bINA) and beta 1H globulin (beta 1H) cleaved the alpha-chain of C3b into 65,000- and 42,000-dalton fragments, both of which remained disulfide-bonded to the intact beta-chain (C3bi). Subsequent treatment with trypsin (0.1 microgram/ml) released 125I into the supernatant and yielded cells coated with a 33,000-dalton fragment of alpha-chain, presumably C3d. These results are in agreement with those obtained by others using fluid phase C3b. C3b-coated cells (EAC1423b) adhered to complement (C) receptors on human erythrocytes, glomeruli, and monocytes. C3bi-coated cells adhered to the receptors on glomeruli and monocytes, but not to those on human erythrocytes. C3d-coated cells adhered only to the monocyte receptors. The findings suggest that the glomerular C receptor recognizes portions of the C3 molecule different from those recognized by either the erythrocyte or monocyte receptors.
D000818:Animals; D001609:Beta-Globulins / Q000494:pharmacology*; D001665:Binding Sites; D003176:Complement C3 / Q000276:immunology* / Q000378:metabolism; D003180:Complement C3b Inactivator Proteins / Q000494:pharmacology*; D003165:Complement System Proteins / Q000276:immunology*; D004591:Electrophoresis, Polyacrylamide Gel; D004912:Erythrocytes / Q000276:immunology; D006168:Guinea Pigs; D006384:Hemagglutination; D006801:Humans; D007678:Kidney Glomerulus / Q000276:immunology; D009000:Monocytes / Q000276:immunology; D011817:Rabbits; D014357:Trypsin / Q000494:pharmacology*
D001609:Beta-Globulins; D003176:Complement C3; D003180:Complement C3b Inactivator Proteins; D003165:Complement System Proteins; D014357:Trypsin