title: The nature of the receptor for complement (C3b) in the human renal glomerulus.
abstract: The physicochemical nature of the human glomerular complement receptor was studied. Receptor activity was measured by determining the avidity of glomeruli of normal human renal tissue for fluorescein-labeled bacteria (S.typhi) coated with C3b. Maximal binding of C3b-coated bacteria to normal human glomeruli took place in phosphate-saline buffers of pH 6.5 and 0.08 to 0.15 mu ionic strength. Pretreatment of renal tissue with neuraminidase enhanced receptor activity. On the other hand, binding of C3b-coated bacteria to the glomeruli was diminished by pretreatment of the tissue with proteolytic enzymes, phospholipase C and certain lipid solvents. The binding of C3b-coated bacteria to the glomeruli was also diminished by pretreatment of the tissue with fluid-phase C3b, or by pretreatment of the bacteria with C3b inactivator. Normal human serum and purified fluid-phase C3 or the absence of magnesium and calcium ions had little effect on glomerular complement receptor activity.
mesh_terms: D001666:Binding Sites, Antibody / Q000187:drug effects; D002648:Child; D003179:Complement C3b; D003180:Complement C3b Inactivator Proteins / Q000494:pharmacology; D046508:Culture Techniques; D006801:Humans; D007678:Kidney Glomerulus / Q000276:immunology*; D009439:Neuraminidase / Q000494:pharmacology; D010206:Papain / Q000494:pharmacology; D010740:Phospholipases / Q000494:pharmacology; D012485:Salmonella typhi / Q000276:immunology; D012997:Solvents / Q000494:pharmacology; D014357:Trypsin / Q000494:pharmacology
chemical_list: D003180:Complement C3b Inactivator Proteins; D012997:Solvents; D003179:Complement C3b; D010740:Phospholipases; D009439:Neuraminidase; D014357:Trypsin; D010206:Papain