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 μ 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.
ASJC Scopus subject areas
- Pathology and Forensic Medicine