Polyanion and complement receptor of the glomerular epithelium. Relationship to pH

Two markers on the surface of glomerular epithelial cells were studied on human and rat tissue. The glomerular polyanion is known to be a sialoglycoprotein present profusely on glomerular epithelial cell surfaces, and it is detected by binding with cationic dyes. This staining is lost after incubation in the pH range 3.8 to 4.4, yet retained at a more acidic or physiologic pH. A receptor for complement is also present on human glomerular epithelial cells. This receptor is also lost as a function of varying pH incubation and this loss parallels the pattern observed for glomerular polyanion. Neuraminidase treatment of renal tissue removes the sialic acid-dependent glomerular polyanion staining but preserves and stabilizes the complement receptor. Both functions are markers of the cell surface of glomerular epithelial cells and behave as peripheral membrane proteins.