Influence of isoelectric point on glomerular deposition of antibodies and immune complexes.
We determined the critical pI (the lowest required pI) for glomerular deposition of monomeric antibodies (Abs) and soluble immune complexes (ICs). For this purpose renal perfusion studies were performed in rats using: (a) a mixture of radiolabeled, affinity-purified native and cationic anti-human serum albumin Abs (anti-HSA Abs, pI range 4- > 9.5), and (b) soluble ICs (HSA-anti-HSA Abs, pI range 4-9.3) prepared with the same Ab mixture. The critical pI for the glomerular deposition of monomeric Abs was more than pH 8.2.24.4% of the Abs eluted from glomeruli of animals receiving ICs revealed a pI lower than pH 8.2. In conclusion our data show that the critical pI for the glomerular deposition of macromolecules is somewhat lower than commonly assumed and that ICs containing neutral and anionic Abs may bind to the glomerular basement membrane in significant amounts.
Woitas
R P
RP
Department of Medicine, University of Bonn, Germany.
Morioka
T
T
D000818:Animals; D000906:Antibodies / Q000378:metabolism*; D000974:Antibodies, Antinuclear / Q000378:metabolism; D000936:Antigen-Antibody Complex / Q000378:metabolism*; D001345:Autoradiography; D005455:Fluorescent Antibody Technique; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D007678:Kidney Glomerulus / Q000378:metabolism*; D008181:Lupus Nephritis / Q000209:etiology; D008297:Male; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar
D000906:Antibodies; D000974:Antibodies, Antinuclear; D000936:Antigen-Antibody Complex