Nephritogenic mAb 5-1-6 is directed at the extracellular domain of rat nephrin

J Clin Invest. 1999 Dec;104(11):1559-66. doi: 10.1172/JCI7728.


mAb 5-1-6 identifies an antigen on rat podocyte slit-diaphragms and induces severe proteinuria when injected into rats. Nephrin, an Ig-like transmembrane protein that is mutated in congenital nephrotic syndrome of the Finnish type, has been localized to the slit-diaphragm on human podocytes. Here we document that the mAb 5-1-6 antigen is rat nephrin. After incubation of rat glomeruli with this mAb, the antibody/antigen complex was chemically cross-linked, extracted, and immunoprecipitated, prior to Western analysis. By mass spectrometry and 2D gel electrophoresis, we identified several peptides with complete identity to human nephrin. In addition, the 185-kDa protein immunoprecipitated by mAb 5-1-6 from rat glomerular extracts reacts with a rabbit anti-mouse nephrin antibody. Finally, nephrin and the mAb 5-1-6 antigen have identical glomerular localization patterns on immunofluorescence of rat kidney. These results demonstrate that the nephritogenic mAb 5-1-6 identifies the extracellular domain of nephrin, thereby documenting the importance of the slit-diaphragm and its component, nephrin, in the regulation of glomerular permselectivity.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibodies, Monoclonal / adverse effects
  • Antibodies, Monoclonal / chemistry
  • Antibodies, Monoclonal / immunology*
  • Antigens / chemistry
  • Antigens / immunology
  • Cross-Linking Reagents
  • Electrophoresis, Gel, Two-Dimensional
  • Fluorescent Antibody Technique
  • Humans
  • Kidney Glomerulus / immunology*
  • Kidney Glomerulus / metabolism
  • Mass Spectrometry
  • Membrane Proteins
  • Molecular Sequence Data
  • Nephrotic Syndrome / immunology*
  • Precipitin Tests
  • Proteins / chemistry
  • Proteins / immunology*
  • Proteinuria / etiology
  • Rats
  • Rats, Sprague-Dawley
  • Sequence Alignment
  • Succinimides


  • Antibodies, Monoclonal
  • Antigens
  • Cross-Linking Reagents
  • Membrane Proteins
  • Proteins
  • Succinimides
  • nephrin
  • 3,3'-dithiobis(sulfosuccinimidyl propionate)