A peptide mimic blocks the cross-reaction of anti-DNA antibodies with glomerular antigens.
Anti-DNA antibodies play a pivotal role in the pathogenesis of lupus nephritis by cross-reacting with renal antigens. Previously, we demonstrated that the binding affinity of anti-DNA antibodies to self-antigens is isotype-dependent. Furthermore, significant variability in renal pathogenicity was seen among a panel of anti-DNA isotypes [derived from a single murine immunoglobulin (Ig)G3 monoclonal antibody, PL9-11] that share identical variable regions. In this study, we sought to select peptide mimics that effectively inhibit the binding of all murine and human anti-DNA IgG isotypes to glomerular antigens. The PL9-11 panel of IgG anti-DNA antibodies (IgG1, IgG2a, IgG2b and IgG3) was used for screening a 12-mer phage display library. Binding affinity was determined by surface plasmon resonance. Enzyme-linked immunosorbent assay (ELISA), flow cytometry and glomerular binding assays were used for the assessment of peptide inhibition of antibody binding to nuclear and kidney antigens. We identified a 12 amino acid peptide (ALWPPNLHAWVP, or 'ALW') which binds to all PL9-11 IgG isotypes. Preincubation with the ALW peptide reduced the binding of the PL9-11 anti-DNA antibodies to DNA, laminin, mesangial cells and isolated glomeruli significantly. Furthermore, we confirmed the specificity of the amino acid sequence in the binding of ALW to anti-DNA antibodies by alanine scanning. Finally, ALW inhibited the binding of murine and human lupus sera to dsDNA and glomeruli significantly. In conclusion, by inhibiting the binding of polyclonal anti-DNA antibodies to autoantigens in vivo, the ALW peptide (or its derivatives) may potentially be a useful approach to block anti-DNA antibody binding to renal tissue.
Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA.|Division of Rheumatology, Albert Einstein College of Medicine, Bronx, NY, USA.
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Xia
Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, USA.
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Eryilmaz
Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA.|Division of Rheumatology, Albert Einstein College of Medicine, Bronx, NY, USA.
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Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA.|Division of Rheumatology, Albert Einstein College of Medicine, Bronx, NY, USA.
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Pawar
Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA.
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Guo
Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, USA.
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Cowburn
Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA.|Division of Rheumatology, Albert Einstein College of Medicine, Bronx, NY, USA.
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Putterman
D000595:Amino Acid Sequence; D000818:Animals; D000974:Antibodies, Antinuclear / Q000276:immunology*; D001324:Autoantigens / Q000276:immunology*; D003429:Cross Reactions; D004247:DNA; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007668:Kidney / Q000276:immunology; D007678:Kidney Glomerulus / Q000276:immunology*; D007700:Kinetics; D008181:Lupus Nephritis / Q000276:immunology; D051379:Mice; D018716:Molecular Mimicry; D019151:Peptide Library; D010455:Peptides / Q000276:immunology* / Q000502:physiology; D011485:Protein Binding
D000974:Antibodies, Antinuclear; D001324:Autoantigens; D007074:Immunoglobulin G; D019151:Peptide Library; D010455:Peptides; D004247:DNA
SLE; anti-DNA antibodies; lupus nephritis; phage display library