A peptide mimic blocks the cross‐reaction of anti‐DNA antibodies with glomerular antigens. (8th December 2015)

• Record Type: Journal Article
• Authors: Xia, Y.; Eryilmaz, E.; Der, E.; Pawar, R. D.; Guo, X.; Cowburn, D.; Putterman, C.
• Is Part Of: Clinical and experimental immunology. Volume 183:Number 3(2016:Mar.)
• Page Start: 369
• Page End: 379
• Publication Date: 2015-12-08
• Subjects: anti‐DNA antibodies -- lupus nephritis -- phage display library -- SLE; Immunopathology -- Periodicals; 616.079
• DOI: 10.1111/cei.12734
• Languages: English
• ISSNs: 0009-9104

Abstract

Summary: 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.