title: The constant region contributes to the antigenic specificity and renal pathogenicity of murine anti-DNA antibodies.
abstract: Affinity for DNA and cross-reactivity with renal antigens are associated with enhanced renal pathogenicity of lupus autoantibodies. In addition, certain IgG subclasses are enriched in nephritic kidneys, suggesting that isotype may determine the outcome of antibody binding to renal antigens. To investigate if the isotype of DNA antibodies affects renal pathogenicity by influencing antigen binding, we derived IgM, IgG1, IgG2b and IgG2a forms of the PL9-11 antibody (IgG3 anti-DNA) by in vitro class switching or PCR cloning. The affinity and specificity of PL9-11 antibodies for nuclear and renal antigens were analyzed using ELISA, Western blotting, surface plasmon resonance (SPR), binding to mesangial cells, and glomerular proteome arrays. Renal deposition and pathogenicity were assayed in mice injected with PL9-11 hybridomas. We found that PL9-11 and its isotype-switched variants had differential binding to DNA and chromatin (IgG3>IgG2a>IgG1>IgG2b>IgM) by direct and competition ELISA, and SPR. In contrast, in binding to laminin and collagen IV the IgG2a isotype actually had the highest affinity. Differences in affinity of PL9-11 antibodies for renal antigens were mirrored in analysis of specificity for glomeruli, and were associated with significant differences in renal pathogenicity in vivo and survival. Our novel findings indicate that the constant region plays an important role in the nephritogenicity of antibodies to DNA by affecting immunoglobulin affinity and specificity. Increased binding to multiple glomerular and/or nuclear antigens may contribute to the renal pathogenicity of anti-DNA antibodies of the IgG2a and IgG3 isotype. Finally, class switch recombination may be another mechanism by which B cell autoreactivity is generated.
authors: The Department of Microbiology & Immunology, Albert Einstein College of Medicine (AECOM), Bronx, NY 10461, USA.
authors: Yumin
authors: Y
authors: Xia
authors: Rahul D
authors: RD
authors: Pawar
authors: Antonio S
authors: AS
authors: Nakouzi
authors: Leal
authors: L
authors: Herlitz
authors: Anna
authors: A
authors: Broder
authors: Kui
authors: K
authors: Liu
authors: Beatrice
authors: B
authors: Goilav
authors: Manxia
authors: M
authors: Fan
authors: Ling
authors: L
authors: Wang
authors: Quan-Zhen
authors: QZ
authors: Li
authors: Arturo
authors: A
authors: Casadevall
authors: Chaim
authors: C
authors: Putterman
mesh_terms: D000818:Animals; D000974:Antibodies, Antinuclear / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D000915:Antibody Affinity; D000918:Antibody Specificity; D001323:Autoantibodies / Q000276:immunology / Q000378:metabolism; D001324:Autoantigens / Q000276:immunology / Q000378:metabolism; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D001666:Binding Sites, Antibody; D002843:Chromatin / Q000276:immunology / Q000378:metabolism; D024141:Collagen Type IV / Q000276:immunology / Q000378:metabolism; D004247:DNA / Q000276:immunology / Q000378:metabolism; D000939:Epitopes / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D005260:Female; D006825:Hybridomas / Q000276:immunology; D017578:Immunoglobulin Class Switching; D007127:Immunoglobulin Constant Regions / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D007132:Immunoglobulin Isotypes / Q000276:immunology / Q000378:metabolism; D007678:Kidney Glomerulus / Q000276:immunology* / Q000473:pathology; D007797:Laminin / Q000276:immunology / Q000378:metabolism; D008181:Lupus Nephritis / Q000276:immunology* / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D016513:Mice, SCID; D011485:Protein Binding
chemical_list: D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D001324:Autoantigens; D002843:Chromatin; D024141:Collagen Type IV; D000939:Epitopes; D007127:Immunoglobulin Constant Regions; D007132:Immunoglobulin Isotypes; D007797:Laminin; D004247:DNA