title: Anti-DNA antibody mediated catalysis is isotype dependent.
abstract: Anti-DNA antibodies are the serological hallmark of systemic lupus erythematosus, and participate in the pathogenesis of lupus nephritis by cross-reacting with multiple renal antigens. Previously, using a panel of murine anti-DNA IgGs that share identical variable regions but that differ in the constant regions, we demonstrated that the cross-reaction and renal pathogenicity of anti-DNA antibodies are isotype dependent. In this study, we investigated the catalytic potential of this anti-DNA antibody panel, and determined its isotype dependency. The three isotype switch variants (IgG1, IgG2a, IgG2b) and the parent IgG3 PL9-11 anti-DNA antibodies were compared in their catalysis of 500 base pair linear double stranded DNA and a 12-mer peptide (ALWPPNLHAWVP), by gel analysis, MALDI-TOF mass spectrometry, and nuclear magnetic resonance spectroscopy. The binding affinity of anti-DNA antibodies to double stranded DNA and peptide antigens were assessed by ELISA and surface plasmon resonance. We found that the PL9-11 antibody isotypes vary significantly in their potential to catalyze the cleavage of both linear and double stranded DNA and the proteolysis of peptides. The degree of the cleavage and proteolysis increases with the incubation temperature and time. While different PL9-11 isotypes have the same initial attack sites within the ALWPPNLHAWVP peptide, there was no correlation between binding affinity to the peptide and proteolysis rates. In conclusion, the catalytic properties of anti-DNA antibodies are isotype dependent. This finding provides further evidence that antibodies that share the same variable region, but which have different constant regions, are functionally distinct. The catalytic effects modulated by antibody constant regions need to be considered in the design of therapeutic antibodies (abzymes) and peptides designed to block pathogenic autoantibodies.
authors.affiliation: Department of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Division of Rheumatology, Albert Einstein College of Medicine, Bronx, NY 10461, USA. Electronic address: ymxia@whu.edu.cn.
authors.forename: Yumin
authors.initials: Y
authors.lastname: Xia
authors.affiliation: Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA. Electronic address: ertan.eryilmaz@boehringer-ingelheim.com.
authors.forename: Ertan
authors.initials: E
authors.lastname: Eryilmaz
authors.affiliation: College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, Zhejiang 310058, China. Electronic address: qiuting_zhang@zju.edu.cn.
authors.forename: Qiuting
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA. Electronic address: david.cowburn@einstein.yu.edu.
authors.forename: David
authors.initials: D
authors.lastname: Cowburn
authors.affiliation: Department of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Division of Rheumatology, Albert Einstein College of Medicine, Bronx, NY 10461, USA. Electronic address: chaim.putterman@einstein.yu.edu.
authors.forename: Chaim
authors.initials: C
authors.lastname: Putterman
mesh_terms: D000818:Animals; D000974:Antibodies, Antinuclear / Q000276:immunology*; D017151:Antibodies, Catalytic / Q000276:immunology*; D000915:Antibody Affinity; D002384:Catalysis; D004797:Enzyme-Linked Immunosorbent Assay; D007132:Immunoglobulin Isotypes / Q000276:immunology*; D008181:Lupus Nephritis / Q000276:immunology; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D020349:Surface Plasmon Resonance
chemical_list: D000974:Antibodies, Antinuclear; D017151:Antibodies, Catalytic; D007132:Immunoglobulin Isotypes
keywords: Anti-DNA antibody; Catalysis; Systemic lupus erythematosus