title: IgG subclass restriction of autoantibody to solid-phase C1q in membranoproliferative and lupus glomerulonephritis.
abstract: The IgG subclass distribution for autoantibodies to solid-phase C1q (anti-spC1q) in sera from 14 patients with membranoproliferative glomerulonephritis (MPGN) and 10 patients with systemic lupus erythematosus (SLE) nephritis was determined by an enzyme-linked immunosorbant assay employing C1q as the immunosorbant in the presence of 2 M NaCl to prevent Fc binding and monoclonal anti-human IgG subclass reagents. The autoantibody to spC1q in MPGN, especially in types I (7 patients) and II (3 patients), was almost entirely restricted to IgG3. In contrast, in SLE anti-spC1q was completely restricted to IgG2 in 3 patients while predominantly IgG2 in the other 7 patients. The different subclass restriction of anti-spC1q in these two disorders suggests that antibody formation is either in response to different epitopes on the collagen-like region of C1q or that patients with SLE and MPGN mount different immunologic responses to the same antigenic stimulus.
authors.affiliation: Division of Pediatric Nephrology, Children's Hospital Research Foundation, Cincinnati, Ohio.
authors.forename: A E
authors.initials: AE
authors.lastname: Prada
authors.forename: C F
authors.initials: CF
authors.lastname: Strife
mesh_terms: D000704:Analysis of Variance; D001323:Autoantibodies / Q000276:immunology*; D015922:Complement C1q / Q000276:immunology*; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D015432:Glomerulonephritis, Membranoproliferative / Q000276:immunology*; D006801:Humans; D007126:Immunoglobulin Allotypes / Q000032:analysis; D007141:Immunoglobulin Fc Fragments / Q000378:metabolism; D007074:Immunoglobulin G / Q000032:analysis*; D008181:Lupus Nephritis / Q000276:immunology*; D012965:Sodium Chloride / Q000494:pharmacology
chemical_list: D001323:Autoantibodies; D007126:Immunoglobulin Allotypes; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D012965:Sodium Chloride; D015922:Complement C1q