title: Inability to detect circulating anti-idiotypic antibodies in human anti-GBM antibody-mediated disease using a splenic PFC assay.
abstract: Anti-idiotypic antibodies are antibodies that are directed against the variable region of the corresponding antibody molecule and have been postulated to have a regulatory role in the immune response. Circulating anti-idiotypic antibodies have been reported in several antibody-mediated autoimmune diseases. We have established the following detection system for anti-idiotypic antibodies in human anti-glomerular basement membrane (GBM) disease. Spleen cells harvested from BALB/c mice immunised with human GBM were incubated with GBM-coated sheep red blood cells in the presence of guinea pig complement. Each spleen cell that produced anti-GBM antibodies resulted in a surrounding plaque where antibodies lysed the GBM-coated RBC. The number of plaques could be inhibited by the addition of heterologous anti-idiotypic antibodies to the plaquing mixture. Anti-idiotypic antibodies were then sought in both acute and convalescent phase sera from patients with anti-GBM disease and in laboratory staff who repeatedly handled GBM and sera containing anti-GBM antibodies. Anti-GBM antibodies were removed from all material before testing and affinity-purified preparations contained concentrations of IgG corresponding to the range that resulted in inhibition when affinity-purified rabbit anti-idiotypic antibody was examined. No anti-idiotypic antibodies could be demonstrated in any of the sera or IgG preparations examined. We conclude that if circulating anti-idiotypic antibodies are present in patients with anti-GBM disease, they must be infrequent, or at concentrations below the limits of detection of this assay (less than 1 mcg/mL). The observations of anti-idiotypic antibodies in other antibody-mediated diseases need to be confirmed.
authors.affiliation: Department of Haematology, Repatriation General Hospital, Heidelberg, Vic., Australia.
authors.forename: J A
authors.initials: JA
authors.lastname: Savige
authors.forename: C M
authors.initials: CM
authors.lastname: Lockwood
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology*; D000888:Antibodies, Anti-Idiotypic / Q000032:analysis*; D001323:Autoantibodies; D005921:Glomerulonephritis / Q000276:immunology*; D006462:Hemolytic Plaque Technique; D006801:Humans; D007678:Kidney Glomerulus / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D013154:Spleen / Q000276:immunology
chemical_list: D000906:Antibodies; D000888:Antibodies, Anti-Idiotypic; D001323:Autoantibodies; C051951:antiglomerular basement membrane antibody