title: Subclasses of immunoglobulins and autoantibodies in autoimmune diseases.
abstract: The differing capacity of subclasses of IgG to bind to protein A and protein G was used in a sequential affinity purification procedure to examine immunoglobulin isotypes and subclasses in autoimmune disease. The utility of the procedure is that affinity-purified fractions containing particular isotypes and subclasses of immunoglobulin can be analyzed for their content of autoantibodies using standard techniques. For each of four autoimmune diseases studied, chronic active hepatitis, Sjogren's syndrome, primary biliary cirrhosis, and rheumatoid arthritis, there were characteristic protein elution profiles and the various disease-specific autoantibodies showed preferential distributions among the isotypes and subclasses. Moreover there was not an absolute correlation between an increased level of a particular subclass and the occurrence of antibodies of that subclass. The occurrence of highly disease-specific immunoglobulin subclass profiles suggests that the hypergammaglobulinemia associated with autoimmunity cannot be attributed entirely to polyclonal B-cell activation. Rather, there are disease-specific alterations in isotype subclass switching which may reflect different cytokine-dependent influences on autoimmune B cells and their products.
authors.affiliation: Centre for Molecular Biology and Medicine, Monash University, Clayton, Victoria, Australia.
authors.forename: I
authors.initials: I
authors.lastname: Outschoorn
authors.forename: M J
authors.initials: MJ
authors.lastname: Rowley
authors.forename: A D
authors.initials: AD
authors.lastname: Cook
authors.forename: I R
authors.initials: IR
authors.lastname: Mackay
mesh_terms: D000918:Antibody Specificity; D001172:Arthritis, Rheumatoid / Q000097:blood; D001323:Autoantibodies / Q000145:classification*; D001327:Autoimmune Diseases / Q000276:immunology*; D003094:Collagen / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D006521:Hepatitis, Chronic / Q000097:blood; D006801:Humans; D007132:Immunoglobulin Isotypes / Q000276:immunology; D007136:Immunoglobulins / Q000145:classification*; D008105:Liver Cirrhosis, Biliary / Q000097:blood; D009101:Multiple Myeloma / Q000097:blood; D009419:Nerve Tissue Proteins / Q000097:blood; D015203:Reproducibility of Results; D012859:Sjogren's Syndrome / Q000097:blood; D013205:Staphylococcal Protein A / Q000097:blood
chemical_list: D001323:Autoantibodies; C029152:G-substrate; D007132:Immunoglobulin Isotypes; D007136:Immunoglobulins; D009419:Nerve Tissue Proteins; D013205:Staphylococcal Protein A; D003094:Collagen