title: Immunologically restricted and inhibitory anti-Ro/SSA in monozygotic twins.
abstract: A pair of monozygotic twins with Sjögren's syndrome are described who both have large amounts of anti-Ro/SSA in their sera by ELISA, but no precipitin in double immunodiffusion. Unique among previously encountered specimens, sera from the twins inhibit the formation of Ro/SSA-precipitins in double immunodiffusion by known anti-Ro/SSA positive SLE patients. The twins have near identical, clonally restricted anti-Ro/SSA autoantibodies as evaluated by isoelectric focusing and bind the same 60 kD Ro/SSA peptides. Thus, this pair of monozygotic twins has an identical fine specificity in their immune response to 60 kD Ro/SSA, despite potential differences in their immune response generated by random processes in the formation of immunoglobulin molecules and T cell receptors. These data imply that the anti-Ro/SSA found in these sera binds less than three epitopes such that soluble antigen/antibody complexes are formed instead of an insoluble complex that precipitates.
authors.affiliation: Arthritis and Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, USA.
authors.forename: R H
authors.initials: RH
authors.lastname: Scofield
authors.forename: B T
authors.initials: BT
authors.lastname: Kurien
authors.forename: M
authors.initials: M
authors.lastname: Reichlin
mesh_terms: D000328:Adult; D000974:Antibodies, Antinuclear / Q000097:blood*; D000918:Antibody Specificity; D001324:Autoantigens / Q000276:immunology*; D004200:Diseases in Twins; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D005779:Immunodiffusion; D020733:RNA, Small Cytoplasmic; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D012261:Ribonucleoproteins / Q000276:immunology*; D012859:Sjogren's Syndrome / Q000235:genetics* / Q000276:immunology*; D014430:Twins, Monozygotic; D000099207:SS-A Antigen
chemical_list: D000974:Antibodies, Antinuclear; D001324:Autoantigens; D020733:RNA, Small Cytoplasmic; D011948:Receptors, Antigen, T-Cell; D012261:Ribonucleoproteins; D000099207:SS-A Antigen; C116006:RO60 protein, human