Monoclonal autoantibodies from patients with autoimmune diseases: synovial fluid B lymphocytes of a patient with rheumatoid arthritis produced an IgG lambda antibody recognizing J-sequences of Ig kappa chains in a conformation-dependent way.
Synovial fluid B cells from a patient with seronegative rheumatoid arthritis were immortalized by electrofusion. The specificity of clone FKN-E12 (IgG1 lambda) was analysed by screening a phage display random peptide library. One heptamer sequence was identified (RASFp1 = HLTFGPG). Three human IgG kappa antibodies contained a highly homologous sequence (xLTFGPG) at the junction of V- and J-regions. Homologies were also found in distinct humans (J kappa 3, J kappa 4) and murine (J kappa 5) J kappa-sequences (TFGPG, LTFGxG), and to a lower degree in all remaining J kappa-sequences (TFGxG). Binding and binding inhibition assays showed that FKN-E12 bound to kappa light chains tested in a conformation-dependent way: it reacted only with IgG kappa or IgA kappa chains adhered to a plastic surface, but not in soluble form. In conclusion, FKN-E12 detects a conformational epitope on probably all kappa light chains, which could be definded by screening a phage library displaying linear epitopes.
Clinical Research Unit for Rheumatology, Albert-Ludwigs-Universität, Freiburg, Germany.
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von Landenberg
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Rzepka
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I
Melchers
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D001323:Autoantibodies / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D006801:Humans; D006825:Hybridomas; D007074:Immunoglobulin G / Q000096:biosynthesis; D007133:Immunoglobulin Joining Region / Q000235:genetics / Q000276:immunology*; D007145:Immunoglobulin kappa-Chains / Q000235:genetics / Q000276:immunology*; D007146:Immunoglobulin lambda-Chains / Q000096:biosynthesis* / Q000235:genetics; D008297:Male; D051379:Mice; D008875:Middle Aged; D008969:Molecular Sequence Data; D019151:Peptide Library; D011487:Protein Conformation; D013582:Synovial Fluid / Q000166:cytology
D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D007074:Immunoglobulin G; D007133:Immunoglobulin Joining Region; D007145:Immunoglobulin kappa-Chains; D007146:Immunoglobulin lambda-Chains; D019151:Peptide Library