Extraction and differentiation of the Su autoantigen from calf thymus nuclei.
Antibodies to Su antigen have been reported previously as a distinct antigen-antibody system associated with connective tissue diseases; most specifically systemic lupus erythematosus and undifferentiated connective tissue disease. The Su antigen was first identified by double immunodiffusion using calf thymus nuclear extract (CTNE) as a source for Su antigen. In this report, enhanced extraction of Su antigen was achieved using deoxyribonuclease I (DNase) for preparation of CTNE. Only the Sm antigen was found in comparable quantities in the DNase CTNE. Western immunoblotting and immunoprecipitation employing DNase CTNE and extracts of [35S]methionine-labeled HeLa cells respectively were used for further characterization and differentiation of the Su antigen. Sera from patients positive for Su antibodies by double immunodiffusion were found to react most specifically with antigen components in a molecular weight range of approximately 50-55 kDa. These methods should assist in further understanding the biochemical properties of the Su antigen.
Department of Medicine, East Carolina University School of Medicine, Greenville 27858-4354.
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Treadwell
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Müller
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Volkman
D000645:Ammonium Sulfate; D000818:Animals; D001324:Autoantigens / Q000032:analysis / Q000302:isolation & purification*; D015153:Blotting, Western; D002417:Cattle; D002467:Cell Nucleus / Q000276:immunology*; D003851:Deoxyribonucleases; D004591:Electrophoresis, Polyacrylamide Gel; D005779:Immunodiffusion; D011233:Precipitin Tests; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins; D017411:Ribonucleoproteins, Small Nuclear; D013950:Thymus Gland / Q000276:immunology*; D055517:snRNP Core Proteins; D000097585:SS-B Antigen; D000099207:SS-A Antigen
D000645:Ammonium Sulfate; D001324:Autoantigens; D003851:Deoxyribonucleases; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins; D017411:Ribonucleoproteins, Small Nuclear; D055517:snRNP Core Proteins; D000097585:SS-B Antigen; D000099207:SS-A Antigen; C116006:RO60 protein, human