Specificity of anti-Scl-70 antibodies in scleroderma: increased sensitivity of detection using purified DNA topoisomerase I from calf thymus.
A large scale purification of DNA topoisomerase I from calf thymus was obtained using the combinations of 62% ammonium sulfate precipitation, Biorex 70, hydroxylapatite and phenylagarose chromatography. Silver staining of the preparation separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed 2 bands of apparent molecular weight of 70 and 60 kDa. Immunoblotting with a serum of anti-Scl-70 specificity also recognized both proteins. Anti-Scl-70 antibodies were detected in 24/32 (75%) patients with diffuse scleroderma by ELISA and 28/32 (87%) had the ability to neutralize the topoisomerase I activity. All of 14 sera with anticentromere antibodies did not react with DNA topoisomerase I by both assays. The presence of anti-Scl-70 antibodies remained disease specific despite the increase in sensitivity of both assays.
Tsay
G J
GJ
Department of Internal Medicine, Chung Shan Medical and Dental College, Taichung, ROC.
Fann
R H
RH
Hwang
J
J
D000818:Animals; D001323:Autoantibodies / Q000032:analysis*; D002417:Cattle; D004264:DNA Topoisomerases, Type I / Q000302:isolation & purification; D004797:Enzyme-Linked Immunosorbent Assay; D005455:Fluorescent Antibody Technique; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D009500:Neutralization Tests; D009687:Nuclear Proteins / Q000276:immunology*; D012595:Scleroderma, Systemic / Q000276:immunology*; D012680:Sensitivity and Specificity; D013950:Thymus Gland / Q000378:metabolism*
D001323:Autoantibodies; D007106:Immune Sera; D009687:Nuclear Proteins; C048100:Scl 70 antigen, human; D004264:DNA Topoisomerases, Type I