OBJECTIVE: To compare the specificity of anti-PM-Scl autoantibodies in serum samples from 43 patients with myositis, scleroderma, or both. METHODS: Anti-PM-Scl immunoprecipitates from HeLa cell extract were used as antigen for immunoblot analyses to determine the antigenic components. A series of complementary DNA fragments was expressed in Escherichia coli for immunoblot examination of the reaction with the 100-kd protein. RESULTS: The immunoblot against immunoprecipitates was sensitive and specific for detecting reactions with components of the PM-Scl antigen: 42 of 43 sera (97.7%) reacted with the 100-kd, 27 of 43 (62.8%) with the 70-kd, and 5 of 43 (11.6%) with the 37-kd protein (not previously recognized as antigenic). Forty-one sera reacted with N-terminal protein S1 (amino acids 11-437), 39 with central protein S2 (amino acids 439-749), and 24 with C-terminal protein S3 (amino acids 750-882). Of 42 sera tested, 28 (66.7%) reacted most strongly with S1, and 6 (14.3%) reacted most strongly with S2. Absorption studies implied additional, conformational epitopes not present on the bacterially expressed antigen. CONCLUSION: There was an overall similarity in reactivity to the PM-Scl antigen, but there were differences in the reactivity to the 70-kd and 37-kd proteins, as well as in the relative strength of the reactivity to the S2 protein.
OBJECTIVE: To compare the specificity of anti-PM-Scl autoantibodies in serum samples from 43 patients with myositis, scleroderma, or both. METHODS: Anti-PM-Scl immunoprecipitates from HeLa cell extract were used as antigen for immunoblot analyses to determine the antigenic components. A series of complementary DNA fragments was expressed in Escherichia coli for immunoblot examination of the reaction with the 100-kd protein. RESULTS: The immunoblot against immunoprecipitates was sensitive and specific for detecting reactions with components of the PM-Scl antigen: 42 of 43 sera (97.7%) reacted with the 100-kd, 27 of 43 (62.8%) with the 70-kd, and 5 of 43 (11.6%) with the 37-kd protein (not previously recognized as antigenic). Forty-one sera reacted with N-terminal protein S1 (amino acids 11-437), 39 with central protein S2 (amino acids 439-749), and 24 with C-terminal protein S3 (amino acids 750-882). Of 42 sera tested, 28 (66.7%) reacted most strongly with S1, and 6 (14.3%) reacted most strongly with S2. Absorption studies implied additional, conformational epitopes not present on the bacterially expressed antigen. CONCLUSION: There was an overall similarity in reactivity to the PM-Scl antigen, but there were differences in the reactivity to the 70-kd and 37-kd proteins, as well as in the relative strength of the reactivity to the S2 protein.
Authors: R Brouwer; G J Hengstman; W Vree Egberts; H Ehrfeld; B Bozic; A Ghirardello; G Grøndal; M Hietarinta; D Isenberg; J R Kalden; I Lundberg; H Moutsopoulos; P Roux-Lombard; J Vencovsky; A Wikman; H P Seelig; B G van Engelen ; W J van Venrooij Journal: Ann Rheum Dis Date: 2001-02 Impact factor: 19.103
Authors: Rick Brouwer; Wilma T M Vree Egberts; Gerald J D Hengstman; Reinout Raijmakers; Baziel G M van Engelen; Hans Peter Seelig; Manfred Renz; Rudolf Mierau; Ekkehard Genth; Ger J M Pruijn; Walther J van Venrooij Journal: Arthritis Res Date: 2001-11-12