Screening of SLE sera using purified recombinant Sm-D1 protein from a baculovirus expression system.
The Sm-D1 polypeptide is a major target of autoantibodies diagnostic for systemic lupus erythematosus (SLE). The cDNA encoding the human antigen was expressed as a full-length, nonfusion protein using a eukaryotic baculovirus expression system. This recombinant version of Sm-D1 (rSm-D1) was purified to apparent homogeneity by a combination of differential extraction steps and FPLC chromatography. A direct antibody-binding ELISA was developed using the purified antigen. There was 96% correlation between the rSm-D1 and bona fide Sm-D1 from either HeLa cells or rabbit thymus when tested against Sm-positive patient sera by ELISA. The baculovirus-expressed Sm-D1 is reactive not only with patient anti-Sm sera, but also with anti-Sm monoclonal antibodies. Our results suggest that this rSm-D1 mimics the bona fide sources, providing a valuable addition to the roster of antigens available for SLE screening, epitope mapping and overall structure study.
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The Agouron Institute, La Jolla, California 92037, USA.
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D000911:Antibodies, Monoclonal / Q000276:immunology; D000937:Antigen-Antibody Reactions; D001324:Autoantigens / Q000235:genetics / Q000276:immunology; D016367:Baculoviridae / Q000235:genetics*; D002412:Cations; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D004926:Escherichia coli / Q000737:chemistry / Q000276:immunology; D015870:Gene Expression; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood* / Q000517:prevention & control; D008403:Mass Screening; D011994:Recombinant Proteins / Q000276:immunology; D017411:Ribonucleoproteins, Small Nuclear / Q000235:genetics / Q000276:immunology; D055517:snRNP Core Proteins
D000911:Antibodies, Monoclonal; D001324:Autoantigens; D002412:Cations; D011994:Recombinant Proteins; D017411:Ribonucleoproteins, Small Nuclear; D055517:snRNP Core Proteins