Description
Intended Uses: This ELISA is a solid phase enzyme immunoassay for the separate qualitative detection of IgG antibodies against eight different cellular and nuclear antigens in human serum. The wells are separately coated with recombinant human 100 kDa PM-Scl, 70 kDa U1-snRNP, SS-B, SS-A 52 kDa, SS-A 60 kDa, Scl 70, centromere protein B (CenpB), Jo-1 and highly purified native human Sm.
Principle of the Assay: Serum samples diluted 1:101 are incubated in the microplates coated with the specific antigen. The antibodies, if present in the specimen, bind to the antigen. The unbound fraction is washed off in the following step. Afterwards anti-human immunoglobulins conjugated to horseradish peroxidase (conjugate) are incubated and react with the antigen-antibody complex of the samples in the microplates. Unbound conjugate is washed off in the following step. Addition of TMB-substrate generates an enzymatic colorimetric (blue) reaction, which is stopped by diluted acid (color changes to yellow). The intensity of color formation from the chromogen is a function of the amount of conjugate bound to the antigen-antibody complex and this is proportional to the initial concentration of the respective antibodies in the sample.
Background: Anti-nuclear antibodies (ANA) are an important tool for the differential diagnosis of systemic rheumatic diseases. Indirect immunofluorescence test (IFT) on eucaryotic cells like HeLa has been the established method for the detection of ANAs. Single antibody specificities are distinguished by fluorescence patterns but more specific testing by ELISAs employing the target antigens are available too for a simple and reliable differentiation of ANAs