Enzyme immunoassay of antibodies to Sjögren's syndrome B antigen
Teppo, A.M.
Clinical Chemistry 27(8): 1341-1345
1981
ISSN/ISBN: 0009-9147 PMID: 7023748 Document Number: 180335
A solid-phase enzyme immunoassay of IgG-, IgA- and IgM-type antibodies to Sjogren's syndrome B antigen is described. Polystyrene tubes are coated with the purified antigen. The antibodies are allowed to bind with their antigens, and then detected with alkaline-phosphatase-conjugated anti-human IgG, IgA or IgM sera. The amount of alkaline phosphatase fixed to the tubes is determined in pH 10.0 diethanolamine buffer at 37.degree. C with p-nitrophenyl phosphate as substrate. The absorbance of the p-nitrophenolate ion liberated in 1 h at 37.degree. C is measured at 406 nm. When rheumatoid factor is present, the values obtained for IgG antibodies are too low, and those for IgM antibodies are too high.