Human IFN gamma Receptor beta / AF-1 ELISA Kit (A311291) employs the sandwich enzyme immunoassay technique for the quantitative measurement of human IFN gamma Receptor beta / AF-1 in serum, plasma or other biological fluids. An antibody specific for IFN gamma Receptor beta / AF-1 has been pre-coated onto a 96-well microtiter plate. The standards and test samples are added into the wells and the IFN gamma Receptor beta / AF-1 present in each sample is bound to the wells by the immobilized antibody. Biotinylated Anti-IFN gamma Receptor beta / AF-1 Antibody, which also binds the IFN gamma Receptor beta / AF-1 present in each sample, and Streptavidin-HRP, which binds the Biotinylated Anti-IFN gamma Receptor beta / AF-1 Antibody, are added and the microtiter plate is incubated. Following incubation, unbound Biotinylated Anti-IFN gamma Receptor beta / AF-1 Antibody and unbound Streptavidin-HRP are removed by washing, and two substrate solutions are added to the wells. Color develops in proportion to the amount of IFN gamma Receptor beta / AF-1 captured in each well. The color development is stopped by addition of stop solution which changes the color from blue to yellow and the intensity of the color is then measured. The concentration of IFN gamma Receptor beta / AF-1 in the samples can then be calculated by reading the O.D. absorbance at 450nm in a microplate reader and referring to the standard curve.