Principle of Assay
Rat Surfactant Protein D/SP-D ELISA Kit (A80168) is a 4 hour sandwich Enzyme-Linked Immunosorbent Assay (sELISA) designed for the in vitro quantitative determination of rat Surfactant Protein D/SP-D in serum, plasma, tissue homogenates, and other biological fluids. A 96-well microtiter plate has been pre-coated with an antibody specific for Surfactant Protein D/SP-D. Standards and samples are added to the wells, where Surfactant Protein D/SP-D binds to the immobilized capture antibody. Following incubation, unbound components are removed by washing and a biotinylated detection antibody specific for Surfactant Protein D/SP-D is added to the wells. The detection antibody binds the captured Surfactant Protein D/SP-D to form an antibody-antigen-antibody sandwich complex. After further incubation and washing, HRP-Streptavidin conjugate is added to the wells. TMB substrate solution is then added to visualize the HRP enzymatic reaction. This produces a blue-coloured product that changes to yellow following addition of acidic stop solution. The intensity of the yellow colour is directly proportional to the amount of Surfactant Protein D/SP-D captured in each well. The concentration of Surfactant Protein D/SP-D is calculated by reading the absorbance at 450 nm and comparing the values with the standard curve.