Principle of Assay
Universal E. coli Host Cell Proteins ELISA Kit (A319470) is a 4 hour sandwich Enzyme-Linked Immunosorbent Assay (sELISA) designed for the in vitro quantitative determination of universal E. coli Host Cell Proteins in serum, plasma, tissue homogenates, and other biological fluids. A 96-well microtiter plate has been pre-coated with an antibody specific for E. coli Host Cell Proteins. Standards and samples are added to the wells, where E. coli Host Cell Proteins binds to the immobilized capture antibody. Following incubation, unbound components are removed by washing and a biotinylated detection antibody specific for E. coli Host Cell Proteins is added to the wells. The detection antibody binds the captured E. coli Host Cell Proteins 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 E. coli Host Cell Proteins captured in each well. The concentration of E. coli Host Cell Proteins is calculated by reading the absorbance at 450 nm and comparing the values with the standard curve.