A new competitive assay for monoclonal antibodies against phi X174 single stranded DNA

A new method using L-lysine-conjugated Sepharose 4B as a matrix for coupling competitors is described for analysis of the specificity of monoclonal antibodies against single stranded DNA. In this assay, competitor-coupled Sepharose 4B is first incubated with an antibody, and then the competitor is removed (together with the antibody that is bound to it) by low-speed centrifugation of the reaction mixture. The supernatant containing only unreacted antibody is then analysed by an enzyme-linked immunosorbent assay. The method is simple and does not use radioactive materials. Moreover it is not subject to the data fluctuation that is caused by the binding of competitors to microplates in a commonly used enzyme-linked immunosorbent assay employing high concentrations of competitors.