A COMPETITION IMMUNOPRECIPITATION ASSAY OF UNLABELED POLIOVIRUS ANTIGENS

An assay method is described for unlabeled, unpurified N(ative) and H( eated) antigens of poliovirus. The method is based on competition betw een the unlabeled antigen and a standard quantity of radiolabeled anti gen, in the presence of a limiting amount of a N- or H-specific, monoc lonal antibody. The immune complexes are removed by protein A-bearing, fixed staphylococci. The method is free from cross-reaction between N and H antigen, and has a detection limit of approximately 2 nM. It wa s applied successfully to the quantitation of poliovirus antigen synth esized by recombinant yeast expressing the viral proteins P1 and 3CD.