EVALUATION OF A POLIOVIRUS-BINDING INHIBITION ASSAY AS AN ALTERNATIVETO THE VIRUS NEUTRALIZATION TEST

An enzyme-linked immunosorbent assay (ELISA)-based poliovirus-binding inhibition (PoBI) test to detect and quantify antibodies to poliovirus es was optimized and evaluated for use in population studies as an alt ernative to the virus neutralization test (NT) in tissue culture, The sensitivities of the inhibition ELISA compared with the NT in an inact ivated poliovirus vaccine (IPV)-vaccinated population were 98.6, 97.4, and 92.1% for serotypes 1, 2, and 3, respectively, The specificities of the PoBI test, as determined with sera from nonvaccinated persons, were also high for all three serotypes (99.0, 95.8, and 100%, respecti vely), Antibodies to other enteroviruses did hot cross-react in the se rotype 1 and 3 PoBI, and only low levels of cross-reactivity were foun d for serotype 2, We found high correlations between the PoBI and NT t iters for serotypes 1 and 2 in IPV-vaccinated blood donors (0.97 and 0 .95), in oral poliovirus vaccine (OPV)-vaccinated blood donors (0.91 a nd 0.95), and in naturally immune persons (0.90 and 0.87), The correla tion coefficient for serotype 3, however, was significantly lower in O PV-vaccinated blood donors (0.73) and in naturally immune persons (0.7 6) than in IPV-vaccinated persons (0.94; P < 0.01), These results indi cate that the antibody response to serotype 3 poliovirus in IPV recipi ents is different from that in OPV recipients and naturally infected p ersons, We conclude that the PoBI test is a suitable alternative to th e NT for estimating the seroprevalence of neutralizing antibodies to p oliovirus, especially in large-scale population studies.