Analysis of Specificity of Antibodies Contained in Antiserum against Poliovirus with Mutants Resistant to Inhibitors in Equine Serum

By propagating poliovirus (Mahoney strain) in cell culture in the presence of normal equine sera, mutant viruses resistant to virus-inhibitory factors in animal sera (inhibitor-resistant mutants) were obtained. Neutralization of various inhibitor-resistant mutants with a number of inhibitory sera showed the presence of five kinds of inhibitory factors (inhibitors) differing in specificity from one another. Further, antibody absorption tests with five different inhibitor-resistant mutants revealed that antiserum against Mahoney strain contained at least five kinds of antibodies with different specificities. On the basis of these results, the antigenic constitution of Mahoney strain was investigated.