Modified radial-plaque-neutralization test for demonstration of enterovirus neutralizing antibodies.

A simple radial method based on the formerly described paper disc technique was developed for demonstration of neutralizing antibodies to enteroviruses with plaque forming ability. Sera administered by 5 microliter wire-loops to wells cut into the agar overlay of virus infected cell monolayers produced radial neutralization zones with a size directly related to their specific antibody contents. Results of poliovirus neutralizing antibody tests performed by the radial plaque neutralization method were found to be in a good agreement with those obtained in antibody titrations either in monolayer tube cultures or in microtitre system. The relatively simple technique makes possible to investigate several hundreds of serum samples in a single experiment, so it is especially suitable for use in expanded serological surveys. It proved to be useful also for identification of enteroviruses and for testing the laboratory strains for identity.