Studies on the non-neutralizable fraction of vaccinia virus

Abstract

Unfiltered (containing aggregates) and filtered (monodisperse) vaccinia virus was investigated in a neutralization test. Ninety per cent of the virus population was found to be neutralized whereas 10% remained infective (non-neutralizable fraction). This non-neutralizable fraction consisted of infective virus antibody complexes (sensitized virus) which could be completely inactivated by anti-antibodies. There was a difference in the kinetics of neutralization between unfiltered and filtered virus but no difference in the formation of the non-neutralizable fraction. The mechanism of virus sensitization and some possible application of anti-antibodies are discussed.