Antigenic Differences Among Strains of Newcastle Disease Virus.

Abstract

Seventeen heterologous combinations of Newcastle disease virus and antiserum have been used in serum neutralization tests. Of these combinations 13 exhibited a difference of greater than 1.0 log between the neutralization of the homologous and the heterologous virus by prepared antiserum. A difference of 5.0 logs was observed between 2 strains.