Antigenic diversity and similarities detected in avian paramyxovirus type 1 (Newcastle disease virus) isolates using monoclonal antibodies

Summary Newcastle disease (ND) virus (APMV‐1) isolates submitted to the International Reference Laboratory for ND were characterised antigenically by their ability to cause binding of mouse monoclonal antibodies (mAbs) to cell cultures infected with the isolate. Since the availability of the mAbs 1526 viruses have been examined using a panel of nine mAbs and 818 with an extended panel of 26 mAbs. Using the nine mAb panel a total of 14 different patterns was seen and viruses grouped by the same pattern showed relationships with each other which were either biological, temporal or geographical or more than one of these. There was a marked tendency of viruses placed in the same group to show similar virulence for chickens. Extension of the panel to 26 mAbs produced 39 distinct patterns, although some of these were seen with only a single virus. Again, viruses inducing similar binding patterns shared similar properties and some binding patterns were specific for viruses causing discrete epizootics. Cluster an...