Characterization of a battery of monoclonal antibodies for differentiation of Newcastle disease virus and pigeon paramyxovirus-1 strains

Twenty monoclonal antibodies (MCAs) prepared against the velogenic GB-Texas strain of Newcastle disease virus (NDV) and the type 1 pigeon paramyxovirus (PPMV-1) were characterized and examined as potential immunodiagnostic reagents. All MCAs generated were found to bind specifically, but with varying reactivity, to various NDV strains in direct binding assays. In addition, MCA 15C4 neutralized and inhibited hemagglutination (HA) of all lentogenic, mesogenic, and velogenic NDV strains tested but not the PPMV-1 strain. Antibody 10D11 also inhibited HA activity, but inhibition was more selective and limited to the mesogenic and domestic or indigenous velogenic strains of NDV. MCA 79 reacted in all serologic assays with an antigenic site common to all serotype 1 avian paramyxoviruses. Passive immunization studies involving three different neutralizing MCAs (35, 79, and 15C4) showed that enhanced, but not complete, protection against virulent NDV challenge was provided when the three MCAs were administered in combination.