COMPARATIVE MOLECULAR CHARACTERIZATION OF FIELD AND VACCINAL STRAINS OF NEWCASTLE DISEASE VIRUS

Seven commercial vaccinal strains and three field isolates from various outbreaks of Newcastle disease were subjected to polypeptide analysis using Sodium Dodysel Sulphate (SDS-PAGE). On electrophoresis, the Newcastle Disaese Vaccine (NDV) proteins were settled into several peptide components related to structural elements of virus. Virus strains procured from different outbreaks, having variable mortality, fragmented into analogous peptide pattern of molecular weights of 181, 112, 89, 74.4, 63, 53, 24 and 12.5 KDa. In addition, the proteins responsible for conferring protection were consistently present in the three field isolates of NDV and were missing in some of the vaccinal strains. Moreover, the vaccinal strains of NDV showed marked variation among themselves in the peptide patterns. Some vaccinal strains had small kilobases of certain proteins. It was concluded that pivotal differences in the peptide patterns of lentogenic strains existed which could materialize to the justification of vaccination flop