Genetic Characterization and Antigenic Analysis of Hemagglutinin-neuraminidase Glycoprotein of Newcastle Disease Virus Isolates

Abstract:

Twenty Newcastle disease virus (NDV) strains were isolated from diseased chicken and geese in field outbreaks during 2005 and 2006 in some regions of Jiangsu and Guangxi, and the antigenic analysis of the all NDV isolates had been done based on the reaction spectrum with a panel of monoclonal antibodies to the HN glycoprotein. The entire ORFs encoding HN protein of these NDV isolates were amplified by RT-PCR successfully, cloned and sequenced. The resultant sequences of HN genes of 13 isolates of chicken origin and 7 isolates of goose origin were gained and analyzed. The results of reaction spectrum showed that there were some distinct differences in the antigenic epitopes among the 20 NDV isolates. And the sequences revealed that the coding regions of the HN genes of these isolates all consisted of 1716 nt characteristic of virulent strains of NDV, coding for 571 amino acids. Neucleotides sequence homology were found to be from 94.8% to 100% among 18 NDV isolates of genotype Ⅶ, and the neucleotides sequence homology be- tween all the isolates and the other genotype Ⅶ strains of recent years in China ranged from 92.1% to99.6%. The deduced amino acid sequences and the receptor-binding regions of HN proteins between the NDV isolates of chicken origin and of goose origin were compared and analyzed. The results showed that some unique amino acid substitutions were found in the genome of the NDV isolates, and the close genetic similarity provided evidence for epidemiological linkage between the NDV isolates of chicken origin and of goose origin in the same period.

Key words:Newcastle disease virus, Monoclonal antibody, Hemagglutinin-neuraminidase gene, Sequence analysis