鸭新城疫病毒分离株抗原表位和遗传演化分析

从规模化养殖场鸭群气管和泄殖腔试子分离到新城疫病毒(NDV)27株,用2株针对NDV HN单抗进行抗原表位分析,并选择4个分离株进行F基因高变区(374bp)和HN基因全长序列分析。抗原表位分析结果显示,27个鸭分离株均能与其中一株单抗C3-B7反应,而与另外一株单抗1E5反应为阴性。F基因(374bp)序列分析结果显示,4个鸭分离株均属于NDV ClassⅠ分支,分离株之间核苷酸同源性为99.2%～100%;分离株与NDV ClassⅡ毒株遗传距离为0.9%～9.9%,与NDV ClassⅠ毒株遗传距离为38.5%～41.7%。根据核苷酸序列推导的氨基酸序列表明,4个鸭NDV分离株F蛋白裂解位点氨基酸模式为:112-EROERL-117。HN基因序列分析结果显示,4个鸭NDV分离株HN基因全长1851bp,编码585个氨基酸;同源性比较发现4个鸭NDV分离株之间核苷酸同源性为99.7%～99.8%,与NDV ClassⅡ毒株核苷酸同源性为68.4%～70.5%,与NDV ClassⅠ毒株核苷酸同源性为95.8%～98.0%。本研究结果显示,鸭分离毒均属于NDV ClassⅠ弱毒,在抗原表位和基因序列上与广泛应用的NDV弱毒疫苗株(LaSota)不同,这些毒株的来源有待进一步深入研究。

Antigenic epitope and phylogenetia analysis of Newcastle disease virus isolated from ducks

Twenty seven NDV isolates were recovered from tracheal and cloacal swabs of clinically healthy ducks in a scaled farm. Two HN monoclonal antibodies(MAbs) were used to analyze the antigenic epitope of these isolates. The HN gene and the variable region of F gene (47-420 bp) of four isolates were sequenced. All the isolates were recog-nized by MAb C3-B7 in HI test, but the reactions were negative between these isolates and the MAb1E5. Based upon phylogenetic analysis of a 374 bp region of F gene,four isolates related to lentogenic class Ⅰ viruses,with nucleotide sequences identities of 99.2%-100%. There were 0.9%-9.9% nucleotide differences between the isolates and other class Ⅰ virus,whereas there were 38.5%-41.7% nucleotide differences between the isolates and classⅡ viruses. The amino acid sequences of the F protein cleavage sites in these isolates were 112-ERQERL-117. The full length of HN gene of these isolates was 1 851 bp,coding 585 amino acids. The homology analysis of the nucleotide sequence of HN gene indicated that there were 2.0%-4.2% nucleotide differences between the isolates and other class Ⅰ viru-ses,whereas there were 29.5%-31.6% differences between the isolates and class Ⅱ viruses. The results shows that these isolates do not appear to be phylogenetically related to the vaccine strain(LaSota) and further work should be done to find the source of these isolates.