新城疫分离毒HN蛋白的抗原性初步分析及分子特性研究

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

摘要:

运用针对NDV囊膜糖蛋白(HN)的单克隆抗体(MAbs), 对2005~2006年间自我国江苏和广西部分地区的20株NDV分离株进行排谱试验, 初步分析了不同毒株之间HN蛋白的抗原表位差异; 并应用RT-PCR技术成功扩增了其HN基因整个编码区, 经克隆、测序最终获得13株鸡源NDV与7株鹅源NDV HN基因的编码区序列, 分析测定核苷酸序列及推导的氨基酸序列, 并将 鹅源NDV与鸡源NDV相应序列进行了比较。结果单抗排谱试验表明, 20株NDV分离株之间 HN蛋白的抗原表位存在差异; 测序结果表明, 测定的HN基因的编码区长度皆为1716nt编码571个氨基酸; 分离株中18株基因Ⅶ型NDV分离株之间HN基因编码区核苷酸序列具有较高的同 源性,达94.8%~100%; 与近几年国内流行的其它基因Ⅶ型NDV之间的核苷酸序列同源性 为92.1%~99.6%。对其推导的HN蛋白一级结构中潜在的糖基化位点及HN蛋白细胞受体结合相关区域的氨基酸序列等进行了比较分析。结果显示, 单抗排谱差异显著株在部分氨基酸位点发生了突变; 同时揭示我国部分地区同期流行的鹅源NDV与鸡源NDV HN基因之间具有较近的亲缘关系。

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.