【摘要】 从患病肉鸡群分离到一株新城疫病毒(NewcastleDiseasevirus,NDV)SQZ04。经蚀斑纯化后接种40日龄SPF鸡可诱发典型病变。经蚀斑纯化前和后的MDT为50·5h和51·2h,ICPI为2·0和1·92,IVPI为2·8和2·68,表明属强毒株。但F基因分型表明SQZ04属基因Ⅱ型,而且其与已知基因Ⅱ型的疫苗株LaSota、B1和Texas48的同源性分别为99·3%、98·7%和96·9%,显著高于与基因Ⅶ或Ⅸ型强毒株的同源性88·3%~88·6%或91·3%~92·1%。这是国内第一株属于基因Ⅱ型的NDV强毒株。SQZ04F多肽氨基酸裂解位点的序列为111GGRQGRL117,与弱毒株序列完全相同,这也是国内外首次报道具有这一氨基酸序列的强毒野毒株。然而,SQZ04株与其他已知强毒株的HN氨基酸同源性高达95·3%~97·3%,显著高于与弱毒株LaSota等的同源性87·8%~89·5%。更多还原

【Abstract】 Newcastle disease virus (NDV) field strain SQZ04 was isolated from a broiler flock with typical symptoms and lesions, and cloned by plaque_purification three times. NDV SQZ04 was determined as a virulent strain with MDT of 50.5h and 51.2h, ICPI of 2.0 and 1.92, IVPI of 2.8 and 2.68 respectively before and after plaque_purification. Analysis of F gene indicated that SQZ04 was determined as a virulent gene type Ⅱ, and its protein amino acid sequence has homologies of 99.3%, 98.7% and 96.9% with published gene type Ⅱvaccine strains LaSota,B1, virulent strain Taxas48,much higher than homologies of 88.3%～88.6% or 91.3%～92.1% with published gene types Ⅶ and Ⅸ. This is the first virulent field strain of gene type Ⅱ reported in China. Further more, the amino acid sequence ~ 111 GGRQGRL~ 117 in the F protein cleavage site in SQZ04 strain is identical to lentogenic strains of NDV, such as vaccine strains LaSota,B1.This is the first report that virulent NDV could have lentogenic amino acid sequence in the cleavage site of F protein, where HN genes was compared SQZ04 has a higher homologies of 95.3%～97.3% with known velogenic strains, but lower homologies of 87.8%～89.5% with published lentogenic strains.更多还原