基于H蛋白基因的犬瘟热病毒遗传变异分析

犬瘟热是犬瘟热病毒(Canine distemper virus,CDV)感染犬和其他食肉动物造成的多发性、致死性传染病,本文从分子水平上探讨CDV遗传进化特性、变异情况与流行规律之间的关系.通过收集2002-2010年在中国地区分离的14株CDV野毒株、2006-2007年在全球各地分离的12株CDV野毒株以及从不同宿主分离的12株CDV野毒株和4株疫苗株,将其分为4组,将前3组野毒株分别与国内外正在使用的4株疫苗株的H基因进行遗传变异分析.分析发现,CDV野毒株与疫苗株间H蛋白基因的核苷酸相似性为86.2％～92.1％,其氨基酸相似性为89.1％～91.9％；H基因的584位的天冬酰胺糖基化位点是Asia-Ⅰ型CDV所特有的；H蛋白3555区域的非同义氨基酸替换概率较高.作者推测H蛋白抗原变异可能造成弱毒疫苗免疫效力降低,不能为某些CDV株的感染提供完全有效的保护.

Genetic Variation Analysis of the Canine Distemper Virus Based on Its H Protein Gene

Canine distemper disease caused by canine distemper virus(CDV) infection of domestic dogs and many carnivores is a deadly infectious disease.The article discussed the genetic characteristics,evolutional situations and epidemic regulation of CDV from molecular level.In this paper,we selected H protein gene of CDV as the target gene to evaluate molecular genetics,variation and epidemic regulation by compared the sequence of wild isolates to vaccine strains,the wild isolates included 14 CDV isolates from different geographical areas of China during the years 2002 to 2010,12 CDV isolates around the world in 2006 to 2007,12 CDV isolates from different hosts and the attenuated vaccine strains consisted of vCh,vCon,vOnder and vLed.The results showed that the nucleotide similarities of H gene between wild isolates and vaccine strains were from 86.2% to 92.1%,and the similarities of the deduced amino acid of H protein were 89.1% to 91.9%;Only Asia-Ⅰhad the N-glycosylation sites of H gene at 584 site;There were a higher non-synonymous substitution rates in 3555 encoded amino acid sequences.And it indicate that antigenic variation of H protein may result in reduced effectiveness of attenuated vaccine,which couldn′t provide complete immune response preservation for some CDV epidemic strains.