H9N2亚型禽流感病毒的遗传进化分析及F株灭活疫苗的免疫效果评价

为了解H9N2亚型禽流感病毒(AIV)变异情况及评价作为H9亚型F株禽流感灭活疫苗的免疫效果,本研究对2009年～2010年期间从免疫鸡群中分离的9个H9N2亚型AIV株进行血凝素(HA)基因序列测定和分析。这9个病毒株HA基因编码区长度均为1 683 nt,HA基因核苷酸序列同源性为90.7%～98.9%,其推导氨基酸序列同源性为92.2%～98.8%;分离株与F株的HA基因之间的核苷酸序列同源性为91.6%～99.6%,氨基酸序列同源性为92.9%～99.3%;9个分离株与F株均属于Beijing/1/94-like进化分支,但分别属于3个不同的基因亚型。免疫试验结果显示:3周龄SPF鸡接种F株灭活疫苗21 d后,产生的HI抗体效价在log2 9以上;而且免疫鸡对分离株及F株攻毒后的喉头和泄殖腔排毒产生明显的抑制作用。本研究数据表明,F株灭活疫苗可以提供对这些分离株的有效免疫保护。

Phylogenetic analysis of H9N2 subtype avian influenza viruses isolated from immunized chicken flocks and protective efficacy of F strain inactivated vaccine

To investigate the phylogenesis and antigenic relationship of H9N2 avian influenza viruses(AIV),the hemagglutinin(HA) genes of 9 isolates from immunized chicken flocks in China during 2009 to 2010 were sequenced and analyzed.The HA genes were 1,683 nt in length,sharing 90.7% to 98.9% nucleotide acid homology and 92.2% to 98.8% amino acid homology.There were high sequence similarities between these isolates and the vaccine strain(F),with 91.6%-99.6% identities at nucleotide acid level,and 92.9% to 99.3% iden...