在疫苗免疫选择压力下H9N2亚型禽流行性感冒病毒HA基因的遗传变异

为了解H9N2亚型禽流行性感冒(流感)病毒在同亚型灭活疫苗的选择压力下的遗传变异情况,对某鸡场的感染鸡群进行连续4年的跟踪监测,对使用疫苗前和持续使用疫苗后不同时段分离到的H9N2亚型禽流感病毒的HA基因进行全序列分析.结果表明,在使用第一次分离的病毒株制备的疫苗后8个月分离到的病毒株,其HA基因仅发生一个氨基酸的差异;但在继续使用该疫苗的第二个和第三个年头分离的病毒株,它们的HA基因则一直在发生较大的变化.这一发现对进一步研究禽流感病毒在不断使用疫苗的选择压力下发生变异的规律,指导制定正确的禽流感防制对策具有重要意义.

Genetic Mutations of the Hemagglutinin Gene of H9N2 Subtype Avian Influenza Viruses under the Selective Pressure of Vaccination

In order to explore the genetic mutations of the hemagglutinin(HA) gene of the H 9N 2 subtype avian influenza viruses(AIV)under selective pressure of vaccination,infection in chicken flocks on a farm was monitored in a four-year period and H 9N 2 subtype viruses were isolated before and after the vaccination procedures were introduced Complete sequence analysis of the HA gene of these isolates showed that HA gene of the isolate,which was isolated 8 months after vaccinating with vaccine prepared from the first isolate,had only one amino acid difference from that of the vaccine strain But greater changes were seen in the HA genes of the other two viruses,which were isolated in the following second year and third year after vaccination This finding may be helpful for making further study of genetic mutations of AIV under selective pressure of vaccination and improving our control strategies of vaccination