H9N2亚型禽流感流行分析及疫苗毒株的筛选

Epidemiological Analysis of H9N2 Subtype Avian Influenza Virus Isolates and Screening of the H9 Vaccine Strains

本研究旨在筛选新型免疫原性好、广谱的优秀H9亚型禽流感病毒疫苗株。通过H9N2分子流行病学调查对分离得到的37株禽流感H9N2亚型病毒进行HA基因分子遗传进化及其关键位点分析,利用交叉HI效价及鸡胚中和试验分析毒株间毒力及其相关性,制备疫苗用毒株进行免疫攻毒保护试验。结果显示,从37株病毒中选出12株病毒作为代表,分为3个分支,同分支之间交叉HI效价及中和效价最高。HI试验及鸡胚中和试验均显示同分支毒株间的相关系数高。免疫攻毒保护试验显示同分支疫苗株安全性高。表明我国禽流感H9N2亚型情况复杂,且疫苗保护效果与疫苗株的抗原匹配性密切相关,生产多种分支H9疫苗株联合更有利于控制H9型禽流感,

Objective The purpose of this study is to select a new H9N2 AIV vaccine strain with good immunogenicity. Methods 37 H9N2 subtype avian influenza virus isolates were analyzed for HA gene molecular genetic evolution and its key sites. Cross-HI titers and chicken embryo neutralization test were used to check virulence and the relevance between the different isolates, and the strains for vaccine production were tested for their immune protection.Results 12 representative strains in the 37 viruses were divided into three subbranches, cross-HI titers and neutralization titers of the same subbranch were the highest. From relevance of HI test and the chicken embryo neutralization test, the correlation coefficient in same subbranch strains were higher than in different subbranch. In the immune protection test, the strains showed safety in the same. Conclusion H9 vaccine with differnet subtype strains is more effective to preventing H9 avain flu. Preventive effect of vaccine is tightly related with antigen matched to the vaccine strain.