Genetic characteristics of hemagglutinin gene of H9N2 avian influenza viruses isolated from live poultry markets in Anhui Province from 2013 to 2018 / 中华疾病控制杂志

ABSTRACT

@#Objective To analyze genetic characteristics of hemagglutinin( HA) gene of H9N2 avian influenza viruses( AIVs) circulating in Anhui Province from 2013 to 2018． Methods All H9N2 positive samples tested by real－time polymerase chain reaction( PCＲ) were inoculated into specific patho- gen free ( SPF) chicken eggs for isolation and purification． Viral ＲNA was reversely transcribed into cD- NA and then amplified with gene specific primers． PCＲ products were sequenced and the gene sequences were analyzed using molecular and bioinformatics software． The DATAMONKEY online server was conducted to analyze selection pressure，and protein structure homology modelling was computed by the SWISS－MODEL server． Ｒesults 33 H9N2 AIVs isolated from live poultry markets belonged to h9．4．2．5 in the phylogenetic tree． The receptor binding sites of HA gene at 183，226 and 227 position were mutated into N，L and M，respectively． Meanwhile 189 and 190 sites presented with genetic polymorphism． Since 2015，all H9N2 viruses in this study carried 6 potential N－linked glycosylation sites． It was found that po- sition 160 of HA gene was subjected greater positive selection pressure，presented 7 spatial conformations at least． Conclusions The H9N2 viruses isolated from live poultry markets in Anhui Province possess the molecular characteristics of infecting mammals and the ability of antigenic drift，so we need to pay more attention to the genetic characteristics of the viruses．