An analysis on genetic characteristics of hemagglutinin and neuraminidase of type B influenza viruses in Guangzhou in 2006 / 病毒学报

ABSTRACT

To understand the genetic characteristics of hemagglutinin (HA) and neuraminidase (NA) of type B influenza viruses in Guangzhou in 2006, three virus strains from etiology surveillance and seven strains from outbreaks were investigated. Genome RNAs of type B influenza viruses were extracted and reverse-transcripted into cDNAs using random primers. The whole-length DNA of HA and NA were amplified by polymerase chain reaction (PCR), cloned into T-A plasmid and sequenced, and analyzed phylogenetically by DNAstar software. The results showed that the HA of type B influenza viruses were similar and the homology were more than 99%. The type B influenza viruses belong to Victoria lineage. The NA of the type B influenza viruses were similar and the homology were more than 98%. Phylogenetic trees of HA and NA showed that the isolates from etiology surveillance formed a cluster, and the isolates from outbreaks were separated from the cluster. The homology of the type B influenza viruses with B/Shanghai/361/2002, which is the WHO recommended influenza vaccine strain in 2005-2006, were 88.9%-89.7%. It suggested the protective effect of influenza vaccine against type B influenza viruses used in 2005-2006 in Guangzhou may not be afforded.