Molecular evolution of influenza A (H3N2) viruses circulated in Fujian Province, China during the 1996–2004 period

• DOI: 10.1007/s11427-008-0050-8
• Publication Date: 2008-03-26T15:16:20Z
• Authors: WenQiong Xiu; YuWei Wen; XiaoNa Shen; JianFeng Xie; ShiQin Yang; BingShan Wu; MeiAi Wang
• Keywords: 0301 basic medicine; China; Influenza A Virus, H3N2 Subtype; Molecular Sequence Data; Hemagglutinin Glycoproteins, Influenza Virus; 3. Good health; Evolution, Molecular; Epitopes; 03 medical and health sciences; Influenza, Human; Mutation; Humans; Amino Acid Sequence; Seasons

We studied the genetic and epidemic characteristics of influenza A (H3N2) viruses circulated in human in Fujian Province, south of China from 1996 to 2004. Phylogenetic analysis was carried out for genes encoding hemagglutinin1 (HA1) of influenza A virus (14 new and 11 previously reported reference sequences). Our studies revealed that in the 8 flu seasons, the mutations of HA1 genes occurred from time to time, which were responsible for about four times of antigenic drift of influenza H3N2 viruses in Fujian, China. The data demonstrated that amino acid changes were limited to some key codons at or near antibody binding sites A through E on the HA1 molecule. The changes at the antibody binding site B or A or sialic acid receptor binding site 226 were critical for antigenic drift. But the antigenic sites might change and the key codons for antigenic drift might change as influenza viruses evolve. It seems important to monitor new H3 isolates for mutations in the positively selected codons of HA1 gene in south of Asia.