Phylogenetic and antigenic analysis of HA gene of influenza virus B (Victoria) in Beijing during 2021-2022 surveillance season
10.3760/cma.j.cn112309-20230210-00026
- VernacularTitle:2021—2022年流感监测季北京市乙型Victoria系流感病毒血凝素基因特性和抗原性分析
- Author:
Guilan LU
1
;
Shujuan CUI
;
Jiachen ZHAO
;
Yimeng LIU
;
Weixian SHI
;
Zhaomin FENG
;
Yang PAN
;
Daitao ZHANG
;
Peng YANG
;
Quanyi WANG
;
Xiaomin PENG
Author Information
1. 北京市疾病预防控制中心传染病地方病控制所，北京 100013
- Keywords:
Influenza B virus;
Hemagglutinin gene;
Genetic mutation;
Phylogenic analysis;
Antigenic analysis
- From:
Chinese Journal of Microbiology and Immunology
2023;43(8):619-626
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the phylogenetic and antigenic characteristics of hemagglutinin (HA) gene of influenza B/Victoria lineage (BV) viruses in Beijing during the 2021-2022 influenza surveillance season, and to analyze whether the circulating BV viruses match the vaccine strain.Methods:Pharyngeal swab specimens from influenza like-illness (ILI) cases in the 2021-2022 influenza surveillance season were collected from surveillance network labs in Beijing and cultured in MDCK cells and chicken embryo to isolate BV viruses. Nucleic acids of the viruses were extracted, and the HA gene was amplified and sequenced. The nucleotide and amino acid sequence identity of the HA gene was analyzed using MEGA5.0 software. A phylogenetic tree of HA gene was constructed using the maximum likelihood method. The N-glycosylation sites in HA were predicted online. Three-dimensional structure of HA was constructed using SWISS-MODEL homologous modeling. Hemagglutination inhibition (HI) test was performed to analyze the antigenicity of BV viruses.Results:A total of 402 BV viruses were collected and 58 strains with full-length HA gene sequences were chosen for further analysis. Compared with the HA gene of this year′s vaccine strain (B/Washington/02/2019), there were 27 amino acid mutations, 11 of which were located in four different antigenic determinants. The phylogenetic analysis revealed that three subgroups of 1A.3, 1A.3a1, and 1A.3a2 co-circulated in Beijing with 54 strains (54/58, 93.10%) clustered to the Clade 1A.3a2, two strains (2/58, 3.45%) clustered to the Clade 1A.3a1, and two strains (2/58, 3.45%) in the same subgroup (Clade 1A.3) as the vaccine component BV strain in 2021-2022. Compared with the vaccine strain (B/Washington/02/2019), two BV strains had an additional N-glycosylation site at residue 197, while the other 56 strains showed no change in N-glycosylation sites. Antigenic analysis showed that 35 BV strains (35/58, 60.34%) were antigenically similar to the vaccine strain and 23 strains (23/58, 39.66%) were low-response strains.Conclusions:Three subgroups of BV viruses co-circulated in Beijing during the 2021-2022 influenza surveillance season. The predominant subgroup was Clade 1A.3a2 (93.10%), showing a certain genetic distance with the vaccine strain (B/Washington/02/2019). Nearly 40% (39.66%) of the viruses were low-response strains. This study indicated that continuous monitoring of the variations of influenza epidemic strains and timely providing laboratory basis for screening vaccine component strains were the basic technical guarantee for coping with influenza pandemic.
