Enterovirus 71 vaccine candidate strains exhibit good immunogenicity and cross-neutralization activity

Announcing a new article publication for Zoonoses journal. In this commentary researchers from Beijing Minhai Biotechnology Co., Ltd., Beijing, China, Hubei Provincial Center for Disease Control and Prevention, Wuhan, China, Guangdong Provincial Institute of Biological Products and Drugs, Guangzhou, China, Gaozhou Center for Disease Control and Prevention, Guangdong, China and the Yangchun Center for Disease Control and Prevention, Guangdong, China consider immungenicity and cross-neutralizing activity of enterovirus 71 vaccine candidate strains.

The authors of this study evaluated enterovirus 71 (EV-A71) vaccine candidate strains, including their genotypes, immunogenicity and cross-neutralization capacity.

Six EV-A71 vaccine candidate strains were identified, all belonging to sub-genotype C4, the prevalent genotype in China. The sequence similarity of the VP1 regions of the six candidate vaccine strains and three approved inactivated vaccines was 97.58%-97.77%, and the VP1 amino acid similarity was 98.65%-99.33%. Experiments were performed to evaluate the immunogenicity and cross-neutralizing activity of the EV-A71 vaccine candidate strains. The strains had good immunogenicity 14 d after two immunizations, inducing an NTAb titer ranging from 1:94 to 1:346. The NTAb seroconversion rates 14 d after one immunization were above 80% (except HB0007), and significantly increased immunogenicity of EV-A71 strains was observed post-inoculation.

Candidate vaccine strains had broad cross-neutralizing activity after challenge with ten sub-genotypes of EV-A71. The highest NTAb titer/lowest NTAb titer ratios of sera against EV-A71 sub-genotypes were 8.0 (JS0002), 8.0 (JS0005), 21.3 (HB0005), 21.3 (HB0007), 10.7 (HB0040) and 8.0 (GD0002), respectively.

The research demonstrates that EV-A71 strains have good immunogenicity and cross-neutralization activity and have the potential to serve as vaccine strains for multivalent hand, foot and mouth disease vaccines.