Effect of difference between EV-A71 virus epidemic strain and “vaccine strain” on neutralizing antibody titer

ABSTRACT

Hand, foot and mouth disease was mainly caused by EV-A71 virus. The main antigen structure of VP1 region of EV-A71 was easily varied. Here, we investigated the seroprevalence of EV-A71 based on a large group of healthy individuals in Beijing, China, in order to study the effectiveness of EV-A71 vaccine in a real-world setting. BrCr and the clinical strain isolated from the Chinese mainland in 2008 (“vaccine strain:”CMU4232/BJ/CHN/2008), EV-A71 C4 epidemic strains isolated in 2010, 2013, and 2016, were tested for neutralizing antibodies (NtAb) in every year. Phylogenetic tree analysis of the EV-A71 strains above, as well as amino acid composition homologous sequence analysis were applied. The “vaccine strain” has 83.0% homology with FY23, H07 and FY7VP5. It belongs to the same branch of C4a as 10 C4, 13 C4 and 16 C4, and differs from the amino acid sites 283 and 293 of 16 C4. Compared with “vaccine strains,” there was a significant difference between the 50–59 years old age group when the NtAb titer of 16 C4 strain was 1:512-1:1024. Our results suggest that changes in the functional epitopes of NtAb caused by amino acid 283 and 293 loci in EV-A71 strains may affect the production of neutralizing antibodies.

KEYWORDS:

• HFMD EV-A71
• NtAb vaccine

Acknowledgements

We would like to thank all study subjects and their parents/guardians/relatives who agreed to participate in this study. The language of this manuscript has been checked by a native speaker of English.

Authors’ contributions

All authors contributed to the study conception and design. Material preparation, manuscript finalization and data analysis were performed by Yiwei Ding, Project supervision was performed by Zhihai Han. All authors read and approved the final manuscript.

Consent to participate

Informed consent was obtained from all individual participants included in the study.

Disclosure statement

No potential conflict of interest was reported by the authors.

Ethics approval

This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Ethics Committee of the Sixth Medical Center of PLA General Hospital, Beijing [No. 201,907,100].

Data Availability statement

The data sets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was approved by the Innovative Cultivation Foundation of The Sixth Medical Center of PLA General Hospital, China [No. CXPY201915]. This work was approved by Military logistics research project [No. BHJ16J011]. The funding body had no role in study design, data collection, data analysis or interpretation or writing of the report.