Assay Development for Quantification of Enterovirus 71 Vaccine Antigens

Dr. Min-Shi Lee (李敏西)
Investigator, Coordinator of Emerging Virus Program,
National Institute of Infectious Diseases and Vaccinology (NIIDV),
National Health Research Institutes (NHRI), Taiwan


Enterovirus 71 (EV71) and polioviruses both belong to enterovirus genus and could cause neurological infections. Based on phylogenetic analysis of VP1 genes, EV71 could be classified into three major genogroups (A, B and C), including eleven genotypes (A, B1~B5, and C1~C5). Since 1997, different EV71 genotypes have caused life-threatening epidemics in Asian countries, including Malaysia, Taiwan, Singapore, Brunei, Vietnam, Cambodia and China. Therefore, development of EV71 vaccines is a national priority in these countries. Currently, five vaccine candidates have been evaluated in clinical trials in China (3 genotype C4 candidates), Singapore (1 genotype B2 candidate), and Taiwan (1 genotype B4 candidate) and the three C4 candidates was recently approved for marketing in China. However, these five vaccine candidates have the following limitations to be improved, including low-growth efficiency (~107 TCID50/ml) and the shortage of standard assays for quantifying vaccine antigens. In this study, we have adapted high-growth genotype B5 vaccine virus which could grow to ~108 TCID50/ml in microcarrier-based and BelloCell-based Vero cell culture systems and induce cross-reactive neutralizing antibody responses against the three EV71 major genogroups in rabbits. In addition, we generated rabbit antisera and mouse monoclonal antibody with high neutralizing antibody titers to develop an enzyme-linked immunosorbent assay (ELISA) which could quantify protective vaccine antigens and predict immunogenicity of vaccine bulks in rabbits. Therefore. this ELISA could be potentially used as in vitro potency assay for product release and in-process control assay for monitoring EV71 vaccine production.

The content is authorized by Dr. Min-Shi Lee on October 30, 2017.

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