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Updated: May 18, 2026
Influenza A Virus Studies in a Mouse Model of Infection
Published on: September 7, 2017
Comparative analysis of the immunogenicity and protective effects of inactivated EV71 vaccines in mice
Qunying Mao1, Chenghong Dong, Xiuling Li
1National Institutes for Food and Drug Control, Beijing, China.
Background:
Enterovirus 71 (EV71) is the major causative agent of hand, foot, and mouth disease (HFMD). Three inactivated EV71 whole-virus vaccines of different strains developed by different manufacturers in mainland China have recently entered clinical trials. Although several studies on these vaccines have been published, a study directly comparing the immunogenicity and protective effects among them has not been carried out, which makes evaluating their relative effectiveness difficult. Thus, properly comparing newly developed vaccines has become a priority, especially in China.
Methods And Findings:
This comparative immunogenicity study was carried out on vaccine strains (both live and inactivated), final container products (FCPs) without adjuvant, and corresponding FCPs containing adjuvant (FCP-As) produced by three manufacturers. These vaccines were evaluated by neutralizing antibody (NAb) responses induced by the same or different dosages at one or multiple time points post-immunization. The protective efficacy of the three vaccines was also determined in one-day-old ICR mice born to immunized female mice. Survival rates were observed in these suckling mice after challenge with 20 LD(50) of EV71/048M3C2. Three FCP-As, in a dose of 200 U, generated nearly 100% NAb positivity rates and similar geometric mean titers (GMTs), especially at 14-21 days post-inoculation. However, the dynamic NAb responses were different among three vaccine strains or three FCPs. The FCP-As at the lowest dose used in clinical trials (162 U) showed good protective effects in suckling mice against lethal challenge (90-100% survival), while the ED(50) of NAb responses and protective effects varied among three FCP-As.
Conclusions:
These studies establish a standard method for measuring the immunogenicity of EV71 vaccines in mice. The data generated from our mouse model study indicated a clear dose-response relationship, which is important for vaccine quality control and assessment, especially for predicting protective efficacy in humans when combined with future clinical trial results.
Insights
This study compared three inactivated Enterovirus 71 (EV71) vaccines, finding that all showed protective effects in mice. Vaccine formulations varied in neutralizing antibody responses and protective efficacy, highlighting the need for standardized comparisons.
Area of Science:
- Virology
- Immunology
- Vaccinology
Background:
- Enterovirus 71 (EV71) is a primary cause of hand, foot, and mouth disease (HFMD).
- Three distinct inactivated EV71 whole-virus vaccines from different manufacturers in China are in clinical trials.
- Direct comparative studies on these vaccines' immunogenicity and protective capabilities are lacking, hindering effectiveness evaluation.
Purpose of the Study:
- To directly compare the immunogenicity and protective efficacy of three different inactivated EV71 vaccines.
- To establish a standardized method for assessing EV71 vaccine performance.
- To evaluate dose-response relationships for vaccine quality control and prediction of human efficacy.
Main Methods:
- Comparative immunogenicity assessment of vaccine strains and final container products (FCPs) with and without adjuvant.
- Measurement of neutralizing antibody (NAb) responses at various dosages and time points.
- Determination of protective efficacy in suckling mice challenged with EV71, observing survival rates.
Main Results:
- All three adjuvanted FCPs (FCP-As) at 200 U induced high NAb positivity rates (nearly 100%) and similar geometric mean titers (GMTs).
- Dynamic NAb responses differed among vaccine strains and FCPs.
- FCP-As at the lowest clinical trial dose (162 U) demonstrated significant protective effects (90-100% survival) in mice, though ED50 varied.
Conclusions:
- The study established a standardized mouse model for measuring EV71 vaccine immunogenicity.
- A clear dose-response relationship was observed, crucial for vaccine quality control.
- The findings are vital for predicting human protective efficacy when correlated with clinical trial data.
