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Open Access Research

Oral immunization with recombinant enterovirus 71 VP1 formulated with chitosan protects mice against lethal challenge

Fushun Zhang1, Chunsheng Hao2, Shuo Zhang1, Aqian Li1, Quanfu Zhang1, Wei Wu1, Lin Liu1, Chuan Li1, Mifang Liang1, Xiuling Li2* and Dexin Li1*

Author Affiliations

1 Key laboratory of Medical Virology, NHFPC; Department of Viral Hemorrhagic Fever, National Institute for Viral Disease Control and Prevention, China CDC, Beijing 102206, China

2 Beijing Institute of Biological Products Co. Ltd, Beijing 101111, China

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Virology Journal 2014, 11:80  doi:10.1186/1743-422X-11-80

Published: 6 May 2014

Abstract

Background

Enterovirus 71 (EV71) is the etiologic agent of hand-foot-and-mouth disease (HFMD) in the Asia-Pacific region, Many strategies have been applied to develop EV71 vaccines but no vaccines are currently available. Mucosal immunization of the VP1, a major immunogenic capsid protein of EV71, may be an alternative way to prevent EV71 infection.

Results

In this study, mucosal immunogenicity and protect function of recombinant VP1 protein (rVP1) in formulation with chitosan were tested and assessed in female ICR mouse model. The results showed that the oral immunization with rVP1 induced VP1-specific IgA antibodies in intestine, feces, vagina, and the respiratory tract and serum-specific IgG and neutralization antibodies in vaccinated mice. Splenocytes from rVP1-immunized mice induced high levels of Th1 (cytokine IFN-γ), Th2 (cytokine IL-4) and Th3 (cytokine TGF-β) type immune responses after stimulation. Moreover, rVP1-immunized mother mice conferred protection (survival rate up to 30%) on neonatal mice against a lethal challenge of 103 plaque-forming units (PFU) EV71.

Conclusions

These data indicated that oral immunization with rVP1 in formulation with chitosan was effective in inducing broad-spectrum immune responses and might be a promising subunit vaccine candidate for preventing EV71 infection.

Keywords:
Enterovirus 71; VP1; Oral immunization; Virus challenge