Multiple linear epitopes (B-cell, CTL and Th) of JEV expressed in recombinant MVA as multiple epitope vaccine induces a protective immune response

Fengjuan Wang,Bin Zhou,Qingtao Liu,Xiaodong Liu,Jin Zhao,Xiuli Feng,Qisheng Zheng,Wenlei Deng,Hongyan Hou,Ran Pang,Ruibing Cao,Puyan Chen

doi:10.1186/1743-422x-9-204

Abstract

Epitope-based vaccination might play an important role in the protective immunity against Japanese encephalitis virus (JEV) infection. The purpose of the study is to evaluate the immune characteristics of recombinant MVA carrying multi-epitope gene of JEV (rMVA-mep). The synthetic gene containing critical epitopes (B-cell, CTL and Th) of JEV was cloned into the eukaryotic expression vector pGEM-K1L, and the rMVA-mep was prepared. BALB/c mice were immunized with different dosages of purified rMVA-mep and the immune responses were determined in the form of protective response against JEV, antibodies titers (IgG1 and IgG2a), spleen cell lymphocyte proliferation, and the levels of interferon-γ and interleukin-4 cytokines. The results showed that live rMVA-mep elicited strongly immune responses in dose-dependent manner, and the highest level of immune responses was observed from the groups immunized with 107 TCID50 rMVA-mep among the experimental three concentrations. There were almost no difference of cytokines and neutralizing antibody titers among 107 TCID50 rMVA-mep, recombinant ED3 and inactivated JEV vaccine. It was noteworthy that rMVA-mep vaccination potentiates the Th1 and Th2-type immune responses in dose-dependent manner, and was sufficient to protect the mice survival against lethal JEV challenge. These findings demonstrated that rMVA-mep can produce adequate humoral and cellular immune responses, and protection in mice, which suggested that rMVA-mep might be an attractive candidate vaccine for preventing JEV infection.

Highlights

The Japanese encephalitis virus (JEV), which belongs to the family Flaviviridae, infects the human central nervous system [1,2]
The levels of IFN-γ and IL-4 were similar among mice immunized with rMVA-mep (107TCID50), inactivated vaccine, EDIII, and recombinant multi-epitope peptide (rMEP). These results suggested that rMVA-mep could induce both Th1 and Th2 type immune response
Anti-rMEP of JEV antibody titers and subtype analysis To estimate the potential roles of rMVA-mep on the humoral immune response, the IgG isotopes profiles of sera from immunized mice at two weeks after three immunizations were measured by ELISA method (Figure 5). These results showed that mice immunized with rMVA-mep generated a significant rMEP-specific antibody response in dose-dependent manner, in which mice injected with 107TCID50 rMVA-mep produced the strongest antibody response among the three reachable dosages (Figure 5A, IgG)

Summary

Introduction

The Japanese encephalitis virus (JEV), which belongs to the family Flaviviridae, infects the human central nervous system [1,2]. The vaccination of swine against JEV should contribute to minimize the occurrence of JE epidemics in humans [6] Both inactivated and live-attenuated vaccines have been widely used in many Asian countries. During the vaccination with both inactivated and live-attenuated JEV vaccines, there are various disadvantageous conditions, including poor availability, high production costs, poor long-term immunity, and the possibility of allergic reactions [8]. These problems may be solved by using epitope-based vaccines containing selected protective epitopes, appropriately presented, which are capable of stimulating effective B cell, T cell, and cytotoxic immune responses while avoiding the induction of undesirable side-effects [9]

Objectives

Methods

Results

Conclusion