| Foot-and-mouth disease virus (FMDV) is the serious causative agent of foot and mouth disease which affects meat-and milk-producing of livestock. Although they are effective for the prevention and control of the disease, inactivated virus which is utilized as current vaccines have considerable potential risk. So it is necessary to develop alternative vaccines. Production of complete VP1 or critical epitopes of VP1 in a diversity of expression systems has been performed in the search for an effective and inexpensive alternative. The mucosal immune system is the first line of defense against major pathogens. Further, mucosal immunization has been shown to induce both mucosal and systemic immunity to pathogens. Moreover, IgA response after vaccination plays a possible role in protection against FMDV infection.Thus, the development of a safe and effective mucosal vaccine against FMDV should be a high priority. The cholera toxin is one of most promising mucosal adjuvant but with potential toxicity, and its B subunit (CTB) itself or with a trace of CT can also enhances organism immunity by the combination with antigen when delivered to mucosa. The development of mucosal bivalent vaccine against FMDV is necessary and practical.In this study, we utilize the E.coli expression system to express the A and O type FMDV epitopes and HBcAg cDNA fusion gene which is designed previously (fused gene was designed by Shao hanjuan, named t8-3s) and cholera toxin B subunit(CTB, the expression vector was constructed by Zhang Guoguang ). Then we develop the expression vector of CTB and t8-3s fused gene. Then, we test the assumed mucosal bivalent vaccine in mice via intranasal and oral immunization. Systemic and mucosal immunity is measured via the test of anti-VP1 IgG and IgA antibody level. The results suggest the feasibility of intranasal immunisation against FMDV with the CTB-t8-3s, while adding a trace amount of holotoxin will notablely improve the immunoreaction.
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