Construction Of Chimeric Vesicular Stomatitis Virus Expressing Glycoprotein Of Ebola And Marburg Virus And Evaluation Of Their Immunogenicity In Mice

Ebola hemorrhagic fever(EHF) and Marburg hemorrhagic fever(MHF), two fulminating zoonoses with the symptoms of acute severe hemorrhagic fever, are caused by Ebola virus(EBOV) and Marburg virus(MARV) respectively. EBOV and MARV, members of the family Filoviridae, are among the most virulent pathogens as their lethality rates can be up to 90%. Although infections only occur frequently in Africa, the viruses, which can be misused as bioterrorism agents, have the potential to spread gloally and are challenge for human health and bioloogical safety. With the development of the international trade and personnel exchanges, these viruses still have a great chance to spread to our country. Previously studies have shown that vaccination in sensitive hosts is effective means to prevent and control the diseases. As a result, it is of great significance to develop a safe and effective vaccine for EBOV and MARV.We generated three recombinant vesicular stomatitis viruses(rVSV?G/ZEBOVGP, rVSV?G/SEBOVGP and rVSV?G/MARVGP) which expressed a single filovirus glycoprotein(GP) in place of the VSV glycoprotein(G) on the basis of the VSV reverse genetics system reformed by modifying a restriction enzyme site. The expression of these three GPs and their location on the surface of the cell membrane were confirmed by western blot and indirect immunofluorescence assay(IFA). The result of immune-electron microscope(IEM) demonstrated that all the three GPs were embedded into the surface of recombinant virus particles which present the typical bullet shape. Further more, to assess their safety, mice were inoculated intramuscularly with recombinant viruses. During the observation period all the mice showed no notable loss of weight or any other signs of symptoms indicating that the three recombinant VSVs(rVSVs) had good safety on mice. To evaluate their immunogenicity, mice were inoculated intramuscularly by single(1×106 pfu) or triple-combination immunization(1×106 pfu for each of the rVSVs) and boosted inoculated 3 weeks later with the same dosage. Specific antibody levels in mice serum were determinted by ELISA and neutralization test and the result showed that single injection was able to induce high level of GP-specific IgGs and neutralizing antibodies and antibody levels significantly improved after boosting.In this research, we constucted three important virulent hemorrhagic fever virus reserve vaccines based on chimeric VSV vector successfully, which is the first report in China, and proved that these vaccines, either used alone or in combination, were safe and could elicit high levels of neutralizing antibodies in mice. The results revealed that the recombinant viruses, rVSV?G/ZEBOVGP, rVSV?G/SEBOVGP and rVSV?G/MARVGP, as important stockpile vaccines against EBOV and MARV have underlying application value. However, the safety and efficacy of recombinant viruses on nonhuman primates still need further evaluation.