Co-expressing of rabies virus glycoprotein and nucleoprotein in the non replicating vaccinia virus Tiantan strain
Objective To improve the efficacy and safety of recombinant vaccinia rabies vaccine, the non replicating recombinants co expressing rabies virus glycoprotein and nucleoprotein were constructed. Methods According to the strategy of transient dominant selection, the rabies virus nucleoprotein (RN) gene was introduced into recombinant vaccinia virus(VTKRG) which expresses rabies virus glycoprotein (RG) gene in the TK locus by homologous recombinant. Results A fragment between fragment C and fragment K associated with the virulence and host range of vaccinia virus was substituted by RN gene, resulting in the VTKRGΔCKLacZRN. Western blot showed that VTKRGΔCKLacZRN expressed G protein and N protein with molecular weights of 65×10 3 and 50.5×10 3 respectively. The genetically modified VTKRGΔCKLacZRN possessed a highly attenuated phenotype, attributed to a decreased replicative capacity when grown in human cell lines. Compared with the non replicating recombinant vaccinia virus VTKRGΔCK expressing G protein only, VTKRGΔCKLacZRN, similar to VTKRG, were able to induce higher virus neutralizing antibody titers faster in mice. Mice inoculated with all of the recombinants were protected from a lethal intramuscularly (i.m.) challenge of rabies virus CVS strain which killed all control mice. Conclusion VTKRGΔCKLacZRN possesses excellent immunogenicity and improved safety in view of clinical application.