Immunogenicity of a plasmid DNA vaccine encoding glycoprotein gene of rabies virus CVS in mice and dogs

A DNA vaccine against rabies utilizing rabies glycoprotein gene from challenge virus standard (CVS) strain was developed by cloning the RT-PCR amplified glycoprotein gene into pTargeT mammalian expression vector. The recombinant plasmid was characterized by restriction endonuclease analysis and nucleotide sequencing. The sequence analysis of the glycoprotein gene in plasmid DNA vaccine revealed 99.4% similarity of the glycoprotein gene with reported sequences for CVS-N2B. This recombinant plasmid DNA vaccine was injected intramuscular into mice and dogs with a dose of 50 μg and 100 μg, respectively. The immunized mice showed complete protection on intracerebral rabies virulent virus (CVS) challenge. The immunized dogs also showed sero-conservation as antibody against rabies was observed in ELISA as well as in virus neutralisation test. The induction of immune responses in dogs indicated the use of this DNA vaccine to immunize the canine reservoir against the disease in mass vaccination.