Adaptation of a Chinese ferret badger strain of rabies virus to high-titered growth in BHK-21 cells for canine vaccine development.

Rabies virus strain JX08-45CC was derived from a Chinese isolate (JX08-45) by serial passage in the BHK-21 cell line, reaching a titer of 10(8) TCID(50)/mL. JX08-45CC produced rabies in adult mice but was nonpathogenic in dogs after intramuscular injection. A comparison of the entire genomes of JX08-45 and JX08-45CC led to the identification of 17 nucleotide substitutions, resulting in seven amino acid changes in the mature G and L proteins. The immunogenicity of β-propiolactone-inactivated JX08-45CC was similar to the immunogenicity of the live vaccine strains widely used in China. The inactivated vaccine induced antibody responses for more than 6 months and provided full protection from an intramuscular challenge in dogs. JX08-45CC has excellent potential for development as an inactivated vaccine for dogs in China.