Analysis of full-length gene sequence of a rabies vaccine strain CTN-1 for human use in China.

CTN-1 is one of the rabies vaccine strains for human use in China,but there has been no report on the full-length gene sequence of CTN-1.In this study,the full-length gene of CTN-1 was amplified by RT-PCR,each PCR product was cloned into T vector and then sequenced,assemblied and compared with other vaccine strains as well as the wild Chinese rabies isolates. The phylogenetic tree of G gene was constructed and the genetic homology was analyzed. The results revealed that CTN-1 was 11 925nt(GenBank accession number:FJ959397)in length and belonged to the genotypeⅠ. The full-length nucleotide homologies among CTN-1 and other rabies virus strains were between 81.5%-93.4%,of which the lowest 81.5% was between CTN-1 strain and bat isolate SHBRV,and the highest 93.4% was between CTN-1 and Chinese isolate HN10.The phylogenetic analysis revealed that the majority of Chinese isolates could be grouped into the same clade with the CTN-1 strain,but aG and some vaccine strains from abroad such as Flury,PM,PV,ERA,RC-HL and a few Chinese strains were grouped in another clade. Comparsion of the G protein genes also showed that the homologies among CTN-1 and most of the Chinese isolates were higher than that of the other vaccine strains to those Chinese strains. Therefore,it suggests that the CTN-1 strain is more suitable and rational to be used for the production of rabies inactivated vaccine in China than the others.