[Completed sequences analysis on the Chinese attenuated yellow fever 17D vaccine strain and the WHO standard yellow fever 17D vaccine strain].

OBJECTIVE

To compare the molecular characteristics of the Chinese attenuated yellow fever 17D vaccine strain and the WHO reference yellow fever 17D vaccine strain.

METHODS

The primers were designed according to the published nucleotide sequences of YFV 17D strains in GenBank. Total RNA of was extracted by the Trizol and reverse transcripted. The each fragments of the YFV genome were amplified by PCR and sequenced subsequently. The fragments of the 5' and 3' end of the two strains were cloned into the pGEM T-easy vector and then sequenced.

RESULTS

The nucleotide acid and amino acid sequences of the homology to both strains were 99% with each other. No obvious nulceotide changes were found in the sequences of the entire genome of each 17D strains. Moreover, there was no obvious changes in the E protein genes. But the E173 of YF17D Tiantan, associted with the virulence, had mutantions. And the two live attenuated yellow fever 17D vaccine strains fell to the same lineage by the phylogenetic analysis.

CONCLUSION

The results indicated that the two attenuated yellow fever 17D vaccine viruses accumulates mutations at a very low frequency and the genomes were relative stable.