Attenuated dengue 2 viruses with deletions in capsid protein derived from an infectious full-length cDNA clone.
A full-length cDNA clone (pD212) of dengue virus type 2 isolated in China (DEN2-43) was constructed. Based on this, we constructed several mutants with deletions in capsid protein C using fusion PCR. These deletions removed part or almost all of the internal stretch of hydrophobic amino acid residues that is probably involved in virion assembly. We thus obtained viable mutant viruses. The propagation capacity of the mutant viruses in cell culture was impaired in parallel with the increasing size of the deletion, and the infectivity of mutant C(Delta42-59), from which all of helix III of capsid protein C was removed, was completely abolished. More importantly, the mutant viruses were highly attenuated in suckling mice but induced high levels of antibodies in adult mice. This study indicates that the structural and functional flexibility of capsid protein C make it a candidate target for the attenuation of dengue virus, which could open a promising new avenue for the development of live attenuated dengue vaccines.
Zhu
Wuyang
W
State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing 100071, China.
Qin
Chengfeng
C
Chen
Shuping
S
Jiang
Tao
T
Yu
Man
M
Yu
Xuedong
X
Qin
Ede
E
D000818:Animals; D001483:Base Sequence; D036022:Capsid Proteins / Q000235:genetics*; D002460:Cell Line; D002681:China; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D003715:Dengue / Q000821:virology; D003716:Dengue Virus / Q000235:genetics* / Q000254:growth & development / Q000302:isolation & purification* / Q000472:pathogenicity; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D010641:Phenotype; D017384:Sequence Deletion; D010948:Viral Plaque Assay; D014774:Virulence / Q000235:genetics
D036022:Capsid Proteins; D017931:DNA Primers; D018076:DNA, Complementary; D004279:DNA, Viral