PLoS ONE (Jan 2012)

Attenuation of vaccinia Tian Tan strain by removal of viral TC7L-TK2L and TA35R genes.

  • Shifu Kan,
  • Yuhang Wang,
  • Lili Sun,
  • Peng Jia,
  • Yanxin Qi,
  • Jiaqiang Su,
  • Lei Liu,
  • Guohua Yang,
  • Liming Liu,
  • Zhuoyue Wang,
  • Jinhui Wang,
  • Guangchen Liu,
  • Ningyi Jin,
  • Xiao Li,
  • Zhuang Ding

DOI
https://doi.org/10.1371/journal.pone.0031979
Journal volume & issue
Vol. 7, no. 2
p. e31979

Abstract

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Vaccinia Tian Tan (VTT) was attenuated by deletion of the TC7L-TK2L and TA35R genes to generate MVTT3. The mutant was generated by replacing the open reading frames by a gene encoding enhanced green fluorescent protein (EGFP) flanked by loxP sites. Viruses expressing EGFP were then screened for and purified by serial plaque formation. In a second step the marker EGFP gene was removed by transfecting cells with a plasmid encoding cre recombinase and selecting for viruses that had lost the EGFP phenotype. The MVTT3 mutant was shown to be avirulent and immunogenic. These results support the conclusion that TC7L-TK2L and TA35R deletion mutants can be used as safe viral vectors or as platform for vaccines.