Flavivirus NS1 protein in infected host sera enhances viral acquisition by mosquitoes

  • Nature Microbiology 1, Article number: 16087 (2016)
  • doi:10.1038/nmicrobiol.2016.87
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The arbovirus life cycle involves viral transfer between a vertebrate host and an arthropod vector, and acquisition of virus from an infected mammalian host by a vector is an essential step in this process. Here, we report that flavivirus nonstructural protein-1 (NS1), which is abundantly secreted into the serum of an infected host, plays a critical role in flavivirus acquisition by mosquitoes. The presence of dengue virus (DENV) and Japanese encephalitis virus NS1s in the blood of infected interferon-α and γ receptor-deficient mice (AG6) facilitated virus acquisition by their native mosquito vectors because the protein enabled the virus to overcome the immune barrier of the mosquito midgut. Active immunization of AG6 mice with a modified DENV NS1 reduced DENV acquisition by mosquitoes and protected mice against a lethal DENV challenge, suggesting that immunization with NS1 could reduce the number of virus-carrying mosquitoes as well as the incidence of flaviviral diseases. Our study demonstrates that flaviviruses utilize NS1 proteins produced during their vertebrate phases to enhance their acquisition by vectors, which might be a result of flavivirus evolution to adapt to multiple host environments.

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This work was funded by grants from the National Natural Science Foundation of China (81301412, 81422028 and 81571975), National Program on Key Research Project of China (Prevention of livestock and poultry diseases and development of comprehensive farming technology), the National Key Basic Research Program of MOST (2013CB911500), Grand Challenges Explorations of the Bill & Melinda Gates Foundation (OPP1021992) and the National Institutes of Health of the USA (AI103807). The authors thank S. B. Halstead for providing critical suggestions for the manuscript. G.C. is a Newton Advanced Fellow (awarded by the Academy of Medical Sciences and the Newton Fund). G.C. is also a Janssen Investigator at Tsinghua University. The authors acknowledge the core facilities of the Center for Life Sciences and Center of Biomedical Analysis for technical assistance (Tsinghua University).

Author information

Author notes

    • Jianying Liu
    •  & Yang Liu

    These authors contributed equally to this work.


  1. Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Medicine, Tsinghua University, Beijing 100084, China

    • Jianying Liu
    • , Yang Liu
    • , Kaixiao Nie
    • , Senyan Du
    • , Xiaojing Pang
    •  & Gong Cheng
  2. SZCDC-SUSTech Joint Key Laboratory for Tropical Diseases, Shenzhen Center for Disease Control and Prevention, Shenzhen, Guangdong 518055, China

    • Yang Liu
    •  & Gong Cheng
  3. School of Life Science, Tsinghua University, Beijing 100084, China

    • Yang Liu
  4. Department of Health Statistics, School of Preventive Medicine, Fourth Military Medical University, Shaanxi 710032, China

    • Jingjun Qiu
  5. Department of Microbiology and Immunology, School of Medicine, New York Medical College, Valhalla, New York 10595, USA

    • Penghua Wang


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G.C. designed the experiments and wrote the manuscript. Y.L. and J.L. performed the majority of the experiments and analysed data. K.N., S.D. and X.P. helped with RNA isolation and qPCR detection. J.Q. assisted in the statistical analysis. P.W. contributed experimental suggestions and improved the writing of the manuscript. All authors reviewed, critiqued and provided comments on the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Gong Cheng.

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    Supplementary Information

    Supplementary Figures 1-11, Supplementary Tables 1 and 2.