title: Eliciting cross-neutralizing antibodies in mice challenged with a dengue virus envelope domain III expressed in  Escherichia coli.
abstract: Dengue viruses (DENVs) are mosquito-borne infectious pathogens that pose a serious global public health threat, and at present, no therapy or effective vaccines are available. Choosing suitable units as candidates is fundamental for the development of a dengue subunit vaccine. Domain III of the DENV-2 E protein (EDIII) was chosen in the present study and expressed in  Escherichia coli  by N-terminal fusion to a bacterial leader (pelB), and C-terminal fusion with a 6×His tag based on the functions of DENV structure proteins, especially the neutralizing epitopes on the envelope E protein. After two-step purification using Ni-NTA affinity and cation-exchange chromatography, the His-tagged EDIII was purified up to 98% homogenicity. This recombinant EDIII was able to trigger high levels of neutralizing antibodies in both BALB/c and C57BL/6 mice. Both the recombinant EDIII and its murine antibodies protected Vero cells from DENV-2 infection. Interestingly, the recombinant EDIII provides at least partial cross-protection against DENV-1 infection. In addition, the EDIII antibodies were able to protect suckling mice from virus challenge in vivo. These data suggest that a candidate molecule based on the small EDIII protein, which has neutralizing epitopes conserved among all 4 DENV serotypes, has important implications.
authors.affiliation: Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Key Laboratory of Microbial Engineering under the Educational Committee in Chongqing, Chongqing 400038, People's Republic of China.
authors.forename: Jie
authors.initials: J
authors.lastname: Yang
authors.forename: Junlei
authors.initials: J
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Zhen
authors.initials: Z
authors.lastname: Hu
authors.forename: Junmin
authors.initials: J
authors.lastname: Zhu
authors.forename: Xin
authors.initials: X
authors.lastname: Fang
authors.forename: Wenchang
authors.initials: W
authors.lastname: Yuan
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Hu
authors.forename: Yinling
authors.initials: Y
authors.lastname: Tan
authors.forename: Fuquan
authors.initials: F
authors.lastname: Hu
authors.forename: Xiancai
authors.initials: X
authors.lastname: Rao
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000378:metabolism*; D000914:Antibodies, Viral / Q000276:immunology; D002522:Chlorocebus aethiops; D056738:Cross Protection; D003715:Dengue / Q000276:immunology* / Q000517:prevention & control / Q000821:virology; D053059:Dengue Vaccines / Q000276:immunology; D003716:Dengue Virus; D000939:Epitopes / Q000276:immunology / Q000378:metabolism; D004926:Escherichia coli / Q000276:immunology / Q000378:metabolism / Q000821:virology; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D014709:Vero Cells; D014759:Viral Envelope Proteins / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D053059:Dengue Vaccines; D000939:Epitopes; D014759:Viral Envelope Proteins