title: Tetravalent recombinant dengue virus-like particles as potential vaccine candidates: immunological properties.
abstract: BACKGROUND
  Currently, a licensed vaccine for Dengue Virus (DENV) is not yet available. Virus-like particles (VLP) have shown considerable promise for use as vaccines and have many advantages compared to many other types of viral vaccines. VLPs have been found to have high immunogenic potencies, providing protection against various pathogens.
  
  
  RESULTS
  In the current study, four DENV-VLP serotypes were successfully expressed in Pichia pastoris, based on co-expression of the prM and E proteins. The effects of a tetravalent VLP vaccine were also examined. Immunization with purified, recombinant, tetravalent DENV1-4 VLPs induced specific antibodies against all DENV1-4 antigens in mice. The antibody titers were higher after immunization with the tetravalent VLP vaccine compared to titers after immunization with any of the dengue serotype VLPs alone. Indirect immunofluorescence assay (IFA) results indicated that sera from VLP immunized mice recognized the native viral antigens. TNF-α and IL-10 were significantly higher in mice immunized with tetravalent DENV-VLP compared to those mice received PBS. The tetravalent VLP appeared to stimulate neutralizing antibodies against each viral serotype, as shown by PRNT50 analysis (1:32 against DENV1 and 2, and 1:16 against DENV3 and 4). The highest titers with the tetravalent VLP vaccine were still a little lower than the monovalent VLP against the corresponding serotype. The protection rates of tetravalent DENV-VLP immune sera against challenges with DENV1 to 4 serotypes in suckling mice were 77, 92, 100, and 100%, respectively, indicating greater protective efficacy compared with monovalent immune sera.
  
  
  CONCLUSIONS
  Our results provide an important basis for the development of the dengue VLP as a promising non-infectious candidate vaccine for dengue infection.
authors.affiliation: Department of Microbiology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, 510080, People's Republic of China. liuyan.0510@163.com.|Key laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, 74 Zhongshan Road 2, Guangzhou, 510080, People's Republic of China. liuyan.0510@163.com.
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Microbiology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, 510080, People's Republic of China. junmeizh@126.com.|Key laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, 74 Zhongshan Road 2, Guangzhou, 510080, People's Republic of China. junmeizh@126.com.
authors.forename: Junmei
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Department of Microbiology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, 510080, People's Republic of China. zhizhun.163@163.com.|Key laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, 74 Zhongshan Road 2, Guangzhou, 510080, People's Republic of China. zhizhun.163@163.com.
authors.forename: Zhizhun
authors.initials: Z
authors.lastname: Yu
authors.affiliation: Department of Microbiology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, 510080, People's Republic of China. angdy@mail.sysu.edu.cn.|Key laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, 74 Zhongshan Road 2, Guangzhou, 510080, People's Republic of China. angdy@mail.sysu.edu.cn.
authors.forename: Danyun
authors.initials: D
authors.lastname: Fang
authors.affiliation: Department of Microbiology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, 510080, People's Republic of China. fuchunyun2008@sina.com.|Key laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, 74 Zhongshan Road 2, Guangzhou, 510080, People's Republic of China. fuchunyun2008@sina.com.
authors.forename: Chunyun
authors.initials: C
authors.lastname: Fu
authors.affiliation: Department of Microbiology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, 510080, People's Republic of China. zhuxun8@mail.sysu.edu.cn.|Key laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, 74 Zhongshan Road 2, Guangzhou, 510080, People's Republic of China. zhuxun8@mail.sysu.edu.cn.
authors.forename: Xun
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Department of Microbiology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, 510080, People's Republic of China. hzj100@163.com.|Key laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, 74 Zhongshan Road 2, Guangzhou, 510080, People's Republic of China. hzj100@163.com.
authors.forename: Zhenjian
authors.initials: Z
authors.lastname: He
authors.affiliation: Department of Microbiology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, 510080, People's Republic of China. yanhj@mail.sysu.edu.cn.|Key laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, 74 Zhongshan Road 2, Guangzhou, 510080, People's Republic of China. yanhj@mail.sysu.edu.cn.
authors.forename: Huijun
authors.initials: H
authors.lastname: Yan
authors.affiliation: Department of Microbiology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, 510080, People's Republic of China. jianglf909@163.com.|Key laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, 74 Zhongshan Road 2, Guangzhou, 510080, People's Republic of China. jianglf909@163.com.
authors.forename: Lifang
authors.initials: L
authors.lastname: Jiang
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D003715:Dengue / Q000276:immunology / Q000517:prevention & control*; D053059:Dengue Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D003716:Dengue Virus / Q000235:genetics / Q000276:immunology; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D015870:Gene Expression; D007116:Immunization, Passive; D016753:Interleukin-10 / Q000378:metabolism; D008807:Mice, Inbred BALB C; D009500:Neutralization Tests; D010843:Pichia / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D016019:Survival Analysis; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D058425:Vaccines, Virus-Like Particle / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D053059:Dengue Vaccines; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D014614:Vaccines, Synthetic; D058425:Vaccines, Virus-Like Particle; D014759:Viral Envelope Proteins; C074932:prM protein, Flavivirus; D016753:Interleukin-10