title: Immunization with recombinant SFTSV/NSs protein does not promote virus clearance in SFTSV-infected C57BL/6J mice.
abstract: The severe fever with thrombocytopenia syndrome (SFTS), caused by a novel Phlebovirus in the Bunyaviridae family named SFTS virus (SFTSV), is an emerging hemorrhagic fever with a wide distribution and high case-fatality rate. Neither effective treatment nor vaccines are available to treat and prevent this disease to date. It was recently reported that SFTSV nonstructural protein in S segment (SFTSV/NSs) functioned as the interferon (IFN) antagonist targeting for suppressing host's innate immunity. This study was designed to investigate the potential of recombinant SFTSV (rSFTSV)/NSs protein for inducing anti-NSs antibodies by pre-exposure vaccination to block SFTSV/NSs in the SFTSV-infected C57BL/6J mice. All mice in the rSFTSV/NSs-vaccinated group, negative control group, and blank control group survived with no visible clinical abnormities throughout the experiment, except for their sacrifice for sampling at each observation point. However, unexpectedly, a negative effect on the bodyweight of rSFTSV/NSs-vaccinated mice was observed after 21 days postinoculation. Pre-exposure vaccination with rSFTSV/NSs did not accelerate virus removal in mice though high titer of anti-NSs antibodies and elevated IFN-γ were detected in sera. Before virus challenge, the rSFTSV/NSs-vaccinated mice and negative control mice had a larger amount of platelets (PLT) than the blank control mice, which indicated that Freund's adjuvants could stimulate PLT production. In the aspect of cytokines, the rSFTSV/NSs-vaccinated mice had a 5- to 10-fold increase in interleukin (IL)-2, IL-5, IL-6, IFN-γ, and tumor necrosis factor-α, which probably just had a negative effect on the bodyweight of mice. In general, therefore, previous vaccination with rSFTSV/NSs did not accelerate virus clearance in the SFTSV-infected mice.
authors.affiliation: 1 School of Public Health, Peking University , Beijing, People's Republic of China .
authors.forename: Rong
authors.initials: R
authors.lastname: Liu
authors.forename: Dou-Dou
authors.initials: DD
authors.lastname: Huang
authors.forename: Jie-Ying
authors.initials: JY
authors.lastname: Bai
authors.forename: Lu
authors.initials: L
authors.lastname: Zhuang
authors.forename: Qing-Bin
authors.initials: QB
authors.lastname: Lu
authors.forename: Xiao-Ai
authors.initials: XA
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Jing-Yu
authors.initials: JY
authors.lastname: Wang
authors.forename: Wu-Chun
authors.initials: WC
authors.lastname: Cao
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001835:Body Weight; D004195:Disease Models, Animal; D064420:Drug-Related Side Effects and Adverse Reactions / Q000473:pathology; D005260:Female; D007371:Interferon-gamma / Q000097:blood; D008810:Mice, Inbred C57BL; D010217:Phlebotomus Fever / Q000517:prevention & control* / Q000821:virology; D016856:Phlebovirus / Q000235:genetics / Q000276:immunology*; D016019:Survival Analysis; D017211:Treatment Failure; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000276:immunology*; D014765:Viral Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D014614:Vaccines, Synthetic; D017361:Viral Nonstructural Proteins; D014765:Viral Vaccines; D007371:Interferon-gamma