Jeong-Eun Kwak1,7, Young-Il Kim2,7, Su-Jin Park2, Min-Ah Yu2, Hyeok-Il Kwon2, Sukyeong Eo1, Tae-Shin Kim3, Joon Seok3, Won-Suk Choi2, Ju Hwan Jeong2, Hyojin Lee4, Youngran Cho4, Jin Ah Kwon4, Moonsup Jeong4, Joel N. Maslow4, Yong-Eun Kim5, Haili Jeon5, Kee K. Kim5, Eui-Cheol Shin1,3, Min-Suk Song2, Jae U. Jung6, Young Ki Choi2,* & Su-Hyung Park1,3,*
1 Biomedical Science and Engineering Interdisciplinary Program, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea.
2 Department of Microbiology, College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju 28644, Republic of Korea.
3 Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea.
4 GeneOne Life Science, Inc., Seoul 06060, Republic of Korea.
5 Department of Biochemistry, Chungnam National University, Daejeon 34134, Republic of Korea.
6 Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
7 These authors contributed equally: Jeong-Eun Kwak, Young-Il Kim.
*Correspondence and requests for materials should be addressed to Y.K.C. or to S.-H.P.
Although the incidence of severe fever with thrombocytopenia syndrome virus (SFTSV) infection has increased from its discovery with a mortality rate of 10–20%, no effective vaccines are currently available. Here we describe the development of a SFTSV DNA vaccine, its immunogenicity, and its protective efficacy. Vaccine candidates induce both a neutralizing antibody response and multifunctional SFTSV-specific T cell response in mice and ferrets. When the vaccine efficacy is investigated in aged-ferrets that recapitulate fatal clinical symptoms, vaccinated ferrets are completely protected from lethal SFTSV challenge without developing any clinical signs. A serum transfer study reveals that anti-envelope antibodies play an important role in protective immunity. Our results suggest that Gn/Gc may be the most effective antigens for inducing protective immunity and non-envelope-specific T cell responses also can contribute to protection against SFTSV infection. This study provides important insights into the development of an effective vaccine, as well as corresponding immune parameters, to control SFTSV infection.