Development of a CTL-based replication-deficient vaccinia virus strain LC16m8-based vaccine for severe fever with thrombocytopenia syndrome

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K17948
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 54030:Infectious disease medicine-related
• Research Institution: National Institute of Infectious Diseases
• Principal Investigator: Kato Hirofumi 国立感染症研究所, 実地疫学研究センター, 研究員 (80827890)
• Project Period (FY): 2021-11-01 – 2024-03-31
• Keywords: 重症熱性血小板減少症候群 / ワクチン / 抗ウイルス薬

Outline of Final Research Achievements

To date, no vaccine or therapeutic agent was approved against severe fever with thrombocytopenia syndrome virus (SFTSV). In the previous study, the recombinant vaccinia virus LC16m8 strain (m8-SFTS) expressing the N, GPC, and N+GPC genes showed efficacy as a vaccine. In this study, the effects of cellular and humoral immunity were investigated. The results showed that the depletion of CD8-positive cells had no reduction on the fatality of mice, suggesting cellular immunity could not influence on vaccine efficacy. On the other hand, the passive serum may have inhibited the transition of body weight of mice after challenge, suggesting humoral immunity may have had an effect. Also, the effects of antiviral drugs were tested. Favipiravir was effective in inhibiting against all genotypes in vitro.

Free Research Field

ウイルス学

Academic Significance and Societal Importance of the Research Achievements

SFTSの報告数は年々増加傾向にあり、致死的な病気でもあることから、ワクチンや治療薬の開発は喫緊の課題である。本研究ではワクチンや治療薬の開発を行ったということで社会的意義が大きい研究であると考えている。