Mechanism of host preference of the zoonotic spirochete Leptospira

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K07100
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 49050:Bacteriology-related
• Research Institution: Tohoku University
• Principal Investigator: NAKAMURA Shuichi 東北大学, 工学研究科, 助教 (90580308)
• Co-Investigator(Kenkyū-buntansha): 小泉 信夫 国立感染症研究所, 細菌第一部, 主任研究官 (10333361)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 細菌 / 運動性 / 細菌べん毛 / 一分子計測 / 分子モーター / スピロヘータ / 細菌感染症 / 光学顕微鏡

Outline of Final Research Achievements

The zoonosis leptospirosis is caused by the genus Leptospira. The pathogenic Leptospira comprises more than 250 serovars, and the resultant symptom is roughly related to the pair of host mammalian species and leptospiral serovars. However, the mechanism of the host preference of Leptospira is not fully elucidated. Leptospira can crawl even while attached to solid surfaces. In this study, focusing on the adhesivity and mobility of Leptospira on host tissues, we investigated the relevance of the Leptospira dynamics with pathogenicity. We infected cultured kidney cells of six mammalian species by three leptospiral strains independently (18 pairs in total) under microscope and analyzed the adhesivity and crawling of individual leptospires. Higher adhesivity and directive crawling were observed in the host-pathogen pairs that cause severer symptom, suggesting that the pathogen’s mobility on the host tissue could be a crucial factor of the host-dependent pathogenicity of Leptospira.

Free Research Field

生物物理学，細菌学

Academic Significance and Societal Importance of the Research Achievements

レプトスピラが感染する動物種の一部は，病原体を無症状のまま腎臓に長期保菌して尿とともに断続的に排出するため，感染症拡大の原因となる。本研究の成果は，レプトスピラの宿主選好性のメカニズムを理解する重要な手掛かりであり，本菌の感染予防や，保菌動物の発生抑止のための戦略提案につながることが期待される。また，本研究が発信する病原体と宿主の相互作用や維持感染に関する新知見は，接着と運動が必須病原因子とされる様々な細菌病原体に関する研究の推進に寄与し，種間競合や異種共生といった生命システムに普遍的な問題の解決にも役立つことが期待される。