The innate immune evasion mechanism of Borrelia miyamotoi

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K20785
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0803:Pathology, infection/immunology, and related fields
• Research Institution: National Institute of Infectious Diseases
• Principal Investigator: Sato Kozue 国立感染症研究所, 細菌第一部, 流動研究員 (70911189)
• Project Period (FY): 2021-08-30 – 2023-03-31
• Keywords: 新興回帰熱 / 血清耐性機構 / ボレリア / Borrelia miyamotoi / 補体制御因子 / マダニ媒介性

Outline of Final Research Achievements

Borrelia miyamotoi was investigated by mechanism of resistance from human complement systems. In this study, we constructed gene library for outer membrane proteins gene of B. miyamotoi by borrelial competent cells which was a human serum-sensitive. Several transformants were showed a serum-resistant phenotype by evaluating serum sensitive assay. These unknown proteins were obtained for functional assay on complement pathway. As a result, the protein A specifically inhibited the classical pathway. Furthermore, the protein B did not inhibit either the classical pathway or the alternative pathway. So that, it is suggesting that involved in the inhibition of the terminal pathway that forms the membrane attack complex.

Free Research Field

マダニ媒介性感染症

Academic Significance and Societal Importance of the Research Achievements

新興回帰熱病原体Borrelia miyamotoiを含む回帰熱群ボレリアでは，自然免疫機構に対する病原体の抵抗性機序の一つとして，ヒトの補体制御因子である血中H因子を介した補体系の負の制御機構が多く知られている．本研究では，B. miyamotoi由来の新規血清耐性因子が古典経路もしくは終末経路の阻害に関与し，さらに複数の因子が存在することを見出した．新規血清耐性因子の発見は，回帰熱群ボレリアだけでなく，ボレリア属全体の病原機構解明に繋がるとともに，血清耐性因子を標的とするワクチン開発等への発展が期待される．