Acquired anti-tick immunity involving mast cells and complement

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K07620
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 49070:Immunology-related
• Research Institution: Okayama University
• Principal Investigator: Yoshikawa Soichiro 岡山大学, 医歯薬学域, 助教 (10549926)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: マスト細胞 / 好塩基球 / 補体 / マダニ / 獲得免疫

Outline of Final Research Achievements

Ticks are blood-sucking ectoparasites that transmit several disease-causing pathogens to their host animals and humans. For certain combinations of animal and tick species, tick infestation elicits acquired tick immunity (ATR) in the host, which can decrease the ability of ticks to feed on blood and transmit pathogens in subsequent tick infestations. Determining the cellular and molecular mechanisms of ATR can advance the development of anti-tick vaccines that prevent tick infestation and tick-borne diseases. In mice infested with larval H longicornis ticks, both mast cells and basophils reportedly play essential roles in ATR. The roles of basophils in ATR have been widely examined, however, the involvement of mast cells remains unclear. We found that mast cells converted C5 to C5a, affecting the mobilization and accumulation of basophils around tick-bite sites during re-infestation. Thus, mast cells may attract basophils around tick-bite sites via C5a/C5aR1 signaling to result in ATR.

Free Research Field

免疫学

Academic Significance and Societal Importance of the Research Achievements

これまで、マダニ媒介性感染症はマダニ感染を防ぐことが最も効果的な対処方法であると考えられてきており、そのために殺ダニ剤などが多く用いられてきたが、薬剤耐性マダニの出現も大きな問題となっており、これに代わる手段としてワクチンを用いた手段が期待されている。　本研究において、その分子メカニズムを明らかになったため、効果的な抗マダニワクチンの開発に繋がり、学術・社会学的な意義も大きく、波及効果も高い。