Analysis of CARD9 function in pulmonary mycobacterial infection

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K16285
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 49070:Immunology-related
• Research Institution: Fukuoka Dental College (2021-2022); Osaka University (2020)
• Principal Investigator: Toyonaga Kenji 福岡歯科大学, 口腔歯学部, 助教 (90791567)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 宿主防御 / 抗酸菌感染 / Th1応答

Outline of Final Research Achievements

CARD9 is known to play an essential role in innate immune signaling via C-type lectin receptors. CARD9-deficient mice were shown to be highly susceptible to Mycobacterium tuberculosis. In CARD9-deficient mice, the antigen-specific T cell response after infection is comparable to that of wild-type (WT) mice, and it is thus considered that CARD9 deficiency affects innate immunity rather than acquired T cell responses during infection. However, the contribution of CARD9 to early mycobacterial infection is poorly understood.
To clarify the role of CARD9 in the early stages of mycobacterial infection, CARD9-deficient mice were infected intratracheally with M. bovis BCG. We found that bacterial loads in the lungs were comparable between WT and CARD9-deficient mice 7 and 21 days after infection. These results suggest that CARD9 might not contribute to the elimination of bacteria in the early stages of pulmonary M. bovis BCG infection.

Free Research Field

免疫学

Academic Significance and Societal Importance of the Research Achievements

マウス感染モデルを用いた解析や、様々な疫学的知見から、CARD9を介した自然免疫活性化は、病原体感染に対する重要な宿主防御機構の一つと考えられ、CARD9経路を増強させることによって、病原体の排除を促す試みもいくつか行われている。このことから、本研究において見出した知見は、CARD9を介した免疫活性化機構の解明だけでなく、関連する感染性疾患の新規治療法開発にも繋がる可能性がある。