Regulation of T-cell activation and cellular immune response by intracellular activation of complement C3 in fish

2022 Fiscal Year Final Research Report

• Project/Area Number: 19H03050
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 40040:Aquatic life science-related
• Research Institution: Kyushu University
• Principal Investigator: NAKAO Miki 九州大学, 農学研究院, 教授 (50212080)
• Co-Investigator(Kenkyū-buntansha): 杣本 智軌 九州大学, 農学研究院, 准教授 (40403993)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 補体 / C3 / 細胞内活性化 / コイ / 白血球

Outline of Final Research Achievements

Recently, physiological effects of intracellular complement activation in mammals have attracted much attention, but its phylogenetic development has not been investigated at all. To elucidate the phylogeny and physiological function of intracellular complement activation, this study aimed to detect activated fragments of the complement component C3 in carp leukocyte cells and to identify proteases involved in intracellular C3 fragmentation. The results suggested that C3 is present in carp leukocytes and undergoes limited hydrolysis, which is different from complement activation, on a permanent basis, and that little remains in the unactivated form; that this limited hydrolysis is caused by proteases other than cathepsin L, unlike that reported for human cells; and that C3 may be taken up and fragmented from the extracellular C3 from outside the cell and fragmentation.

Free Research Field

比較免疫学

Academic Significance and Societal Importance of the Research Achievements

本研究では、プロテアーゼの特定には至らなかったものの、コイPBL内C3の存在と断片化が示された。本研究成果は、学術的には細胞内補体系の系統発生と生理機能の理解を深める重要な知見であるだけでなく、細胞内補体活性化を指標とした、魚類の生体防御能レベルのモニタリング法の開発などの応用につながると期待される。