Molecular mechanism of activation and regulation of immune response by thrombocytes in fish

2016 Fiscal Year Final Research Report

• Project/Area Number: 25292127
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Aquatic life science
• Research Institution: Kyushu University
• Principal Investigator: Nakao Miki 九州大学, (連合)農学研究科(研究院), 教授 (50212080)
• Co-Investigator(Kenkyū-buntansha): 杣本 智軌 九州大学, (連合)農学研究科(研究院), 准教授 (40403993)
• Project Period (FY): 2013-04-01 – 2017-03-31
• Keywords: 魚類 / 栓球 / 免疫 / 血液凝固 / 白血球 / 食細胞 / 貪食活性

Outline of Final Research Achievements

Thrombocytes are regarded as the functional equivalent of anucleated mammalian platelets. Additional immune functions, including phagocytosis, have also been suggested, but no conclusive experimental evidence for their potential ingestion and clearance of infiltrating microbes has been provided till date. Here we demonstrate the active phagocytic ability of thrombocytes in lower vertebrates using teleost fishes and amphibian models. Carp thrombocytes were able to ingest live bacteria and kill them. We found that thrombocytes represented nearly half of the phagocyte population in the common carp total peripheral blood leukocyte pool. Phagocytosis efficiency was further enhanced by serum opsonization. Particle internalization led to phagolysosome fusion and killing of internalized bacteria, pointing to a robust ability for microbe elimination. We find that this potent phagocytic activity is shared across fish and frogs, implying its conservation throughout the lower vertebrate lineage.

Free Research Field

比較免疫学