Infection by oral mitis group streptococci induces impairment of mast cell function and allergic response

2020 Fiscal Year Final Research Report

• Project/Area Number: 17K11958
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Orthodontics/Pediatric dentistry
• Research Institution: Osaka University
• Principal Investigator: Okahashi Nobuo 大阪大学, 歯学研究科, 准教授 (40150180)
• Co-Investigator(Kenkyū-buntansha): 中田 匡宣 鹿児島大学, 医歯学域歯学系, 教授 (90444497)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Keywords: 口腔レンサ球菌 / マスト細胞 / アレルギー / 細胞死

Outline of Final Research Achievements

Mast cells play central roles in allergic reaction. In this study, we found that H2O2 produced by mitis group streptococci such as Streptococcus oralis reduced degranulation of mast cells stimulated with IgE-antigen complex. The reduction of the degranulation was related to the H2O2-induced cell death. Lysosomal dysfunction by H2O2 seemed to contribute to the unique cell death. Using mouse model of pollen allergy, we found that streptococcus-derived H2O2 reduced the sneezing of the sensitized mice challenged with cedar pollen. These results suggest that H2O2 produced by the oral mitis group streptococci is able to disrupt the host allergic reaction.

Free Research Field

口腔細菌学

Academic Significance and Societal Importance of the Research Achievements

口腔ミティス群レンサ球菌が産生する低濃度の過酸化水素が宿主の免疫応答やアレルギー応答に影響を与える可能性が示された．口腔常在細菌の代謝産物にそのような作用があることは従来全く想定されておらず、常在細菌が宿主に与える影響を考え直す必要があるのではないかと思われる．