Investigation of suppressive effects on food allergy and type 1 diabetes by means of oral administration of oral bacteria.

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K10096
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 57020:Oral pathobiological science-related
• Research Institution: Asahi University
• Principal Investigator: Kataoka Hideo 朝日大学, 歯学部, 講師 (60451390)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 食物アレルギー / 微生物叢 / Ⅰ型糖尿病

Outline of Final Research Achievements

We previously reported that Citrobacter species, which have propagated in the feces of mice with food allergy and type 1 diabetes, were found to worsen allergic symptoms by inducing IL-33 production in intestinal epithelial cells. In this study, we therefore analyzed whether Citrobacter koseri induces IL-33 production in dendritic cells. Bacterial LPS derived C. koseri JCM1658 was extracted by phenol-water method. Expression of Il33 in a DC2.4 mouse dendritic cell line was detected by real time PCR. Expression of Il33 was induced by live bacteria of C. koseri, but not by extracted LPS in DC2.4. LPS reduced Expression of Il33 induced by live bacteria and DC2.4 proliferation. Live bacteria of C. koseri increased ATP concentration in the culture supernatant but LPS inhibited this increment. From the above, C. koseri increases IL-33 production through ATP production but LPS restricted the production by inhibiting dendritic cell proliferation.

Free Research Field

微生物学　免疫学

Academic Significance and Societal Importance of the Research Achievements

この研究成果は、食物アレルギーと腸内細菌の関連性を分子レベルで明らかにしたものであり、今後、食物アレルギーの予防と治療において新たな方法を確立するための知見となり得る。腸内細菌のLPSがTLR4シグナルを介して、アレルギー症状の増悪につながるTh2応答を抑制しているという知見は、常在細菌叢と自然免疫応答のバランスが免疫疾患の予防につながる可能性を示唆したものであり、食物アレルギーにとどまらず、他の免疫疾患の予防法にも応用が期待できる。