Analysis of structure of a lipoticoic acid with adjuvanticity exposed on the surface of lactic acid bacteria

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K06935
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Biofunction/Bioprocess
• Research Institution: Kansai University
• Principal Investigator: Katakura Yoshio 関西大学, 化学生命工学部, 教授 (50263207)
• Co-Investigator(Kenkyū-buntansha): 山崎 思乃 関西大学, 化学生命工学部, 准教授 (50602182)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 乳酸菌 / リポテイコ酸 / 腸管免疫

Outline of Final Research Achievements

Several strains of lactic acid bacteria contribute to the development and activation of the intestinal immune system. In this study, to understand how Lactobacillus antri JCM 15950 enhanced immunoglobulin A production, we began with identification of a component that caused immune-stimulation and analyzed its structure. This strain stimulated Toll-like receptor 2 of the host that recognizes the cell wall component of Gram-positive bacteria. In addition, the immunostimulatory activity disappeared by the removal of lipids from the bacterial cells. Based on these results, immunomodulatory component was presumed to be lipoteichoic acid (LTA). LTA was extracted from the cell wall fraction and purified using various chromatographic techniques. We found that this strain has two types of LTA, with different immunostimulatory activities. Based on the difference in the structures of these two LTAs, we predicted the partial structure important for immunostimulation.

Free Research Field

生物化学工学

Academic Significance and Societal Importance of the Research Achievements

LTAの構造と免疫調節作用との相関は、病原性細菌では一部理解されているものの、乳酸菌を含むプロバイオティクスでは不明な点が多い。幅広い世代にとって摂取が容易なプロバイオティクスの免疫賦活作用は、感染症の予防の観点からもますます注目されると考えられる。本研究の知見は、免疫賦活作用をもたらすプロバイオティクスのスクリーニング指標となるとともに、LTAの構造や表層への露出様式といった菌体の表層構造の設計に基づく機能性の向上にも貢献できると期待される。