TITLE:
Anti-Allergic Effect of Soluble Beta-Glucan on Japanese Cedar Pollinosis and Mechanism Underlying Its Allergy-Ameliorating Action
AUTHORS:
Mutsumi Tanaka, Tetsu Sawamoto, Keiko Mizuyama, Fusako Mitsunaga, Shin Nakamura
KEYWORDS:
Functional Foods, Pollinosis, Dectin-1, DNA Microarray
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.17 No.10,
October
28,
2026
ABSTRACT: Background: Japanese cedar (sugi) pollinosis is triggered by sensitization to sugi pollen, which contains sugi antigens, sugi basic proteins (SBP: Cryj1 and Cryj2), and adjuvant polysaccharides, including insoluble β-glucan particles (IBGN: a dectin-1 agonist). The presence of IBGN in sugi pollen enhances the production of SBP-specific IgE, which contributes to the inflammatory response through mast cell activation, leading to degranulation and resulting in symptoms such as sneezing. Another β-glucan derived from black yeast, soluble β-glucan (SBGN: a dectin-1 antagonist), is recognized for its anti-allergic properties. Objective: This study aimed to elucidate the anti-allergic effects of SBGN and to uncover the mechanisms underlying its anti-allergic action in a mouse model of sugi pollinosis. Methods: Mice were utilized in both studies, focusing on the pollinosis model and gut microbiota. The study on pollinosis comprised three groups: a control group (Ctr), a pollinosis group (Polli), and an SBGN-administered pollinosis group (SBGN + Polli). A DNA microarray was employed to uncover molecular events associated with SBGN-mediated anti-allergic action using RNA extracted from the iliac lymph nodes of the three groups. The gut microbiota was analyzed using real-time PCR on DNA samples from the two groups. Results: Oral administration of SBGN suppressed both SBP-specific IgE production and SBP-induced sneezing in the sugi pollinosis mouse model. DNA microarray analyses revealed that SBGN mitigated the dysregulated expression of 19 immune-inflammatory genes, including Igk and Chi3l3, which were abnormally up- or down-regulated in the iliac lymph nodes of mice with sugi pollinosis. Furthermore, SBGN administration affected gut microbiota by increasing probiotic bacteria such as bifidobacteria, which are known to produce short-chain fatty acids (SCFAs). Conclusion: SBGN exhibited anti-allergic effects against sugi pollinosis by inhibiting the immune response (SBP-induced IgE production) and by reducing the inflammatory reaction (SBP-induced sneezing). Additionally, SBGN was shown to increase SCFA-producing gut bacteria, thereby suggesting a role in regulating mast cell activation.