Effect of Euglena gracilis EOD-1 species-derived paramylon intake on lung mucosal anti-β-glucan IgA antibody production in mice

Paramylon (PM) is an insoluble dietary fiber derived from Euglena gracilis . Mechanisms underlying the health-promoting effects of Paramylon ingestion remain unclear. Hence, this study aimed to investigate the effect of PM derived from E. gracilis strain EOD-1 (EOD1PM) intake on mucosal antibody production, elucidate its mechanism, and clarify its effect on infection prevention. EOD1PM ingestion in mice increased anti- β-glucan IgA antibody titer. The anti- Candida β-glucan IgA antibody titer in bronchoalveolar lavage was higher in the EOD1PM group than that in the control. EOD1PM intake also increased interleukin-6- and inducible nitric oxide synthase-producing cells involved in IgA class switching. EOD1PM is suggested to induces IgA production following recognition by Dectin-1. Collectively, EOD1PM induces IgA-producing cells in the intestine and promotes IgA production in the respiratory mucosa, potentially via immune cell activation. The findings suggested that EOD1PM activated mucosal immunity, potentially contributing to prevention of respiratory infections.