ORAL EXPOSURE TO YEAST-DERIVED BETA-GLUCAN INDUCES INNATE IMMUNE PRIMING IN VARIOUS IMMUNE COMPARTMENTS IN MICE

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Description

Numerous in vitro and in vivo studies in animals and humans have demonstrated immunostimulatory effects of yeast and fungal β-glucans. Data on the in vivo effects have largely been obtained after systemic (either intraperitoneal or intravenous) administration. Oral administration provides a more applicable way for humans to consume β-glucans, but evidence for immune-enhancing effects after oral intake is limited. In the present study, we therefore investigated whether oral exposure to yeastderived whole β-glucan particle (WGP) induces innate immune priming in mice. C57BL/6 mice were fed either a control diet or a diet supplemented with WGP at a concentration of 1, 2.5, or 5% w/w for two weeks. Mice were subsequently sacrificed and cells from the bone marrow, blood, and spleen were harvested for ex vivo stimulation with LPS, PAM3Cys, or heat-killed Pseudomonas aeruginosa (HK-PA). Supernatants were collected and analyzed for TNFα and IL-6 concentrations. Oral exposure to 1 and 2.5% w/w WGP enhanced the TNFα and IL-6 production upon LPS, PAM3Cys, and HK-PA stimulation in adherent bone marrow cells compared to control animals. Comparable effects were observed when the whole bone marrow population was stimulated. Five percent w/w WGP did not affect the cytokine production in both cell populations. Priming effects were also observed after whole blood stimulation with LPS. All three WGP-enriched diets increased the TNFα production compared to animals on control diet. No effects were observed for IL-6. In the spleen, cytokine production was not affected by oral exposure to WGP, neither in the whole splenocyte population nor in the adherent cells. To our knowledge, this is the first demonstration where oral exposure to β-glucans resulted in immune priming in mouse blood and bone marrow compartments. Strongest effects were observed at the lower concentrations tested, namely at 1 and 2.5% w/w. The potency of dietary β-glucans to enhance the responsiveness of the immune system needs to be substantiated in future human trials, with a particular focus on dosage.
Period29 May 202331 May 2023
Event title5th International Symposium on Trained Immunity
Event typeConference
LocationNapoli, ItalyShow on map