Effect of Saccharomyces cerevisiae β-glucan on the T helper cytokine profile

ABBi16 is a high-complexity blend of β-1,3/1,6-glucans from Saccharomyces cerevisiae with strong immunomodulatory activities, that have been recently shown to support anti-tumoral immune responses through the induction of trained immunity. Whether ABBi16 also modulates the balance between the various T helper (Th) lymphocyte responses is not known. Here, we show that ABBi16 induces Th1 responses, as indicated by stimulation of IFNγ and TNF production by human peripheral blood mononuclear cells (PBMCs). Moreover, the elevated secretion of IL-10 and IL-22 suggests a potential regulatory response of the Th1/Th2/Th17 balance. Co-stimulating PBMCs with ABBi16 alongside Bacille Calmette-Guerin (BCG), IL-1beta + IL-23, and IL-12 + IL-18 cytokine combinations further enhanced Th1 polarization and IL-22 induction, hinting at an additive effect of β-glucan on both Th1 and regulatory Th17 immune responses. ABBi16 did not induce IL-17 production, the prototype pro-inflammatory product of Th17 responses, suggesting that it can be safely used as an oral supplement in patients with autoimmune conditions. These results highlight the potential of ABBi16 to regulate the Th1/Th2/Th17 balance toward antimicrobial and regulatory effects.