Effects of Dietary Yeast β-1,3/1,6-D-Glucan on Immunomodulation in RAW 264.7 Cells and Methotrexate-Treated Rat Models

A new subclass of nutraceuticals, called immunoceuticals, is dedicated to immunological regulation. Although yeast-derived β-1,3/1,6-D-glucan shows promise as an immunoceutical candidate, further studies are needed to define its precise immune-enhancing processes and to standardize its use. Following methotrexate (MTX)-induced immunosuppression in rats, we evaluated the immunomodulatory efficacy of a highly pure and standardized β-1,3/1,6-D-glucan sample (YBG) in RAW 264.7 macrophages. In in vitro and in vivo models, YBG demonstrated remarkable immunomodulatory effects, such as repair of immune organ damage, elevation of blood cytokine levels, and enhanced phagocytosis and nitric oxide production in RAW 264.7 cells. These results are consistent with the established immunostimulatory properties of β-glucan. It is noteworthy that this research indicates the potential of YBG as an immunomodulatory nutraceutical, as it is among the first to demonstrate immunological augmentation in an immunosuppression setting produced by MTX. Based on these observations, further investigation of YBG is warranted, particularly given its potential to emerge as a combination immunoceutical to mitigate immunosuppression and reduce the risk of infection in rheumatoid arthritis (RA) patients receiving long-term MTX therapy.