Abstract
Edible mushrooms are promising sources of immunomodulatory β-glucans, yet the in vivo immunological effects of Pleurotus sajor-caju remain incompletely understood. This study investigated the immunomodulatory activity of a characterized, β-glucan-rich vinegar extract of P. sajor-caju (VPSC) in an ovalbumin (OVA)-sensitized BALB/c mouse model. Mice received orally vehicle, VPSC or ginseng extract (Positive Control) for 10 weeks, comprising 6 weeks of pretreatment and 4 weeks of OVA immunization. VPSC attenuated OVA-induced splenomegaly and enhanced ex vivo macrophage phagocytosis, natural killer (NK) cell cytotoxicity, and ex vivo stimulus-induced splenocyte proliferation. VPSC also modulated adaptive immune responses by enhancing Th1-associated IFN-γ and IL-2 production while suppressing Th2-associated IL-4 and reducing IL-6 at the highest dose. These changes were accompanied by decreased serum anti-OVA IgE and IgG1 levels. Flow cytometry analysis further revealed normalization of OVA-associated increases in splenic CD4+CD25+ T-cell proportions without substantial changes in major lymphocyte subsets. Complementary molecular docking predicted favorable interactions between a representative β-(1,3)-glucan oligomer (laminarihexaose) and the innate immune receptors Dectin-1 and TLR2. Collectively, these findings demonstrate the potential of VPSC to modulate innate and adaptive immune responses and support its further investigation as a functional food ingredient for promoting immune health.