Investigating the Immune-Stimulating Potential of β-Glucan from Aureobasidium pullulans in Cancer Immunotherapy.

β-glucan, a polysaccharide found in various sources, exhibits unique physicochemical properties, yet its high polymerization limits clinical applications because of its solubility. Addressing this limitation, we introduce PPTEE-glycan, a highly purified soluble β-1,3/1,6-glucan derived from Aureobasidium pullulans . The refined PPTEE-glycan demonstrated robust immune stimulation in vitro , activated dendritic cells, and enhanced co-stimulatory markers, cytokines, and cross-presentation. Formulated as a PPTEE + microemulsion (ME), it elevated immune responses in vivo , promoting antigen-specific antibodies and CD8+ T cell proliferation. Intratumoral administration of PPTEE + ME in tumor-bearing mice induced notable tumor regression, which was linked to the activation of immunosuppressive cells. This study highlights the potential of high-purity Aureobasidium pullulans -derived β-glucan, particularly PPTEE, as promising immune adjuvants, offering novel avenues for advancing cancer immunotherapy.