Debaryomyces hansenii CBS 8339 β-glucan enhances immune responses and down-stream gene signaling pathways in goat peripheral blood leukocytes

Debaryomyces hansenii-derived beta-glucan has shown immunostimulant effect on aquaculture species and recently on goat peripheral blood leukocytes. Moreover, the marine yeast D. hansenii CBS 8339 has demonstrated to enhance fish immune response. Nonetheless, the associated immune signaling pathways induced by beta-glucan from this marine yeast have not been characterized yet. This study described the effects of beta-glucan from D. hansenii CBS 8339 against challenge with Escherichia colt and activation of possible mechanisms on goat peripheral blood leukocytes. The proton nuclear magnetic resonance spectra showed that D. hansenii had beta-(1,3) (1,6)-glucan. The phagocytic ability enhanced after E. colt challenge, and nitric oxide production increased before and after challenge in leukocytes stimulated with D. hansenii beta-glucan. In addition, an early gene expression stimulation was found related to 13-glucan recognition by TLR2 and Dectin-1 receptors, intracellular regulation by Syk, TRAF6, MyD88 and transcription factor NF kappa B, and effector functions of pro-inflammatory cytokine, such as IL-1 beta and TNF-alpha. Interestingly, simulation with D. hansenii-derived beta-glucan increased leukocyte viability after E. coli challenge. In conclusion, beta-glucan from D. hansenii CBS 8339 reduced cytotoxic effects of E. colt and modulated signaling pathways and innate immune response in goat peripheral blood leukocytes.