Objective The aim of this study was to examine whether immune tolerance was reversed by trained immunity in both in vivo and in vitro models. Methods Glucan is a prototypical trained immunity inducer. To establish the in vitro trained immunity model, BMDMs were stimulated with 40 μg / mL β-glucan for 24 h. BMDMs were washed once with warm PBS. After 24 h, they were incubated for 6 days in culture medium that was changed once at day 3. Trained BMDMs were stimulated with 100 ng / mL LPS at day 7. To establish the in vivo trained immunity model, wildtype C57BL/6J mice were injected intraperitoneally with 1 mg β-glucan in 200 mL PBS. As a control, intraperitoneal injection of PBS alone was performed. After 7 days, mice were infected with Staphylococcus aureus intraperitoneally (1 × 10⁴ / 200 mL PBS per mice). BMDMs were stimulated with LPS to induce immune tolerance in vitro. β-glucan was added at 24 h post-LPS stimulation to reverse immune tolerance. Cytokine production capacity was determined by LPS restimulation. CLP was carried out in mice to induce immune tolerance in vivo. Intraperitoneal injection of 1 mg β-glucan was performed to reverse CLP-induced tolerance. The efficacy of tolerance reversal was reflected by the survival rate post-reinfection with non-lethal doses of bacteria or fungi. Results (1)Glucan-trained BMDMs produced higher levels of proinflammatory cytokines, such as TNF-α and IL-6, and more nitric oxide. The energy metabolism of trained macrophages shifted to aerobic glycolysis, leading to lactate accumulation and enhanced m-TOR activation. (2)β-glucan-induced trained immunity was protective in vivo. (3) β-glucan reversed LPS-induced immune tolerance in vitro. (4) Administration of β-glucan did not reverse the CLP-induced immune tolerance in the current experimental setting. Conclusion This study successfully established β- glucan trained immune models in vitro and in vivo, and demonstrated that β-glucan can reverse LPS-induced immune tolerance in vitro. However, the current Results have not confirmed that β-glucan can reverse CLP-induced immune tolerance in vivo and improve secondary infection survival.