Bakuchicin (BKC), dexamethasone (DEX), AGK2, ovalbumin (OVA), and LPS (Escherichia coli, 055:B5) were purchased from Sigma-Aldrich (St. Louis, MO, USA). The alum adjuvant was purchased from Thermo Scienti c (Waltham, MA, USA). The enzyme-linked immunosorbent assay kits for mouse TNF-α, IL-1β, IL-4, IL-5, IL-6, IgE, IgG1, and IgG2a were purchased from BD Biosciences (San Diego, CA, USA).