Immunoregulatory effects of Bifidobacterium animalis subsp. animalis QC08 on cyclophosphamide-induced immunosuppression in mice.

This study investigated the immunomodulatory effects of Bifidobacterium animalis subsp. animalis QC08 on cyclophosphamide (CTX)-induced immunosuppression in male Kunming mice, randomly divided into five groups: normal, control, positive control (levamisole hydrochloride, 40 mg/kg), low-dose QC08 (2 × 108 CFU/kg), and high-dose QC08 (2 × 1010 CFU/kg). After 21 days of intervention, assessments revealed that both QC08 groups significantly improved body weight, spleen/thymus indices, and histopathological damage in thymus/spleen compared to the model group. Serum pro-inflammatory cytokines (IL-1, TNF-α, IL-6) decreased while anti-inflammatory IL-4 increased. Quantitative real-time PCR of ileal tissue showed upregulated expression of intestinal barrier genes (claudin-1, ZO-1, JAM-A, MUPP1, IKKα, IKKγ) and downregulated inflammatory signaling genes (p50, p52). These results demonstrate that QC08 effectively ameliorates CTX-induced immunosuppression by modulating immune responses and enhancing intestinal barrier integrity, supporting the potential of B. animalis subsp. animalis QC08 for immune-enhancing health food development.