Immunoenhancing Effect of Lactobacillus Kefiranofaciens ZW18 Postbiotic On Cyclophosphamide-induced Immunosuppressed...

Lactobacillus kefiranofaciens, a lactic acid bacterium isolated from kefir grains, has various probiotic functions, including antioxidant activity, improvement of intestinal health, and immunomodulation. However, the effect of its postbiotic on immune modulation has been rarely reported. In this study, the immunomodulatory activities of the Lactobacillus kefiranofaciens ZW18 postbiotic (Post-ZW18) were investigated both in vitro and in vivo. We discovered that Post-ZW18 increased the phagocytosis of RAW264.7 cells (P > 0.05) and promoted the secretion of cytokines, including NO, IL-6, and TNF-α (P < 0.05), thereby activating the immune response in macrophages in vitro. In vivo, Post-ZW18 reversed cyclophosphamide (CTX)-induced weight loss and organ damage in immunosuppressed mice (P < 0.05), and enhanced the immune response by activating the TLR2/NF-κB signaling pathway, promoting T cell activation and differentiation, and modulating the production of cytokines such as TNF-α, IL-6, and INF-γ (P < 0.05). Furthermore, Post-ZW18 remodeled the intestinal flora, increased the Firmicutes/Bacteroidetes (F/B) ratio (P > 0.05), and upregulated the abundance of bacteria associated with immune activation, specifically increasing unclassified_Lachnospiraceae, Odoribacter, and Lachnospiraceae_NK4A136_group (P < 0.05). In summary, this study provided evidence that Post-ZW18 may serve as a novel dietary supplement for immune regulation.