Lactiplantibacillus plantarum SLpl116 attenuates OVA-induced food allergy with ecological restoration of the gut microbiota and immune rebalancing.

Gut dysbiosis is increasingly recognized as a key contributor to food allergy, yet probiotic strains capable of restoring allergic microbiota and rebalancing host immunity remain limited. Here, we identified Lactiplantibacillus plantarum SLpl116 through a multi-criteria screening pipeline integrating anti-allergic activity, safety, and processing stability, and evaluated its efficacy in a prophylactic ovalbumin (OVA)-induced murine food allergy model. SLpl116 significantly attenuated allergic symptoms, including diarrhea and hypothermia, and suppressed serum IgE, IgG1, OVA-specific immunoglobulins, and mucosal mast cell protease-1. It was also associated with suppression of Th2-related responses and enhancement of systemic Th1-associated signaling, indicating restoration of Th1/Th2 immune balance. Microbiome analysis showed that SLpl116 was associated with ecological restoration of the dysbiotic gut community, including suppression of allergy-associated taxa such as Alistipes finegoldii and Bacteroides and enrichment of beneficial commensals, particularly Lachnospiraceae. Correlation analysis supported an association between microbial reconfiguration and immune rebalancing, while PICRUSt2-based functional prediction suggested enriched butyrate-associated metabolic potential in the effective strain groups. Comparative genome-informed analysis further indicated that SLpl116 possessed distinctive phenotype-linked features, providing a plausible molecular rationale for its favorable phenotype. Together, these findings identify SLpl116 as a promising strain-level probiotic candidate associated with direct immune rebalancing and microbiome-associated ecological restoration.