Immunostimulatory effects of dietary Lactococcus lactis subsp. lactis KCCM13334P from rice wine on macrophages and cyclophosphamide-induced immunosuppressed mice via Toll-like receptor 2

Lactococcus lactis subsp. lactis KCCM13334P (KMGR) is present in the traditional Korean rice wine Makgeolli, analyzed the characteristics and functional annotation of the whole genome. Results showed that IFN-γ-primed RAW 264.7 cells, treatment with KMGR (6.25, 12.5, or 25 μg/mL) significantly enhanced immune response mediator and cytokines production. KMGR significantly activated NF-κB and AP-1 signaling pathways. KMGR improved macrophage activity by stimulating TAK1 and TRAF6 via TLR2 signaling. In CTX-induced immunosuppressed mice, KMGR administration recovered body weight and spleen and mesenteric lymph node indices. KMGR restored CTX-suppressed natural killer cell activity and populations of immune cells. Additionally, KMGR repaired the CTX-induced histological structure of the colon and the expression of tight junction proteins, mucin-2, and TLR2. KMGR treatment maintained a gut microbiota composition similar to the control groups. Taken together, our data suggest that KMGR shows potential as a functional postbiotic with immune-enhancing activity.