Induction of Th1 cytokines by Leuconostoc mesenteroides subsp. mesenteroides (KCTC 3100) under Th2-type conditions and the requirement of NF-kappaB and p38/JNK.

Leuconostoc mesenteroides subsp. mesenteroides (LMM) KCTC 3100, is one of the prominent species in the fermentation of kimchi, a traditional Korean food. In the present study, we investigated the capacity of this microorganism in inducing Th1 cytokines in the presence of Th2 signals in vitro and in vivo and the requirement of NF-kappaB and MAPK signaling. Stimulation with heat-killed LMM in mouse splenocytes induced the expression of IFN-gamma, which was dependent on IL-12 production by LMM. Pre-treatment with LMM in vitro augmented the production of IFN-gamma and IL-4 in response to anti-CD3 plus recombinant IL-4 (rIL-4). LMM administration to mice, beginning either before or after the development of OVA sensitization, increased OVA-restimulated IFN-gamma production in the splenocytes and reduced serum total and OVA-specific IgE levels. However, only the pre-sensitization treatment induced a slight reduction in IL-4 from the same cells, but the post-sensitization treatment did not. Induction of IL-12 by LMM in peritoneal macrophages involved NF-kappaB, p38 and JNK, but not ERK1/2. In conclusion, our data presented the upregulation of IFN-gamma by LMM under the pro-Th2 conditions and the requirement of NF-kappaB, p38 and JNK for IL-12 production. These observations suggest that this microorganism can be a useful Th1-inducing agent in modulating the Th1/Th2 imbalance.