Induction of ALDH activity in intestinal dendritic cells by Lactobacillus plantarum NRIC0380

Lactic acid bacteria have been reported to have various immune-regulating activities. We also found in the previous study that the oral administration of heat-killed Lactobacillus plantarum NRIC0380 induced CD4(+)CD25(+)Foxp3(+) cells (Treg cells). We examine in this present study the influence of NRIC0380 on the function of intestinal dendritic cells (DCs) in vitro and in vivo. The aldehyde dehydrogenase (ALDH) activity was significantly induced in DCs obtained from the mesenteric lymph node (MLN) by culturing with NRIC0380. The oral administration of NRIC0380 also significantly increased ALDH-positive DCs in MLN. NRIC0380 significantly enhanced the production of TGF-β from MLN cells in vitro. These effects were not apparent in cells from the Peyer's patch (PP) and spleen (SPL). NRIC0380 also significantly enhanced the expression of B7-H1 on DCs of all organs in vitro. The effects of NRIC0380 on DCs, especially those located in MLN, might be involved in its function to induce Treg cells.