This study evaluated the immunostimulative effect on bone marrow-derived dendritic cells (DCs) of adjuvant-active exopolysaccharide (EPS) produced by Leuconostoc mesenteroides strain NTM048. EPS stimulation increased IL-6, IL-10, IL-12, and retinal dehydrogenase (RALDH) gene expression levels and induced retinoic acid-synthesizing RALDH-active DCs, which play a crucially important role in controlling adaptive immune responses in mucosa.