biostudies-literatureKawanabe-Matsuda HJapan Agency for Medical Research and DevelopmentMinistry of Education, Culture, Sports, Science and TechnologyNational Health and Medical Research Council1336-1355https://www.ebi.ac.uk/biostudies/studies/S-EPMC9662940biostudies-literatureUnknown12(5)Microbes and their byproducts have been reported to regulate host health and immune functions. Here we demonstrated that microbial exopolysaccharide produced by Lactobacillus delbrueckii subsp. bulgaricus OLL1073R-1 (EPS-R1) induced CCR6+ CD8+ T cells of mice and humans. In mice, ingestion of EPS-R1 augmented antitumor effects of anti-CTLA-4 or anti-PD-1 monoclonal antibody against CCL20-expressing tumors, in which infiltrating CCR6+ CD8+ T cells were increased and produced IFNγ accompanied by a substantial immune response gene expression signature maintaining T-cell functions. Of note, the antitumor adjuvant effect of EPS-R1 was also observed in germ-free mice. Furthermore, the induction of CCR6 expression was mediated through the phosphorylated structure in EPS-R1 and a lysophosphatidic Cancer discoveryDietary Lactobacillus-Derived Exopolysaccharide Enhances Immune-Checkpoint Blockade Therapy.PMC96629401173958 and 113251915K1441020gm0010004h990419H0336618K19483 and 18H02695Okumura KNakamura MKano KEberl GKawanabe-Matsuda HNishimukai MMakino SAoki JBoneca IGOhno TUwamizu AOmi JYagita HTakeda KKarasaki TKakimi KSmyth MJfalseDietary Lactobacillus-Derived Exopolysaccharide Enhances Immune-Checkpoint Blockade Therapy.Microbes and their byproducts have been reported to regulate host health and immune functions. Here we demonstrated that microbial exopolysaccharide produced by Lactobacillus delbrueckii subsp. bulgaricus OLL1073R-1 (EPS-R1) induced CCR6+ CD8+ T cells of mice and humans. In mice, ingestion of EPS-R1 augmented antitumor effects of anti-CTLA-4 or anti-PD-1 monoclonal antibody against CCL20-expressing tumors, in which infiltrating CCR6+ CD8+ T cells were increased and produced IFNγ accompanied by a substantial immune response gene expression signature maintaining T-cell functions. Of note, the antitumor adjuvant effect of EPS-R1 was also observed in germ-free mice. Furthermore, the induction of CCR6 expression was mediated through the phosphorylated structure in EPS-R1 and a lysophosphatidic 2022-01-01T00:00:00Z2022 May2026-05-28T22:40:06.819Z2025-04-04T20:21:48.002ZS-EPMC96629403518030310.1158/2159-8290.CD-21-0929