title: Nod2-mediated recognition of the microbiota is critical for mucosal adjuvant activity of cholera toxin.
abstract: Cholera toxin (CT) is a potent adjuvant for inducing mucosal immune responses. However, the mechanism by which CT induces adjuvant activity remains unclear. Here we show that the microbiota is critical for inducing antigen-specific IgG production after intranasal immunization. After mucosal vaccination with CT, both antibiotic-treated and germ-free (GF) mice had reduced amounts of antigen-specific IgG, smaller recall-stimulated cytokine responses, impaired follicular helper T (TFH) cell responses and reduced numbers of plasma cells. Recognition of symbiotic bacteria via the nucleotide-binding oligomerization domain containing 2 (Nod2) sensor in cells that express the integrin CD11c (encoded by Itgax) was required for the adjuvanticity of CT. Reconstitution of GF mice with a Nod2 agonist or monocolonization with Staphylococcus sciuri, which has high Nod2-stimulatory activity, was sufficient to promote robust CT adjuvant activity, whereas bacteria with low Nod2-stimulatory activity did not. Mechanistically, CT enhanced Nod2-mediated cytokine production in dendritic cells via intracellular cyclic AMP. These results show a role for the microbiota and the intracellular receptor Nod2 in promoting the mucosal adjuvant activity of CT.
authors.affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, USA.|Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan, USA.
authors.forename: Donghyun
authors.identifier: 0000-0002-5137-2213
authors.initials: D
authors.lastname: Kim
authors.affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, USA.|Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan, USA.
authors.forename: Yun-Gi
authors.initials: YG
authors.lastname: Kim
authors.affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, USA.|Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan, USA.
authors.forename: Sang-Uk
authors.initials: SU
authors.lastname: Seo
authors.affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, USA.|Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan, USA.
authors.forename: Dong-Jae
authors.initials: DJ
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, Michigan, USA.
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Kamada
authors.affiliation: Department of Immunology, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Dave
authors.initials: D
authors.lastname: Prescott
authors.forename: Mathias
authors.initials: M
authors.lastname: Chamaillard
authors.affiliation: Department of Immunology, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Dana J
authors.initials: DJ
authors.lastname: Philpott
authors.affiliation: Institute of Clinical Molecular Biology, University of Kiel, Kiel, Germany.
authors.forename: Philip
authors.initials: P
authors.lastname: Rosenstiel
authors.affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, USA.|Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan, USA.
authors.forename: Naohiro
authors.initials: N
authors.lastname: Inohara
authors.affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, USA.|Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan, USA.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Núñez
mesh_terms: D000119:Acetylmuramyl-Alanyl-Isoglutamine / Q000494:pharmacology; D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D039521:CD11c Antigen / Q000378:metabolism; D002772:Cholera Toxin / Q000494:pharmacology*; D000242:Cyclic AMP / Q000276:immunology; D016207:Cytokines / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology; D058501:Enzyme-Linked Immunospot Assay; D005434:Flow Cytometry; D005856:Germ-Free Life / Q000276:immunology*; D018928:Immunity, Mucosal / Q000187:drug effects* / Q000276:immunology; D051379:Mice; D018345:Mice, Knockout; D064307:Microbiota / Q000187:drug effects* / Q000276:immunology; D009092:Mucous Membrane / Q000276:immunology; D009297:Nasal Mucosa / Q000276:immunology; D053473:Nod2 Signaling Adaptor Protein / Q000819:agonists / Q000187:drug effects* / Q000276:immunology; D060888:Real-Time Polymerase Chain Reaction; D013154:Spleen / Q000166:cytology; D013203:Staphylococcal Infections / Q000276:immunology*; D013210:Staphylococcus
chemical_list: D000276:Adjuvants, Immunologic; D000900:Anti-Bacterial Agents; D039521:CD11c Antigen; D016207:Cytokines; D053473:Nod2 Signaling Adaptor Protein; C495945:Nod2 protein, mouse; D000119:Acetylmuramyl-Alanyl-Isoglutamine; D002772:Cholera Toxin; D000242:Cyclic AMP