title: Oral tolerance induction with antigen conjugated to cholera toxin B subunit generates both Foxp3+CD25+ and Foxp3-CD25- CD4+ regulatory T cells.
abstract: Oral administration of Ag coupled to cholera toxin B subunit (CTB) efficiently induces peripheral immunological tolerance. We investigated the extent to which this oral tolerance is mediated by CD25+CD4+ regulatory T cells (T(reg)). We found that total T(reg), KJ1-26+ T(reg) and CTLA-4+ T(reg) were all increased in Peyer's patches, mesenteric lymph nodes, and, to a lesser extent, in spleen of mice after intragastric administration of OVA/CTB conjugate, which also increased TGF-beta in serum. This could be abolished by co-administering cholera toxin or by treatment with anti-TGF-beta mAb. CD25+ T(reg), but also CD25-CD4+ T cells from OVA/CTB-treated BALB/c or DO11.10 mice efficiently suppressed effector T cell proliferation and IL-2 production in vitro. Following adoptive transfer, both T cell populations also suppressed OVA-specific T cell and delayed-type hypersensitivity responses in vivo. Foxp3 was strongly expressed by CD25+ T(reg) from OVA/CTB-treated mice, and treatment also markedly expanded CD25+Foxp3+ T(reg). Furthermore, in Rag1(-/-) mice that had adoptively received highly purified Foxp3-CD25-CD4+ OT-II T cells OVA/CTB feeding efficiently induced CD25+ T(reg) cells, which expressed Foxp3 more strongly than naturally developing T(reg) and also had stronger ability to suppress effector OT-II T cell proliferation. A remaining CD25- T cell population, which also became suppressive in response to OVA/CTB treatment, did not express Foxp3. Our results demonstrate that oral tolerance induced by CTB-conjugated Ag is associated with increase in TGF-beta and in both the frequency and suppressive capacity of Foxp3+ and CTLA-4+ CD25+ T(reg) together with the generation of both Foxp3+ and Foxp3-CD25- CD4+ T(reg).
authors.affiliation: Department of Microbiology and Immunology, Institute of Biomedicine and Göteborg University Vaccine Research Institute, Sahlgrenska Academy at Göteborg University, 405 30 Göteborg, Sweden. jia-bin.sun@microbio.gu.se
authors.forename: Jia-Bin
authors.initials: JB
authors.lastname: Sun
authors.forename: Sukanya
authors.initials: S
authors.lastname: Raghavan
authors.forename: Asa
authors.initials: A
authors.lastname: Sjöling
authors.forename: Samuel
authors.initials: S
authors.lastname: Lundin
authors.forename: Jan
authors.initials: J
authors.lastname: Holmgren
mesh_terms: D000284:Administration, Oral; D019264:Adoptive Transfer; D000818:Animals; D049109:Cell Proliferation; D002772:Cholera Toxin / Q000008:administration & dosage / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000276:immunology / Q000378:metabolism*; D007108:Immune Tolerance; D007376:Interleukin-2 / Q000096:biosynthesis; D053645:Interleukin-2 Receptor alpha Subunit / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010047:Ovalbumin / Q000008:administration & dosage / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse; D007376:Interleukin-2; D053645:Interleukin-2 Receptor alpha Subunit; D010047:Ovalbumin; D002772:Cholera Toxin