title: Low-dose tolerance is mediated by the microfold cell ligand, reovirus protein sigma1.
abstract: Mucosal tolerance induction generally requires multiple or large Ag doses. Because microfold (M) cells have been implicated as being important for mucosal tolerance induction and because reovirus attachment protein sigma1 (psigma1) is capable of binding M cells, we postulated that targeting a model Ag to M cells via psigma1 could induce a state of unresponsiveness. Accordingly, a genetic fusion between OVA and the M cell ligand, reovirus psigma1, termed OVA-psigma1, was developed to enhance tolerogen uptake. When applied nasally, not parenterally, as little as a single dose of OVA-psigma1 failed to induce OVA-specific Abs even in the presence of adjuvant. Moreover, the mice remained unresponsive to peripheral OVA challenge, unlike mice given multiple nasal OVA doses that rendered them responsive to OVA. The observed unresponsiveness to OVA-psigma1 could be adoptively transferred using cervical lymph node CD4(+) T cells, which failed to undergo proliferative or delayed-type hypersensitivity responses in recipients. To discern the cytokines responsible as a mechanism for this unresponsiveness, restimulation assays revealed increased production of regulatory cytokines, IL-4, IL-10, and TGF-beta1, with greatly reduced IL-17 and IFN-gamma. The induced IL-10 was derived predominantly from FoxP3(+)CD25(+)CD4(+) T cells. No FoxP3(+)CD25(+)CD4(+) T cells were induced in OVA-psigma1-dosed IL-10-deficient (IL-10(-/-)) mice, and despite showing increased TGF-beta1 synthesis, these mice were responsive to OVA. These data demonstrate the feasibility of using psigma1 as a mucosal delivery platform specifically for low-dose tolerance induction.
authors.affiliation: Veterinary Molecular Biology, Montana State University, Bozeman, MT 59718, USA.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Rynda
authors.forename: Massimo
authors.initials: M
authors.lastname: Maddaloni
authors.forename: Dagmara
authors.initials: D
authors.lastname: Mierzejewska
authors.forename: Javier
authors.initials: J
authors.lastname: Ochoa-Repáraz
authors.forename: Tomasz
authors.initials: T
authors.lastname: Maslanka
authors.forename: Kathryn
authors.initials: K
authors.lastname: Crist
authors.forename: Carol
authors.initials: C
authors.lastname: Riccardi
authors.forename: Beata
authors.initials: B
authors.lastname: Barszczewska
authors.forename: Kohtaro
authors.initials: K
authors.lastname: Fujihashi
authors.forename: Jerry R
authors.initials: JR
authors.lastname: McGhee
authors.forename: David W
authors.initials: DW
authors.lastname: Pascual
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D017209:Apoptosis; D001402:B-Lymphocytes / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D036022:Capsid Proteins / Q000276:immunology*; D016207:Cytokines / Q000276:immunology / Q000378:metabolism; D005260:Female; D007108:Immune Tolerance; D007114:Immunization; D016753:Interleukin-10 / Q000276:immunology / Q000378:metabolism*; D008024:Ligands; D008213:Lymphocyte Activation; D051379:Mice; D008817:Mice, Mutant Strains; D018165:Orthoreovirus / Q000276:immunology; D010047:Ovalbumin / Q000008:administration & dosage / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D036022:Capsid Proteins; D016207:Cytokines; D008024:Ligands; D011993:Recombinant Fusion Proteins; C031728:sigma 1 protein, reovirus; D016753:Interleukin-10; D010047:Ovalbumin