title: Cutting edge: Immunosuppressant as adjuvant for tolerogenic immunization.
abstract: Vaccination for autoimmune and alloimmune diseases has long been an attractive idea. Yet, there is no suitable adjuvant to forcefully steer the immune response toward tolerance. In this study we show that dexamethasone, a potent glucocorticoid immunosuppressant, can function as a tolerogenic adjuvant when applied together with peptide immunogen. BALB/c mice with pre-established delayed-type hypersensitivity to hen OVA were immunized with an OVA-derived, MHC II-restricted peptide (OVA(323-339)) in the presence of dexamethasone. The treatment caused long-term desensitization in treated animals to hen OVA via a dexamethasone-dependent tolerogenic mechanism that blocks maturation of dendritic cells and expands OVA(323-339)-specific CD4(+)CD25(+)Foxp3(+) regulatory T cells in vivo. Similar treatment of NOD mice using dexamethasone and an insulin-derived, MHC II-restricted peptide (B:9-23) prevented predisposed spontaneous diabetes. Remarkably, in both models, dexamethasone-augmented immunization induced long-term persistent, Ag-specific regulatory T cells responsive to recall Ags. These results reveal for the first time the potential usefulness of immunosuppressants as tolerogenic adjuvants.
authors.affiliation: Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, Illinois 61107, USA.
authors.forename: Youmin
authors.initials: Y
authors.lastname: Kang
authors.forename: Lipeng
authors.initials: L
authors.lastname: Xu
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.forename: Aoshuang
authors.initials: A
authors.lastname: Chen
authors.forename: Guoxing
authors.initials: G
authors.lastname: Zheng
mesh_terms: D000276:Adjuvants, Immunologic; D000818:Animals; D003907:Dexamethasone / Q000008:administration & dosage / Q000276:immunology*; D005938:Glucocorticoids / Q000008:administration & dosage / Q000276:immunology; D006968:Hypersensitivity, Delayed / Q000276:immunology / Q000517:prevention & control*; D007108:Immune Tolerance; D007114:Immunization; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000276:immunology*; D007328:Insulin / Q000008:administration & dosage / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D016688:Mice, Inbred NOD; D008822:Mice, Transgenic; D010047:Ovalbumin / Q000276:immunology; D010455:Peptides / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D005938:Glucocorticoids; D007166:Immunosuppressive Agents; D007328:Insulin; D010455:Peptides; D003907:Dexamethasone; D010047:Ovalbumin