title: Engraftment of retrovirally transduced Bet v 1-GFP expressing bone marrow cells leads to allergen-specific tolerance.
abstract: Molecular chimerism is a promising strategy to induce tolerance to disease-causing antigens expressed on genetically modified haematopoietic stem cells. The approach was employed successfully in models of autoimmunity and organ transplantation. Recently, we demonstrated that molecular chimerism induces robust and lasting tolerance towards the major grass pollen allergen Phl p 5. Since allergens are a group of antigens differing widely in their function, origin and structure we further examined the effectiveness of molecular chimerism using the Phl p 5-unrelated major birch pollen allergen Bet v 1, co-expressed with the reporter GFP. Besides, inhibition of CD26 was used to promote engraftment of modified stem cells. Retrovirus VSV-Betv1-GFP was generated to transduce 5-FU-mobilized BALB/c hematopoietic cells to express membrane-bound Bet v 1 (VSV-GFP virus was used as control). Myeloablated BALB/c mice received Betv1-GFP or GFP expressing bone marrow cells, pre-treated with a CD26 inhibitor. Chimerism was followed by flow cytometry. Tolerance was assessed by measuring allergen-specific isotype levels in sera, RBL assays and T-cell proliferation assays. Mice transplanted with transduced BMC developed multi-lineage molecular chimerism which remained stable long-term (>8 months). After repeated immunizations with Bet v 1 and Phl p 5 serum levels of Bet v 1-specific antibodies (IgE, IgG1, IgG2a, IgG3 and IgA) remained undetectable in Betv1-GFP chimeras while high levels of Phl p 5-specific antibodies developed. Likewise, basophil degranulation was induced in response to Phl p 5 but not to Bet v 1 and specific non-responsiveness to Bet v 1 was observed in proliferation assays. These data demonstrate successful tolerization towards Bet v 1 by molecular chimerism. Stable long-term chimerism was achieved under inhibition of CD26. These results provide evidence for the broad applicability of molecular chimerism as tolerance strategy in allergy.
authors.affiliation: Division of Transplantation, Department of Surgery, Medical University of Vienna, Austria.
authors.forename: Martina
authors.initials: M
authors.lastname: Gattringer
authors.forename: Ulrike
authors.initials: U
authors.lastname: Baranyi
authors.forename: Nina
authors.initials: N
authors.lastname: Pilat
authors.forename: Karin
authors.initials: K
authors.lastname: Hock
authors.forename: Christoph
authors.initials: C
authors.lastname: Klaus
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Buchberger
authors.forename: Haley
authors.initials: H
authors.lastname: Ramsey
authors.forename: John
authors.initials: J
authors.lastname: Iacomini
authors.forename: Rudolf
authors.initials: R
authors.lastname: Valenta
authors.forename: Thomas
authors.initials: T
authors.lastname: Wekerle
mesh_terms: D000818:Animals; D052179:Antigens, Plant / Q000235:genetics / Q000276:immunology*; D001491:Basophils / Q000276:immunology*; D001854:Bone Marrow Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D016026:Bone Marrow Transplantation; D015550:Cell Degranulation; D002478:Cells, Cultured; D018819:Dipeptidyl Peptidase 4 / Q000378:metabolism; D005472:Fluorouracil / Q000008:administration & dosage; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D056724:Immunity, Humoral; D051379:Mice; D008807:Mice, Inbred BALB C; D015202:Protein Engineering; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D012190:Retroviridae; D014161:Transduction, Genetic; D018183:Transplantation Chimera / Q000276:immunology*; D023001:Transplantation Tolerance / Q000276:immunology*
chemical_list: D052179:Antigens, Plant; D011993:Recombinant Fusion Proteins; C061312:Bet v 1 allergen, Betula; D049452:Green Fluorescent Proteins; D018819:Dipeptidyl Peptidase 4; D005472:Fluorouracil
keywords: 5-FU; 5-fluoruracil; Allergy; BMC; BMT; EAE; FCM; HSC; LTR; MHC; Molecular chimerism; RBL; S; SD; SEM; TMD; Tolerance; VSV; bone marrow cells; bone marrow transplantation; experimental autoimmune encephalomyelitis; flow cytometry; hematopoietic stem cells; long terminal repeat; mAb; major histocompatibility complex; monoclonal antibodies; rat basophile leukaemia; signal sequence; standard error; standard error of the mean; transmembrane domain; vesicular stomatitis virus