title: Bet v 1-specific T-cell receptor/forkhead box protein 3 transgenic T cells suppress Bet v 1-specific T-cell effector function in an activation-dependent manner.
abstract: BACKGROUND
  Regulatory T (Treg) cells establish and maintain tolerance to self-antigens and many foreign antigens, such as allergens, by suppressing effector T-cell proliferation and function. We have previously shown that human T-cell receptor (TCR) αβ-chains specific for allergen-derived epitopes confer allergen specificity on peripheral blood T cells of individuals with and without allergy.
  
  
  OBJECTIVE
  To study the feasibility of generating allergen-specific human Treg cells by retroviral transduction of a transcription unit encoding forkhead box protein 3 (FOXP3) and allergen-specific TCR αβ-chains.
  
  
  METHODS
  cDNAs encoding the α and β-chains of a Bet v 1(142-153)-specific TCR (TCR alpha variable region 6/TCR beta variable region 20) and human FOXP3 were linked via picornaviral 2A sequences and expressed as single translational unit from an internal ribosomal entry site-green fluorescence protein-containing retroviral vector. Retrovirally transduced peripheral blood T cells were tested for expression of transgenes, Treg phenotype, and regulatory capacity toward allergen-specific effector T cells.
  
  
  RESULTS
  Transduced T cells displayed a Treg phenotype with clear-cut upregulation of CD25, CD39, and cytotoxic T-lymphocyte antigen 4. The transduced cells were hyporesponsive in cytokine production and secretion and, like naturally occurring Treg cells, did not proliferate after antigen-specific or antigen-mimetic stimulation. However, proliferation was inducible upon exposure to exogenous IL-2. In coculture experiments, TRAV6(+)TRBV20(+)FOXP3(+) transgenic T cells, unlike FOXP3(+) single transgenic T cells or naturally occurring Treg cells, highly significantly suppressed T cell cytokine production and proliferation of corresponding allergen-specific effector T cells in an allergen-specific, dose-dependent manner.
  
  
  CONCLUSIONS
  We demonstrate a transgenic approach to engineer human allergen-specific Treg cells that exert their regulatory function in an activation-dependent manner. Customized Treg cells might become useful for tolerance induction therapies in individuals with allergic and other immune-mediated diseases.
authors.affiliation: Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
authors.forename: Klaus G
authors.initials: KG
authors.lastname: Schmetterer
authors.forename: Daniela
authors.initials: D
authors.lastname: Haiderer
authors.forename: Victoria M
authors.initials: VM
authors.lastname: Leb-Reichl
authors.forename: Alina
authors.initials: A
authors.lastname: Neunkirchner
authors.forename: Beatrice
authors.initials: B
authors.lastname: Jahn-Schmid
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Küng
authors.forename: Karina
authors.initials: K
authors.lastname: Schuch
authors.forename: Peter
authors.initials: P
authors.lastname: Steinberger
authors.forename: Barbara
authors.initials: B
authors.lastname: Bohle
authors.forename: Winfried F
authors.initials: WF
authors.lastname: Pickl
mesh_terms: D000485:Allergens / Q000235:genetics / Q000276:immunology; D052179:Antigens, Plant / Q000235:genetics* / Q000276:immunology; D029662:Betula; D002469:Cell Separation; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000235:genetics* / Q000276:immunology; D005818:Genetic Engineering / Q000379:methods*; D005822:Genetic Vectors; D057809:HEK293 Cells; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology; D011058:Pollen; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics* / Q000276:immunology; D012190:Retroviridae; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism; D014161:Transduction, Genetic; D014162:Transfection; D019076:Transgenes
chemical_list: D000485:Allergens; D052179:Antigens, Plant; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D016693:Receptors, Antigen, T-Cell, alpha-beta