title: House dust mite-driven asthma and allergen-specific T cells depend on B cells when the amount of inhaled allergen is limiting.
abstract: BACKGROUND
  Allergic asthma is a CD4 TH2-lymphocyte driven disease characterized by airway hyperresponsiveness and eosinophilia. B cells can present antigens to CD4 T cells and produce IgE immunoglobulins that arm effector cells; however, mouse models are inconclusive on whether B cells are necessary for asthma development.
  
  
  OBJECTIVE
  We sought to address the role of B cells in a house dust mite (HDM)-driven TH2-high asthma mouse model.
  
  
  METHODS
  Wild-type and B cell-deficient muMT mice were sensitized and challenged through the airways with HDM extracts. The antigen-presenting capacities of B cells were studied by using new T-cell receptor transgenic 1-DER mice specific for the Der p 1 allergen.
  
  
  RESULTS
  In vitro-activated B cells from HDM-exposed mice presented antigen to 1-DER T cells and induced a TH2 phenotype. In vivo B cells were dispensable for activation of naive 1-DER T cells but necessary for full expansion of primed 1-DER T cells. At high HDM challenge doses, B cells were not required for development of pulmonary asthmatic features yet contributed to TH2 expansion in the mediastinal lymph nodes but not in the lungs. When the amount of challenge allergen was decreased, muMT mice had reduced asthma features. Under these limiting conditions, B cells contributed also to expansion of TH2 effector cells in the lungs and central memory T cells in the mediastinal lymph nodes.
  
  
  CONCLUSIONS
  B cells are a major part of the adaptive immune response to inhaled HDM allergen, particularly when the amount of inhaled allergen is low, by expanding allergen-specific T cells.
authors.affiliation: Laboratory of Immunoregulation and Mucosal Immunology, VIB Inflammation Research Center, Ghent University, Ghent, Belgium; Department of Respiratory Medicine, Ghent University Hospital, Ghent, Belgium.
authors.forename: Melissa
authors.initials: M
authors.lastname: Dullaers
authors.affiliation: Laboratory of Immunoregulation and Mucosal Immunology, VIB Inflammation Research Center, Ghent University, Ghent, Belgium; Department of Respiratory Medicine, Ghent University Hospital, Ghent, Belgium.
authors.forename: Martijn J
authors.initials: MJ
authors.lastname: Schuijs
authors.affiliation: Laboratory of Immunoregulation and Mucosal Immunology, VIB Inflammation Research Center, Ghent University, Ghent, Belgium; Department of Respiratory Medicine, Ghent University Hospital, Ghent, Belgium.
authors.forename: Monique
authors.initials: M
authors.lastname: Willart
authors.affiliation: Laboratory of Immunoregulation and Mucosal Immunology, VIB Inflammation Research Center, Ghent University, Ghent, Belgium; Department of Respiratory Medicine, Ghent University Hospital, Ghent, Belgium.
authors.forename: Kaat
authors.initials: K
authors.lastname: Fierens
authors.affiliation: Laboratory of Immunoregulation and Mucosal Immunology, VIB Inflammation Research Center, Ghent University, Ghent, Belgium; Department of Respiratory Medicine, Ghent University Hospital, Ghent, Belgium.
authors.forename: Justine
authors.initials: J
authors.lastname: Van Moorleghem
authors.affiliation: Laboratory of Immunoregulation and Mucosal Immunology, VIB Inflammation Research Center, Ghent University, Ghent, Belgium; Department of Respiratory Medicine, Ghent University Hospital, Ghent, Belgium.
authors.forename: Hamida
authors.initials: H
authors.lastname: Hammad
authors.affiliation: Laboratory of Immunoregulation and Mucosal Immunology, VIB Inflammation Research Center, Ghent University, Ghent, Belgium; Department of Respiratory Medicine, Ghent University Hospital, Ghent, Belgium; Department of Pulmonary Medicine, ErasmusMC, Rotterdam, The Netherlands. Electronic address: bart.lambrecht@ugent.be.
authors.forename: Bart N
authors.initials: BN
authors.lastname: Lambrecht
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D039741:Antigens, Dermatophagoides / Q000276:immunology*; D001249:Asthma / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D016207:Cytokines / Q000276:immunology; D008198:Lymph Nodes / Q000166:cytology; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D039981:Pyroglyphidae / Q000276:immunology; D013154:Spleen / Q000166:cytology; D018418:Th2 Cells / Q000276:immunology*
chemical_list: D039741:Antigens, Dermatophagoides; D016207:Cytokines
keywords: Allergic asthma; B cells; T(H)2 cells; antigen presentation; house dust mite