title: CD23 surface density on B cells is associated with IgE levels and determines IgE-facilitated allergen uptake, as well as activation of allergen-specific T cells.
abstract: Increasing evidence suggests that the low-affinity receptor for IgE, CD23, plays an important role in controlling the activity of allergen-specific T cells through IgE-facilitated allergen presentation.
  
  
  
  We sought to determine the number of CD23 molecules on immune cells in allergic patients and to investigate whether the number of CD23 molecules on antigen-presenting cells is associated with IgE levels and influences allergen uptake and allergen-specific T-cell activation.
  
  
  
  Numbers of CD23 molecules on immune cells of allergic patients were quantified by using flow cytometry with QuantiBRITE beads and compared with total and allergen-specific IgE levels, as well as with allergen-induced immediate skin reactivity. Allergen uptake and allergen-specific T-cell activation in relation to CD23 surface density were determined by using flow cytometry in combination with confocal microscopy and T cells transfected with the T-cell receptor specific for the birch pollen allergen Bet v 1, respectively. Defined IgE-allergen immune complexes were formed with human monoclonal allergen-specific IgE and Bet v 1.
  
  
  
  In allergic patients the vast majority of CD23 molecules were expressed on naive IgD+B cells. The density of CD23 molecules on B cells but not the number of CD23+cells correlated with total IgE levels (RS= 0.53, P = .03) and allergen-induced skin reactions (RS= 0.63, P = .008). Uptake of allergen-IgE complexes into B cells and activation of allergen-specific T cells depended on IgE binding to CD23 and were associated with CD23 surface density. Addition of monoclonal IgE to cultured PBMCs significantly (P = .04) increased CD23 expression on B cells.
  
  
  
  CD23 surface density on B cells of allergic patients is correlated with allergen-specific IgE levels and determines allergen uptake and subsequent activation of T cells.
authors.affiliation: Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria.
authors.forename: Regina
authors.initials: R
authors.lastname: Selb
authors.affiliation: Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria.
authors.forename: Julia
authors.initials: J
authors.lastname: Eckl-Dorna
authors.affiliation: Christian Doppler Laboratory for Immunomodulation, Medical University of Vienna, Vienna, Austria; Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
authors.forename: Alina
authors.initials: A
authors.lastname: Neunkirchner
authors.affiliation: Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria.
authors.forename: Klaus
authors.initials: K
authors.lastname: Schmetterer
authors.affiliation: Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
authors.forename: Katharina
authors.initials: K
authors.lastname: Marth
authors.affiliation: Section for Medical Statistics, Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University of Vienna, Vienna, Austria.
authors.forename: Jutta
authors.initials: J
authors.lastname: Gamper
authors.affiliation: Division of Experimental Allergology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
authors.forename: Beatrice
authors.initials: B
authors.lastname: Jahn-Schmid
authors.affiliation: Christian Doppler Laboratory for Immunomodulation, Medical University of Vienna, Vienna, Austria; Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
authors.forename: Winfried F
authors.initials: WF
authors.lastname: Pickl
authors.affiliation: Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Valenta
authors.affiliation: Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria. Electronic address: verena.niederberger@meduniwien.ac.at.
authors.forename: Verena
authors.initials: V
authors.lastname: Niederberger
mesh_terms: D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000276:immunology*; D052179:Antigens, Plant / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D002460:Cell Line; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology*; D008297:Male; D006109:Poaceae / Q000276:immunology; D011058:Pollen / Q000276:immunology; D017455:Receptors, IgE / Q000276:immunology*; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology; D012882:Skin Tests; D013601:T-Lymphocytes / Q000276:immunology*; D055815:Young Adult
chemical_list: D000485:Allergens; D052179:Antigens, Plant; D017455:Receptors, IgE; D007073:Immunoglobulin E
keywords: B cell; CD23; IgE; allergen; allergy; low-affinity IgE receptor