title: Inhibition of allergen-IgE binding to B cells by IgG antibodies after grass pollen immunotherapy.
abstract: BACKGROUND
  Among atopic individuals, levels of allergen-specific IgG antibodies have been inversely associated with the degree of allergen sensitization. Additionally, allergen-specific IgG antibodies are markedly increased by allergen injection immunotherapy. These observations have led to proposals that allergen-specific IgG antibodies might have protective properties in atopic individuals.
  
  
  OBJECTIVE
  We hypothesized that after grass pollen immunotherapy, these antibodies disrupt IgE-dependent allergen processing by antigen-presenting cells.
  
  
  METHODS
  We have developed a novel flow cytometric assay based on detection of allergen-IgE binding to the low-affinity IgE receptor on B cells to examine the blocking effects of sera collected from 18 patients who participated in a double-blind, controlled trial of grass pollen immunotherapy for 1 year.
  
  
  RESULTS
  In all 10 patients who received active therapy, there was induction of activity that inhibited allergen-IgE binding to B cells (P =.02, vs placebo subjects), as well as subsequent allergen presentation to T cells. This activity copurified with IgG and was allergen specific, because sera taken from patients treated with grass pollen immunotherapy but who were also birch pollen sensitive did not inhibit IgE-birch pollen allergen binding to B cells.
  
  
  CONCLUSIONS
  We conclude that allergen-specific IgG antibodies induced by immunotherapy can disrupt formation of allergen-IgE complexes that bind to antigen-presenting cells and facilitate allergen presentation.
authors: Upper Respiratory Medicine, Imperial College School of Medicine at the National Heart and Lung Institute, London, United Kingdom.
authors: Petra A
authors: PA
authors: Wachholz
authors: Nanna Kristensen
authors: NK
authors: Soni
authors: Stephen J
authors: SJ
authors: Till
authors: Stephen R
authors: SR
authors: Durham
mesh_terms: D000328:Adult; D000485:Allergens / Q000276:immunology*; D017951:Antigen Presentation / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000097:blood / Q000276:immunology / Q000628:therapy*; D007073:Immunoglobulin E / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology*; D007167:Immunotherapy / Q000379:methods; D008297:Male; D008875:Middle Aged; D006109:Poaceae / Q000276:immunology*; D011058:Pollen / Q000276:immunology; D017455:Receptors, IgE / Q000276:immunology; D013997:Time Factors
chemical_list: D000485:Allergens; D007074:Immunoglobulin G; D017455:Receptors, IgE; D007073:Immunoglobulin E