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. CONCLUSION: 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.
RCT Entities:
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. CONCLUSION: 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: Zsolt Szépfalusi; Waltraud Emminger; Franz Eitelberger; Manfred Götz; Andrea Grillenberger; Elisabeth Horak; Isidor Huttegger; Dieter Koller; Helmut Litscher; Rudolf Schmitzberger; Eva-Maria Varga; Josef Riedler Journal: Wien Klin Wochenschr Date: 2009 Impact factor: 1.704
Authors: Carol T Cady; Maree S Powell; Ronald J Harbeck; Patricia C Giclas; James R Murphy; Rohit K Katial; Richard W Weber; P Mark Hogarth; Syd Johnson; Ezio Bonvini; Scott Koenig; John C Cambier Journal: Immunol Lett Date: 2009-12-30 Impact factor: 3.685