A Nonallergenic Birch Pollen Allergy Vaccine Consisting of Hepatitis PreS–Fused Bet v 1 Peptides Focuses Blocking IgG toward IgE Epitopes and Shifts Immune Responses to a Tolerogenic and Th1 Phenotype

Abstract

Allergen-specific immunotherapy is the only allergen-specific and disease-modifying treatment for allergy. The construction and characterization of a vaccine for birch pollen allergy is reported. Two nonallergenic peptides, PA and PB, derived from the IgE-reactive areas of the major birch pollen allergen Bet v 1 were fused to the hepatitis B surface protein, PreS, in four recombinant fusion proteins containing different numbers and combinations of the peptides. Fusion proteins expressed in Escherichia coli and purified to homogeneity showed a lack of IgE reactivity and allergenic activity when tested with sera and basophils from patients allergic to birch pollen. Compared to Bet v 1 allergen, peptides PA and PB showed reduced T cell activation in PBMCs from allergic patients, whereas PreS fusion proteins induced less IL-5 and more IL-10 and IFN-γ. Immunization of rabbits with the fusion proteins, in particular with a PreS fusion protein 2PAPB-PreS, containing two copies of each peptide, induced high levels of IgG Abs against the major IgE-reactive site on Bet v 1 and related allergens. These IgG Abs inhibited allergic patients’ IgE binding to Bet v 1 better than did IgG induced by immunization with complete Bet v 1. Furthermore, 2PAPB-PreS–induced IgG inhibited Bet v 1–induced basophil activation in allergic patients and CD23-facilitated allergen presentation. Our study exemplifies novel beneficial features for a PreS carrier–based peptide vaccine for birch pollen, which, in addition to the established reduction in allergenic activity, include the enhanced focusing of blocking Ab responses toward IgE epitopes, immunomodulatory activity, and reduction of CD23-facilitated allergen presentation.

Epitope Mapping of Rhi o 1 and Generation of a Hypoallergenic Variant

“…MTT Assay and Cytokine Assay-Around 2 ϫ 10 6 PBMCs from each of six patients were cultured as described (18) and stimulated for 7 days with a 10 g/ml concentration of either endotoxin-free allergens, tetanus toxoid (Medline India), or medium only. Lymphocyte proliferation was determined using the Vybrant MTT cell proliferation assay kit (Thermo Scientific) and expressed as the proliferation index (stimulated A 570 / unstimulated A 570 ).…”

Association between specific timothy grass antigens and changes in TH1- and TH2-cell responses following specific immunotherapy

“…Significant efforts have been devoted to developing approaches to modulate allergen-specific T-cell responses without inducing IgE-meditated, immediate-type reactions. These approaches include developing hypoallergens that do not contain IgE-binding epitopes 16, 17 , allergens that are coupled to adjuvants and carriers of bacterial or viral origin 18 , or peptides that contain dominant T-cell epitopes 19 and do not react with IgE in allergic individuals.…”

Antigenic cross‐reactivity between Schistosoma mansoni and peanut: a role for cross‐reactive carbohydrate determinants (CCDs) and implications for the hygiene hypothesis

“…in schistosome‐endemic areas, the inverse association observed between infection with the parasite and allergies could be due to the anti‐schistosome CCD IgG in some way blocking the activity of allergen‐specific IgE, thereby preventing allergic reactivity. In this context, allergen‐specific immunotherapy is commonly found to induce production of anti‐allergen IgG antibodies, particularly of the IgG4 subclass, and these have been shown to block in vitro reactions mediated by allergen‐specific IgE . IgG antibodies induced by helminth infection may have a similar effect.…”

“…In this context, allergen-specific immunotherapy is commonly found to induce production of anti-allergen IgG antibodies, particularly of the IgG4 subclass, and these have been shown to block in vitro reactions mediated by allergen-specific IgE. 22,76,77 IgG antibodies induced by helminth infection may have a similar effect.…”