Allergen-Specific IgG Antibodies Purified from Mite-Allergic Patients Sera Block the IgE Recognition ofDermatophagoides pteronyssinusAntigens: AnIn VitroStudy

Isabella Lima Siman,Juliana Silva Miranda,Ana Claudia Arantes Marquez Pajuaba,Lais Martins De Aquino,Jair Pereira Cunha-Júnior,Deise Aparecida Oliveira Silva,Ernesto Akio Taketomi,Leandro Hideki Ynoue

doi:10.1155/2013/657424

Isabella Lima Siman, Juliana Silva Miranda + Show 6 more

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https://doi.org/10.1155/2013/657424

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Abstract

One of the purposes of specific immunotherapy (SIT) is to modulate humoral immune response against allergens with significant increases in allergen-specific IgG levels, commonly associated with blocking activity. The present study investigated in vitro blocking activity of allergen-specific IgG antibodies on IgE reactivity to Dermatophagoides pteronyssinus (Dpt) in sera from atopic patients. Dpt-specific IgG antibodies were purified by ammonium sulfate precipitation followed by protein-G affinity chromatography. Purity was checked by SDS-PAGE and immunoreactivity by slot-blot and immunoblot assays. The blocking activity was evaluated by inhibition ELISA. The electrophoretic profile of the ammonium sulfate precipitated fraction showed strongly stained bands in ligand fraction after chromatography, compatible with molecular weight of human whole IgG molecule. The purity degree was confirmed by detecting strong immunoreactivity to IgG, negligible to IgA, and no reactivity to IgE and IgM. Dpt-specific IgG fraction was capable of significantly reducing levels of IgE anti-Dpt, resulting in 35%–51% inhibition of IgE reactivity to Dpt in atopic patients sera. This study showed that allergen-specific IgG antibodies purified from mite-allergic patients sera block the IgE recognition of Dermatophagoides pteronyssinus antigens. This approach reinforces that intermittent measurement of serum allergen-specific IgG antibodies will be an important objective laboratorial parameter that will help specialists to follow their patients under SIT.

Highlights

Allergic diseases are considered one of the major health problems worldwide and constitute a breakdown in the immune tolerance against natural exposure to environmental antigens [1]
All patients from the atopic group had clinical history of allergic rhinitis related to house dust mites (HDMs) exposure and positive skin prick test (SPT) to aeroallergen extracts, with higher concomitant sensitization to HDMs, D. pteronyssinus, and D. farinae (97%) than to Blomia tropicalis (64%) and to other aeroallergens (
Levels of IgG1 anti-Dermatophagoides pteronyssinus (Dpt) were higher in atopics than nonatopics (P < 0.05), the positivity was similar between groups

Summary

Introduction

Allergic diseases are considered one of the major health problems worldwide and constitute a breakdown in the immune tolerance against natural exposure to environmental antigens [1]. Recent data from World Allergy Organization (WAO) show that the prevalence of allergic diseases has occurred in 30%–40% of the world population, of which 400 million suffer from allergic rhinitis [4]. The immediate symptoms of allergic rhinitis are caused by allergen-induced crosslinking of mast cell-bound IgE antibodies and release of inflammatory mediators as histamine and leukotrienes [5]. Several studies have been performed focusing on the development of new treatments beyond the pharmacotherapy already established, aiming to relieve the symptoms caused by exacerbated responses of the organism against allergens [6]. Allergen-specific immunotherapy (SIT) is the main treatment used for allergy and involves mechanisms that include the production of blocking antibodies, the shifts toward

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