Block Copolymer/DNA Vaccination Induces a Strong Allergen-Specific Local Response in a Mouse Model of House Dust Mite Asthma

et al. (2014) Block Copolymer/DNA Vaccination Induces a Strong Allergen-Specific Local Response in a Mouse Model of House Dust Mite Asthma. PLoS ONE 9(1): e85976. doi:10.1371/journal.pone.0085976 Block Copolymer/DNA Vaccination Induces a Strong Allergen-Specific Local Response in a Mouse Model of House Dust Mite Asthma Camille Rolland-Debord 0 David Lair 0 Tiphaine Roussey-Bihoue e 0 Dorian Hassoun 0 Justine Evrard 0 Marie-Aude Cheminant 0 Julie Chesne 0 Faouzi Braza 0 Guillaume Mahay 0 Vincent Portero 0 Christine Sagan 0 Bruno Pitard 0 Antoine Magnan 0 Irving Coy Allen, Virginia Tech University, United States of America 0 1 Unite Mixte de Recherche, Institut National de la Sante et de la Recherche Me dicale (U1087), Centre national de la recherche scientifique (6291) , Nantes , France , 2 Universite de Nantes, l'institut du thorax, Nantes, France, 3 Centre Hospitalier Universitaire, Service d'anatomie et cytologique pathologiques , Nantes , France Background: Allergic asthma is caused by abnormal immunoreactivity against allergens such as house dust mites among which Dermatophagoides farinae (Der f) is a common species. Currently, immunotherapy is based on allergen administration, which has variable effect from patient to patient and may cause serious side effects, principally the sustained risk of anaphylaxis. DNA vaccination is a promising approach by triggering a specific immune response with reduced allergenicity. Objective: The aim of the study is to evaluate the effects of DNA immunization with Der f1 allergen specific DNA on allergic sensitization, inflammation and respiratory function in mice. Methods: Mice were vaccinated 28 and 7 days before allergen exposure with a Der f1-encoding plasmid formulated with a block copolymer. Asthma was induced by skin sensitization followed by intra-nasal challenges with Der f extract. Total lung, broncho-alveolar lavage (BAL) and spleen cells were analyzed by flow cytometry for their surface antigen and cytokine expression. Splenocytes and lung cell IFN-c production by CD8+ cells in response to Der f CMH1-restricted peptides was assessed by ELISPOT. IgE, IgG1 and IgG2a were measured in serum by ELISA. Specific bronchial hyperresponsiveness was assessed by direct resistance measurements. Results: Compared to animals vaccinated with an irrelevant plasmid, pVAX-Der f1 vaccination induced an increase of B cells in BAL, and an elevation of IL-10 and IFN-c but also of IL-4, IL-13 and IL-17 producing CD4+ lymphocytes in lungs and of IL-4 and IL-5 in spleen. In response to CD8-restricted peptides an increase of IFN-c was observed among lung cells. IgG2a levels non-specifically increased following block copolymer/DNA vaccination although IgE, IgG1 levels and airways resistances were not impacted. Conclusions & Clinical Relevance: DNA vaccination using a plasmid coding for Der f1 formulated with the block copolymer 704 induces a specific immune response in the model of asthma used herein. - Funding: This work was supported by grants from the Societe Francaise dAllergologie, Societe de Pneumologie de Langue Francaise, Fondation Recherche Medicale, Fondation Genavie (Nantes, France), and Region Pays de La Loire. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have the following interests: A total extract of Der f was kindly provided by Stallerge`nes (Antony, France). This does not alter the authors adherence to all the PLOS ONE policies on sharing data and materials, as detailed online in the guide for authors. . These authors contributed equally to this work. Asthma is a frequent disease, affecting approximately 300 million people worldwide [1]. Allergic asthma is the most frequent form of the disease, occurring in atopic subjects, and mainly due to indoor allergens such as house dust mites (HDM) and pet fur. In western countries, the most commonly encountered species of HDM responsible for asthma are Dermatophagoides pteronyssimus (Der p) and Dermatophagoides farinae (Der f). Allergic asthma results from an allergen-driven Th2-mediated inflammation in which Th2 cells induce plasma cells to produce IgE and activate mast cells and eosinophils to release mediators and cytokines responsible for smooth muscle contraction, epithelial damages and airway narrowing. Current asthma treatments are based on the control of inflammation by the use of corticosteroids. Inhaled steroids control the vast majority of cases but in some of them oral steroids are necessary to achieve asthma control, providing inacceptable adverse effects. Curative treatments of asthma do not exist, but allergen-specific immunotherapy (SIT) has been proposed for years to induce an immune tolerance towards allergens [2]. SIT consists in administrating increasing doses of allergen through the subcutaneous or the sublingual route. SIT is a long term treatment lasting from 3 to 5 years with at least 50 sub-cutaneous injections over 3 years. It was showed to decrease symptoms and medication requirements in asthma due to HDM and some pollens. SIT was showed to decrease the Th2 commitment of allergen specific CD4+ T cells and induce T regulatory (Treg) and Th1 cells [3]. The usage of SIT is however limited by the requirement of repeated administration, the variable effect from a patient to another, and the sustained risk of anaphylaxis [2]. The use of DNA vaccination is a promising strategy of SIT, with few administrations required to get a strong immune response. Such strategy was proposed before in several studies. Jarman et al showed a decrease in Th2-type cytokines in bronchoalveolar lavage (BAL) after administration of a plasmid containing DNA encoding an immunodominant peptide of Der p1, a major allergen of Der p intramuscularly in asthmatic compared to untreated mice [4]. In addition, the DNA vaccination-induced immune response can be modulated towards a Th1 or Th2 bias when combining adjuvant to the vaccine, as reported by Kim et al who co-administrated DNA of Der p and the Calmette-Guerin bacillus, known for its pro-Th1 immunomodulatory effects [5]. They improved the asthmatic phenotype with increased production of IFN-c in BAL. However in these studies high quantities of DNA were required, which precludes any application in humans [6]. Formulations associating plasmid DNA in tetrafunctional block copolymer as a vector, allow to safely increase the transfection efficiency of reporter or therapeutic genes in lung, skeletal and cardiac muscle in healthy and animal models compared with results obtained with naked DNA [710]. It was also showed that the tetrafunctional block copolymer 704 is able to promote low-dose DNA vaccination efficiency [6]. In a previous study, only two injections of a DNA vaccine encoding the Der f1 gene, a major allergen of Der f, formulated with synthetic vector, induced a strong humoral and cellular response with a Th1-bias, (...truncated)