Phylogenetic Approach to Plant Allergy Vaccines

描述(申请人提供)：在工业化国家，包括哮喘和过敏性鼻炎在内的呼吸道过敏性疾病正在增加，目前高达30%的人口受到影响。雪松花粉是美国中部、南欧和日本季节性过敏性鼻炎(花粉症)的主要原因。有效的免疫接种是预防和治疗过敏性疾病的最大希望。目前的免疫治疗受到产生IgE介导的局部或过敏反应的风险的限制。这项建议中要检验的假设是，植物的分子生物多样性可以用来识别自然来源的过敏原，这些过敏原结合IgE的能力降低，同时保持它们诱导T辅助细胞反应的能力。验证这一假设的具体目的是：1)通过对多达138种雪松/柏树的基因组和cDNA进行PCR扩增和自动核苷酸测序，创建两种主要山地雪松变应原同源物的遗传序列文库。2)在该文库中确定变应原的遗传变异，其中IgE结合位点(表位)的氨基酸序列与致敏变应原的氨基酸序列不同，并使用新的计算算法和自动同源建模来确定在哪些变异体中一个或多个IgE表位的三维结构可能被破坏。3)将所选变应原基因表达为融合蛋白，检测其与美国中南欧和日本雪松过敏患者血清IgE的结合、诱导雪松过敏患者外周血嗜碱性粒细胞脱颗粒的能力和诱导T辅助细胞反应的能力。这些研究将由一个由免疫学家、结构生物学家和一名植物学家组成的成熟的多学科团队进行，他们在雪松过敏原的发现和表征方面具有经验。成功完成这些研究将产生新一代过敏疫苗，其有效性可以测试，而不需要昂贵的安全性测试。更好地了解变应原表位的结构特征将加快针对多种过敏原的新疫苗的开发。

DESCRIPTION (provided by applicant): Allergic diseases of the airways, including asthma and allergic rhinitis are increasing in industrialized countries, where up to 30% of some populations are now affected. Cedar pollen is a major cause of seasonal allergic rhinitis (pollinosis) in Central U.S.A, Southern Europe and Japan. Effective immunization holds the greatest promise for preventing and treating allergic diseases. Current immunotherapy is limited by the risk of producing IgE-mediated, localized or anaphylactic reactions. The hypothesis to be tested in this proposal is that the molecular biodiversity of plants can be used to identify natural sources of allergens with reduced capacity to bind IgE, while retaining their capacity to induce T-helper cell responses. The specific aims to test this hypothesis are to: 1) Create a library of genetic sequences for homologues of two major mountain cedar allergens, by PCR amplification and automated nucleotide sequencing of genomic and cDNA from up to 138 cedar / cypress species. 2) Identify within this library genetic variants of the allergens, in which the amino acid sequence of the IgE binding sites (epitopes) differ from those of the sensitizing allergens and use novel computational algorithms and automated homology modeling to determine in which variants the 3-D structures of one or more IgE epitopes are likely to be disrupted. 3) Express the genes for the selected variants of the allergens as fusion proteins and test their binding of serum IgE from cedar allergic patients from Central U.S.A, Southern Europe and Japan, their ability to induce degranulation of blood basophils from cedar-allergic patients, and to induce T-helper responses. These studies will be performed by an established, multidisciplinary team of immunologists, structural biologists and a botanist, who have experience in the discovery and characterization of cedar allergens. Successful completing these studies will result in a new generation of allergy vaccines, the efficacy of which can be tested, without expensive safety testing. A better understanding of the structural characteristics of allergenic epitopes will expedite the development of new vaccines against numerous allergens.