Frequency and phenotype of Fel d 1-specific T cells after peptide therapy

项目总结(见说明)： 这项研究提案的广泛和长期目标是了解多肽免疫疗法如何利用主要过敏原(FEL D 1)的有效T细胞表位，使用独特的MHC II类四聚体试剂来调节FEL d 1特异性T细胞的频率和功能表型。 我们假设，在多肽免疫治疗之后，多肽免疫治疗导致了过敏原特异性T细胞的频率和功能表型的调节。 特定目的1将确定多肽免疫疗法(PIT)对猫过敏性哮喘日益严重的受试者FEL-1特异性(四聚体+)T细胞的影响。从猫过敏性哮喘患者多肽免疫治疗的II期临床试验(按严重程度分组)中收集的冷冻外周血单个核细胞(PBMC)档案将用于确定过敏原特异性(MHC II类四聚体+)T细胞的频率和功能表型。 特定目的2将采用多肽免疫疗法治疗猫变应性鼻炎的前瞻性临床试验。在治疗结束后不久(第18-22周)和研究开始一年后，将在基线上抽取大量血液(200毫升)。四聚体+T细胞将通过顺序磁净化进行浓缩 目的：确定多肽免疫治疗是否改变变应原特异性四聚体+T细胞的频率、记忆表型、趋化因子受体表达和调节T细胞功能的标志物。 具体目标3将阐述疫苗多肽与MHC的亲和力如何影响多肽的临床疗效(其诱导免疫耐受的能力)。由于表达的MHC分子的复杂性，以及每个肽都与多个MHC分子结合，这项研究不能在人体内进行。 因此，这项研究将在表达人类MHC基因人类白细胞抗原-DR4的小鼠身上进行。AIMS 1和AIMS 2中使用的7种多肽疫苗对人类白细胞抗原DR4具有不同的亲和力。将对每种多肽进行评估，以确定疗效与亲和力的关系。

PROJECT SUMMARY (See instructions): The broad, long term objective of this research proposal is to understand how peptide immunotherapy, using validated T cell epitopes of a major allergen (Fel d 1), modulates the frequency and functional phenotype of Fel d 1-specific T cells, using unique MHC Class II tetramer reagents. We hypothesize that peptide immunotherapy results in modulation of the frequency and functional phenotype of allergen-specific T cells following peptide immunotherapy. Specific Aim 1 will determine the effects of peptide immunotherapy (PIT) on Fel d 1-specific (tetramer+) T cells in subjects with cat allergic asthma of increasing severity. An archive of frozen peripheral blood mononuclear cells (PBMC) collected from a Phase II clinical trial of peptide immunotherapy in subjects with cat allergic asthma (groups stratified for severity) will be used to determine the frequency and functional phenotype of allergen-specific (MHC class II tetramer+) T cells. Specific Aim 2 will employ a prospective clinical trial of peptide immunotherapy in cat allergic rhinitis. Large volumes (200ml) of blood will be drawn at baseline, shortly after the end of treatment (week 18-22) and one year after the initiation of the study. Tetramer+ T cells will be enriched using sequential magnetic purification to determine whether peptide immunotherapy changes frequency, memory phenotype, chemokine receptor expression and markers of regulatory T cell function among allergen-specific tetramer+ T cells. Specific Aim 3 will address how the affinity of vaccine peptides for the MHC affects the clinical efficacy of the peptide (its ability to induce immunological tolerance). This study cannot be performed in human subject due to the complexity of MHC molecules expressed and because each peptide binds to multiple MHC molecules. Therefore the study will be conducted in mice that express the human MHC gene, HLA-DR4. The 7 peptides comprising the peptide vaccine employed in Aims 1 & 2 have differing affinity for HLA-DR4. Each peptide will be evaluated to determine how efficacy relates to affinity.