Department of Immunology, Monash University, Melbourne, Australia.
J Allergy Clin Immunol. 2011 Mar;127(3):608-15.e1-5. doi: 10.1016/j.jaci.2010.09.027. Epub 2010 Nov 18.
Peanut allergy is a life-threatening condition; there is currently no cure. Although whole allergen extracts are used for specific immunotherapy for many allergies, they can cause severe reactions, and even fatalities, in peanut allergy.
This study aimed to identify short, T-cell epitope-based peptides that target allergen-specific CD4(+) T cells but do not bind IgE as candidates for safe peanut-specific immunotherapy.
Multiple CD4(+) T-cell lines specific for the major peanut allergen Ara h 2 were generated from PBMCs of 16 HLA-diverse subjects with peanut allergy by using 5,6-carboxyfluorescein diacetate succinimidylester-based methodology. Proliferation and ELISPOT assays were used to identify dominant epitopes recognized by T-cell lines and to confirm recognition by peripheral blood T cells of epitope-based peptides modified for therapeutic production. HLA restriction of core epitope recognition was investigated by using anti-HLA blocking antibodies and HLA genotyping. Serum-IgE peptide-binding was assessed by dot-blot.
Five dominant CD4(+) T-cell epitopes were identified in Ara h 2. In combination, these were presented by HLA-DR, HLA-DP, and HLA-DQ molecules and recognized by T cells from all 16 subjects. Three short peptide variants containing these T-cell epitopes were designed with cysteine-to-serine substitutions to facilitate stability and therapeutic production. Variant peptides showed HLA-binding degeneracy, did not bind peanut-specific serum IgE, and could directly target T(H)2-type T cells in peripheral blood of subjects with allergy.
Short CD4(+) T-cell epitope-based Ara h 2 peptides were identified as novel candidates for a T-cell-targeted peanut-specific immunotherapy for an HLA-diverse population.
花生过敏是一种危及生命的疾病，目前尚无治愈方法。尽管全过敏原提取物被用于许多过敏的特异性免疫治疗，但它们会在花生过敏中引起严重反应，甚至致命。
本研究旨在鉴定针对过敏原特异性 CD4+T 细胞的短肽，这些肽基于 T 细胞表位，不与 IgE 结合，作为安全的花生特异性免疫治疗的候选物。
通过使用 5,6-羧基荧光素二乙酸琥珀酰亚胺酯（carboxyfluorescein diacetate succinimidylester）方法，从 16 位具有花生过敏的 HLA 多样化个体的 PBMC 中生成针对主要花生过敏原 Ara h 2 的多个 CD4+T 细胞系。使用增殖和 ELISPOT 测定来鉴定由 T 细胞系识别的优势表位，并确认基于修饰用于治疗生产的表位的肽的外周血 T 细胞的识别。通过使用抗 HLA 阻断抗体和 HLA 基因分型来研究核心表位识别的 HLA 限制。通过斑点印迹评估血清 IgE 肽结合。
在 Ara h 2 中鉴定出五个主要的 CD4+T 细胞表位。这些表位组合在一起，由 HLA-DR、HLA-DP 和 HLA-DQ 分子呈递，并被 16 位受试者的所有 T 细胞识别。含有这些 T 细胞表位的三个短肽变体设计有半胱氨酸到丝氨酸取代，以促进稳定性和治疗生产。变体肽显示 HLA 结合简并性，不结合花生特异性血清 IgE，并且可以直接靶向过敏受试者外周血中的 T(H)2 型 T 细胞。
短的基于 CD4+T 细胞表位的 Ara h 2 肽被鉴定为针对 HLA 多样化人群的 T 细胞靶向花生特异性免疫治疗的新型候选物。
