Kabasser Stefan, Kalic Kamath Tanja, Eber Ernst, Podzhilkova Aleksandra, Lupinek Christian, Hemmer Wolfgang, Bublin Mugdim, Croote Derek, Maleki Soheila J, Breiteneder Heimo, Hoffmann-Sommergruber Karin, Radauer Christian, Bublin Merima
Institute of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
Institute of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria; Department of Dermatology, University Hospital St. Pölten, Karl Landsteiner University of Health Sciences, St. Pölten, Austria.
Allergol Int. 2025 Jun 23. doi: 10.1016/j.alit.2025.05.007.
Convergent selection has been identified in the IgE antibody repertoires of peanut-allergic individuals, primarily targeting the 2S albumin Ara h 2 and cross-reacting with two other major allergens, the vicilin Ara h 1 and the legumin Ara h 3. In this study, we aimed to investigate the structural and functional basis of this cross-reactivity and its contribution to the co-sensitization to tree nuts often observed in peanut-allergic subjects.
Six convergent antibodies, targeting the immunodominant Ara h 2-DPYSPS motif-associated sequence, and their reverted germline version, were produced as human IgG1 and IgE. Antibody specificity to natural and recombinant peanut and tree nut allergens and allergen-derived peptides was evaluated using ELISA, immunoblotting, inhibition tests, and basophil activation assays.
The six antibodies showed reactivity to Ara h 1, Ara h 2, Ara h 3 and weak reactivity to tree nut legumins, especially from almond, walnut and Brazil nut. The germline antibody exclusively recognized Ara h 2. Basophils sensitized with the individual antibodies were activated by Ara h 2 at a concentration of 10 ng/ml and at 100-fold higher concentrations by Ara h 1 and Ara h 3, but not by tree nut legumins. The three Ara h 1- and two Ara h 3-derived antibody-binding peptides, with one from each group previously identified as immunodominant, are in close proximity and may contribute to conformational epitopes.
The biological activity of affinity-matured cross-reactive antibodies with Ara h 2-associated sequence convergence may explain the high allergenic potency of peanut and clinically irrelevant co-sensitizations to tree nuts commonly observed in peanut-allergic patients.
在花生过敏个体的IgE抗体库中已发现趋同选择，主要针对2S白蛋白Ara h 2，并与其他两种主要过敏原发生交叉反应，即豌豆球蛋白Ara h 1和豆球蛋白Ara h 3。在本研究中，我们旨在探究这种交叉反应性的结构和功能基础，以及其对花生过敏患者中常见的对坚果的共同致敏作用的贡献。
制备了六种靶向免疫显性Ara h 2 - DPYSPS基序相关序列的趋同抗体及其回复的胚系版本，作为人IgG1和IgE。使用ELISA、免疫印迹、抑制试验和嗜碱性粒细胞活化试验评估抗体对天然和重组花生及坚果过敏原以及过敏原衍生肽的特异性。
这六种抗体对Ara h 1、Ara h 2、Ara h 3有反应，对坚果豆球蛋白反应较弱，尤其是来自杏仁、核桃和巴西坚果的豆球蛋白。胚系抗体仅识别Ara h 2。用单个抗体致敏的嗜碱性粒细胞在Ara h 2浓度为10 ng/ml时被激活，在Ara h 1和Ara h 3浓度高100倍时也被激活，但不受坚果豆球蛋白激活。三种Ara h 1衍生和两种Ara h 3衍生的抗体结合肽，每组各有一个先前被确定为免疫显性，它们靠得很近，可能有助于构象表位的形成。
具有与Ara h 2相关序列趋同的亲和力成熟的交叉反应性抗体的生物学活性，可能解释了花生的高致敏性以及花生过敏患者中常见的对坚果的临床无关的共同致敏现象。
