Smith Scott A, Shrem Rebecca A, Lança Bruno B C, Zhang Jian, Wong Joyce J W, Croote Derek, Peebles R Stokes, Spiller Benjamin W
Department of Medicine, Vanderbilt University Medical Center, Nashville, Tenn; Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tenn.
Department of Pharmacology, Vanderbilt University School of Medicine, Vanderbilt University, Nashville, Tenn.
J Allergy Clin Immunol. 2025 May;155(5):1547-1556.e3. doi: 10.1016/j.jaci.2024.12.1095. Epub 2025 Jan 11.
Human IgE mAbs recognizing peanut allergens have recently become available, but we lack a detailed understanding of how these IgEs target allergens.
We sought to determine the molecular details of the antibody-allergen interaction for a panel of clinically important human IgE mAbs and to develop strategies to disrupt disease causing antibody-allergen interactions.
We identified candidates from a panel of epitope binned human IgE mAbs that recognize 2 important and homologous peanut allergens, Ara h 2 and Ara h 6. Crystal structures were determined revealing the interfaces (antigenic sites) of exemplars of 5 common IgE bins.
Among the common antigenic sites on Ara h 2 and Ara h 6, 2 sites (A and B) are highly conserved between the allergens, explaining the cross-reactivity of antibodies that recognize these sites. Three sites (C, D, and F) involve residues that are not conserved between the allergens. Of the 5 common sites, 3 sites (B, C, and D) involve residues that are near each other only when the allergens are properly folded, such that these sites are conformational. Two additional sites (sites A and F) involve largely linear stretches of amino acids. Site F targeted antibody, 38B7, binds to a peptide sequence DPYSPS, in which hydroxylation of the last proline is critical for binding. This sequence is repeated 2 or 3 times depending on the Ara h 2 isoform, enabling 38B7 to induce anaphylaxis as a single mAb, without a second antibody. We have mutated key residues in each site and created a panel of hypoallergens, having reduced IgE mAb binding and lacking the ability to induce anaphylaxis in our murine model.
We created a structural map of the IgE antibody response to the most important peanut allergen proteins to enable the design of new allergy immunotherapies and vaccines.
近年来已出现识别花生过敏原的人源IgE单克隆抗体，但我们对这些IgE如何靶向过敏原缺乏详细了解。
我们试图确定一组临床上重要的人源IgE单克隆抗体与过敏原相互作用的分子细节，并制定策略破坏导致疾病的抗体-过敏原相互作用。
我们从一组表位分类的人源IgE单克隆抗体中筛选出能够识别2种重要且同源的花生过敏原Ara h 2和Ara h 6的候选抗体。通过测定晶体结构，揭示了5种常见IgE分类中示例的界面（抗原位点）。
在Ara h 2和Ara h 6的常见抗原位点中，有2个位点（A和B）在过敏原之间高度保守，这解释了识别这些位点的抗体的交叉反应性。3个位点（C、D和F）涉及过敏原之间不保守的残基。在这5个常见位点中，3个位点（B、C和D）仅在过敏原正确折叠时涉及彼此靠近的残基，因此这些位点是构象性的。另外2个位点（位点A和F）主要涉及氨基酸的线性延伸。靶向位点F的抗体38B7与肽序列DPYSPS结合，其中最后一个脯氨酸的羟基化对于结合至关重要。根据Ara h 2同工型，该序列重复2或3次，使得38B7作为单个单克隆抗体能够引发过敏反应，而无需第二种抗体。我们对每个位点的关键残基进行了突变，并创建了一组低过敏原，其与IgE单克隆抗体的结合减少，并且在我们的小鼠模型中缺乏引发过敏反应的能力。
我们绘制了针对最重要的花生过敏原蛋白的IgE抗体反应的结构图，以助力新型过敏免疫疗法和疫苗的设计。
