Department of Medicine, Uniformed Services University, Bethesda, MD 20814, United States of America.
Department of Microbiology & Immunology, Uniformed Services University, Bethesda, MD 20814, United States of America.
Clin Immunol. 2019 Oct;207:49-54. doi: 10.1016/j.clim.2019.07.009. Epub 2019 Jul 17.
Allergy is a major public health concern, the main treatment for which is symptomatic relief with anti-inflammatory drugs. A key clinical challenge is to induce specific tolerance in order to control allergen-specific memory B and T cells, and specifically block effector cell responses. Our lab recently developed antigen-specific regulatory T-cell (Treg) therapies as a treatment for adverse responses. Recently, we created a chimeric antigen receptor (CAR) approach in which we engineered a target protein antigen, ovalbumin (OVA), linked with the transmembrane and signal transduction domains, CD28-CD3ζ to directly target B cells and sensitized mast cells in an allergy model. We named this receptor "BAR" for B-cell Antibody Receptor. Murine or human Tregs, transduced with a BAR containing OVA or control Tregs expressing an unrelated antigen, were successfully expanded in vitro and tested in the murine OVA-alum allergy model with measurable titers of anti-OVA IgE. Because BAR Tregs express the target antigen and could interact with specific IgE on sensitized mast cells, we first demonstrated that intravenously injected OVA-BAR Tregs did not directly lead to a drop in temperature or release of mediators in plasma indicative of anaphylaxis. Forty-eight hours later, mice were challenged intraperitoneally with 200 μg OVA to induce an anaphylactic reaction, and temperature immediately measured for 30 min. We found that OVA-BAR Tregs protected mice from hypothermia, whereas mice given control BARs (expressing an unrelated antigen) or PBS showed substantial temperature drops indicative of anaphylaxis when systemically challenged with OVA. Importantly, this effect was also demonstrated in a passive anaphylaxis model in which mice that received anti-OVA IgE antibody were protected from hypothermia when treated with OVA-BAR Tregs prior to systemic OVA challenge. These results provide proof of principle that engineered allergen-specific T-regulatory cells can provide clinical protection against severe allergic reactions in individuals already IgE-sensitized to an allergen.
过敏是一个主要的公共卫生问题，其主要治疗方法是使用抗炎药物缓解症状。一个关键的临床挑战是诱导特异性耐受，以控制过敏原特异性记忆 B 和 T 细胞，并特异性阻断效应细胞反应。我们的实验室最近开发了抗原特异性调节性 T 细胞（Treg）疗法，作为治疗不良反应的一种方法。最近，我们创建了一种嵌合抗原受体（CAR）方法，我们将靶蛋白抗原卵清蛋白（OVA）与跨膜和信号转导结构域 CD28-CD3ζ 连接起来，直接靶向过敏模型中的 B 细胞和致敏肥大细胞。我们将这种受体命名为“BAR”，代表 B 细胞抗体受体。用含有 OVA 的 BAR 或表达无关抗原的对照 Treg 转导的鼠或人 Treg 在体外成功扩增，并在小鼠 OVA-明矾过敏模型中进行了测试，可测量抗 OVA IgE 的效价。由于 BAR Treg 表达靶抗原，并且可以与致敏肥大细胞上的特异性 IgE 相互作用，我们首先证明静脉注射 OVA-BAR Treg 不会直接导致体温下降或血浆中介质释放，表明发生过敏反应。48 小时后，用 200μg OVA 腹膜内攻击小鼠，诱导过敏反应，并立即测量 30 分钟的体温。我们发现 OVA-BAR Treg 可保护小鼠免受体温过低，而用对照 BAR（表达无关抗原）或 PBS 处理的小鼠在全身用 OVA 攻击时表现出明显的体温下降，表明发生过敏反应。重要的是，在被动过敏模型中，当在全身性 OVA 挑战之前用 OVA-BAR Treg 治疗接受抗 OVA IgE 抗体的小鼠时，也观察到了这种效应。这些结果提供了一个原理证明，即工程化的过敏原特异性 T 调节细胞可以为已经对过敏原 IgE 敏感的个体提供针对严重过敏反应的临床保护。
