Suppression of established IgE-mediated disease

描述(由申请人提供)： 这项提案将优化两种抑制已建立的IgE介导的过敏反应的方法，在食物过敏的小鼠模型中测试这些方法，并确定它们是如何工作的。食物过敏影响2-4%的成年人，在美国每年约有30,000次急诊室就诊。我们由退伍军人管理局赞助的小鼠模型研究更好地定义了食物过敏的机制，并发现了可以抑制既定疾病的方法。取得的成果包括：1)摄取的抗原必须被全身吸收(在这种情况下，它可以被免疫球蛋白抗体中和)才能引起过敏反应；2)针对高亲和力IgE受体IgE结合链的单抗Fc5RI1可以引起过敏反应，这可以通过快速脱敏方法和皮质类固醇加抗组胺的预处理来预防；3)抗Fc5RI1单抗治疗可以抑制已建立的食物过敏；以及4)单剂抗CD4mAb显著增强了抗Fc5RI1单抗对已建立的食物过敏的抑制作用。此外，我们还利用人类过敏患者的IgE抗体开发了一种过敏反应的小鼠模型。我们现在将在这些成果的基础上，通过更好地定义对我们的观察负责的机制，并优化我们抑制既定食物过敏的方法。这应该为将这些方法应用于对食物过敏的人类奠定基础。首先，我们将检验一个假设，即细胞因子IL-4和IL-13对非骨髓来源的细胞，如血管内皮细胞、平滑肌细胞和肠上皮细胞的影响，在食物过敏的效应阶段是关键的。我们将使用单抗、骨髓IL-4受体1链(IL-4R1)嵌合小鼠和从特定细胞类型中缺失的小鼠来评估：a)一旦食物过敏形成，是否可以用抗IL-4R1单抗治疗系统性休克和过敏性腹泻；b)非骨髓来源细胞上缺乏IL-4受体的小鼠是否正常发生食物诱导的过敏反应；以及c)选择性缺乏平滑肌细胞、肠道上皮细胞和/或血管内皮细胞上的IL-4R1的小鼠是否正常发生食物诱导的过敏反应。接下来，我们将确定抗Fc5RI1 mAb和抗CD4mAb联合如何抑制已建立的食物过敏，并将通过联合mAb治疗优化对食物过敏的抑制。虽然这两种单抗联合使用对严重的、已建立的食物过敏的协同抑制作用部分是由于阻止了中和仓鼠抗鼠Fc5RI1单抗的抗仓鼠Ig G抗体的产生，但在中和抗仓鼠Ig抗体之前，联合使用抗Fc5RI1单抗和抗Td4单抗也比单独使用抗Fc5RI1单抗抑制食物过敏效果更好。我们将使用体外和体内实验来确定：a)增强抗Fc5RI1单抗对已建立的食物过敏的抑制是与增强对抗原攻击的IL-4和IL-13反应的抑制一致，还是加强对肥大细胞脱颗粒的抑制，或者两者兼而有之；b)加强抗Fc5RI1单抗对已建立的食物过敏的抑制所需的CD4+T细胞抑制的程度 食品过敏；c)在没有抗CD4mAb的情况下，非外来的抗Fc5RI1 mAb是否能完全抑制严重的已建立的食物过敏；以及d)抗Fc5RI1 mAb与抗CD4mAb的组合如何诱导长期抑制已建立的食物过敏。我们的第三个目标将确定系统免疫和IL-4R1阻断的组合是否协同抑制已建立的食物过敏。由于免疫球蛋白抗体可抑制已建立的食物过敏反应，而抗IL-4R1mAb可在不抑制免疫球蛋白反应的情况下抑制IgE反应，因此我们推测，联合应用抗IL-4R1mAb治疗和过敏原免疫将有效地抑制已建立的食物过敏。综上所述，这些拟议的研究应该为抑制食物过敏和其他IgE介导性疾病提供强有力的新方法，并通过确定这些方法如何工作，确定进一步改进它们的方法。 公共卫生相关性： 退伍军人症患者和其他美国成年人一样对过敏反应敏感，但还有另外三个风险因素：1)大量老年人口，开了大量的治疗药物；2)高龄，使过敏引起的低血压发作更有可能引发中风和心肌梗死；3)吸烟和随后的COPD高发，这增加了过敏相关哮喘的后果。因此，有助于预防和治疗过敏反应的新方法的拟议研究结果将特别有利于VA患者群体。虽然我们的研究重点是食物过敏而不是药物引起的过敏反应，但这是因为食物过敏是一种更好的IgE介导的过敏反应的小鼠模型，而注射抗原引起的过敏反应可以由免疫球蛋白介导。从我们的研究中吸取的经验教训应该适用于所有形式的IgE介导的过敏反应，并且很可能适用于所有形式的IgE介导的过敏反应。

DESCRIPTION (provided by applicant): This proposal will optimize 2 approaches to suppress established IgE-mediated allergy, test these approaches in a mouse model of food allergy and determine how they work. Food allergy affects 2-4% of adults and is responsible for ~30,000 emergency room visits/year in the U.S. Our VA-sponsored, mouse model studies have better defined the mechanisms responsible for food allergy and discovered approaches that can suppress established disease. Achievements include demonstrations that: 1) ingested antigen must be absorbed systemically (where it can be neutralized by IgG antibodies) to induce anaphylaxis; 2) a monoclonal antibody (mAb) to the IgE binding chain of the high affinity IgE receptor, Fc5RI1, can induce anaphylaxis, which can be prevented by a rapid desensitization approach and by pre-treatment with corticosteroids plus antihistamine; 3) anti-Fc5RI1 mAb treatment can suppress established food allergy; and 4) addition of a single dose of anti-CD4 mAb considerably enhances anti-Fc5RI1 mAb suppression of established food allergy. In addition we have developed a mouse model of anaphylaxis that utilizes IgE antibodies from human allergy patients. We will now build on these achievements by better defining the mechanisms responsible for our observations and optimizing our approaches for suppression of established food allergy. This should set the stage for applying these approaches to food-allergic humans. First, we will test the hypothesis that effects of the cytokines IL-4 and IL-13 on non-bone marrow derived cells, such as vascular endothelial cells, smooth muscle cells, and intestinal epithelial cells, are critical during the effector phase of food allergy. We will use mAbs, bone marrow IL-4 receptor 1 chain (IL-4R1) chimeric mice and mice that have deleted from specific cell types to evaluate: a) whether systemic shock and allergic diarrhea can be suppressed by treating mice with anti-IL-4R1 mAb once food allergy has become established; b) whether mice that lack IL-4 receptors on non-bone marrow-derived cells develop food-induced anaphylaxis normally; and c) whether mice that selectively lack IL-4R1 on smooth muscle cells, intestinal epithelial cells, and/or vascular endothelial cells develop food-induced anaphylaxis normally. Next, we will determine how the combination of anti-Fc5RI1 mAb and anti-CD4 mAb suppresses established food allergy and will optimize suppression of food allergy by combined mAb treatment. Although the synergistic suppression of severe, established food allergy by the combination of these two mAb results, in part, from prevention of development of anti-hamster IgG antibodies that neutralize the hamster anti-mouse Fc5RI1 mAb, the combination of anti-Fc5RI1 mAb and anti-CD4 mAb also suppresses food allergy better than anti-Fc5RI1 mAb alone prior to the development of neutralizing anti-hamster IgG antibody. We will use in vitro and in vivo experiments to determine: a) whether enhancement of anti-Fc5RI1 mAb suppression of established food allergy by anti-CD4 mAb coincides with enhanced suppression of the IL-4 and IL-13 responses to Ag challenge, enhanced suppression of mast cell degranulation, or both; b) the extent of CD4+ T cell inhibition required to enhance anti-Fc5RI1 mAb suppression of established food allergy; c) whether an anti-Fc5RI1 mAb that is not seen as foreign can completely suppress severe established food allergy in the absence of anti-CD4 mAb; and d) how the combination of anti-Fc5RI1 mAb plus anti-CD4 mAb induces long-lasting suppression of established food allergy. Our third aim will determine whether the combination of systemic immunization and IL-4R1 blockade synergistically suppresses established food allergy. Because IgG antibodies can suppress established food allergy and anti-IL-4R1 mAb can suppress IgE responses without suppressing IgG responses, we hypothesize that combining anti-IL-4R1 mAb treatment with allergen immunization will potently suppress established food allergy. Taken together, these proposed studies should provide powerful new approaches for the suppression of food allergy and other IgE-mediated disease and, by determining how these approaches work, identify ways to improve them further. PUBLIC HEALTH RELEVANCE: The VA patient population is just as susceptible as other adult Americans to anaphylaxis, but has 3 additional risk factors: 1) its large elderly population that is prescribed large numbers of therapeutic drugs; 2) its advanced age, which makes hypotensive episodes caused by anaphylaxis more likely to induce strokes and myocardial infarcts; and 3) its high incidence of tobacco use and consequent COPD, which increases the consequences of anaphylaxis-associated asthma. Results of the proposed studies that contribute to new approaches for the prevention and treatment of anaphylaxis would thus be particularly beneficial to the VA patient population. Although our study focuses on food allergy rather than drug-induced anaphylaxis, this is because food allergy is a better mouse model for IgE-mediated anaphylaxis than anaphylaxis induced by injected antigens, which can be mediated by IgG. The lessons learned from our studies should apply to all forms of IgE-mediated anaphylaxis and very likely to all forms of IgE-mediated allergy.