Suppression of established IgE-mediated disease

描述（由申请人提供）： 该提案将优化2种方法来抑制已建立的IgE介导的过敏，在食物过敏的小鼠模型中测试这些方法并确定它们如何工作。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。我们的VA赞助的小鼠模型研究更好地定义了食物过敏的机制，并发现了可以抑制已建立疾病的方法。取得的成果包括：1）摄入的抗原必须被全身吸收2）针对高亲和力IgE受体Fc 5 RI 1的IgE结合链的单克隆抗体（mAb）可以诱导过敏反应，这可以通过快速脱敏方法和通过用皮质类固醇加抗组胺剂预处理来预防; 3）抗-Fc 5 RI 1 mAb治疗可以抑制已建立的食物过敏;和4）添加单剂量的抗-CD 4 mAb显著增强抗-Fc 5 RI 1 mAb对已建立的食物过敏的抑制。此外，我们还开发了一种利用人类过敏患者IgE抗体的过敏反应小鼠模型。我们现在将在这些成就的基础上更好地定义负责我们观察的机制，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食物过敏的人奠定基础。首先，我们将测试的假设，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，是关键的效应阶段的食物过敏。我们将使用单克隆抗体、骨髓IL-4受体1链（IL-4 R1）嵌合小鼠和特定细胞类型缺失的小鼠来评估：a）一旦建立食物过敏，用抗IL-4 R1单克隆抗体治疗小鼠是否可以抑制全身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地发生食物诱导的过敏反应;和c）在平滑肌细胞、肠上皮细胞和/或血管内皮细胞上选择性缺乏IL-4 R1的小鼠是否正常地发生食物诱导的过敏反应。接下来，我们将确定抗-Fc 5 RI 1 mAb和抗-CD 4 mAb的组合如何抑制已建立的食物过敏，并将通过组合mAb治疗优化食物过敏的抑制。尽管这两种mAb的组合对严重的、已建立的食物过敏的协同抑制部分是由于防止中和仓鼠抗小鼠Fc 5 RI 1 mAb的抗仓鼠IgG抗体的产生，但在中和性抗仓鼠IgG抗体产生之前，抗Fc 5 RI 1 mAb和抗CD 4 mAb的组合也比单独的抗Fc 5 RI 1 mAb更好地抑制食物过敏。我们将使用体外和体内实验来确定：a）通过抗CD 4 mAb增强抗Fc 5 RI 1 mAb对已建立的食物过敏的抑制是否与增强对Ag激发的IL-4和IL-13应答的抑制、增强对肥大细胞脱粒的抑制或两者一致; B）增强抗Fc 5 RI 1 mAb对已建立的食物过敏的抑制所需的CD 4 + T细胞抑制的程度， 食物过敏; c）在不存在抗CD 4 mAb的情况下，不被视为外来的抗Fc 5 RI 1 mAb是否可以完全抑制严重的已建立的食物过敏;以及我们的第三个目标是确定全身免疫和IL-4 R1阻断的组合是否协同抑制已建立的食物过敏。由于IgG抗体可以抑制已建立的食物过敏，而抗IL-4 R1 mAb可以抑制IgE反应而不抑制IgG反应，因此我们假设抗IL-4 R1 mAb治疗与过敏原免疫接种相结合将有效抑制已建立的食物过敏。总之，这些拟议的研究应该为抑制食物过敏和其他IgE介导的疾病提供强有力的新方法，并通过确定这些方法的工作原理，确定进一步改善它们的方法。 公共卫生相关性： VA患者人群与其他成年美国人一样易受过敏反应的影响，但有3个额外的风险因素：1）其庞大的老年人群，处方了大量的治疗药物; 2）其高龄，这使得由过敏反应引起的过度发作更可能诱发中风和心肌梗死;和3）其烟草使用和随之发生的COPD的高发病率，这增加了过敏相关哮喘的后果。因此，有助于预防和治疗速发过敏反应的新方法的拟定研究结果对VA患者人群特别有益。尽管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比注射抗原引起的过敏反应更好的小鼠模型，而注射抗原引起的过敏反应可以由IgG介导。从我们的研究中吸取的教训应该适用于所有形式的IgE介导的过敏反应，并很可能适用于所有形式的IgE介导的过敏。

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.