Nitration immunology

描述（由申请人提供）：呼吸道蛋白质上酪氨酸残基的硝化作用已被证明发生在炎症性肺部疾病，包括哮喘、慢性阻塞性肺病、囊性纤维化和闭塞性细支气管炎。硝基酪氨酸的形成是无机的，但也由多形核白细胞的酶催化，包括嗜酸性粒细胞过氧化物酶和中性粒细胞过氧化物酶。硝基酪氨酸与许多描述良好的半抗原具有明显的结构和化学相似性，半抗原是一种低分子量化合物，当与蛋白质共价结合时，会激发免疫反应。我们假设，在先天免疫过程早期蛋白质硝化过程中形成的硝基酪氨酸作为半抗原起作用，是启动针对其结合蛋白的获得性免疫反应的关键因素。我们计划首先对吸入过敏原的硝化作用进行评估。我们将确定天然和重组尘螨蛋白硝化的最佳化学条件，并将这些条件与呼吸道炎症（如普通感冒）中发现的条件进行比较。在支持性初步数据的基础上，我们将同时研究硝化过敏原增强免疫反应的潜力，通过在体外评估暴露于硝化过敏原与非硝化过敏原相比，人外周血单个核细胞的增殖反应。此外，我们将通过皮肤试验和血清试验检测针对硝化蛋白的特异性抗体，寻找人类对硝化过敏原的免疫反应。我们预计，与初步数据一致，蛋白质的硝化将启动和增强免疫反应。随着硝化蛋白从组织中移除，促炎信号应该被消除。这个新颖的项目可能有助于阐明先天免疫和获得性免疫之间的重要联系——确定一种激发和调节免疫反应的高度新颖的机制。

DESCRIPTION (provided by applicant): Nitration of tyrosine residues on proteins in the respiratory tract has been shown to occur during inflammatory lung diseases including asthma, chronic obstructive pulmonary disease, cystic fibrosis, and bronchiolitis obliterans. Formation of nitrotyrosine occurs inorganically, but also is catalyzed by enzymes of polymorphonuclear leukocytes including eosinophil peroxidase and neutrophil myeloperoxidase. Nitrotyrosine bears pronounced structural and chemical similarity to many well-described haptens--low molecular weight compounds that when covalently bound to proteins incite immune responses. We hypothesize that nitrotyrosine--formed during nitration of proteins early during innate immune processes--functions as a hapten and is a key factor initiating acquired immune responses against the protein in which it is bound. We plan initially to evaluate this hypothesis with respect to nitration of inhaled allergens. We will determine optimum chemical conditions for nitration of natural and recombinant dust mite proteins, and compare these conditions to those found in the airways during inflammation such as occurs with the common cold. Expanding upon supportive preliminary data, we will concurrently investigate the potential of nitrated allergen to augment immune responses by evaluating in vitro the proliferative responses of human peripheral blood mononuclear cells upon exposure to nitrated allergen in comparison to non-nitrated allergen. Further, we will seek immune responses to nitrated allergen in humans by assaying for specific antibody to nitrated proteins with skin testing and serum assays. We anticipate that, consistent with preliminary data, nitration of proteins will initiate and augment immune responses. The pro-inflammatory signals should then be eliminated as nitrated proteins are removed from the tissue. This novel project may serve to elucidate an important link between innate and acquired immunity--identifying a highly novel mechanism for both inciting and regulating immune responses.