Etiologic Antigens in Sarcoidosis

结节病是一种病因不明的多系统肉芽肿性疾病，超过90%的患者累及肺部，可能导致终末期纤维化、肺心病和死亡。 结节病的病理特征是非干酪化性肉芽肿性炎症。 由于皮内注射的病变组织提取物引起结节病患者的肉芽肿性炎症病灶，与自发性肉芽肿（Kveim反应）难以区分，我们假设结节病组织提取物含有疾病相关抗原。 Kveim提取物中活性成分的生物物理性质包括相对热稳定性、对中性洗涤剂和蛋白酶的耐受性以及对三级结构的依赖性。 本申请的总体目标是鉴定结节病中的这些致病组织抗原。 我们的中心假设是结节病是由T和B细胞对微生物来源的改变的蛋白质聚集体的免疫反应引起的。 与这一假设一致，我们的初步研究表明存在少量蛋白酶抗性、中性洗涤剂不溶性蛋白，通过免疫印迹分析，这些蛋白是结节病患者而不是健康对照的T细胞依赖性IgG的靶点。 MALDI-TOF质谱和免疫印迹分析已经鉴定了来自结核分枝杆菌（mKatG）或M.在来自结节病的这些蛋白质级分中，但不是对照组织中的smeglycin。初步研究表明，T和B细胞对结节病中的mKatG蛋白的应答，表明mKatG蛋白是结节病中的相关致病抗原。 为了验证结核分枝杆菌KatG蛋白是结节病致病抗原的假设，我们提出了研究，以确定结核分枝杆菌KatG蛋白的存在，结节病和控制组织使用MALDI-TOF质谱和蛋白质免疫印迹分析。 为了确定这些微生物蛋白是否诱导疾病特异性免疫应答，我们将确定B和T细胞对M.结核和M.本发明的目的在于检测mKatG蛋白和所选肽的表达，并确定mKatG蛋白是否优先扩增结节病患者和对照受试者中表达特异性Valpha/Vbeta的T细胞。 总之，这些研究提供了鉴定参与结节病肉芽肿性炎症发病机制的一组特定微生物抗原的可能性，从而为治疗这种疾病提供了新的靶点。

Sarcoidosis is a multisystem granulomatous disorder of unknown etiology that involves the lungs in over 90 percent of affected individuals and may cause end-stage fibrosis, cor pulmonale, and death. The pathologic hallmark of sarcoidosis is non-caseating granulomatous inflammation. Since extracts of diseased tissue injected intradermally elicit a nidus of granulomatous inflammation in patients with sarcoidosis that is indistinguishable from spontaneously arising granulomas (the Kveim reaction), we postulate that sarcoid tissue extracts contain disease-relevant antigens. Biophysical properties of the active component in Kveim extracts include relative heat stability, resistance to neutral detergents and proteases, and a dependence on tertiary structure. The overall goal of this application is to identify these pathogenic tissue antigens in sarcoidosis. Our central hypothesis is that sarcoidosis is caused by linked T and B cell immune responses to aggregates of altered proteins of microbial origin. Consistent with this hypothesis, our preliminary studies demonstrate the presence of a small number of protease-resistant, neutral-detergent insoluble proteins that by immunoblot analysis are targets of T cell dependent IgG from patients with sarcoidosis but not healthy controls. MALDI-TOF mass spectrometry and immunoblot analysis has identified the mycobacterial catalase-peroxidase protein from Mycobacterium tuberculosis (mKatG) or M. smegmatis in these protein fractions from sarcoidosis but not control tissues. Preliminary studies demonstrate both T and B cell responses to mKatG proteins in sarcoidosis, suggesting the mKatG proteins are relevant, pathogenic antigens in sarcoidosis. To test the hypothesis that mycobacterial KatG proteins are pathogenic antigens in sarcoidosis, we propose studies to determine the presence of mycobacterial KatG proteins in sarcoidosis and control tissues using MALDI-TOF mass spectrometry and protein immunoblot analyses. To determine whether these microbial proteins induce disease-specific immune responses, we will determine the molecular basis of the B and T cell immune responses to both M. tuberculosis and M. smegmatis KatG proteins and selected peptides, and determine whether mKatG proteins preferentially expand specific Valpha/Vbeta expressing T cells in patients with sarcoidosis and control subjects. Together, these studies offer the potential of identifying a specific group of microbial antigens involved in the pathogenesis of granulomatous inflammation in sarcoidosis, thus providing a novel target for therapy of this disease.