Identifying Specific Antigenic Targets of Kawasaki Disease

项目总结/摘要 川崎病（KD）是发达国家儿童获得性心脏病的主要病因。KD 可能导致冠状动脉瘤，导致终身心脏病，心肌梗死， 死亡临床和流行病学特征支持遗传易感儿童的感染性病因， 但50多年的研究都没有找到病因。延误和漏诊会增加 冠状动脉瘤迫切需要的诊断测试和改进的治疗方法的发展是 取决于病因的确定在初步研究中，我们分析了外周血浆母细胞 用单细胞RT-PCR检测KD发热后1-3周的反应，并制备了60株单克隆抗体 (Mab)从这些浆母细胞。我们用这些单克隆抗体来确定它们的靶抗原。我们发现32/60 来自9/11名KD患者的Mab鉴定纤毛细胞胞浆内病毒样包涵体（ICI） KD儿童的支气管上皮细胞，而非婴儿对照。使用肽阵列鉴定结合表位， 氨基酸置换芯片和ELISA检测，我们发现32个单克隆抗体中有5个（16%）来自3名KD患者 与冠状动脉瘤，识别KD肽表位1。KD肽1完全阻断 这些Mab与KD ICI的结合表明ICI中存在具有结合表位序列的蛋白质。 此外，来自发热发作后> 8天的5/8名KD患者的治疗前血清，但0/17名婴儿对照血清， 针对肽表位的IgG抗体。我们最近用这种方法鉴定了另外两个表位， 需要进一步研究。这些发现支持了我们的假设，即至少有一部分KD病例是由以下原因引起的： 感染目前未鉴定的、普遍存在的含有KD肽表位1的病毒病原体 顺序在这个提议中，我们假设，浆母细胞应答所针对的抗原的鉴定 对KD的研究可导致病原学的鉴定和KD血清学试验的发展。测试这些 1）鉴定由我们的KD单克隆抗体组识别的与KD结合的特异性蛋白质， 组织，2）筛选由对KD的免疫应答识别的另外的抗原靶标，和3）评估 KD和对照血清对KD抗原的抗体应答。我们的发现将为KD的发病机制提供信息， 长期目标是改善KD的诊断和治疗，实现预防， 儿童时期冠状动脉瘤的长期后果导致的医疗费用。

PROJECT SUMMARY/ABSTRACT Kawasaki Disease (KD) is the leading cause of acquired heart disease in children in developed nations. KD can result in coronary artery aneurysms that can lead to lifelong heart disease, myocardial infarction, and death. The clinical and epidemiologic features support an infectious etiology in genetically susceptible children, but the cause has eluded more than 50 years of study. Delayed and missed diagnoses increase the risk of coronary artery aneurysms. The development of urgently needed diagnostic tests and improved therapies are dependent upon identifying the etiology. In preliminary studies, we analyzed the peripheral blood plasmablast response at 1-3 weeks after KD fever onset using single cell RT-PCR and made 60 monoclonal antibodies (Mab) from these plasmablasts. We used these Mab to determine their target antigens. We found that 32/60 Mab, derived from 9/11 KD patients, identify intracytoplasmic virus-like inclusion bodies (ICI) in ciliated bronchial epithelium of KD children but not infant controls. Using peptide arrays to identify binding epitope(s), amino acid substitution arrays, and ELISA, we found that 5 of the 32 (16%) Mab, derived from 3 KD patients with coronary artery aneurysms, recognize KD peptide epitope 1. KD peptide 1 completely blocks binding of these Mab to KD ICI, indicating that a protein with the binding epitope sequence is present in the ICI. Moreover, pre-treatment sera from 5/8 KD patients >day 8 after fever onset but 0/17 infant control sera have IgG antibody to the peptide epitope. We recently identified two additional epitopes using this approach that require further study. These findings support our hypothesis that at least a subset of KD cases results from infection with a presently unidentified, ubiquitous viral causative agent containing the KD peptide epitope 1 sequence. In this proposal, we hypothesize that identification of antigens targeted by the plasmablast response to KD can lead to identification of the etiology(ies) and development of KD serologic tests. To test these hypotheses, we will: 1) identify the specific proteins recognized by our panel of KD Mab that bind to KD tissues, 2) screen for additional antigenic targets recognized by the immune response to KD, and 3) evaluate the antibody responses of KD and control sera to KD antigens. Our findings will inform pathogenesis of KD, with the long-term goals of improving diagnosis and treatment of KD, enabling prevention, and reducing healthcare costs from the long-term consequences of coronary artery aneurysms arising in young childhood.