Diagnostic Assays for early Lyme Borreliosis using in-vivo expressed antigens

描述(申请人提供)：莱姆病，由于感染硬蜱传播的伯氏疏螺旋体螺旋体，是美国最常见的媒介传播疾病，2009年向疾控中心报告了38,000多例确诊和可能病例。螺旋体首先在皮肤上感染，然后传播到内部器官，如心脏、关节和神经系统，在那里可以看到疾病。感染在早期发现时对抗生素最敏感，但那些播散性感染或治疗延迟的人可能会经历对抗生素不敏感的衰弱疾病。及时和准确地诊断莱姆病对于优化治疗反应和预防该病的长期后遗症至关重要。检测伯氏杆菌抗体的血清学试验(酶联免疫吸附试验和免疫印迹试验)是目前莱姆病最敏感和最广泛使用的实验室试验。这些检测利用培养的伯氏杆菌实验室菌株的全细胞裂解物作为抗原源，因此不检测主要在体内表达的伯氏杆菌蛋白的抗体。推荐的两级法，即用免疫印迹法确认阳性或可疑的ELISA，在感染的早期阶段只有~30%的敏感性，而且由于伯氏杆菌抗原与其他感染源的交叉反应而降低了特异性。这一第一阶段的应用旨在通过使用体内表达的伯氏杆菌特异性蛋白作为抗原来改进目前可用的莱姆病血清学测试。我们最近发现了一组新的伯氏杆菌基因和蛋白，这些基因和蛋白在伯氏杆菌感染的最初几周表达，并对早期莱姆病患者的血清进行免疫球蛋白夹心法检测。我们建议在多重格式分析中使用来自明确定义的莱姆病病例、从未接触过伯氏杆菌以及其他传染病和风湿病的受试者的人血清样本来评估这些候选抗原的敏感性和特异性。多肽针阵列会将候选抗原的免疫优势表位与莱姆病血清以酶联免疫吸附试验的形式进行映射，以纳入到改进的多重分析中。这项第一阶段研究的结果将为莱姆病新的敏感和特异的血清学测试的开发奠定基础，这些测试将更准确地反映在受感染宿主中激发免疫反应的伯氏杆菌抗原。 公共卫生相关性：莱姆病是由伯氏疏螺旋体感染引起的，可引起皮肤、心脏、关节和神经系统的多系统疾病。目前莱姆病的血液检测在感染早期对抗生素最敏感的时候不那么敏感。这项应用将确定一种新的莱姆病检测方法，该方法基于螺旋体最初感染皮肤时表达的一组新蛋白质，是否能够准确地检测到莱姆病的早期阶段。

DESCRIPTION (provided by applicant): Lyme disease, due to infection with the Ixodes tick-transmitted spirochete Borrelia burgdorferi, is the most common vector-borne disease in the United States, with over 38,000 confirmed and probable cases reported to the CDC in 2009. Spirochetes first establish infection in the skin and then disseminate to internal organs such as the heart, the joints, and the nervous system where disease can be seen. The infection is most responsive to antibiotics when identified early, but those with disseminated infection or in whom treatment is delayed can experience debilitating disease that can become unresponsive to antibiotics. The timely and accurate diagnosis of Lyme disease is essential for optimizing the response to therapy and for preventing long- term sequelae of the disease. Serologic tests (ELISA and immunoblot) that detect antibodies against B. burgdorferi are currently the most sensitive and widely available laboratory tests for Lyme disease. These tests utilize whole-cell lysates of cultured laboratory strains of B. burgdorferi as a source of antigens, and therefore do not detect antibodies to B. burgdorferi proteins expressed predominantly in vivo. The recommended two-tiered approach in which a positive or equivocal ELISA is confirmed by immunoblot has only ~30% sensitivity in early stages of infection, and specificity is reduced due to cross-reactivity of B. burgdorferi antigens with those of other infectious agents. This Phase I application seeks to improve upon the currently available serologic tests for Lyme disease through the use of in vivo expressed, B. burgdorferi- specific proteins as antigens. We have recently identified a novel panel of B. burgdorferi genes and proteins that are expressed in the first few weeks of B. burgdorferi infection and to which sera from patients with early Lyme disease react on IgG ELISA. We propose to evaluate these candidate antigens in multiplex format assay for their sensitivity and specificity using human sera samples from well-defined cases of Lyme disease, subjects who have had no known exposure to B. burgdorferi, and other infectious and rheumatic diseases. Peptide pin arrays will map the immunodominant epitopes of candidate antigens with Lyme disease sera in an ELISA format for incorporation into a refined multiplex assay. The results of this Phase I study will set the stage for the development of new sensitive and specific serologic tests for Lyme disease that more accurately reflect the B. burgdorferi antigens inciting immune responses in the infected host. PUBLIC HEALTH RELEVANCE: Lyme disease, due to infection with the spirochete Borrelia burgdorferi, can cause a multisystem illness involving the skin, heart, joints and nervous system. Current blood tests for Lyme disease are not as sensitive early in infection when the infection is most responsive to antibiotics. This application will determine whether a new assay for Lyme disease based on a novel panel of proteins expressed by spirochetes when they initially infect the skin accurately detects Lyme disease in its earliest stages.