PHOSPHOLIPASE: A TARGET TO DIAGNOSE INVASIVE CANDIDIASIS

描述（由申请人提供）：免疫功能低下的患者是最容易发生侵袭性念珠菌病的个体。念珠菌病免疫功能低下患者的死亡率估计在38- 50%之间，即使有治疗。目前可用的诊断测试，包括常规血培养缺乏敏感性和特异性。因此，开发能够提供感染早期证据和/或补充当前培养和血清学检测的创新实验室方法势在必行。本课题组的最新研究结果表明，由白色念珠菌分泌的磷脂酶B可能是念珠菌病的一个新的诊断靶点。当我们检测一对C.白色念珠菌的不同之处仅在于它们分泌PLB的能力，在两种不同的念珠菌病小鼠模型中，并显示cap 1b 1突变体的毒力显著减弱。本提案中描述的实验旨在开发和评估基于Plb 1的侵袭性念珠菌病诊断测试。该建议的总体假设是Plb 1可以用作诊断标志物。为了支持这一假设，我们已经表明，Plb 1分泌，并在体内宿主组织入侵过程中检测。重要的是，我们还表明，从侵袭性念珠菌病患者（n=33）的血清中含有显着更高水平的抗Plb 1抗体相比，从健康对照组（P = 0.042）。我们将通过追求以下具体目标来进一步检验这一假设：1）鉴定、表达和纯化Plb 1 p推导的氨基酸区域的特异性区域。这些肽将用于评价Plb 1作为特异性诊断标志物的潜力。2)兔血清中抗Plb 1 p抗体和抗原的检测3)使用人血清评价Plb 1 p的诊断效用。将在已建立的侵袭性和粘膜念珠菌病实验动物模型、经培养证实的侵袭性念珠菌病患者和研究对照中评价每种方法的有效性。

DESCRIPTION (provided by applicant): Immunocompromised patients are among the most susceptible individuals to develop invasive candidiasis. Mortality rates among candidemic immunocompromised patients have been estimated at between 38-50%, even with therapy. Currently available diagnostic tests including routine blood cultures lack sensitivity and specificity. Thus, development of innovative laboratory methods capable of providing early evidence of infection and/or complement current cultural and serological tests is imperative. Recent findings from our group suggest that phospholipase B, secreted by Candida albicans may be a novel diagnostic target for candidiasis. This was evident when we tested an isogenic strain pair of C. albicans differing only in their ability to secret PLB, in two different murine models of candidiasis, and showed that the virulence of caplb1 mutants is significantly attenuated. The experiments described in this proposal aim at developing and evaluating Plb1-based diagnostic tests for invasive candidiasis. The overall hypothesis of this proposal is that Plb1 could be useful as a diagnostic marker. In support of this hypothesis, we have shown that Plb1 is secreted and is detectable during host tissue invasion in vivo. Importantly, we also showed that sera from patients with invasive candidiasis (n=33) contained significantly higher levels of anti-Plb1 antibody compared to sera obtained from healthy controls (P = 0.042). We will examine this hypothesis further by pursuit of the following specific objectives: 1) Identification, expression and purification of regions specific to Plb1p deduced amino acid regions. These peptides will be used to evaluate the potential of Plb1 as a specific diagnostic marker. 2) Detection of circulating anti-Plb1p antibody and Plb1p antigen in rabbit sera. 3) Evaluations of diagnostic utility of Plb1p using human sera. The effectiveness of each approach will be evaluated in established experimental animal models of invasive and mucosal candidiasis and patients with culture-proven invasive candidiasis and controls for the study.