Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Universités de Montpellier II et I, CNRS UMR 5235, Montpellier, France.
PLoS One. 2011;6(9):e25078. doi: 10.1371/journal.pone.0025078. Epub 2011 Sep 22.
New diagnosis tests are urgently needed to address the global tuberculosis (TB) burden and to improve control programs especially in resource-limited settings. An effective in vitro diagnostic of TB based on serological methods would be regarded as an attractive progress because immunoassays are simple, rapid, inexpensive, and may offer the possibility to detect cases missed by standard sputum smear microscopy. However, currently available serology tests for TB are highly variable in sensitivity and specificity. Lipolytic enzymes have recently emerged as key factors in lipid metabolization during dormancy and/or exit of the non-replicating growth phase, a prerequisite step of TB reactivation. The focus of this study was to analyze and compare the potential of four Mycobacterium tuberculosis lipolytic enzymes (LipY, Rv0183, Rv1984c and Rv3452) as new markers in the serodiagnosis of active TB.
Recombinant proteins were produced and used in optimized ELISA aimed to detect IgG and IgM serum antibodies against the four lipolytic enzymes. The capacity of the assays to identify infection was evaluated in patients with either active TB or latent TB and compared with two distinct control groups consisting of BCG-vaccinated blood donors and hospitalized non-TB individuals.
A robust humoral response was detected in patients with active TB whereas antibodies against lipolytic enzymes were infrequently detected in either uninfected groups or in subjects with latent infection. High specifity levels, ranging from 93.9% to 97.5%, were obtained for all four antigens with sensitivity values ranging from 73.4% to 90.5%, with Rv3452 displaying the highest performances. Patients with active TB usually exhibited strong IgG responses but poor IgM responses.
These results clearly indicate that the lipolytic enzymes tested are strongly immunogenic allowing to distinguish active from latent TB infections. They appear as potent biomarkers providing high sensitivity and specificity levels for the immunodiagnosis of active TB.
为了应对全球结核病（TB）负担并改善控制计划，特别是在资源有限的环境中，迫切需要新的诊断检测方法。基于血清学方法的有效 TB 体外诊断方法将被视为一项有吸引力的进展，因为免疫测定简单、快速、廉价，并且可能有机会检测到标准痰涂片显微镜检查遗漏的病例。然而，目前用于 TB 的血清学检测在灵敏度和特异性方面差异很大。脂解酶最近成为休眠和/或非复制生长阶段退出期间脂质代谢的关键因素，这是 TB 再激活的前提步骤。本研究的重点是分析和比较四种结核分枝杆菌脂解酶（LipY、Rv0183、Rv1984c 和 Rv3452）作为活动性 TB 血清诊断的新标志物的潜力。
生产重组蛋白并用于优化 ELISA，旨在检测针对四种脂解酶的 IgG 和 IgM 血清抗体。通过将这些检测方法用于活动性 TB 患者、潜伏性 TB 患者和两个不同的对照组（卡介苗接种的献血者和住院非 TB 个体）来评估其识别感染的能力。
在活动性 TB 患者中检测到强烈的体液反应，而在未感染组或潜伏性感染患者中很少检测到针对脂解酶的抗体。所有四种抗原的特异性水平均很高，范围为 93.9%至 97.5%，敏感性值范围为 73.4%至 90.5%，其中 Rv3452 的性能最高。活动性 TB 患者通常表现出强烈的 IgG 反应，但 IgM 反应较弱。
这些结果清楚地表明，测试的脂解酶具有很强的免疫原性，可以区分活动性和潜伏性 TB 感染。它们作为强有力的生物标志物，为活动性 TB 的免疫诊断提供了高灵敏度和特异性水平。
