Background

Leptospirosis is the most common zoonotic disease worldwide. The diagnostic performance of a serological test for human leptospirosis is mainly influenced by the antigen used in the test assay. An ideal serological test should cover all serovars of pathogenic leptospires with high sensitivity and specificity and use reagents that are relatively inexpensive to produce and can be used in tropical climates. Peptide-based tests fulfil at least the latter two requirements, and ORFeome phage display has been successfully used to identify immunogenic peptides from other pathogens.

Methodology/Principal findings

Two ORFeome phage display libraries of the entire Leptospira spp. genomes from five local strains isolated in Malaysia or seven WHO reference strains were constructed. Subsequently, 18 unique Leptospira peptides were identified in a screen using a pool of sera from patients with acute leptospirosis. Five of these were validated by titration ELISA using different pools of patient or control sera. The diagnostic performance of these five peptides was then assessed against 16 individual sera from patients with acute leptospirosis and 16 healthy donors and was compared to that of two recombinant reference proteins from L. interrogans. This analysis revealed two peptides (SIR16-D1 and SIR16-H1) from the local isolates with good accuracy for the detection of acute leptospirosis (area under the ROC curve: 0.86 and 0.78, respectively; sensitivity: 0.88 and 0.94; specificity: 0.81 and 0.69), which was close to that of the reference proteins LipL32 and Loa22 (area under the ROC curve: 0.91 and 0.80; sensitivity: 0.94 and 0.81; specificity: 0.75 and 0.75).

Conclusions/Significance

This analysis lends further support for using ORFeome phage display to identify pathogen-associated immunogenic peptides, and it suggests that this technique holds promise for the development of peptide-based diagnostics for leptospirosis and, possibly, of vaccines against this pathogen.

中文翻译：

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钩端螺旋体的发现。使用ORFeome噬菌体展示的血清反应性肽

背景

钩端螺旋体病是全世界最常见的人畜共患病。血清学检测对人类钩端螺旋体病的诊断性能主要受检测分析中使用的抗原的影响。理想的血清学检测应以高灵敏度和特异性覆盖所有病原性钩端螺旋体的血清，并使用生产成本相对较低且可用于热带气候的试剂。基于肽的测试至少满足后两个要求，ORFeome噬菌体展示已成功用于鉴定来自其他病原体的免疫原性肽。

方法/主要发现

整个钩端螺旋体属的两个ORFeome噬菌体展示文库。从马来西亚分离出的五种本地菌株或世卫组织的七种参考菌株中构建了基因组。随后，使用来自急性钩端螺旋体病患者的血清池在筛查中鉴定出18种独特的钩端螺旋体肽。其中五种通过使用不同患者或对照血清库的滴定ELISA进行了验证。然后评估了这五种肽的诊断性能，分别针对急性钩端螺旋体病患者的16份血清和16位健康供体的血清，并与来自L.的两种重组参考蛋白进行了比较。询问者。该分析揭示了来自本地分离株的两种肽（SIR16-D1和SIR16-H1），具有很高的准确度，可用于检测急性钩端螺旋体病（ROC曲线下的面积分别为0.86和0.78;灵敏度：0.88和0.94;特异性：0.81和0.69），接近于参考蛋白LipL32和Loa22（ROC曲线下的面积：0.91和0.80；灵敏度：0.94和0.81；特异性：0.75和0.75）。

结论/意义

该分析为使用ORFeome噬菌体展示鉴定病原体相关的免疫原性肽提供了进一步的支持，并且表明该技术为开发基于钩端螺旋体病的基于肽的诊断方法以及可能针对该病原体的疫苗提供了希望。