抗 Lassa 病毒核蛋白特异性免疫球蛋白 M 和 G 的抗体捕获免疫分析的建立和评价。
Development and evaluation of antibody-capture immunoassays for detection of Lassa virus nucleoprotein-specific immunoglobulin M and G.
机构信息
Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
Institute of Lassa Fever Research and Control, Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria.
出版信息
PLoS Negl Trop Dis. 2018 Mar 29;12(3):e0006361. doi: 10.1371/journal.pntd.0006361. eCollection 2018 Mar.
BACKGROUND
The classical method for detection of Lassa virus-specific antibodies is the immunofluorescence assay (IFA) using virus-infected cells as antigen. However, IFA requires laboratories of biosafety level 4 for assay production and an experienced investigator to interpret the fluorescence signals. Therefore, we aimed to establish and evaluate enzyme-linked immunosorbent assays (ELISA) using recombinant Lassa virus nucleoprotein (NP) as antigen.
METHODOLOGY/PRINCIPAL FINDINGS: The IgM ELISA is based on capturing IgM antibodies using anti-IgM, and the IgG ELISA is based on capturing IgG antibody-antigen complexes using rheumatoid factor or Fc gamma receptor CD32a. Analytical and clinical evaluation was performed with 880 sera from Lassa fever endemic (Nigeria) and non-endemic (Ghana and Germany) areas. Using the IFA as reference method, we observed 91.5-94.3% analytical accuracy of the ELISAs in detecting Lassa virus-specific antibodies. Evaluation of the ELISAs for diagnosis of Lassa fever on admission to hospital in an endemic area revealed a clinical sensitivity for the stand-alone IgM ELISA of 31% (95% CI 25-37) and for combined IgM/IgG detection of 26% (95% CI 21-32) compared to RT-PCR. The specificity of IgM and IgG ELISA was estimated at 96% (95% CI 93-98) and 100% (95% CI 99-100), respectively, in non-Lassa fever patients from non-endemic areas. In patients who seroconverted during follow-up, Lassa virus-specific IgM and IgG developed simultaneously rather than sequentially. Consistent with this finding, isolated IgM reactivity, i.e. IgM in the absence of IgG, had no diagnostic value.
CONCLUSIONS/SIGNIFICANCE: The ELISAs are not equivalent to RT-PCR for early diagnosis of Lassa fever; however, they are of value in diagnosing patients at later stage. The IgG ELISA may be useful for epidemiological studies and clinical trials due its high specificity, and the higher throughput rate and easier operation compared to IFA.
背景
检测拉沙病毒特异性抗体的经典方法是使用感染病毒的细胞作为抗原的免疫荧光检测（IFA）。然而，IFA 需要生物安全 4 级实验室进行检测生产，并且需要有经验的调查人员来解释荧光信号。因此，我们旨在建立和评估使用重组拉沙病毒核蛋白（NP）作为抗原的酶联免疫吸附试验（ELISA）。
方法/主要发现：IgM ELISA 基于使用抗 IgM 捕获 IgM 抗体，而 IgG ELISA 基于使用类风湿因子或 Fcγ受体 CD32a 捕获 IgG 抗体-抗原复合物。使用来自拉沙热流行（尼日利亚）和非流行（加纳和德国）地区的 880 份血清进行了分析和临床评估。使用 IFA 作为参考方法，我们观察到 ELISA 检测拉沙病毒特异性抗体的分析准确性为 91.5-94.3%。在流行地区入院时对 ELISA 进行拉沙热诊断的评估显示，单独 IgM ELISA 的临床灵敏度为 31%（95%CI 25-37），而 IgM/IgG 联合检测的灵敏度为 26%（95%CI 21-32）与 RT-PCR 相比。非流行地区非拉沙热患者的 IgM 和 IgG ELISA 的特异性估计分别为 96%（95%CI 93-98）和 100%（95%CI 99-100）。在随访期间发生血清转化的患者中，拉沙病毒特异性 IgM 和 IgG 同时而不是顺序出现。与这一发现一致的是，孤立的 IgM 反应，即没有 IgG 的 IgM，没有诊断价值。
结论/意义：ELISA 不适用于拉沙热的早期诊断；然而，它们对于诊断后期患者具有价值。与 IFA 相比，IgG ELISA 因其高特异性、更高的通量率和更简单的操作而可用于流行病学研究和临床试验。
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