Division of Influenza Virus, Center for Infectious Diseases, Korea National Institute of Health, Korea Centers for Disease Control and Prevention, Chungcheongbuk-do, South Korea.
J Med Virol. 2013 Apr;85(4):709-15. doi: 10.1002/jmv.23484.
During the influenza pandemic of 2009-2010, rapid influenza diagnostic tests (RIDTs) were used to detect influenza viral infections because they are quick and simple to use. However, retrospective studies showed that RIDTs performed poorly when used to diagnose pandemic viral infections. Determining how amino acid sequence changes in pandemic or epidemic influenza viral antigens impact clinical value of RIDTs has not been possible, because the viral epitopes recognized by RIDTs have been not mapped. In this study, the effect of escape-variations or mutations in influenza viral antigens upon the sensitivity and specificity of an RIDT was investigated by characterizing the immunological properties of the antibodies used in the RIDT. Escape-mutants were generated by cultivating A/Korea/01/2009 in the presence of an excess of the same antibodies used in the RIDT. Escape-mutants not recognized by the RIDT were selected. Epitopes recognized by the RIDT were mapped by comparing the sequence and immunological analysis of the escape-variants and wild-type isolates. The RIDT antibodies recognized epitopes on the Sa antigenic site and in the F subdomain in hemagglutinin. Variants bearing mutations in these epitopes were not detected by the RIDT. The frequency of escape-variants emerging since the 2009-2010 pandemic was calculated as 1.27% using in silico surveillance of influenza sequence databases. These results suggest that mapping the relevant epitopes of RIDTs and making such information available to clinics would be helpful for determining whether RIDTs match newly emergent strains and subtypes prior to retrospective re-evaluation of the RIDTs using clinical specimens.
在 2009-2010 年流感大流行期间，快速流感诊断检测（RIDT）被用于检测流感病毒感染，因为它们使用起来快速而简单。然而，回顾性研究表明，RIDT 在用于诊断大流行病毒感染时表现不佳。由于 RIDT 识别的病毒表位尚未定位，因此无法确定大流行或流行的流感病毒抗原的氨基酸序列变化如何影响 RIDT 的临床价值。在这项研究中，通过表征 RIDT 中使用的抗体的免疫特性，研究了流感病毒抗原中的逃逸变异或突变对 RIDT 的敏感性和特异性的影响。通过在过量使用 RIDT 中相同的抗体存在下培养 A/Korea/01/2009 来产生逃逸突变体。选择不被 RIDT 识别的逃逸突变体。通过比较逃逸变异体和野生型分离物的序列和免疫分析，定位了 RIDT 识别的表位。RIDT 抗体识别血凝素 Sa 抗原位点和 F 亚结构域上的表位。这些表位发生突变的变体不能被 RIDT 检测到。使用流感序列数据库的计算监测，计算了自 2009-2010 年大流行以来出现的逃逸变异体的频率为 1.27%。这些结果表明，绘制 RIDT 的相关表位，并将此类信息提供给临床医生，将有助于在使用临床标本对 RIDT 进行回顾性重新评估之前，确定 RIDT 是否与新出现的菌株和亚型匹配。
