Highly pathogenic influenza A viruses (IAVs) cause substantial damage to the poultry industry. A simple and quick testing method is required for strict control of this infectious agent. The fluorescence polarization immunoassay (FPIA) is a rapid test based on antigen–antibody binding, which can detect antigen-specific antibody in the infected animal samples within a few minutes. FPIA is a one-step reaction assay that does not require a secondary antibody and complicated steps. We evaluated the usefulness of FPIA for the detection of anti-IAV antibodies, including those against internal proteins and H5 subtype HA, in sera. In the FPIA using fluorescent peptides of internal NP and M1 proteins, millipolarization units (MPUs), which increase depending on the amount of antibody, were higher in antibody-positive sera than in antibody-negative sera. Moreover, in FPIA using fluorescent recombinant H5 subtype HA proteins, anti-H5 serum gave the highest MPUs among the antisera raised in goats against individual H1–H15 subtype IAVs. Our results support the utility of FPIA for the detection of anti-IAV antibodies, especially the anti-H5 antibody.

高致病性甲型流感病毒 (IAV) 对家禽业造成重大损害。需要一种简单快速的测试方法来严格控制这种传染性病原体。荧光偏振免疫分析 (FPIA) 是一种基于抗原抗体结合的快速检测方法，可在几分钟内检测出受感染动物样本中的抗原特异性抗体。FPIA 是一种一步反应检测，不需要二抗和复杂的步骤。我们评估了 FPIA 在检测血清中抗 IAV 抗体（包括针对内部蛋白和 H5 亚型 HA 的抗体）中的有用性。在使用内部 NP 和 M1 蛋白荧光肽的 FPIA 中，根据抗体量增加的毫极化单位 (MPU) 在抗体阳性血清中高于抗体阴性血清。此外，在使用荧光重组 H5 亚型 HA 蛋白的 FPIA 中，抗 H5 血清在针对个体 H1-H15 亚型 IAV 的山羊抗血清中产生最高的 MPU。我们的结果支持 FPIA 用于检测抗 IAV 抗体，尤其是抗 H5 抗体的效用。