Division of Avian Infectious Diseases, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, the People's Republic of China.
Viral Immunol. 2023 Dec;36(10):649-658. doi: 10.1089/vim.2023.0049. Epub 2023 Oct 30.
Infectious bronchitis virus (IBV), a gammacoronavirus within the Coronaviridae family, is an economically important etiological disease agent in chickens. Both early diagnosis and determination of the immune status of chickens are important for controlling IBV outbreaks in chicken flocks. The N protein is the most abundantly expressed virus-derived protein during IBV infection and can induce a strong immune response by producing antibodies during early infection or immunization. In this study, we found that the amino acid sequences of the N protein between CK/CH/LJL/04I and the other 22 IBVs were conserved, especially in the 1-160 amino acid region. Based on the sequence similarities, the three recombinant proteins, rN160 (amino acid positions 1-160), rN266 (144-409), and rN409 (1-409), were expressed using the system and subsequently purified. The results demonstrated that the antigenicity and reactivity of rN160 were better than those of rN266 and rN409. As a result, an indirect enzyme-linked immunosorbent assay (ELISA) (rN160 ELISA) was developed to detect the IBV antibody based on the rN160 protein. Using 1,500 clinical field serum samples, the relative sensitivity, specificity, and accuracy of the rN160 ELISA were 98.97%, 92.34%, and 97.93%, respectively, compared to those of a commercial ELISA kit (IDEXX), indicating a strong positive correlation between the two methods. Taken together, these results reveal that the rN160 ELISA is a rapid, simple, and sensitive method for detecting group-specific IBV antibodies for epidemiological investigation and antibody-level monitoring.
传染性支气管炎病毒（IBV）是冠状病毒科冠状病毒属的一员，是鸡群中一种具有重要经济意义的病原。早期诊断和确定鸡群的免疫状态对于控制鸡群中 IBV 的爆发非常重要。N 蛋白是 IBV 感染过程中表达量最多的病毒衍生蛋白，它可以通过在早期感染或免疫时产生抗体来诱导强烈的免疫反应。在本研究中，我们发现 CK/CH/LJL/04I 株与其他 22 株 IBV 株的 N 蛋白氨基酸序列具有保守性，特别是在 1-160 个氨基酸区域。基于序列相似性，使用 系统表达了三个重组蛋白，rN160（氨基酸位置 1-160）、rN266（144-409）和 rN409（1-409），并进行了纯化。结果表明，rN160 的抗原性和反应性优于 rN266 和 rN409。因此，基于 rN160 蛋白建立了一种间接酶联免疫吸附试验（rN160 ELISA）来检测 IBV 抗体。使用 1500 份临床血清样本，rN160 ELISA 的相对敏感性、特异性和准确性分别为 98.97%、92.34%和 97.93%，与商业 ELISA 试剂盒（IDEXX）相比，表明两种方法具有很强的正相关性。综上所述，这些结果表明 rN160 ELISA 是一种快速、简单、敏感的方法，可用于群体特异性 IBV 抗体的检测，用于流行病学调查和抗体水平监测。
