State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin, 150069, China.
Virol J. 2024 Mar 4;21(1):53. doi: 10.1186/s12985-024-02330-0.
Atypical porcine pestivirus (APPV) is a newly discovered swine pestivirus, which can cause congenital tremor and high mortality in newborn piglets and subclinical infection in adult pigs, leading to significant impacts on the pig industry. Currently, there is no approved serological method to assess APPV infection status in pig farms.
In this study, the envelope glycoprotein E2 of APPV was highly expressed in suspension HEK293 cells, and further an indirect enzyme-linked immunosorbent assay based on the recombinant E2 protein (E2-iELISA) was developed and evaluated.
The reaction parameters of the E2-iELISA were optimized, and the cutoff value was determined to be 0.2 by analyzing S/P values of 165 negative sera against APPV that were confirmed by virus neutralization test (VNT). Specificity test showed that the method had no cross-reaction with other common swine viruses. The E2-iELISA was evaluated using a panel of swine sera, and showed high sensitivity (113/120, 94.2%) and specificity (65/70, 92.9%), and the agreement rate with VNT was 93.7% (178/190). Subsequently, the E2-iELISA was utilized to investigate the seroprevalence of APPV in pig herds of China. When detecting 1368 pig serum samples collected from nine provinces in China, the overall seroprevalence of APPV was 73.9% (1011/1368).
Our findings suggest that the E2-iELISA is specific and sensitive, and could be a valuable tool for serological surveillance of APPV infection in pigs.
非典型猪瘟病毒（APPV）是一种新发现的猪瘟病毒，可引起新生仔猪先天性震颤和高死亡率，以及成年猪亚临床感染，对养猪业造成重大影响。目前，尚无批准的血清学方法来评估猪场 APPV 的感染状况。
本研究在悬浮 HEK293 细胞中高表达 APPV 的包膜糖蛋白 E2，进一步建立并评估了基于重组 E2 蛋白的间接酶联免疫吸附试验（E2-iELISA）。
优化了 E2-iELISA 的反应参数，通过分析经病毒中和试验（VNT）确认的 165 份 APPV 阴性血清的 S/P 值，确定了截断值为 0.2。特异性试验表明，该方法与其他常见猪瘟病毒无交叉反应。用一组猪血清评估了 E2-iELISA，结果显示该方法具有较高的敏感性（120 份血清中的 113 份，94.2%）和特异性（70 份血清中的 65 份，92.9%），与 VNT 的符合率为 93.7%（190 份血清中的 178 份）。随后，该 E2-iELISA 用于调查中国猪群中 APPV 的血清流行率。在检测来自中国 9 个省份的 1368 份猪血清样本时，APPV 的总血清流行率为 73.9%（1368 份血清中的 1011 份）。
我们的研究结果表明，E2-iELISA 具有特异性和敏感性，可作为 APPV 感染血清学监测的有用工具。
