Development and evaluation of indirect double-antibody sandwich ELISA for rapid detection of Salmonid Alphavirus using Baculoviridae expressed E1 Protein

• Published in: Aquaculture 2021-11, Vol.544, p.737081, Article 737081
• Main Authors: Gao, Shuai, Wang, Na, Yang, Jiawei, Sun, Jinhui, Wang, Yuting, Xia, Dong, Tian, Jingwen, Zhao, Yuntong, Feng, Ying, Zhou, Ying, Guan, Xueting, Shi, Wen, Liu, Min
• Format: Article
• Language: English
• Subjects: Baculovirus; Diagnostic; IDAS-ELISA; Salmonid Alphavirus
• ISSN: 0044-8486; 1873-5622
• DOI: 10.1016/j.aquaculture.2021.737081

Salmon alphavirus (SAV) is a widespread virus that infects Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss) in Europe. It has a fatality rate of ≤48% and can cause pancreatic and sleeping disease. With the frequent exchange of salmon farming trade, it may become a global pathogen; therefore, a sensitive, effective, and high-throughput detection method is necessary. The serological diagnoses for SAV are indirect immunofluorescence assays (IFA) and indirect enzyme-linked immunosorbent assays (ELISA), which can only detect one of the six subtypes of SAV. In this study, an insect cell/baculovirus expression system was used for simultaneous detection of multiple genotypes (SAV1, SAV2, and SAV5) and an indirect double-antibody sandwich-enzyme linked immunosorbent assay (IDAS-ELISA) method was adopted, based on the highly conserved region (E1) of SAV1-6. The results showed that the IDAS-ELISA had no cross-reaction with other common RNA viruses and high sensitivity with 103.4TCID50/0.1 mL detection line. SAV 1 (98.33%) and SAV 2 (91.67%) samples were positively identified by IDAS-ELISA and real-time polymerase chain reaction (PCR), respectively. This assay can simultaneously detect multiple subtypes of SAV and provide technical support for clinical diagnosis and the epidemiology of SAV. •An IDAS-ELISA was established to detect multiple SAV genotypes.•Bac-to-Bac system was used to prepare SAV E1 positive products due to its high safety and high protein content.•This assay has high specificity and sensitivity, and is suitable for the diagnosis and control of SAV infection.