Establishment of an indirect immunofluorescence assay for the detection of African swine fever virus antibodies

Wan Wang; Zhenjiang Zhang; Weldu Tesfagaber; Jiwen Zhang; Fang Li; Encheng Sun; Lijie Tang; Zhigao Bu; Yuanmao Zhu; Dongming Zhao

Journal of Integrative Agriculture (Jan 2024)

Establishment of an indirect immunofluorescence assay for the detection of African swine fever virus antibodies

Wan Wang,
Zhenjiang Zhang,
Weldu Tesfagaber,
Jiwen Zhang,
Fang Li,
Encheng Sun,
Lijie Tang,
Zhigao Bu,
Yuanmao Zhu,
Dongming Zhao

Affiliations

Wan Wang: State Key Laboratory for Animal Disease Control and Prevention, National African Swine Fever Para-reference Laboratory, National High Containment Facilities for Animal Diseases Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China
Zhenjiang Zhang: State Key Laboratory for Animal Disease Control and Prevention, National African Swine Fever Para-reference Laboratory, National High Containment Facilities for Animal Diseases Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China; College of Veterinary Medicine, Northeast Agricultural University, Harbin 150069, China
Weldu Tesfagaber: State Key Laboratory for Animal Disease Control and Prevention, National African Swine Fever Para-reference Laboratory, National High Containment Facilities for Animal Diseases Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China
Jiwen Zhang: State Key Laboratory for Animal Disease Control and Prevention, National African Swine Fever Para-reference Laboratory, National High Containment Facilities for Animal Diseases Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China
Fang Li: State Key Laboratory for Animal Disease Control and Prevention, National African Swine Fever Para-reference Laboratory, National High Containment Facilities for Animal Diseases Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China
Encheng Sun: State Key Laboratory for Animal Disease Control and Prevention, National African Swine Fever Para-reference Laboratory, National High Containment Facilities for Animal Diseases Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China
Lijie Tang: College of Veterinary Medicine, Northeast Agricultural University, Harbin 150069, China
Zhigao Bu: State Key Laboratory for Animal Disease Control and Prevention, National African Swine Fever Para-reference Laboratory, National High Containment Facilities for Animal Diseases Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China
Yuanmao Zhu: State Key Laboratory for Animal Disease Control and Prevention, National African Swine Fever Para-reference Laboratory, National High Containment Facilities for Animal Diseases Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China; Correspondence Yuanmao Zhu
Dongming Zhao: State Key Laboratory for Animal Disease Control and Prevention, National African Swine Fever Para-reference Laboratory, National High Containment Facilities for Animal Diseases Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China; Correspondence Dongming Zhao

Journal volume & issue: Vol. 23, no. 1
pp. 228 – 238

Abstract

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African swine fever (ASF) continues to cause enormous economic loss to the global pig industry. Since there is no safe and effective vaccine, accurate and timely diagnosis of ASF is essential to implement control measures. Indirect immunofluorescence assay (IFA) is a gold standard serological method recommended by the World Organization for Animal Health (WOAH). In this study, we used primary fetal kidney cells to establish a wild boar cell line (BK2258) that supported the efficient replication of ASF virus (ASFV) SD/DY-I/21 and showed visible cytopathic effect (CPE). Moreover, using BK2258, we established a sensitive and specific IFA for ASFV antibody detection. To standardize and evaluate the performance of this assay, we used serum samples from pigs infected with the low virulent genotype I SD/DY-I/21 and genotype II HLJ/HRB1/20, and immunized with the vaccine candidate HLJ/18-7GD, field samples, and negative serum samples. The IFA reacted with the ASFV-positive sera and displayed bright fluorescence foci. There was no non-specific green fluorescence due to cellular senescence or other cell damage-causing factors. Compared to a commercial indirect enzyme-linked immunosorbent assay (iELISA), ASFV antibodies were detected 1–4 days earlier using our IFA. The detection limits of the IFA and iELISA for the same ASFV-antibody positive serum samples were 1:25,600 and 1:6,400, respectively, indicating that the IFA is more sensitive than iELISA. The newly established IFA was highly specific and did not cross-react with sera positive for six other important porcine pathogens (i.e., Classical swine fever virus (CSFV), Porcine reproductive and respiratory syndrome virus (PRRSV), Porcme circovirus type 2 (PCV2), Pseudorabies virus (PRV), Foot-and-Mouth disease virus type O (FMDV/O), and Porcine epidemic diarrhea virus (PEDV)). This study thus provides a sensitive, specific, and reliable detection method that is suitable for the serological diagnosis of ASF.

Published in Journal of Integrative Agriculture

ISSN: 2095-3119 (Print); 2352-3425 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Agriculture: Agriculture (General)
Website: https://www.journals.elsevier.com/journal-of-integrative-agriculture

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