Characterization of Anti-p54 Monoclonal Antibodies and Their Potential Use for African Swine Fever Virus Diagnosis.

Weldu Tesfagaber,Haoyue Huangfu,Encheng Sun,Lulu Wang,Zhigao Bu,Jiwen Zhang,Dongming Zhao,Fei Xi,Ghebremedhin Tsegay,Yibrah Tekle Hagoss,Zhenjiang Zhang,Fang Li

doi:10.3390/pathogens10020178

Abstract

African swine fever (ASF) is a highly lethal hemorrhagic viral disease of domestic pigs caused by African swine fever virus (ASFV). Although a good advance has been made to understand the virus, a safe and effective vaccine against ASFV is still lacking and its eradication solely depends on its early and accurate diagnosis. Thus, improving the available diagnostic assays and adding some validated techniques are useful for a range of serological investigations. The aim of this study was to produce and characterize p54 monoclonal antibodies with an ultimate goal of developing a monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA) for ASFV antibody detection. Five monoclonal antibodies against p54 protein expressed in Escherichia coli was generated and their characterizations were investigated. Furthermore, a competitive enzyme-linked immunosorbent assay (cELISA) based on a monoclonal antibody designated as 2A7 was developed. To evaluate the performance of the assay, a total of 365 pig serum samples (178 negative and 187 positive samples) were tested and a receiver-operating characteristic (ROC) analysis was applied to determine the cut-off value. Based on the ROC analysis, the area under the curve (AUC) was 0.982 (95% confidence interval: 96.9% to 99.4%), besides a sensitivity of 92.5% and a specificity of 98.9% was achieved when the percent inhibition of 20% was selected as a threshold. Moreover, the result showed an excellent agreement when compared to other commercially available blocking ELISA (kappa value = 0.912) and showed no reaction to other swine pathogens. Overall, the newly developed cELISA method offers a promising approach for a rapid and convenient ASFV serodiagnosis, which could be used as alternative to other serological assays for screening possible ASFV infection.

Highlights

African swine fever (ASF) is a highly lethal hemorrhagic viral disease of swine that usually results to a mortality rate approaching 100% in domestic pigs and is classified as a notifiable disease by the World Organization for Animal Health (OIE)
It is the major threat to global pig industry and is caused by African swine fever virus (ASFV), a large and complex double stranded DNA virus with icosahedral morphology [1,2]
ASFV antibody detection using the most antigenic proteins p72, p30, pp62 together with p54 have been proved to be effective, improving the available diagnostic assays and adding some validated techniques are useful for a range of serological investigations and are a timely demand to mitigate ASFV

Summary

Introduction

African swine fever (ASF) is a highly lethal hemorrhagic viral disease of swine that usually results to a mortality rate approaching 100% in domestic pigs and is classified as a notifiable disease by the World Organization for Animal Health (OIE). In domestic pigs there is a variation in the clinical manifestations depending on the virus strains, which differs from an acute, highly lethal hemorrhagic disease to a mild inapparent infection [3,4]. On the contrary, it leads to a mild subclinical infection in the natural reservoir’s hosts (wart hogs and bush pigs), which are the potential source of infection to domestic pigs. To detect sub-acute or chronic nature of ASF either in domestic pigs or the reservoir hosts, a range of sensitive serological investigations are needed and antibody detection is a rational approach

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