Development of a fluorescent ASFV strain that retains the ability to cause disease in swine

Manuel V Borca,Douglas P Gladue,Lauren G Holinka,Guillermo R Risatti,Vivian O’Donnell,Brent Sanford,Paul A Azzinaro

doi:10.1038/srep46747

Abstract

African swine fever is a contagious and often lethal disease for domestic pigs with a significant economic impact for the swine industry. The etiological agent, African swine fever virus (ASFV), is a highly structurally complex double stranded DNA virus. No effective vaccines or antiviral treatment are currently commercially available. We present here the development of a strain of ASFV that has been shown to retain its ability to cause disease in swine, efficiently replicate in swine macrophage and that is fluorescently tagged. The insertion of an EGFP cassette replacing the reading frames for two neighboring genes, MGF360-13L and MGF360-14L, in highly virulent field isolate Georgia/2007, did not affect virus replication in cell cultures and did not affect disease progression in swine, the natural host for ASFV. A virulent fluorescently tagged ASFV is a suitable tool to conduct pathogenesis studies in swine, study on virus-macrophage interaction and to run large scale screens that require a sensitive high throughput output. Utilizing an EGFP reporter system for observing ASFV replication and infectivity can circumvent the time and labor-intensive steps associated with viral antigen-based assays such as the observation of hemadsorption or cytopathic effect.

Highlights

African swine fever virus (ASFV) is the only member of the Asfarviridae family and is the etiological agent of African swine fever (ASF)
Recombinant ASFV Georgia/2007 (ASFV-G)-ΔMGF-13/14-enhanced green fluorescent protein (EGFP) was generated by homologous recombination between the parental ASFV-G genome and a recombination transfer vector following infection and transfection of swine macrophage cell cultures[18]
The recombinant transfer vector (p72ΔMGF13/14-EGFP) (Fig. 1) contained flanking genomic regions, the left arm is located between genomic positions 29352-30551 and the right arm is located between genomic positions 32914-33615

Summary

Introduction

African swine fever virus (ASFV) is the only member of the Asfarviridae family and is the etiological agent of African swine fever (ASF). Recombinant ASFV-G-ΔMGF-13/14-EGFP was generated by homologous recombination between the parental ASFV-G genome and a recombination transfer vector following infection and transfection of swine macrophage cell cultures[18].

Results

Conclusion