Development and In Vivo Evaluation of a MGF110-1L Deletion Mutant in African Swine Fever Strain Georgia.

Elizabeth Ramirez-Medina,Douglas P Gladue,Elizabeth Vuono,Ayushi Rai,Sarah Pruitt,James Zhu,Ediane Silva,Manuel V Borca,Lauro Velazquez-Salinas,Nallely Espinoza

doi:10.3390/v13020286

Abstract

African swine fever (ASF) is currently causing an epizootic, affecting pigs throughout Eurasia, and causing significant economic losses in the swine industry. ASF is caused by African swine fever virus (ASFV) that consists of a large dsDNA genome that encodes for more than 160 genes; few of these genes have been studied in detail. ASFV contains four multi-gene family (MGF) groups of genes that have been implicated in regulating the immune response and host specificity; however, the individual roles of most of these genes have not been well studied. Here, we describe the evaluation of the previously uncharacterized ASFV MGF110-1L open reading frame (ORF) using a deletion mutant of the ASFV currently circulating throughout Eurasia. The recombinant ASFV lacking the MGF110-1L gene (ASFV-G-ΔMGF110-1L) demonstrated in vitro that the MGF110-1L gene is non-essential, since ASFV-G-ΔMGF110-1L had similar replication kinetics in primary swine macrophage cell cultures when compared to parental highly virulent field isolate Georgia2007 (ASFV-G). Experimental infection of domestic pigs with ASFV-G-ΔMGF110-1L produced a clinical disease similar to that caused by the parental ASFV-G, confirming that deletion of the MGF110-1L gene from the ASFV genome does not affect viral virulence.

Highlights

Until recently, African swine fever (ASF) was historically endemic in Africa and Sardinia (Italy)
ASF is a frequently lethal viral disease of swine caused by a large dsDNA virus
It is important to understand the role of individual genes in African swine fever virus (ASFV), as well as how their possible manipulation could be used to develop experimental vaccines, and/or to have the tools necessary to develop the generation of ASF vaccines

Summary

Introduction

African swine fever (ASF) was historically endemic in Africa and Sardinia (Italy). In 2007, a highly virulent strain of African swine fever virus (ASFV), ASFV strain Georgia (ASFV-G), was introduced into the Republic of Georgia, quickly spreading into neighboring countries throughout Eastern Europe [1]. In 2020, ASF was first detected in Germany, as of this publication it has been detected only in the wild boar population. This continued seemingly uncontrolled spread of ASFV has the potential to cause a worldwide protein availability shortage, as well as large economic losses in the swine industry [2]. ASF is a frequently lethal viral disease of swine caused by a large dsDNA virus (180–190 kilobase pairs), known as ASFV. It is important to understand the role of individual genes in ASFV, as well as how their possible manipulation could be used to develop experimental vaccines, and/or to have the tools necessary to develop the generation of ASF vaccines

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Results