A seven-gene-deleted African swine fever virus is safe and effective as a live attenuated vaccine in pigs

Abstract

African swine fever (ASF) is a devastating infectious disease in swine that is severely threatening the global pig industry. An efficacious vaccine is urgently required. Here, we used the Chinese ASFV HLJ/18 as a backbone and generated a series of genedeleted viruses. The virulence, immunogenicity, safety, and protective efficacy evaluation in specific-pathogen-free pigs, commercial pigs, and pregnant sows indicated that one virus, namely HLJ/18-7GD, which has seven genes deleted, is fully attenuated in pigs, cannot convert to the virulent strain, and provides complete protection of pigs against lethal ASFV challenge.Our study shows that HLJ/-18-7GD is a safe and effective vaccine against ASFV, and as such is expected to play an important role in controlling the spread of ASFV.

Development and Evaluation of Duplex TaqMan Real-Time PCR Assay for Detection and Differentiation of Wide-Type and MGF505 Gene-Deleted African Swine Fever Viruses

“…Recently, several promising attenuated vaccine candidates have been reported using gene deletion strategy. MGF505, MGF360, CD2v, 9GL, DP148R, UK and I177L have been shown to be important virulence determinants of different ASFVs [6,[10][11][12][13]. However, the safety and effectivity of most potential vaccine candidates were not fully assessed, and virulence changes induced by gene deletion in one ASFV strain may not be similar in other strains [6].…”

“…MGF505, MGF360, CD2v, 9GL, DP148R, UK and I177L have been shown to be important virulence determinants of different ASFVs [6,[10][11][12][13]. However, the safety and effectivity of most potential vaccine candidates were not fully assessed, and virulence changes induced by gene deletion in one ASFV strain may not be similar in other strains [6]. Deletion MGF505 and MGF360 genes (MGF505-1R, 2R, 3R and MGF360-12L, 13L, 14L) or combined with CD2v did highly attenuated the different ASFV strains and protected pigs against challenge with the virulent parental virus with a satisfactory security [6,10,14].…”

“…In order to successfully cope with the threat of ASFV, in addition to a very high level of biological safety system, vaccine is the most effective tool to control ASF in the future. Recently, some gene-deleted ASFVs might be potential as live attenuated vaccines [6,[10][11][12][13]. Among them, multigene family (MGF) 360-505R and CD2v gene-deleted vaccines, have become one of the most promising ASF vaccine candidates [6,10].…”

“…Recently, some gene-deleted ASFVs might be potential as live attenuated vaccines [6,[10][11][12][13]. Among them, multigene family (MGF) 360-505R and CD2v gene-deleted vaccines, have become one of the most promising ASF vaccine candidates [6,10]. Thus, it is necessary to develop a diagnosis method to distinguishingwide-type ASFVs infection or gene-deleted vaccine immunization.…”

Integrated Micropillar Polydimethylsiloxane Accurate CRISPR Detection (IMPACT) System for Rapid Viral DNA Sensing

“…6 It took over an additional month to show its effectiveness in laboratory tests, and it still needs to be proven effective in the field. 7 Currently, there are no proven treatments for either COVID-19 or ASFV. Even if one were to be developed soon, it can take years to prove its effectiveness in clinical trials and mass produce the vaccine, not to mention distribute and administer it in affected areas.…”