Genomic deletion in African swine fever vaccine allowing efficient growth in stable cell lines
Inventors
Gladue, Douglas P. • Borca, Manuel V.
Assignees
US Department of Agriculture USDA
Publication Number
US-11766476-B2
Publication Date
2023-09-26
Expiration Date
2040-12-22
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Abstract
Provided herein are details on the construction of a recombinant African Swine Fever Virus (ASFV) live attenuated vaccine for prevention of ASF caused by various strains of ASFV, such as the highly virulent Georgia 2007 isolate (“ASFV-G”). An exemplary vaccine comprises a deletion of multiple genes allowing for industrial-scale growth in stable cell lines.
Core Innovation
The invention provides a recombinant African Swine Fever Virus (ASFV) live attenuated vaccine designed for prevention of ASF caused by various ASFV strains, such as the highly virulent Georgia 2007 isolate (ASFV-G). The vaccine comprises a deletion of multiple genes enabling industrial-scale growth in stable cell lines.
A significant problem addressed is that existing ASFV vaccine strains replicate efficiently only in primary swine macrophage cultures, which hinders large-scale production at an industrial level. There is no commercial vaccine currently available for ASF, so disease control depends on movement management and culling.
The disclosed solution is a genetically modified ASFV-G strain that includes a deletion of approximately 10.8 kb in the Left Variable Region (LVR) of the genome, affecting 10 viral genes and allowing efficient growth in a continuous stable porcine cell line. This mutant, ASFV-G-ΔI177LΔLVR, maintains genomic stability over multiple passages, preserves attenuation, immunogenicity, and protective efficacy against virulent ASFV-G challenge. This represents the first rationally designed ASFV vaccine candidate able to grow in stable cell lines, enabling industrial-scale production.
Claims Coverage
The patent includes seven independent claims covering genetically modified ASFV strains, vaccine compositions containing them, methods of protecting swine, and methods for producing virus in stable cell lines. These claims delineate all inventive features.
Genetically modified ASFV with specific genome identity
A genetically modified virus having a genome at least 95% identical to SEQ ID NO: 1, including those exactly matching SEQ ID NO: 1.
Live attenuated vaccine compositions against ASFV
Vaccine compositions comprising the genetically modified virus, particularly targeting ASFV-Georgia 2007 isolate (ASFV-G).
Methods for protecting swine using live attenuated ASFV vaccines
Methods involving administering a live attenuated vaccine comprising the genetically modified virus in an effective amount (102-106 HAD50) to protect swine from clinical ASFV disease caused by ASFV-G.
Recombinant ASFV mutant with specific gene deletions
A recombinant ASFV mutant virus having deletions or partial deletions of ORFs MGF360-4L, MGF360-6L, X69R, MGF300-1L, MGF300-2R, MGF300-4L, MGF3608L, MGF360-9L, MGF360-10L, and MGF360-11L, with deletions at least 95% identical to SEQ ID NO:2, comprising genomes at least 99% identical to SEQ ID NO:1.
Vaccines comprising the recombinant deletion mutant ASFV
Vaccine compositions comprising the recombinant ASFV mutant with the specific gene deletions effective against ASFV-G.
Protection methods using the recombinant deletion mutant virus
Administering live attenuated vaccines comprising the recombinant deletion mutant in amounts effective (102-106 HAD50) to protect swine against ASFV-G clinical disease.
Method for producing ASFV in stable cell lines
Producing ASFV at titers of 10^4-10^7 HAD50/mL by inoculating genetically modified virus (≥95% identical to SEQ ID NO:1) into a cultured stable cell line (porcine fetal kidney line engineered to express bovine αVβ6 integrin), incubating under viral replication conditions, and growing to specified titers.
The claims comprehensively cover the genetically modified ASFV with deletions enabling growth in stable cell lines, vaccine formulations incorporating these viruses, methods of protection in swine, and viral production methods in engineered cell lines, collectively embodying the inventive features of the disclosure.
Stated Advantages
The mutant ASFV vaccine can be efficiently grown in stable porcine cell lines, enabling industrial-level vaccine production compared to limitations of primary macrophage cultures.
The deletion mutant maintains genomic stability over extensive passages in stable cell lines, preserving attenuation, immunogenicity, and protective efficacy against virulent ASFV-G strains.
This is the first rationally designed ASF vaccine candidate to combine cell line growth adaptation with complete attenuation and protective efficacy.
Documented Applications
Use as a live attenuated vaccine for prevention of African Swine Fever in swine species, including domestic and wild pigs.
Production of ASFV vaccine virus at industrial scale by propagating the genetically modified virus in stable, engineered porcine fetal kidney cell lines expressing bovine αVβ6 integrin.
Methods for protecting swine by administering effective doses of the live attenuated recombinant ASFV vaccines to induce protective immunity.
Interested in licensing this patent?