Development of a marker foot and mouth disease virus vaccine candidate that is attenuated in the natural host
Inventors
Rieder, Aida E. • Rodriguez, Luis L. • Hollister, Jason R. • Uddowla, Sabena
Assignees
US Department of Agriculture USDA
Publication Number
US-8765141-B2
Publication Date
2014-07-01
Expiration Date
2031-06-09
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Abstract
We have generated novel molecularly marked FMDV A24LL3DYR and A24LL3BPVKV3DYR vaccine candidates. The mutant viruses contain a deletion of the leader coding region (LL) rendering the virus attenuated in vivo and negative antigenic markers introduced in one or both of the viral non-structural 3Dpol and 3B proteins. The vaccine platform includes unique restriction endonuclease sites for easy swapping of capsid proteins for different FMDV subtypes and serotypes. The mutant viruses produced no signs of FMD and no shedding of virulent virus in cattle. No clinical signs of disease or fever were observed and no transmission to in-contact animals was detected in pigs inoculated with live A24LL3DYR. Cattle immunized with chemically inactivated vaccine candidates showed an efficacy comparable to a polyvalent commercial FMDV vaccine. These vaccine candidates used in conjunction with a cELISA provide a suitable target for DIVA companion tests.
Core Innovation
This invention provides a novel, safe, molecular-based attenuated Foot and Mouth Disease Virus (FMDV) vaccine platform for control and eradication of FMD. The platform includes genetically modified viruses with deletions of the leader proteinase (Lpro) coding region rendering them attenuated in the natural host and negative antigenic markers introduced via mutations in two non-structural viral proteins 3B and 3Dpol. These markers eliminate two antigenic epitopes recognized by specific antibodies, thus enabling differentiation of naturally infected animals from vaccinated animals (DIVA).
The vaccine platform is further enhanced by the inclusion of unique restriction endonuclease sites flanking the capsid-coding region, facilitating easy swapping of capsid proteins for different FMDV subtypes and serotypes. This modular cassette design enables rapid replacement of capsid sequences, allowing custom vaccine design against circulating field strains.
The problem addressed is the risk and shortcomings of current FMD vaccines which are chemically inactivated vaccines produced in high-containment facilities using virulent FMDV, which pose risks of escape of virulent viruses causing outbreaks. Additionally, existing vaccines do not easily permit differentiation between vaccinated and naturally infected animals, complicating disease control strategies. Moreover, current vaccines require precise serotype matching and do not provide broad protection or DIVA capabilities. This invention provides an attenuated vaccine virus with marker mutations that elicit protective immunity and are compatible with serological DIVA tests, that grow well in cell culture but are highly attenuated in natural hosts, reducing risks in vaccine manufacture and improving disease control.
Claims Coverage
The claims encompass four main inventive features related to genetically marked FMDV DNA molecules, their encoded viruses, and vaccines, described in independent claims.
Genetically marked FMDV DNA with Lpro deletion and 3Dpol negative marker mutation
An isolated DNA molecule encoding a genetically marked FMDV comprising deletion of the Lpro coding sequence, unique restriction endonuclease sites for capsid replacement, and a negative marker mutation in non-structural viral protein 3Dpol where amino acids His27 and Asn31 are replaced with Tyr and Arg from Bovine Rhinovirus type 2.
Genetically marked double marker FMDV DNA with Lpro deletion and mutations in 3Dpol and 3B
An isolated DNA molecule encoding a double marker FMDV with deletion of Lpro coding sequence, unique restriction sites for capsid replacement, a 3Dpol mutation replacing His27 and Asn31 by Tyr and Arg, and a 3B mutation replacing amino acids RQKP by PVKV from BRV2.
Genetically marked chimeric FMDV DNA with substituted capsid region
An isolated DNA molecule encoding a chimeric FMDV wherein the capsid region between unique restriction sites has been replaced by capsid sequences from a different FMDV strain such as Asia1 or Type A-Turkey/06, combined with Lpro deletion and negative marker mutations.
Generation of chemically inactivated vaccines from genetically marked FMDVs
Methods of producing chemically inactivated vaccines comprising expressing infectious RNA from the indicated genetically marked DNA molecules (single marker, double marker, or chimeric), recovering virus, and chemically inactivating an effective amount of virus for immunization.
In summary, the claims cover isolated DNA molecules encoding genetically attenuated FMDVs with deletions in Lpro and negative antigenic marker mutations in 3Dpol and optionally 3B, including chimeric capsid substitutions. These DNA molecules encode viruses used as either live attenuated or chemically inactivated vaccines that allow differentiation of vaccinated from infected animals. The claims also cover methods for producing such vaccines and using them to protect animals against FMDV infection.
Stated Advantages
Enables differentiation of naturally infected animals from vaccinated animals (DIVA) through negative antigenic markers in 3B and 3Dpol proteins.
Produces FMDV vaccine candidates attenuated in natural hosts reducing risks of virulent virus escape during vaccine production.
Facilitates easy capsid replacement using unique restriction sites allowing rapid generation of vaccines matching different serotypes and subtypes.
Chemically inactivated vaccines derived from these genetically marked viruses achieve protection comparable to commercial polyvalent vaccines.
The vaccine platform supports effective immunoprotection without causing clinical signs or viral shedding.
Documented Applications
Vaccination of cattle and swine against Foot and Mouth Disease Virus (FMDV) using genetically marked, attenuated live or chemically inactivated vaccines.
Use in combination with serological DIVA companion diagnostic tests for differentiation of infected versus vaccinated animals.
Generation of custom vaccines against various FMDV serotypes and subtypes by swapping capsid coding regions using engineered restriction enzyme sites.
Production and large-scale manufacture of safer FMDV vaccines in lower biosafety containment due to lack of virulence in genetically marked vaccine viruses.
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