Recombinant live attenuated foot-and-mouth disease (FMD) vaccine containing mutations in the L protein coding region
Inventors
De Los Santos, Teresa B. • Zhu, James J. • Segundo, Fayna Diaz-San • Grubman, Marvin J. • Koster, Marla J.
Assignees
US Department of Agriculture USDA
Publication Number
US-8846057-B2
Publication Date
2014-09-30
Expiration Date
2031-01-19
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Abstract
Previously we have identified a conserved domain (SAP, for SAF-A/B, Acinus, and PIAS) in the foot-and-mouth disease virus (FMDV) leader (L) protein coding region that is required for proper sub-cellular localization and function. Mutation of isoleucine 55 and leucine 58 to alanine (I55A, L58A) within the SAP domain resulted in a viable virus that displayed a mild attenuated phenotype in cell culture, along with altered sub-cellular distribution of L and failure to induce degradation of the transcription factor nuclear factor kappa-B. Here we report that inoculation of swine and cattle with this mutant virus results in the absence of clinical disease, the induction of a significant FMDV-specific neutralizing antibody response, and protection against subsequent homologous virus challenge. Remarkably, swine vaccinated with SAP mutant virus are protected against wild type virus challenge as early as two days post-vaccination suggesting that a strong innate as well as adaptive immunity is elicited. This variant could serve as the basis for construction of a live-attenuated FMD vaccine candidate.
Core Innovation
The invention relates to a novel live attenuated foot-and-mouth disease (FMD) vaccine comprising mutated virulence determinants within the coding region of the SAP domain of the leader protein (Lpro) of foot-and-mouth disease virus (FMDV). Specifically, a double mutation at amino acid positions 55 and 58 (I55A, L58A) within the SAP domain results in an attenuated virus that does not cause clinical disease in swine and cattle, induces a significant FMDV-specific neutralizing antibody response, and protects against subsequent homologous virus challenge.
Foot-and-mouth disease (FMD) is a highly contagious disease affecting cloven-hoofed animals, causing severe economic losses worldwide. Existing vaccines, such as chemically inactivated vaccines and recombinant adenovirus-based vaccines, have limitations including biosafety requirements, inability to differentiate infected from vaccinated animals, risk of carrier animals, long onset times for protection, and high manufacturing costs. Attempts to develop live attenuated FMD vaccines have faced challenges such as instability of mutant phenotypes and risk of reversion to virulence. This invention addresses the need for a stable, live attenuated FMD vaccine that confers significant attenuation and protection without clinical disease.
The invention demonstrates that mutation in the conserved SAP domain of FMDV Lpro alters the sub-cellular localization of Lpro, prevents degradation of the transcription factor nuclear factor kappa-B (NF-κB), and results in a virus that elicits strong innate and adaptive immune responses. Animals inoculated with this mutant virus exhibit no clinical disease despite viral replication, maintain high neutralizing antibody titers, and are protected against wild-type virus challenge as early as two days post-vaccination. This mutant virus serves as a basis for a live-attenuated FMD vaccine candidate, potentially capable of longer-lasting protection and serving as a platform for introducing additional mutations to enhance safety and serological differentiation.
Claims Coverage
The patent contains several claims related to live-attenuated FMD vaccine compositions and methods of immunization, with three independent claims covering the composition and methods.
Live-attenuated FMD vaccine composition with double SAP domain mutations
An effective live-attenuated FMD vaccine composition comprising a recombinant FMDV mutant containing two single point mutations at amino acid positions 55 and 58 in the coding region of the SAP domain of the leader proteinase (Lpro), formulated in an amount effective to protect swine and cattle from clinical FMD upon challenge with virulent FMDV.
Enhanced attenuation and stability via additional mutations
A recombinant FMDV mutant comprising the two single point mutations in the SAP domain as above, combined with additional mutation(s) that further attenuate the virus and decrease the probability of reversion to virulence.
Serological differentiation capability
A recombinant FMDV mutant comprising the double SAP domain mutations and additional mutation(s) enabling serological distinction between vaccinated animals and animals infected with wild-type FMDV.
Methods of immunization and protection
Methods for immunizing and protecting swine and cattle against FMD by administering an effective amount of the live-attenuated FMD vaccine comprising the recombinant mutant FMDV with the double SAP mutations, with or without the additional mutations.
Method to distinguish vaccinated from infected animals
A method of differentiating animals infected with FMD from those vaccinated with the recombinant mutant FMDV vaccine by analyzing serum binding specifically to the mutant SAP epitope.
The independent claims cover the live-attenuated FMD vaccine comprising the double point SAP domain mutations alone or with further modifications to enhance attenuation, stability, and serological differentiation, as well as methods of immunization, protection, and differentiation of vaccinated versus infected animals.
Stated Advantages
The mutant virus shows significant attenuation, causing no clinical disease in swine and cattle even at high doses.
It induces a strong FMDV-specific neutralizing antibody response and provides protection against homologous virus challenge.
Vaccination with the SAP mutant virus confers rapid protection as early as two days post-vaccination, indicating activation of both innate and adaptive immunity.
The double mutation is stable with no reversion to wild-type observed in inoculated animals.
The mutant virus allows for potential additional mutations to further decrease reversion risk and enable serological distinction between infected and vaccinated animals.
Documented Applications
Use as a live-attenuated vaccine to protect swine and cattle against clinical foot-and-mouth disease.
Vaccination of swine, cattle, goats, and sheep with the mutant virus to induce protective immunity against FMD.
Use of the mutant virus as a vaccine platform allowing incorporation of additional mutations for enhanced attenuation and serological differentiation of vaccinated animals from infected animals.
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