Equine encephalitis virus vaccines and methods of using thereof
Inventors
Dupuy, Lesley • Schmaljohn, Connie S.
Assignees
US Army Medical Research Institute of Infectious Diseases
Publication Number
US-9555090-B2
Publication Date
2017-01-31
Expiration Date
2032-05-25
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Abstract
Disclosed herein are nucleotide sequences which encode a plurality of structural proteins, except the capsid, of an equine encephalitis virus, wherein the nucleotide sequence is codon-optimized for mammalian expression. The nucleotide sequences are codon-optimized for expression in humans. As disclosed herein, the nucleotide sequences confer protection against Venezuelan equine encephalitis virus (VEEV), western equine encephalitis virus (WEEV), and/or eastern equine encephalitis virus (EEEV).
Core Innovation
The invention provides nucleotide sequences encoding multiple structural proteins, excluding the capsid, of equine encephalitis viruses (EEVs), specifically Venezuelan equine encephalitis virus (VEEV), eastern equine encephalitis virus (EEEV), and western equine encephalitis virus (WEEV). These sequences are codon-optimized for mammalian, preferably human, expression and are contained within vectors such as the eukaryotic expression vector pWRG7077. The optimized structural proteins include E3, E2, 6K, and E1. Plasmids comprising these sequences, referred to as EEVCO plasmids, are disclosed along with compositions containing one or more EEVCO plasmids and/or antibodies raised against the encoded proteins.
The problem addressed is the lack of safe and effective vaccines against encephalitic alphavirus infections in humans. Existing live-attenuated and formalin-inactivated vaccines, available under Investigational New Drug (IND) status, have significant limitations including adverse reactions, insufficient neutralizing antibody responses, frequent boosting requirements, and inadequate protection against aerosolized virus challenges. Prior DNA vaccines expressing wild-type structural genes showed low neutralizing antibody responses and incomplete protection. Attempts to enhance immunogenicity through genetic recombination were labor-intensive and failed to improve protection against EEEV and WEEV.
The invention solves these problems by providing codon-optimized DNA vaccines that exclude the capsid protein, thereby enhancing expression of envelope glycoproteins and eliciting robust, durable, and protective immune responses with low DNA doses and fewer vaccinations. The vaccines induce strong total IgG and neutralizing antibody responses, balanced Th1/Th2 responses, and improved protection in mouse, rabbit, and nonhuman primate models. The platform also enables multivalent vaccines combining VEEV, EEEV, and WEEV sequences that confer comprehensive protection without immune interference.
Claims Coverage
The patent includes 19 claims with multiple inventive features covering plasmid compositions, vaccine compositions, and methods of immunization against equine encephalitis viruses.
Plasmid comprising codon-optimized nucleotide sequences encoding multiple structural proteins excluding the capsid
A plasmid comprising a vector sequence and a nucleotide sequence encoding structural proteins (E3, E2, 6K, E1) of an equine encephalitis virus, where the nucleotide sequence has at least 85% sequence identity to SEQ ID NO:1, SEQ ID NO:3, or SEQ ID NO:5.
Use of eukaryotic expression vector pWRG7077 as plasmid backbone
The plasmid uses the eukaryotic expression vector pWRG7077 as the vector sequence to enhance mammalian expression.
Nucleotide sequences explicitly selected from specific sequences
The nucleotide sequence is selected from SEQ ID NO:1, SEQ ID NO:3, and SEQ ID NO:5, or has high sequence identity thereto.
Plasmid sequence identity thresholds covering entire plasmid sequences
The plasmid sequences exhibit sequence identity of at least 85%, preferably up to 99%, to SEQ ID NO:7, SEQ ID NO:8, or SEQ ID NO:9, encompassing the vector and insert.
Compositions comprising one or more plasmids
Compositions comprising one or more of the plasmids as described, optionally including pharmaceutically acceptable carriers and/or adjuvants.
Method of eliciting an immune response by administering plasmid or composition
Methods of eliciting an immune response in a subject by administering an immunogenic amount of at least one plasmid or a composition comprising the plasmid, with immune responses observable by cellular immune assays and superior antibody responses compared to wild-type controls.
Immunization conferring protective immunity and full survivability
Methods of immunizing subjects against one or more equine encephalitis viruses conferring 100% survivability, including aerosolized virus challenges, by delivering immunogenic amounts typically by particle-mediated epidermal delivery.
Multivalent vaccine composition comprising three plasmids encoding different equine encephalitis viruses
Compositions comprising three plasmids, each comprising nucleotide sequences encoding structural proteins of VEEV, EEEV, and WEEV respectively, with specific sequence identity thresholds as defined.
The claims cover plasmid constructs encoding codon-optimized structural proteins of EEVs excluding capsid, vaccine compositions with these plasmids, methods of vaccination eliciting robust immune responses and protection, and multivalent compositions targeting multiple EEVs simultaneously.
Stated Advantages
The codon-optimized DNA vaccines elicit robust and durable protective immune responses with low DNA doses and fewer vaccinations.
Enhanced expression of envelope glycoproteins results in higher total IgG and neutralizing antibody titers compared to wild-type sequences.
The vaccines provide complete protection against lethal aerosol challenges in animal models, including mice and nonhuman primates.
Electroporation delivery significantly augments immune responses compared to injection alone.
Balanced Th1/Th2 immune responses are induced, indicating broad and effective immune activation.
Multivalent DNA vaccine compositions can simultaneously protect against VEEV, EEEV, and WEEV without immune interference and with potential synergistic protection.
Documented Applications
Vaccination of subjects, preferably mammals and humans, to elicit immune responses against Venezuelan equine encephalitis virus, eastern equine encephalitis virus, and western equine encephalitis virus infections.
Use as prophylactic vaccines for preventing disease symptoms and death caused by natural or aerosolized exposure to equine encephalitis viruses.
Administration by particle-mediated epidermal delivery methods to induce neutralizing antibody and cellular immune responses.
Use as multivalent vaccines combining plasmids encoding structural proteins from different equine encephalitis viruses for broad protection.
Therapeutic use involving immunization regimens including initial and booster doses to achieve durable immunity.
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