WO2015128731A2

WO2015128731A2 - Compositions and methods for treatment of hepatitis c

Info

Publication number: WO2015128731A2
Application number: PCT/IB2015/000397
Authority: WO
Inventors: David E. Anderson
Original assignee: Variation Biotechnologies, Inc.
Priority date: 2014-02-25
Filing date: 2015-02-24
Publication date: 2015-09-03
Also published as: WO2015128731A3

Abstract

The present disclosure provides compositions and methods useful for treating HCV infection. As described herein, the compositions and methods are based on development of immunogenic compositions that include virus-like particles (VLPs) which comprise one or more Moloney Murine leukemia virus (MMLV) core proteins and include one or more HCV epitopes, such as, for example, from HCV envelope glycoprotein El and/or E2 or variants thereof (e.g., E2G) and/or non-structural proteins NS3 and/or NS4A. Among other things, the present invention encompasses the recognition that a combination of antigens (e.g., envelope glycoproteins and interior non-structural proteins) can lead to beneficial immune responses, for example that include both a humoral response (e.g., production of neutralizing antibodies) and a cellular response (e.g., T-cell activation).

Description

COMPOSITIONS AND METHODS FOR TREATMENT OF HEPATITIS C

Cross Reference to Related Applications

[0001] This application claims the benefit of U.S. Provisional Application No.

61/944,264, filed February 25, 2014, the contents of which are hereby incorporated by reference herein in their entireties.

Background

[0002] Hepatitis C is an infectious disease affecting primarily the liver, caused by the hepatitis C virus (HCV). HCV is spread primarily by blood-to-blood contact associated with intravenous drug use, poorly sterilized medical equipment and transfusions. More than

170 million people globally are infected with hepatitis C with another 3 million people newly infected each year (Halliday J et al., (2011) Expert Rev. Vaccines 10:659-672). The virus persists in the liver in about 85% of those infected. This chronic infection can be treated with medication: the standard therapy is a combination of pegylated interferon and ribavirin. This is expensive, prolonged, has an extensive side effect profile and frequently fails. No therapeutic or prophylactic vaccine is currently available.

[0003] Most virus infections are self-limited because host mechanisms eliminate the virus. Infections with certain viruses like HCV, however, often fail to resolve and become chronic. Such infections can persist for many years, often for the lifetime of the infected individual often causing serious progressive disease and early death and are a significant cause of human morbidity and mortality. To establish persistence, a virus must establish infection and evade eradication by the host immune response, in particular by cytotoxic T lymphocytes (CTL). HCV is one example of viruses that establish persistence in part by suppressing the CTL response of the infected host. Persistent infection is associated with a weak, frequently undetectable HCV-specific T-cell response. There remains a need for effective vaccines able to induce CTL responses to protect against HCV infection as well as a humoral response to induce neutralizing antibodies. Summary

[0004] Among other things, the present invention provides methods and compositions useful for prophylaxis, therapeutic treatment, and/or study of chronic viral infections exemplified by HCV. In some embodiments, the present invention provides virus-like particles (VLPs) which comprise one or more Moloney Murine leukemia virus (MMLV) core proteins and include one or more viral epitopes, such as, for example, from HCV envelope glycoproteins El and/or E2 and/or non-structural proteins such as NS3 and/or NS4A. Among other things, the present invention encompasses the recognition that a combination of heterologous viral antigens (e.g., envelope glycoproteins and/or non-structural proteins) with a retroviral core protein can lead to improved induction of beneficial immune responses, for example that include both a humoral response (e.g., production of neutralizing antibodies) and a cellular response (e.g., T- cell activation). Among other things, the present invention encompasses the recognition that a HCV VLP vaccine can facilitate delivery of neutralizing antibody- and core-specific T-cell eptitopes in a single construct resembling mature HCV virions. This can lead to improved induction of beneficial immune responses, for example that include both a humoral response (e.g., production of neutralizing antibodies) and a cellular response (e.g., T-cell activation). Provided VLPs may be characterized in that they contain no viral DNA and are non-infectious.

[0005] In some embodiments, provided VLPs are surrounded by a lipid membrane, optionally containing one or more epitopes from viral envelope glycoproteins (e.g., El and/or E2 for HCV) which are antigens that play a role in induction of virus-neutralizing antibodies.

[0006] In some embodiments, provided VLPs contain one or more epitopes from internal viral proteins (e.g., HCV non-structural proteins such as NS3 and/or NS4A) which are antigens that play a role in induction of cellular immune responses (e.g., T-cell response). In some embodiments, utilized viral internal proteins (e.g., non-structural proteins such as NS3 and/or NS4A) both stimulate formation of T-helper cells and also induce cytotoxic T lymphocytes (CTL) against HCV. In some embodiments, the present invention provides fusion proteins of a Gag polypeptide and one or more internal non-structural viral proteins. In some embodiments, the present invention provides VLPs comprising fusion proteins of a Gag polypeptide and one or more internal non- structural viral proteins. [0007] In some embodiments, the present invention provides viral envelope glycoprotein variants (e.g., El and/or E2 variants). In some embodiments, a viral envelope glycoprotein variant is or comprises a fusion protein (e.g., a fusion protein comprising El and/or E2, or a portion thereof). In some embodiments, a viral envelope protein variant comprises a

heterologous protein domain (e.g., a transmembrane and/or cytoplasmic domain from a different protein).

[0008] As used in this application, the terms "about" and "approximately" are used as equivalents. Any numerals used in this application with or without about/approximately are meant to cover any normal fluctuations appreciated by one of ordinary skill in the relevant art.

[0009] Other features, objects, and advantages of the present invention are apparent in the detailed description that follows. It should be understood, however, that the detailed description, while indicating embodiments of the present invention, is given by way of illustration only, not limitation. Various changes and modifications within the scope of the invention will become apparent to those skilled in the art from the detailed description.

Brief Description of the Drawings

[0010] The drawings are for illustration purposes only, not for limitation.

[0011] Figure 1 shows the DNA expression plasmid map (A) and construction of exemplary recombinant expression plasmids for E2-G and Gag/NS3-NS4A (B).

[0012] Figure 2 shows an exemplary Gag/NS3-NS4A expression plasmid map.

[0013] Figure 3 shows an exemplary E2-G expression plasmid map.

[0014] Figure 4 shows FACS analysis of exemplary heterologous E2-G surface antigens on HEK 293 packaging cells. FIG. 4A is analysis of cells transfected with 4μg E2-G plasmid DNA(pDNA) and 2μg Gag pDNA. FIG. 4B is analysis of cells transfected with 2μg E2-G pDNA and 2μg Gag pDNA. FIG. 4C is analysis of cells transfected with ^g E2-G pDNA and 2μg Gag pDNA. FIG. 4D is analysis of cells transfected with 2μg Gag pDNA. FIG. 4E is analysis of cells transfected with 4μg E2-G pDNA and 2μg Gag/NS3-NS4A pDNA. FIG. 4F is analysis of cells transfected with 2μg E2-G pDNA and 2μg Gag/NS3-NS4A pDNA. FIG. 4G is analysis of cells transfected with ^g E2-G pDNA and 2μg Gag/NS3-NS4A pDNA. FIG. 4H is analysis of cells transfected with 2μg Gag/NS3-NS4A pDNA. FIG. 41 is analysis of cells transfected with 0.1 μg E1E2 pDNA and 2μg Gag pDNA. FIG. 4J is analysis of cells transfected with 4μg E2-G pDNA and 2μg Gag pDNA, stained with only secondary antibodies (negative control).

[0015] Figure 5 shows Coomasie Blue Staining of SDS PAGE of exemplary monovalent and bivalent eVLPs formed from expression plasmids for E2-G and Gag or Gag/NS3-NS4A.

[0016] Figure 6 shows Western Blot Detection of Gag Protein in exemplary monovalent and bivalent eVLPs formed from expression plasmids for E2-G and Gag or Gag/NS3-NS4A.

[0017] Figure 7 shows Western Blot Detection of E2-G Protein in exemplary bivalent eVLPs formed from expression plasmids for Gag/NS3-NS4A and E2-G.

Definitions

[0018] In order for the present invention to be more readily understood, certain terms are first defined below. Additional definitions for the following terms and other terms are set forth throughout the specification.

[0019] Amino acid: As used herein, term "amino acid," in its broadest sense, refers to any compound and/or substance that can be incorporated into a polypeptide chain. In some embodiments, an amino acid has the general structure H₂N-C(H)(R)-COOH. In some embodiments, an amino acid is a naturally occurring amino acid. In some embodiments, an amino acid is a synthetic amino acid; in some embodiments, an amino acid is a d-amino acid; in some embodiments, an amino acid is an 1-amino acid. "Standard amino acid" refers to any of the twenty standard 1-amino acids commonly found in naturally occurring peptides. "Nonstandard amino acid" refers to any amino acid, other than the standard amino acids, regardless of whether it is prepared synthetically or obtained from a natural source. As used herein, "synthetic amino acid" encompasses chemically modified amino acids, including but not limited to salts, amino acid derivatives (such as amides), and/or substitutions. Amino acids, including carboxy- and/or amino-terminal amino acids in peptides, can be modified by methylation, amidation, acetylation, protecting groups, and/or substitution with other chemical groups that can change the peptide's circulating half-life without adversely affecting their activity. Amino acids may participate in a disulfide bond. Amino acids may comprise one or posttranslational modifications, such as association with one or more chemical entities (e.g., methyl groups, acetate groups, acetyl groups, phosphate groups, formyl moieties, isoprenoid groups, sulfate groups, polyethylene glycol moieties, lipid moieties, carbohydrate moieties, biotin moieties, etc.). The term "amino acid" is used interchangeably with "amino acid residue," and may refer to a free amino acid and/or to an amino acid residue of a peptide. It will be apparent from the context in which the term is used whether it refers to a free amino acid or a residue of a peptide.

[0020] Antigen: As used herein, the term "antigen" refers to a substance containing one or more epitopes (either linear, conformational or both) that are recognized by antibodies. In certain embodiments, an antigen is or comprises a virus or a viral polypeptide. In some embodiments, the term "antigen" refers to a subunit antigen (i.e., an antigen which is separate and discrete from a whole virus with which the antigen is associated in nature; e.g., an antigen which is associated with a virus-like particle). Alternatively or additionally, in some

embodiments, the term "antigen" refers to killed, attenuated or inactivated viruses. In certain embodiments, an antigen is an "immunogen."

[0021] Approximately or about: As used herein, the term "approximately" or "about," as applied to one or more values of interest, refers to a value that is similar to a stated reference value. In certain embodiments, the term "approximately" or "about" refers to a range of values that fall within 25%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%), 6%), 5%, 4%, 3%, 2%>, 1%), or less in either direction (greater than or less than) of the stated reference value unless otherwise stated or otherwise evident from the context (except where such number would exceed 100% of a possible value).

[0022] Amelioration: As used herein, the term "amelioration" is meant the prevention, reduction or palliation of a state, or improvement of the state of a subject. Amelioration includes, but does not require complete recovery or complete prevention of a disease, disorder or condition (e.g., HCV infection). The term "prevention" refers to a delay of onset of a disease, disorder or condition. Prevention may be considered complete when onset of a disease, disorder or condition has been delayed for a predefined period of time.

[0023] Characteristic portion: As used herein, the term a "characteristic portion" of a substance, in the broadest sense, is one that shares a designated degree of structural identity with intact substance. In certain embodiments, a characteristic portion shares at least one functional characteristic with the intact substance. For example, a "characteristic portion" of a protein or polypeptide is one that contains a continuous stretch of amino acids, or a collection of continuous stretches of amino acids, that together are characteristic of a protein or polypeptide. In some embodiments, each such continuous stretch generally contains at least 2, 5, 10, 15, 20, 50, or more amino acids. In general, a characteristic portion of a substance (e.g., of a protein, antibody, etc.) is one that, in addition to the sequence and/or structural identity specified above, shares at least one functional characteristic with the relevant intact substance. In some embodiments, a characteristic portion may be biologically active.

[0024] Characteristic sequence: A "characteristic sequence" is a sequence that is found in all members of a family of polypeptides or nucleic acids, and therefore can be used by those of ordinary skill in the art to define members of the family.

[0025] Cytoplasmic domain: As is known in the art, polypeptides sometimes have transmembrane, cytoplasmic, and/or extracellular domains. In general, a "cytoplasmic domain", as used herein, refers to a domain that has an attribute of being present in the cytoplasm. As will be appreciated, it is not required that every amino acid in a cytoplasmic domain be present in the cytoplasm. For example, in some embodiments, a cytoplasmic domain is characterized in that a designated stretch or portion of a protein is substantially located in the cytoplasm. As is well known in the art, amino acid or nucleic acid sequences may be analyzed using a variety of algorithms to predict protein subcellular localization (e.g., cytoplasmic localization). Exemplary such programs include psort (PSORT.org), Prosite (prosite.expasy.org), among others.

[0026] Dosage form: As used herein, the terms "dosage form" and "unit dosage form" refer to a physically discrete unit of a therapeutic agent for the patient to be treated. Each unit contains a predetermined quantity of active material calculated to produce the desired therapeutic effect. It will be understood, however, that the total dosage of the composition will be decided by the attending physician within the scope of sound medical judgment.

[0027] Dosing regimen: A "dosing regimen" (or "therapeutic regimen"), as that term is used herein, is a set of unit doses (typically more than one) that are administered individually to a subject, typically separated by periods of time. In some embodiments, a given therapeutic agent has a recommended dosing regimen, which may involve one or more doses. In some embodiments, a dosing regimen comprises a plurality of doses each of which are separated from one another by a time period of the same length; in some embodiments, a dosing regimen comprises a plurality of doses and at least two different time periods separating individual doses.

[0028] Expression: As used herein, "expression" of a nucleic acid sequence refers to one or more of the following events: (1) production of an R A template from a DNA sequence {e.g., by transcription); (2) processing of an RNA transcript {e.g. , by splicing, editing, 5 ' cap formation, and/or 3' end formation); (3) translation of an RNA into a polypeptide or protein; and/or (4) post-translational modification of a polypeptide or protein.

[0029] Extracellular domain: As is known in the art, polypeptides sometimes have transmembrane, cytoplasmic, and/or extracellular domains. In general, an "extracellular domain", as used herein, refers to a domain that has an attribute of being present outside a cell. As will be appreciated, it is not required that every amino acid in an extracellular domain be present outside the cell. For example, in some embodiments, an extracellular domain is characterized in that a designated stretch or portion of a protein is substantially located outside the cell. As is well known in the art, amino acid or nucleic acid sequences may be analyzed using a variety of algorithms to predict protein subcellular localization (e.g., extracellular localization). Exemplary such programs include psort (PSORT.org), Prosite

(prosite.expasy.org), among others.

[0030] Fusion protein: As used herein, the term "fusion protein" generally refers to a polypeptide including at least two segments, each of which shows a high degree of amino acid identity to a peptide moiety that (1) occurs in nature, and/or (2) represents a functional domain of a polypeptide. Typically, a polypeptide containing at least two such segments is considered to be a fusion protein if the two segments are moieties that (1) are not included in nature in the same peptide, and/or (2) have not previously been linked to one another in a single polypeptide, and/or (3) have been linked to one another through action of the hand of man.

[0031] Gene: As used herein, the term "gene" has its meaning as understood in the art.

It will be appreciated by those of ordinary skill in the art that the term "gene" may include gene regulatory sequences {e.g., promoters, enhancers, etc.) and/or intron sequences. It will further be appreciated that definitions of gene include references to nucleic acids that do not encode proteins but rather encode functional RNA molecules such as tRNAs, RNAi-inducing agents, etc. For the purpose of clarity we note that, as used in the present application, the term "gene" generally refers to a portion of a nucleic acid that encodes a protein; the term may optionally encompass regulatory sequences, as will be clear from context to those of ordinary skill in the art. This definition is not intended to exclude application of the term "gene" to non-protein- coding expression units but rather to clarify that, in most cases, the term as used in this document refers to a protein-coding nucleic acid.

[0032] Gene product or expression product: As used herein, the term "gene product" or

"expression product" generally refers to an R A transcribed from the gene (pre-and/or postprocessing) or a polypeptide (pre- and/or post-modification) encoded by an RNA transcribed from the gene.

[0033] Heterologous: As used herein, the term "heterologous" with respect to a protein or a polypeptide refers to a protein or polypeptide that is non-naturally occurring in a particular organism, such as a retrovirus or VLP. In some embodiments, a heterologous protein or polypeptide is non-naturally occurring in a particular retrovirus virion. As used herein, the term "heterologous" with respect to a protein domain generally refers to a protein domain that is non- naturally occurring in a particular protein.

[0034] Immunogenic: As used herein, the term "immunogenic" means capable of producing an immune response in a host animal against a non-host entity (e.g., an HCV antigen). In certain embodiments, this immune response forms the basis of the protective immunity elicited by a vaccine against a specific infectious organism (e.g., an HCV).

[0035] Immune response: As used herein, the term "immune response" refers to a response elicited in an animal. An immune response may refer to cellular immunity, humoral immunity or may involve both. An immune response may also be limited to a part of the immune system. For example, in certain embodiments, an immunogenic composition may induce an increased IFNy response. In certain embodiments, an immunogenic composition may induce a mucosal IgA response (e.g., as measured in nasal and/or rectal washes). In certain embodiments, an immunogenic composition may induce a systemic IgG response (e.g., as measured in serum). In certain embodiments, an immunogenic composition may induce virus- neutralizing antibodies or a neutralizing antibody response. In certain embodiments, an immunogenic composition may induce a CTL response. [0036] Improve, increase, or reduce: As used herein, the terms "improve," "increase" or

"reduce," or grammatical equivalents, indicate values that are relative to a baseline measurement, such as a measurement in the same individual prior to initiation of the treatment described herein, or a measurement in a control individual (or multiple control individuals) in the absence of the treatment described herein.

[0037] Individual, subject, patient: As used herein, the terms "subject," "individual" or

"patient" refer to a human or a non-human mammalian subject. The individual (also referred to as "patient" or "subject") being treated is an individual (fetus, infant, child, adolescent, or adult) suffering from a disease, for example, HCV infection. In some embodiments, the subject is at risk for HCV infection. In some embodiments, the subject is an immunosuppressed subject. For example, in some embodiments, the immunosuppressed subject is selected from the group consisting of an HIV-infected subject, an AIDS patient, a transplant recipient, a pediatric subject, and a pregnant subject. In some embodiments, the subject has been exposed to HCV infection. In some embodiments, the subject is a human.

[0038] Isolated: As used herein, the term "isolated" refers to a substance and/or entity that has been (1) separated from at least some of the components with which it was associated when initially produced (whether in nature and/or in an experimental setting), and/or (2) produced, prepared, and/or manufactured by the hand of man. Isolated substances and/or entities may be separated from about 10%, about 20%>, about 30%>, about 40%>, about 50%>, about 60%>, about 70%, about 80%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%o, about 97%, about 98%>, about 99%, or more than about 99% of the other components with which they were initially associated. In some embodiments, isolated agents are about 80%, about 85%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%o, about 98%>, about 99%, or more than about 99% pure. As used herein, a substance is "pure" if it is substantially free of other components. As used herein, calculation of percent purity of isolated substances and/or entities should not include excipients {e.g., buffer, solvent, water, etc.).

[0039] Linker: As used herein, the term "linker" refers to, e.g., in a fusion protein, an amino acid sequence of an appropriate length other than that appearing at a particular position in the natural protein and is generally designed to be flexible and/or to interpose a structure, such as an a-helix, between two protein moieties. In general, a linker allows two or more domains of a fusion protein to retain 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or more of the biological activity of each of the domains. A linker may also referred to as a spacer.

[0040] N-terminal portion of gag: As used herein, "N-terminal portion of gag" refers to a polypeptide that includes amino acid residues from an N-terminal region of a gag polypeptide. In some embodiments, an N-terminal portion of gag is a self-assembling portion of a gag polypeptide. In some embodiments, an N-terminal portion of gag includes from amino acid 1 to about amino acid 100, 200, 300, or more, of a gag polypeptide, e.g., a portion having at least 70%, 75%, 80%, 85%, 90%, 95%, or 100% identity with a self-assembling portion of a reference gag polypeptide having an amino acid sequence of SEQ ID NO: 1.

[0041] Nucleic acid: As used herein, the term "nucleic acid," in its broadest sense, refers to any compound and/or substance that is or can be incorporated into an oligonucleotide chain. In some embodiments, a nucleic acid is a compound and/or substance that is or can be incorporated into an oligonucleotide chain via a phosphodiester linkage. In some embodiments, "nucleic acid" refers to individual nucleic acid residues {e.g., nucleotides and/or nucleosides). In some embodiments, "nucleic acid" refers to an oligonucleotide chain comprising individual nucleic acid residues. As used herein, the terms "oligonucleotide" and "polynucleotide" can be used interchangeably. In some embodiments, "nucleic acid" encompasses RNA as well as single and/or double-stranded DNA and/or cDNA. Furthermore, the terms "nucleic acid," "DNA," "RNA," and/or similar terms include nucleic acid analogs, i.e., analogs having other than a phosphodiester backbone. For example, the so-called "peptide nucleic acids," which are known in the art and have peptide bonds instead of phosphodiester bonds in the backbone, are considered within the scope of the present invention. The term "nucleotide sequence encoding an amino acid sequence" includes all nucleotide sequences that are degenerate versions of each other and/or encode the same amino acid sequence. Nucleotide sequences that encode proteins and/or RNA may include introns. Nucleic acids can be purified from natural sources, produced using recombinant expression systems and optionally purified, chemically synthesized, etc. Where appropriate, e.g., in the case of chemically synthesized molecules, nucleic acids can comprise nucleoside analogs such as analogs having chemically modified bases or sugars, backbone modifications, etc. A nucleic acid sequence is presented in the 5' to 3' direction unless otherwise indicated. The term "nucleic acid segment" is used herein to refer to a nucleic acid sequence that is a portion of a longer nucleic acid sequence. In many embodiments, a nucleic acid segment comprises at least 3, 4, 5, 6, 7, 8, 9, 10, or more residues. In some embodiments, a nucleic acid is or comprises natural nucleosides (e.g., adenosine, thymidine, guanosine, cytidine, uridine, deoxyadenosine, deoxythymidine, deoxyguanosine, and deoxy cytidine); nucleoside analogs (e.g., 2-aminoadenosine, 2-thiothymidine, inosine, pyrrolo-pyrimidine, 3-methyl adenosine, 5-methylcytidine, C-5 propynyl-cytidine, C-5 propynyl-uridine, 2-aminoadenosine, C5-bromouridine, C5-fluorouridine, C5-iodouridine, C5-propynyl-uridine, C5-propynyl- cytidine, C5-methylcytidine, 2-aminoadenosine, 7-deazaadenosine, 7-deazaguanosine, 8- oxoadenosine, 8-oxoguanosine, 0(6)-methylguanine, and 2-thiocytidine); chemically modified bases; biologically modified bases (e.g., methylated bases); intercalated bases; modified sugars (e.g., 2'-fluororibose, ribose, 2'-deoxyribose, arabinose, and hexose); and/or modified phosphate groups (e.g., phosphorothioates and 5'-N-phosphoramidite linkages). In some embodiments, the present invention is specifically directed to "unmodified nucleic acids," meaning nucleic acids (e.g., polynucleotides and residues, including nucleotides and/or nucleosides) that have not been chemically modified in order to facilitate or achieve delivery.

[0042] Pharmaceutically acceptable: The term "pharmaceutically acceptable" as used herein, refers to substances that, within the scope of sound medical judgment, are suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio.

[0043] Polypeptide: As used herein, a "polypeptide", generally speaking, is a string of at least two amino acids attached to one another by a peptide bond. In some embodiments, a polypeptide may include at least 3-5 amino acids, each of which is attached to others by way of at least one peptide bond. Those of ordinary skill in the art will appreciate that polypeptides sometimes include "non-natural" amino acids or other entities that nonetheless are capable of integrating into a polypeptide chain, optionally.

[0044] Polyprotein: As used herein, the term "polyprotein", generally refers to a protein that, after synthesis, may be cleaved to produce several functionally distinct polypeptides. A polyprotein is typically encoded by a single amino acid sequence. In some embodiments, an uncleaved polyprotein retains biological activity of its component parts. Some viruses produce such polyproteins, e.g., a Gag polyprotein, which can be retained as a functional polyprotein or can be processed into several functionally distinct polypeptides. Functionally, the Gag polyprotein is divided into three domains: the membrane binding domain, which targets the Gag polyprotein to the cellular membrane; the interaction domain which promotes Gag

polymerization; and the late domain which facilitates release of nascent virions from the host cell. In general, the form of the Gag protein that mediates viral particle assembly is the polyprotein.

[0045] Self-assembling portion: In general, a "self-assembling portion", as used herein, refers to a relevant stretch of an entity that adopts a defined arrangement without guidance or management from an outside source. In some embodiments, the entity is a protein. In some embodiments, the entity is a polyprotein. In some such embodiments, the relevant stretch is at least 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400, 425, 450, 475, 500 or more residues. Self-assembly may be exhibited, for example, within the context of a cell (e.g., in vivo). Alternatively or

additionally, self-assembly may be exhibited outside the context of a cell (e.g., in vitro). Self- assembly may be intramolecular (e.g., folding) and/or intermolecular. In some embodiments, self-assembly may be macromolecular whereby entities self-assemble into a complex and/or extended macromolecular structure. Self-assembled entities may exhibit a wide range of structural motifs, including, but not limited to particles, fibers, sheets, and ribbons. In some embodiments, self-assembly of an entity is important for a biological function of the entity. For example, in some embodiments, self-assembly of a lipid leads to formation of a cell membrane structure. In some embodiments, self-assembly of a protein (e.g., a viral structural protein) in a cellular context leads to formation of a particle structure (e.g., a viral particle structure). For example, a viral structural polyprotein may contain a targeting sequence that is capable of directing its localization to a cellular membrane of its host cell (e.g., plasma membrane, endosome, etc.) from which the viral structural polyprotein may bud out to form a VLP that contains host cellular membranous material surrounding the viral structural polyprotein.

[0046] Substantial homology: The phrase "substantial homology" is used herein to refer to a comparison between amino acid or nucleic acid sequences. As will be appreciated by those of ordinary skill in the art, two sequences are generally considered to be "substantially homologous" if they contain homologous residues in corresponding positions. Homologous residues may be identical residues. Alternatively, homologous residues may be non-identical residues will appropriately similar structural and/or functional characteristics. For example, as is well known by those of ordinary skill in the art, certain amino acids are typically classified as "hydrophobic" or "hydrophilic" amino acids., and/or as having "polar" or "non-polar" side chains Substitution of one amino acid for another of the same type may often be considered a "homologous" substitution.

[0047] As is well known in this art, amino acid or nucleic acid sequences may be compared using any of a variety of algorithms, including those available in commercial computer programs such as BLASTN for nucleotide sequences and BLASTP, gapped BLAST, and PSI- BLAST for amino acid sequences. Exemplary such programs are described in Altschul, et al, Basic local alignment search tool, J. Mol. Biol, 215(3): 403-410, 1990; Altschul, et al, Methods in Enzymology; Altschul, et al, "Gapped BLAST and PSI-BLAST: a new generation of protein database search programs", Nucleic Acids Res. 25:3389-3402, 1997; Baxevanis, et al,

Bioinformatics : A Practical Guide to the Analysis of Genes and Proteins, Wiley, 1998; and Misener, et al, (eds.), Bioinformatics Methods and Protocols (Methods in Molecular Biology, Vol. 132), Humana Press, 1999. In addition to identifying homologous sequences, the programs mentioned above typically provide an indication of the degree of homology. In some

embodiments, two sequences are considered to be substantially homologous if at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%) or more of their corresponding residues are homologous over a relevant stretch of residues. In some embodiments, the relevant stretch is a complete sequence. In some embodiments, the relevant stretch is at least 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400, 425, 450, 475, 500 or more residues.

[0048] Substantial identity: The phrase "substantial identity" is used herein to refer to a comparison between amino acid or nucleic acid sequences. As will be appreciated by those of ordinary skill in the art, two sequences are generally considered to be "substantially identical" if they contain identical residues in corresponding positions. As is well known in this art, amino acid or nucleic acid sequences may be compared using any of a variety of algorithms, including those available in commercial computer programs such as BLASTN for nucleotide sequences and BLASTP, gapped BLAST, and PSI-BLAST for amino acid sequences. Exemplary such programs are described in Altschul, et al., Basic local alignment search tool, J. Mol. Biol., 215(3): 403-410, 1990; Altschul, et al., Methods in Enzymology; Altschul et al., Nucleic Acids Res. 25:3389-3402, 1997; Baxevanis et al., Bioinformatics : A Practical Guide to the Analysis of Genes and Proteins, Wiley, 1998; and Misener, et al., (eds.), Bioinformatics Methods and Protocols (Methods in Molecular Biology, Vol. 132), Humana Press, 1999. In addition to identifying identical sequences, the programs mentioned above typically provide an indication of the degree of identity. In some embodiments, two sequences are considered to be substantially identical if at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%o, 97%), 98%), 99%> or more of their corresponding residues are identical over a relevant stretch of residues. In some embodiments, the relevant stretch is a complete sequence. In some embodiments, the relevant stretch is at least 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400, 425, 450, 475, 500 or more residues.

[0049] Suffering from: An individual who is "suffering from" a disease, disorder, or condition (e.g., HCV infection) has been diagnosed with and/or exhibits one or more symptoms of the disease, disorder, or condition.

[0050] Susceptible to: An individual who is "susceptible to" a disease, disorder, or condition (e.g., HCV infection) is at risk for developing the disease, disorder, or condition. In some embodiments, an individual who is susceptible to a disease, disorder, or condition does not display any symptoms of the disease, disorder, or condition. In some embodiments, an individual who is susceptible to a disease, disorder, or condition has not been diagnosed with the disease, disorder, and/or condition. In some embodiments, an individual who is susceptible to a disease, disorder, or condition is an individual who has been exposed to conditions associated with development of the disease, disorder, or condition (e.g., the individual has been exposed to HCV).

[0051] Symptoms are reduced: According to the present invention, "symptoms are reduced" when one or more symptoms of a particular disease, disorder or condition is reduced in magnitude (e.g., intensity, severity, etc.) or frequency. For purposes of clarity, a delay in the onset of a particular symptom is considered one form of reducing the frequency of that symptom. It is not intended that the present invention be limited only to cases where the symptoms are eliminated. The present invention specifically contemplates treatment such that one or more symptoms is/are reduced (and the condition of the subject is thereby "improved"), albeit not completely eliminated.

[0052] Therapeutically effective amount: As used herein, the term "therapeutically effective amount" refers to an amount sufficient to confer a therapeutic effect on the treated subject, at a reasonable benefit/risk ratio applicable to any medical treatment. The therapeutic effect may be objective (i.e., measurable by some test or marker) or subjective (i.e., subject gives an indication of or feels an effect). In particular, the "therapeutically effective amount" refers to an amount of a therapeutic protein or composition effective to treat, ameliorate, or prevent a desired disease or condition, or to exhibit a detectable therapeutic or preventative effect, such as by ameliorating symptoms associated with the disease, preventing or delaying the onset of the disease, and/or also lessening the severity or frequency of symptoms of the disease. A therapeutically effective amount is commonly administered in a dosing regimen that may comprise multiple unit doses. For any particular immunogenic composition, a therapeutically effective amount (and/or an appropriate unit dose within an effective dosing regimen) may vary, for example, depending on route of administration, on combination with other pharmaceutical agents. Also, the specific therapeutically effective amount (and/or unit dose) for any particular patient may depend upon a variety of factors including the disorder being treated and the severity of the disorder; the activity of the specific pharmaceutical agent employed; the specific composition employed; the age, body weight, general health, sex and diet of the patient; the time of administration, route of administration, and/or rate of excretion or metabolism of the specific immunogenic composition employed; the duration of the treatment; and like factors as is well known in the medical arts.

[0053] Transmembrane domain: As is known in the art, polypeptides sometimes have transmembrane, cytoplasmic, and/or extracellular domains. In general, a "transmembrane domain", as used herein, refers to a domain having an attribute of being present in the membrane (e.g., spanning a portion or all of a cellular membrane). As will be appreciated, it is not required that every amino acid in a transmembrane domain be present in the membrane. For example, in some embodiments, a transmembrane domain is characterized in that a designated stretch or portion of a protein is substantially located in the membrane. As is well known in the art, amino acid or nucleic acid sequences may be analyzed using a variety of algorithms to predict protein subcellular localization (e.g., transmembrane localization). Exemplary such programs include psort (PSORT.org), Prosite (prosite.expasy.org), among others.

[0054] Treatment: As used herein, the term "treatment" (also "treat" or "treating") refers to any administration of an immunogenic composition that partially or completely alleviates, ameliorates, relieves, inhibits, delays onset of, reduces severity of and/or reduces incidence of one or more symptoms or features of a particular disease, disorder, and/or condition (e.g., HCV infection) or the predisposition toward the disease. Such treatment may be of a subject who does not exhibit signs of the relevant disease, disorder and/or condition and/or of a subject who exhibits only early signs of the disease, disorder, and/or condition. Alternatively or additionally, such treatment may be of a subject who exhibits one or more established signs of the relevant disease, disorder and/or condition. In certain embodiments, the term "treating" refers to the vaccination of a patient.

[0055] Vaccination: As used herein, the term "vaccination" refers to the administration of a composition intended to generate an immune response, for example to a disease-causing agent (e.g., HCV). For the purposes of the present invention, vaccination can be administered before, during, and/or after exposure to a disease-causing agent, and in certain embodiments, before, during, and/or shortly after exposure to the agent. In some embodiments, vaccination includes multiple administrations, appropriately spaced in time, of a vaccinating composition.

[0056] Vector: As used herein, "vector" refers to a nucleic acid molecule capable of transporting another nucleic acid to which it is associated. In some embodiments, vectors are capable of extra-chromosomal replication and/or expression of nucleic acids to which they are linked in a host cell such as a eukaryotic and/or prokaryotic cell. Vectors capable of directing the expression of operatively linked genes are referred to herein as "expression vectors."

Detailed Description of Certain Embodiments

[0057] Among other things, the present invention provides methods and compositions useful for prophylaxis, therapeutic treatment, and/or study of Hepatitis C Virus (HCV) infection. HCV viruses persist in many cell types, including lymphocytes and macrophages. Immunogenic compositions described herein can be used to induce CTL responses (in addition to inducing antiviral neutralizing antibodies in a humoral response). Such compositions are useful for conferring protection against subsequent establishment of persistence of a virus in infected tissues. Additionally or alternatively, such compositions facilitate delivery of neutralizing antibody- and core-specific T-cell eptitopes in a single construct resembling mature HCV virions. Additionally or alternatively, such compositions are useful for inducing both a humoral response (e.g., production of neutralizing antibodies) and a cellular response (e.g., T-cell activation).

HCV

[0058] Development of an effective vaccine against the hepatitis C virus (HCV) has long been defined as a difficult challenge due to the variability of this RNA virus and the absence of well-defined immune correlates of protection from HCV infection. However, substantial progress has been made recently in the understanding of the impact of immune responses for control of HCV infection (Ciuffreda D. et al., (2011) Curr Opin HIV AIDS 6:559-565; Edwards VC. Et al., (2012) J Gen Virol 93: 1-19) and it is now admitted that an effective vaccine against HCV will need to induce both cellular and humoral immune responses and address viral heterogeneity to prevent immune escape (Torresi J. et al., (2011) J Hepatol). Several approaches to HCV vaccine development have now been studied and include recombinant El and E2 proteins, synthetic peptides, DNA and prime-boost strategies (Torresi J. et al, (2011) J Hepatol). The use of recombinant HCV envelope proteins as a vaccine candidate has been met with variable success. In contrast, recombinant HCV virus-like particles (VLPs) composed of HCV envelope glycoproteins (core, El and E2) are capable of inducing both strong and broad humoral and cellular immune responses in mice (Murata K. et al., (2003) Proc Natl Acad Sci USA 100:6753-6758) and protective immunity in chimpanzees (Elmowalid GA. et al., (2007) Proc Natl Acad Sci USA 104:8427-8432). Alternatively, HCV antigens can be displayed on heterologous VLPs used as antigenic platforms and assume an immunogenicity similar to that of the underlying particle. Many different heterologous VLP types have been adapted for HCV vaccination and there have been notable successes (Denis J. et al, (2007) Virology 363:59-68; Mihailova M. et al, (2006) Vaccine 24:4369-4377; Netter HJ. et al, (2001) 75:2130-2141). Specific targets for cross-reactive T-cell response induction are the highly conserved nonstructural proteins expressed among many HCV genotypes. Methods and Compositions - General

[0059] The body's natural immune response provides a most effective mechanism for terminating viral and many other infections, and for providing protection against new infection. The immune response consists of the humoral response with activated B cells secreting antibody (which can neutralize the infectivity of extracellular virus) and the cellular response, including activated Thl cells (which provide help for the generation of cytotoxic T lymphocytes, CTLs). The Thl response and activated CTLs play the key role in terminating virus infection. In contrast, the activation of Th2 predominant immune responses is associated with persistence and exacerbation of virus infection. Immunoregulatory molecules, including lymphokines that direct T cell differentiation and growth, and cell surface molecules, such as those that provide co- stimulation signals for T cell activation are determining the type of immune response.

[0060] Activation of a strong Thl and antigenically diverse CTL response in individuals with acute and chronic viral infections appears to be a critical mechanism for terminating the infection. Individuals that clear viral infection have strong CTL responses that are specific for multiple different viral epitopes, including the viral envelope antigens and core antigens. In contrast, individuals that become chronic carriers have weak and antigenically restricted CTL responses. Thus, a T cell response to a broad array of viral epitopes appears to be important for resolution of chronic persistent infections.

[0061] In some embodiments, compositions described herein are useful for prophylaxis, therapeutic treatment, and/or study of Hepatitis C Virus (HCV) infection. In some embodiments, the present invention provides virus-like particles (VLPs) which comprise one or more Moloney Murine leukemia virus (MMLV) core proteins and include one or more HCV epitopes, such as, for example, HCV envelope glycoproteins El and/or E2 (or a portion thereof) and/or nonstructural proteins NS3 and/or NS4A (or a portion thereof). Among other things, the present invention encompasses the recognition that a combination of antigens (e.g., envelope

glycoproteins and internal proteins) can lead to improved induction of beneficial immune responses, for example that include both a humoral response (e.g., production of neutralizing antibodies) and a cellular response (e.g., T-cell activation). In some embodiments, provided VLPs contain no viral R A or DNA and are non-infectious. In some embodiments, provided VLPs do contain viral R A or DNA and are infectious. In some such embodiments, provided VLPs are useful as a DNA vaccine.

[0062] In some embodiments, the humoral immune response in a subject is sustained for at least about 1 month, at least about 2 months, at least about 3 months, at least about 4 months, at least about 5 months, at least about 6 months, at least about 7 months, at least about 8 months, at least about 9 months, at least about 10 months, at least about 1 1 months, or at least 12 months. In some embodiments, the cellular immune response in a subject is sustained for at least about 1 month, at least about 2 months, at least about 3 months, at least about 4 months, at least about 5 months, at least about 6 months, at least about 7 months, at least about 8 months, at least about 9 months, at least about 10 months, at least about 1 1 months, or at least 12 months.

[0063] In some embodiments, provided VLPs are surrounded by a lipid membrane, optionally containing one or more epitopes from viral envelope glycoproteins (e.g., El and/or E2 from HCV) which are antigens that play a role in induction of virus-neutralizing antibodies.

[0064] In some embodiments, provided VLPs contain one or more epitopes from internal viral proteins (e.g., non-structural proteins NS3 and/or NS4A (or a portion thereof)) which are antigens that play a role in induction of cellular immune responses (e.g., T-cell response). In some embodiments, utilized internal viral proteins (e.g., NS3 and/or NS4A (or a portion thereof)) both stimulate formation of T-helper cells (T_H) and also induce cytotoxic T lymphocytes (CTL) against HCV.

[0065] In some embodiments, the present invention provides variants of viral envelope glycoproteins (e.g., El and/or E2 from HCV). In some embodiments, a variant viral envelope glycoprotein is or comprises a fusion protein. In some embodiments, a variant of a viral glycoprotein comprises a heterologous protein domain (e.g., a transmembrane and/or

cytoplasmic domain from a different protein). In some embodiments, a variant of an internal viral protein comprises a heterologous antigen or epitope. In some embodiments, the present invention provides VLPs comprising variants of internal viral proteins. In some embodiments, a variant of an internal viral protein is or comprises a fusion protein. Virus-Like Particles (VLPs)

[0066] Retroviruses are enveloped RNA viruses that belong to the family Retroviridae.

After infection of a host cell by a retrovirus, RNA is transcribed into DNA via the enzyme reverse transcriptase. DNA is then incorporated into the host cell's genome by an integrase enzyme and thereafter replicates as part of the host cell's DNA. The Retroviridae family includes the following genus Alpharetrovirus, Betaretrovirus, Gammearetrovirus,

Deltaretrovirus, Epsilonretrovirus, Lentivirus and Spumavirus. The hosts for this family of retroviruses generally are vertebrates. Retroviruses produce an infectious virion containing a spherical nucleocapsid (the viral genome in complex with viral structural proteins) surrounded by a lipid bilayer derived from the host cell membrane.

[0067] Retroviral vectors can be used to generate enveloped virions that are infectious and either replication-competent or replication-defective. Replication-competent infectious retroviral vectors contain all of the necessary genes for virion synthesis and continue to propagate themselves once infection of the host cell occurs. Replication-defective infectious retroviral vectors do not spread after the initial infection. This is accomplished by replacement of most of the coding regions of the retrovirus with genes or nucleotide sequences to be transferred; so that the vector is incapable of making proteins required for additional rounds of replication.

[0068] Alternatively or additionally, retroviral vectors can be used to generate virus-like particles (VLPs) that lack a retrovirus-derived genome and are both non-infectious and non- replicating. Because of VLPs advantageous properties, VLPs may be utilized as an antigen delivery system. Furthermore, because VLPs are non-infectious, they can be administered safely as an immunogenic composition (e.g., a vaccine). VLPs are generally structurally similar to enveloped virions described above, but lack a retrovirus-derived genome, making it unlikely that viral replication will occur. Expression of capsid proteins (e.g., Gag) of some viruses (e.g., murine leukemia viruses, such as Moloney Murine leukemia virus (MMLV)) leads to self- assembly into particles similar to the corresponding native virus, which particles are free of viral genetic material.

[0069] A wide variety of VLPs have been prepared. For example, VLPs including single or multiple capsid proteins either with or without envelope proteins and/or surface glycoproteins have been prepared. In some cases, VLPs are non-enveloped and assemble by expression of just one major capsid protein, as shown for VLPs prepared from hepadnaviruses (e.g., Engerix™, GSK and Recombivax HB™, Merck), papillomaviruses (e.g., Cervarix™ , GSK and Gardasil™, Merck), paroviruses, or polyomaviruses. In some embodiments, VLPs are enveloped and can comprise multiple antigenic proteins found in the corresponding native virus. VLPs typically resemble their corresponding native virus and can be multivalent particulate structures. In some embodiments, antigenic proteins may be presented internally within the VLP, as a component of the VLP structure, and/or on the surface of the VLP. The present invention encompasses the recognition that presentation of an antigen in the context of a VLP is advantageous for induction of neutralizing antibodies against the antigen as compared to other forms of antigen presentation, e.g., soluble antigens not associated with a VLP. Neutralizing antibodies most often recognize tertiary or quarternary structures; this often requires presenting antigenic proteins, like envelope glycoproteins, in their native viral conformation. Alternatively or additionally, VLPs may be useful for presenting antigens in a context which induces cellular immunity (e.g., T cell response). The present invention further encompasses the insight that use of antigen

combinations in VLP systems can generate improved immune response.

Retroviral Structural Proteins

[0070] In some embodiments, the present invention utilizes VLPs comprising or consisting of one or more retroviral structural proteins (e.g., Gag). In some embodiments, a structural protein for use in accordance with the present invention is Alpharetrovirus (e.g., Avian Leukosis Virus), Betaretrovirus (Mouse Mammary Tumor Virus), Gammearetrovirus (Murine Leukemia Virus), Deltaretrovirus (Bovine Leukemia Virus), Epsilonretrovirus (Walley Dermal Sarcoma Virus), Lentivirus (Human Immunodeficiency Virus 1) or Spumavirus (Chimpanzee Foamy Virus) structural protein. In certain embodiments, a structural polyprotein is a Murine Leukemia Virus (MLV) structural protein(e.g., a Moloney Murine Leukemia Virus (MMLV) structural protein. Genomes of these retroviruses are readily available in databases. The Gag genes of all these retroviruses have an overall structural similarity and within each group of retroviruses are conserved at the amino acid level. Retroviral Gag proteins primarily function in viral assembly. The Gag gene in the form of a polyprotein gives rise to the core structural proteins of the VLP. The MLV Gag gene encodes a 65kDa polyprotein precursor which is proteo lyrically cleaved into 4 structural proteins (Matrix (MA); pi 2; Capsid (CA); and

Nucleocapsid (NC)), by MLV protease, in the mature virion. Retroviruses assemble immature capsid composed of the Gag polyprotein formed from the Gag polypeptide but devoid of other viral elements like viral protease with Gag as the structural protein of the immature virus particle. Functionally, the Gag polyprotein is divided into three domains: the membrane binding domain, which targets the Gag polyprotein to the cellular membrane; the interaction domain which promotes Gag polymerization; and the late domain which facilitates release of nascent virions from the host cell. The form of the Gag protein that mediates viral particle assembly is the polyprotein.

[0071] In some embodiments, a retroviral structural protein for use in accordance with the present invention is a Gag polypeptide. As used herein, the term "Gag polypeptide" is the retrovirus derived structural polypeptide that is responsible for formation of the VLPs described herein and refers to a polypeptide sequence whose amino acid sequence includes at least one characteristic sequence of Gag. A wide variety of Gag sequences from various retroviruses are known in the art and those of ordinary skill in the art, referring to such sequences, can readily identify sequences that are characteristic of Gag proteins generally, and/or of particular Gag polypeptides.

[0072] An exemplary Gag polypeptide for use in accordance with the present invention has the amino acid sequence of SEQ ID NO: 1. In some embodiments, a suitable Gag polypeptide is substantially homologous to a known retroviral Gag polypeptide. For example, a Gag polypeptide may be a modified retroviral Gag polypeptide containing one or more amino acid substitutions, deletions, and/or insertions as compared to a wild-type or naturally-occurring Gag polypeptide (e.g., SEQ ID NO: l), while retaining substantial self-assembly activity. In some embodiments, a Gag polypeptide suitable for the present invention is substantially homologous to SEQ ID NO: l . In some embodiments, a Gag polypeptide suitable for the present invention has an amino acid sequence at least 50%, 55%, 60%>, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or more homologous to SEQ ID NO: l . In some embodiments, a Gag polypeptide suitable for the present invention is substantially identical to SEQ ID NO: 1. In some embodiments, a Gag polypeptide suitable for the present invention has an amino acid sequence at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or more identical to SEQ ID NO: l . [0073] In some embodiments, a Gag polypeptide is encoded by a nucleotide sequence shown as SEQ ID NO:2. In some embodiments, a suitable Gag polypeptide is encoded by a nucleotide sequence substantially homologous to a known nucleotide sequence encoding a retroviral Gag polypeptide. For example, a Gag polypeptide may be encoded by a modified retroviral Gag nucleotide sequence containing one or more nucleotide substitutions, deletions, and/or insertions as compared to a wild-type or naturally-occurring Gag nucleotide sequence (e.g., SEQ ID NO:2), while retaining substantial self-assembly activity. In some embodiments, a Gag polypeptide suitable for the present invention is encoded by a nucleotide sequence substantially homologous to SEQ ID NO:2. In some embodiments, a Gag polypeptide suitable for the present invention is encoded by a nucleotide sequence that is least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or more homologous to SEQ ID NO:2. In some embodiments, a Gag polypeptide suitable for the present invention is encoded by a nucleotide sequence substantially identical to SEQ ID NO:2. In some embodiments, a Gag polypeptide suitable for the present invention is encoded by a nucleotide sequence that is at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or more identical to SEQ ID NO:2.

[0074] In some embodiments, the present invention provides nucleic acids which encode a Gag polypeptide or a characteristic portion of a Gag polypeptide. In certain embodiments, nucleic acids can be DNA or RNA, and can be single stranded or double-stranded. In some embodiments, inventive nucleic acids may include one or more non-natural nucleotides; in other embodiments, inventive nucleic acids include only natural nucleotides. In some embodiments, a Gag polypeptide is encoded by a codon-optimized nucleotide sequence, e.g., altered for increased expression in a particular host cell. In some embodiments, a Gag polypeptide is encoded by the nucleotide sequence of SEQ ID NO:3.

[0075] Typically in nature, a Gag protein includes a large C-terminal extension which may contain retroviral protease, reverse transcriptase, and integrase enzymatic activity.

Assembly of VLPs, however, generally does not require the presence of such components. In some cases, a retroviral Gag protein alone (e.g., lacking a C-terminal extension, lacking one or more of genomic RNA, reverse transcriptase, viral protease, or envelope protein) can self- assemble to form VLPs both in vitro and in vivo (Sharma S et al., 1997 Proc. Natl. Acad. Sci. USA 94: 10803-8). Retroviral Gag polyprotein alone can oligomerize and assemble into VLPs. [0076] In some embodiments, a Gag polypeptide for use in accordance with the present invention lacks a C-terminal extension and/or contains a modified C-terminal extension. A Gag polypeptide may optionally be expressed with one or more additional polypeptides (e.g., a heterologous antigen). In some embodiments, a Gag polypeptide is co-expressed with a heterologous antigen (e.g., under separate promoters and/or as separate proteins). In some embodiments, a Gag polypeptide is expressed as a fusion protein with a heterologous antigen. The Gag polypeptide can be linked to a heterologous antigen to create a fusion protein without altering Gag function. For example, a coding sequence for a heterologous antigen may be spliced into the Gag polypeptide coding sequence, e.g., at the 3' end of the Gag polypeptide coding sequence. In some embodiments, a coding sequence for a heterologous antigen may be spliced in frame into the Gag polypeptide coding sequence. In some embodiments, a Gag polypeptide-coding sequence and heterologous antigen may be expressed by a single promoter. In some embodiments, a heterologous antigen is inserted at (e.g., fused to) the C-terminus of a Gag polypeptide. Without wishing to be bound by any theory, it is thought that fusion of a self- assembling Gag polypeptide to a heterologous antigen creates a fusion protein that acts as unmodified Gag and as a result will allow the antigen to be incorporated into the structural components of a resulting VLP. In some embodiments, VLP structural components serve as effective immunogens (e.g., for induction of cellular immune response).

Heterologous Viral Antigens from HCV

[0077] HCV is an enveloped, positive sense, single stranded RNA virus of the

Flaviviridae family. Development of an effective vaccine against HCV has long been defined as a difficult challenge due to variability of this RNA virus and the absence of well-defined immune correlates of protection from HCV infection. Envelope proteins of HCV, such as glycoproteins El and E2, are important targets for production of neutralizing antibodies against HCV, as neutralizing antibodies are generally able to prevent infection. Several approaches to HCV vaccine development have been studied and include recombinant El and E2 proteins, synthetic peptides, DNA and prime -boost strategies (Torresi J. et al, (2011) J Hepatol 54:1273-1285). The use of recombinant HCV envelope proteins as a vaccine candidate has been met with variable success. The reasons which have been suggested for the limited efficacy of recombinant vaccines exclusively on El and/or E2 of HCV are thought to be due to inadequate induction of a cellular immune response, and structural restrictions on antigen used, whose epitopes are thought to be conformation-dependent. The present inventors recognized that development of an HCV vaccine comprising one or more envelope polypeptide antigens presented in their native conformation on the surface of a VLP leads to induction of neutralizing antibodies (e.g., via a humoral immune response) and an HCV vaccine comprising one or more interior protein antigens (e.g., non-structural protein NS3 and/or NS4A) leads to induction of helper T cells (T_# lymphocytes) and cytotoxic T cells (CTL) (e.g., via a cell-mediated immune response).

Neutralizing antibodies are generally formed against viral envelope proteins, and especially against HCV glycoproteins El and E2. Ύ_Η cells are stimulated by non-structural interior proteins of a virus, such as, for example, HCV NS3 and/or NS4A. In addition, NS3 and/or NS4A plays an important role in induction of a CTL response against HCV.

[0078] It will be appreciated that provided VLPs may comprise any heterologous antigen, including heterologous antigens from HCV. For example, in some embodiments, a VLP in accordance with the present invention comprises one or more HCV envelope polypeptides. In some embodiments, a VLP in accordance with the present invention comprises one or more HCV interior non-structural polypeptides. In some embodiments, a VLP in accordance with the present invention comprises one or more HCV envelope polypeptides and one or more HCV interior non-structural polypeptides. A list of exemplary, but non-limiting HCV antigens is provided below.

HCV Envelope Proteins

[0079] In some embodiments, the present invention utilizes HCV VLPs comprising one or more envelope polypeptides from HCV (e.g., El and/or E2). A wide variety of envelope glycoprotein sequences from various viruses, including, but not limited to HCV, are known in the art and those of ordinary skill in the art, referring to such sequences, can readily identify sequences that are characteristic of envelope glycoproteins generally, and/or of particular envelope glycoproteins. In some embodiments, HCV VLPs comprise one or more envelope polypeptide variants comprising a cytoplasmic, transmembrane and/or extracellular portion or domain. Particular, non-limiting examples of HCV envelope proteins include El and E2. [0080] Structural Envelope glycoprotein El (30-35 kDa) is highly glycosylated and has

4-5 N-linked glycans. El is important in viral cell entry and serves as the fusogenic subunit. Envelope glycoprotein E2 (70-72 kDa) is also highly glycosylated and has 11 N-glycosylation sites. E2 is also important in viral cell entry and acts as the receptor binding protein.

HCV Envelope Protein Variants

[0081] In some embodiments, a VLP described herein includes an HCV envelope polypeptide, or a portion thereof, that includes a heterologous transmembrane and/or cytoplasmic domain (i.e., that is not found in nature in the HCV envelope polypeptide). For example, in some embodiments, a VLP described herein includes an HCV envelope protein variant comprising an extracellular region of an El and/or E2 polypeptide and a heterologous transmembrane domain (or portion thereof) and/or a heterologous cytoplasmic domain (or portion thereof) found in nature in vesicular stomatitis virus (VSV). As is known in the art, polypeptides sometimes have transmembrane, cytoplasmic, and/or extracellular domains. In general, a "transmembrane domain", as used herein, refers to a domain that has an attribute of being present in the membrane (e.g., spanning a portion or all of a cellular membrane). As will be appreciated, it is not required that every amino acid in a transmembrane domain be present in the membrane. For example, in some embodiments, a transmembrane domain is characterized in that a designated stretch or portion of a protein is substantially located in the membrane. As is well known in the art, amino acid or nucleic acid sequences may be analyzed using a variety of algorithms to predict protein subcellular localization (e.g., transmembrane localization).

Exemplary such programs include psort (PSORT.org), Prosite (prosite.expasy.org), among others. In general, a "cytoplasmic domain", as used herein, refers to a domain that has an attribute of being present in the cytoplasm. As will be appreciated, it is not required that every amino acid in a cytoplasmic domain be present in the cytoplasm. For example, in some embodiments, a cytoplasmic domain is characterized in that a designated stretch or portion of a protein is substantially located in the cytoplasm. As is well known in the art, amino acid or nucleic acid sequences may be analyzed using a variety of algorithms to predict protein subcellular localization (e.g., cytoplasmic localization). Exemplary such programs include psort (PSORT.org), Prosite (prosite.expasy.org), among others. [0082] The transmembrane domain of VSV-G functions to target the viral glycoprotein to the cell membrane (Compton T et al, 1989 Proc Natl Acad Sci USA 86:4112-4116).

Swapping the transmembrane and cytoplasmic domains of VSV-G for the transmembrane and cytoplasmic domains of another protein has been used to direct a protein to the cell membrane when the native protein does not naturally do this or requires accessory co-expressed proteins to accomplish this (Garrone et al., Sci Transl Med 3:94ra71 (2011)).

[0083] An exemplary HCV envelope protein variant includes an extracellular domain of an E2 polypeptide, a transmembrane domain of VSV-G, and a cytoplasmic domain of VSV-G ("E2-G"). For example, an HCV envelope protein variant can be an extracellular domain of E2 (e.g., amino acids 59-343 of SEQ ID NO:4) joined to (e.g., fused to) a transmembrane domain of VSV-G and a cytoplasmic domain of VSV-G (e.g., amino acids 344-387 of SEQ ID NO:4). In some embodiments, an HCV envelope protein variant comprises or consists of an amino acid sequence that is substantially homologous to SEQ ID NO:4, or a portion thereof. In some embodiments, an HCV envelope protein variant comprises or consists of an amino acid sequence that is at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%o, 97%), 98%o, 99%) or more homologous to SEQ ID NO:4, or a portion thereof. In some embodiments, an HCV envelope protein variant comprises or consists of an amino acid sequence that is substantially identical to SEQ ID NO:4, or a portion thereof. In some embodiments, an HCV envelope protein variant comprises or consists of an amino acid sequence that is at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or more identical to SEQ ID NO:4, or a portion thereof. In some embodiments, an HCV envelope protein variant comprises or consists of the amino acid sequence of SEQ ID NO:4, or a portion thereof.

HCV Interior Non-Structural Proteins

[0084] In some embodiments, a VLP in accordance with the present invention comprises one or more HCV interior non-structural proteins. Exemplary, nonlimiting HCV interior nonstructural proteins include p7, NS2, NS3, NS4A, NS4B, NS5A, and NS5B.

[0085] The p7 protein is dispensable for viral genome replication but plays a critical role in virus morphogenesis. This protein is a 63 amino acid membrane spanning protein which locates itself in the endoplasmic reticulum. Cleavage of p7 is mediated by the endoplasmic reticulum's signal peptidases. Two transmembrane domains of p7 are connected by a cytoplasmic loop and are oriented towards the endoplasmic reticulum's lumen.

[0086] NS2 protein is 21-23 kiloDalton (kDa) and contains a domain, predicted to interact with the N-terminus of the adjacent NS3 protein. The resulting NS2/3 proteinase is specific for the NS2/NS3 cleavage site. Cleavage at the NS2/NS3 junction is the first

posttranslational autocatalytic cleavage of the large polyprotein (Hijikata M. et al., (1993) J Virol 67:4665-4675). Except for the above described proteinase activity, no other function of NS2 protein has yet been described.

[0087] NS3 protein is a 70 kDa and consists of two domains; the N-terminal domain has serine protease activity and the C-terminal domain has NTPase/helicase activity (Kim DW. et al., (1995) Biochem Biophys Res Commun 215: 160-166). Serine protease is necessary for HCV infectivity as well as for co- and post-translational cleavage at NS3/4A, NS4A/4B, NS4B/5A and NSB5A/5B sites. The cleavage at NS3/4A site is cis, and all remaining cleavages are trans. NS4A (described below) is a serine protease co-factor essential for all of the above mentioned cleavages with the exception of NS5A/5B. The structure of HCV NS3 protease is similar to the structure of other members of trypsin protease superfamily. Unlike the others NS4A cofactor is an integral part of its structure and interacts with N-terminus residues (Tai CL. et al., (1996) J Virol 70:8477-8484). HCV NS3 helicase is a member of Asp-Glu-Cys-His subgroup of so- called "DEAD-box" helicases; its ATPase activity is stimulated by ssRNA. The exact role of RNA helicase in the replication process is not known. Nevertheless NS3 mutations, which alter helicase activity, affect HCV infectivity in vitro. Besides the role in HCV replication and posttranslational editing, the NS3 protein presumably has other functions that interfere with host cell functions.

[0088] NS4A protein is 8 kDa and contains a hydrophobic domain at the N-terminus, which is likely to interact with the membranes and with other replicase components. NS4A protein is also an essential cofactor of NS3 protease and its presence is vital for posttranslational cleavage of the primary large polyprotein (Tanji Y. et al., (1995) J Virol 69: 1575-1581; Tomei L. et al, (1996) J Gen Virol 77: 1065-1070). The serine protease cofactor activity of this protein is located in the central portion of NS4A. [0089] NS4B protein is 27 kDa and is a hydrophobic integral membrane protein with 4 transmembrane domains. It is located within the endoplasmic reticulum and plays an important role for recruitment of other viral proteins. It induces morphological changes to the endoplasmic reticulum forming a structure termed the membranous web (Gosert R. et al., (2003) J Virol 77:5487-5492).

[0090] NS5A protein is a hydrophilic phosphoprotein that is bound to membranes and exists in at least 2 forms with molar masses of 56 and 58 kDa. These forms are thought to be the product of different phosphorylation. Recent studies demonstrate that the influence on NS5A phosphorylation is multifactorial, and virtually all NS proteins localized upstream of NS5A are involved (Koch JO. et al, (1999) J Virol 73:7138-7146). It is assumed that NS5A is a component of the HCV replication complex. The kinase responsible for NS5A phosphorylation is probably of cellular origin. Detailed understanding of the role of NS5A protein and NS5A phosphorylation in the process of viral replication is not fully understood.

[0091] NS5B protein is 65 kDa and is the viral RNA dependent RNA polymerase. NS5B has the key function of replicating the HCV's viral RNA by using the viral positive RNA strand as its template and catalyzes the polymerization of ribonucleoside triphosphates (rNTP) during RNA replication (Moradpour D. et al, (2007) Nat Rev Microbiol 5:453-463; Rigat K. et al, (2010) Antiviral Res 88: 197-206). NS5B coding region is highly heterogeneous among particular HCV strains. This variability was used to establish the classification system of HCV strains into genotypes and subtypes (Simmonds P. et al, (1993) J Gen Virol 74:2391-2399).

Fusion Proteins of Gag and HCV Interior Non-Structural Proteins

[0092] In some embodiments, provided HCV VLPs comprise a retroviral Gag

polypeptide (e.g., MMLV Gag) joined to (e.g., fused to) one or more interior nonstructural proteins of HCV (e.g., NS3 and/or NS4A, or a portion thereof). In some embodiments, a suitable Gag fusion polypeptide includes a Gag polypeptide that is substantially homologous to a known retroviral Gag polypeptide. For example, a Gag fusion polypeptide may include a modified retroviral Gag polypeptide containing one or more amino acid substitutions, deletions, and/or insertions as compared to a wild-type or naturally-occurring Gag polypeptide (e.g., SEQ ID NO: l), while retaining substantial self-assembly activity. In some embodiments, a fusion protein of a Gag and one or more HCV interior nonstructural proteins comprises Gag, NS3, and NS4A (a Gag/NS3-NS4A fusion protein). In some embodiments, the NS3 polypeptide consists of or comprises amino acids 539-978 of SEQ ID NO:7 (or a portion thereof). In some embodiments, the NS4A polypeptide consists of or comprises amino acids 980-1033 of SEQ ID NO:7 (or a portion thereof) In some embodiments, a Gag/NS3-NS4A fusion protein comprises or consists of an amino acid sequence that is substantially homologous to SEQ ID NO:7, or a portion thereof. In some embodiments, a Gag/NS3-NS4A fusion protein comprises or consists of an amino acid sequence that is at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or more homologous to SEQ ID NO:7, or a portion thereof. In some embodiments, a Gag/NS3-NS4A fusion protein comprises or consists of an amino acid sequence that is substantially identical to SEQ ID NO:7, or a portion thereof. In some embodiments, a Gag/NS3-NS4A fusion protein comprises or consists of an amino acid sequence that is at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or more identical to SEQ ID NO:7, or a portion thereof. In some embodiments, a Gag/NS3-NS4A fusion protein comprises or consists of the amino acid sequence of SEQ ID NO:7, or a portion thereof.

HCV VLPs

[0093] Some embodiments of the present invention encompass the recognition that VLPs containing a structural component of a virus (e.g., MLV, e.g., MMLV) and one or more heterologous surface antigens (e.g., HCV envelope protein) are especially effective for antigen delivery and induction of an immune response against the heterologous antigen.

[0094] In some embodiments, a Gag polypeptide isexpressed with one or more additional polypeptides (e.g., one or more heterologous HCV antigens, e.g., one or more HCV envelope proteins or HCV envelope protein variants). In some embodiments, a Gag polypeptide is co- expressed with one or more heterologous HCV antigens (e.g., under separate promoters and/or as separate proteins). The Gag polypeptide can be co-expressed with one or more heterologous HCV antigens without altering Gag function. Without wishing to be bound by any theory, it is thought that co-expression of a self-assembling Gag polypeptide with one or more heterologous HCV envelope protein will allow the HCV envelope protein to be incorporated into the envelope or lipid bilayer of a resulting VLP. In some embodiments, VLP envelope components serve as effective immunogens (e.g., for induction of humoral immune response).

[0095] In some embodiments, a Gag polypeptide (e.g., MMLV Gag) is expressed with an

El and/or E2 envelope protein, or an El and/or E2 envelope protein variant (or a portion thereof) described herein. In some embodiments, the variant includes an extracellular domain of an El and/or E2 polypeptide, a transmembrane domain found in VSV-G, and a cytoplasmic domain found in VSV-G. In some such embodiments, an El, El variant, E2, and/or E2 variant is incorporated into the VLP and serves as an antigen for eliciting an immune response against HCV.

[0096] Some embodiments of the present invention encompass the recognition that VLPs containing a structural component (e.g., a Gag polypeptide) of a virus (e.g., MLV, e.g., MMLV) joined to (e.g., fused to) one or more heterologous antigens (e.g., one or more HCV interior nonstructural proteins) are effective for antigen delivery and induction of an immune response against the heterologous antigen.

[0097] In some embodiments, a Gag polypeptide is expressed as a fusion protein with a heterologous HCV antigen (e.g., one or more HCV interior non-structural proteins or portion thereof). For example, a coding sequence for one or more heterologous HCV interior nonstructural proteins may be spliced into the Gag polypeptide coding sequence, e.g., at the 3' end of the Gag polypeptide coding sequence. In some embodiments, a coding sequence for one or more HCV interior non-structural proteins may be spliced in frame into the Gag polypeptide coding sequence. In some embodiments, a Gag polypeptide-coding sequence and a coding sequence for one or more HCV interior non-structural proteins may be expressed by a single promoter. In some embodiments, one or more HCV interior non-structural proteins is inserted at (e.g., fused to) the C-terminus of a Gag polypeptide. Without wishing to be bound by any theory, it is thought that fusion of a self-assembling Gag polypeptide to a heterologous HCV antigen (e.g., HCV interior non-structural protein) will allow the HCV antigen (e.g., HCV interior non-structural protein) to be incorporated into the structural components of a resulting VLP. In some embodiments, VLP structural components serve as effective immunogens (e.g., for induction of cellular immune response). For example, provided VLPs may comprise a retroviral gag polypeptide (e.g., MLV gag, e.g., MMLV gag) and an interior non-structural protein of HCV (e.g., NS3 and/or NS4A). In some such embodiments, NS3 and/or NS4A is incorporated into the VLP and serves as an antigen for eliciting an immune response, e.g., a CTL response, against HCV.

[0098] Provided VLPs may contain a structural retroviral protein (e.g., Gag polypeptide) that is arranged and constructed such that it self-assembles to form the VLP and is positioned in the VLP interior. In some embodiments, provided VLPs contain an HCV envelope protein (e.g., El and/or E2, or an El and/or E2 envelope variant protein) that is arranged and constructed such that one or more epitopes of the HCV envelope protein (e.g., El and/or E2, or an El and/or E2 envelope variant protein) is positioned on the VLP surface. In some embodiments, provided VLPs contain a fusion of a Gag polypeptide and an HCV interior non-structural protein (e.g., a Gag-NS3 and/or NS4A fusion protein) that is arranged and constructed such that one or more epitopes of the HCV interior protein (e.g., NS3 and/or NS4A) is positioned in the VLP interior. In some embodiments, provided VLPs contain (i) a fusion of a Gag polypeptide and an HCV interior non-structural protein (e.g., a Gag/NS3 and/or NS4A fusion protein) and (ii) an HCV envelope protein or HCV envelope protein variant described herein.

Production of VLPs

[0099] It will be appreciated that a composition comprising VLPs can typically include a mixture of VLPs with a range of sizes. It is to be understood that the diameter values listed below correspond to the most frequent diameter within the mixture. In some embodiments > 90% of the vesicles in a composition will have a diameter which lies within 50% of the most frequent value (e.g., 1000 ± 500 nm). In some embodiments the distribution may be narrower, e.g., > 90%) of the vesicles in a composition may have a diameter which lies within 40, 30, 20, 10 or 5% of the most frequent value. In some embodiments, sonication or ultra-sonication may be used to facilitate VLP formation and/or to alter VLP size. In some embodiments, filtration, dialysis and/or centrifugation may be used to adjust the VLP size distribution.

[0100] In general, VLPs produced in accordance with the methods of the present disclosure may be of any size. In certain embodiments, the composition may include VLPs with diameter in range of about 20 nm to about 300 nm. In some embodiments, a VLP is

characterized in that it has a diameter within a range bounded by a lower limit of 20, 30, 40, 50, 60, 70, 80, 90, or 100 nm and bounded by an upper limit of 300, 290, 280, 270, 260, 250, 240, 230, 220, 210, 200, 190, 180, or 170 nm. In some embodiments, VLPs within a population show an average diameter within a range bounded by a lower limit of 20, 30, 40, 50, 60, 70, 80, 90, or 100 nm and bounded by an upper limit of 300, 290, 280, 270, 260, 250, 240, 230, 220, 210, 200, 190, 180, or 170 nm. In some embodiments, VLPs in a population have a polydispersity index that is less than 0.5 (e.g., less than 0.45, less than 0.4, or less than 0.3). In some embodiments, VLP diameter is determined by nanosizing. In some embodiments, VLP diameter is determined by electron microscopy.

In vitro / Ex vivo VLP Production

[0101] Provided VLPs in accordance with the present invention may be prepared according to general methodologies known to the skilled person. For example, various nucleic acid molecules, genomes or reconstituted vectors or plasmids may be prepared using sequences of known viruses. Such sequences are available from banks, and material may be obtained from various collections, published plasmids, etc. These elements can be isolated and manipulated using techniques well known to the skilled artisan, or isolated from plasmids available in the art. Various synthetic or artificial sequences may also be produced from computer analysis or through (high throughput) screening of libraries. Recombinant expression of the polypeptides for VLPs requires construction of an expression vector containing a polynucleotide that encodes one or more polypeptide(s). Once a polynucleotide encoding one or more polypeptides has been obtained, the vector for production of the polypeptide may be produced by recombinant DNA technology using techniques known in the art. Expression vectors that may be utilized in accordance with the present invention include, but are not limited to mammalian expression vectors, baculovirus expression vectors, plant expression vectors (e.g., Cauliflower Mosaic Virus (CaMV), Tobacco Mosaic Virus (TMV)), plasmid expression vectors (e.g., Ti plasmid), among others. An exemplary VLP expression plasmid that may be used in accordance with the present invention has the nucleotide sequence of SEQ ID NO: 10.

[0102] In some embodiments, VLPs are prepared using one or more nucleotide sequences of SEQ ID NO:2, 5, or 8. In some embodiments, VLPs are prepared using one or more nucleotide sequences substantially homologous to SEQ ID NO:2, 5, or 8. In some embodiments, VLPs are prepared using one or more nucleotide sequences that are at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or more homologous to SEQ ID NO:2, 5, or 8. In some embodiments, VLPs are prepared using one or more nucleotide sequences substantially identical to SEQ ID NO:2, 5, or 8. In some embodiments, VLPs are prepared using one or more nucleotide sequences that are at least 50%>, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or more identical to SEQ ID NO:2, 5, or 8.

[0103] In some embodiments, VLPs are prepared using nucleotide sequences that are codon optimized. Codon optimization is well known in the art and involves modification of codon usage so that higher levels of protein are produced. In some embodiments, VLPs are prepared using one or more nucleotide sequences of SEQ ID NO:3, 6, or 9. In some

embodiments, VLPs are prepared using one or more nucleotide sequences substantially homologous to SEQ ID NO:3, 6, or 9. In some embodiments, VLPs are prepared using one or more nucleotide sequences that are at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or more homologous to SEQ ID NO:3, 6, or 9. In some embodiments, VLPs are prepared using one or more nucleotide sequences substantially identical to SEQ ID NO:3, 6, or 9. In some embodiments, VLPs are prepared using one or more nucleotide sequences that are at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or more identical to SEQ ID NO:3, 6, or 9.

[0104] Provided VLPs may be prepared according to techniques known in the art. For example, in some embodiments, provided VLPs may be produced in any available protein expression system. Typically, the expression vector is transferred to a host cell by conventional techniques and the transfected cells are then cultured by conventional techniques to produce VLPs. In some embodiments, VLPs are produced using transient transfection of cells. In some embodiments, VLPs are produced using stably transfected cells. Typical cell lines that may be utilized for VLP production include, but are not limited to, mammalian cell lines such as human embryonic kidney (HEK) 293, WI 38, Chinese hamster ovary (CHO), monkey kidney (COS), HT1080, CIO, HeLa, baby hamster kidney (BHK), 3T3, CI 27, CV-1 , HaK, NS/O, and L-929 cells. Specific non-limiting examples include, but are not limited to, BALB/c mouse myeloma line (NSO/1, ECACC No: 851 10503); human retinoblasts (PER.C6 (CruCell, Leiden, The Netherlands)); monkey kidney CV1 line transformed by SV40 (COS-7, ATCC CRL 1651); human embryonic kidney line (293 or 293 cells subcloned for growth in suspension culture, Graham et al, J. Gen Virol, 36:59 (1977)); baby hamster kidney cells (BHK, ATCC CCL 10); Chinese hamster ovary cells +/-DHFR (CHO, Urlaub and Chasin, Proc. Natl. Acad. Sci. USA, 77:4216 (1980)); mouse Sertoli cells (TM4, Mather, Biol. Reprod., 23:243-251 (1980)); monkey kidney cells (CV1 ATCC CCL 70); African green monkey kidney cells (VERO-76, ATCC CRL- 1 587); human cervical carcinoma cells (HeLa, ATCC CCL 2); canine kidney cells (MDCK, ATCC CCL 34); buffalo rat liver cells (BRL 3A, ATCC CRL 1442); human lung cells (W138, ATCC CCL 75); human liver cells (Hep G2, HB 8065); mouse mammary tumor (MMT 060562, ATCC CCL51); TRI cells (Mather et al, Annals N. Y. Acad. Sci., 383:44-68 (1982)); MRC 5 cells; FS4 cells; and a human hepatoma line (Hep G2). In some embodiments, cell lines that may be utilized for VLP production include insect (e.g., Sf-9, Sf-21, Hi5) or plant (e.g.,

Leguminosa, cereal, or tobacco) cells. It will be appreciated in some embodiments, particularly when glycosylation is important for protein function, mammalian cells are preferable for protein expression and/or VLP production (see, e.g., Roldao A et al, 2010 Expt Rev Vaccines 9: 1149- 76).

[0105] It will be appreciated that a cell strain may be chosen which modulates the expression of the inserted sequences, or modifies and processes the gene product in a specific way. Such modifications (e.g., glycosylation) and processing (e.g., cleavage or transport to the membrane) of protein products may be important for generation of a VLP or function of a VLP polypeptide or additional polypeptide (e.g., an adjuvant or additional antigen). Different cells have characteristic and specific mechanisms for post-translational processing and modification of proteins and gene products. Appropriate cell lines or host systems can be chosen to ensure the correct modification and processing of the foreign protein expressed. Generally, eukaryotic host cells (also referred to as packaging cells (e.g., 293T human embryo kidney cells) which possess appropriate cellular machinery for proper processing of the primary transcript, glycosylation and phosphorylation of the gene product may be used in accordance with the present invention.

[0106] VLPs may be purified according to known techniques, such as centrifugation, gradients, chromatography (e.g., ion exchange, affinity and sizing column chromatography), or differential solubility, among others. Alternatively or additionally, cell supernatant may be used directly, with no purification step. Additional entities, such as additional antigens or adjuvants may be added to purified VLPs. In vivo VLP Production

[0107] Provided VLPs in accordance with the present invention may be prepared as DNA vaccines according to methods well known in the art. For example, in some embodiments, one or more vectors or plasmids, e.g., such as those described above, is administered to a subject such that recipient cells express polypeptides encoded by the vector or plasmid. In some embodiments, recipient cells expressing such polypeptides produce VLPs comprising the polypeptides.

Mono-, di-, trivalent eVLPs

[0108] In accordance with the present invention, cells may be transfected with a single expression vector as described herein. In some embodiments, a single expression vector encodes more than one element of a VLP (e.g., more than one of structural polyprotein, HCV interior non- structural protein, HCV glycoprotein, etc.).

[0109] For example, cells may be transfected with a single expression vector that encodes a retroviral Gag polypeptide described herein and one or more HCV interior nonstructural proteins and/or one or more HCV envelope proteins. In some embodiments, a single expression vector encodes two or more elements of a HCV VLP. In some embodiments, a single expression vector encodes three or more elements of a HCV VLP.

[0110] In some embodiments, cells may be transfected with one or more expression vectors. For example, cells may be transfected with a vector encoding a Gag/NS3-NS4A fusion polypeptide. In some such embodiments, "bivalent" HCV VLPs comprising two HCV interior non-structural proteins (NS3 and NS4A) are produced.

[0111] In some embodiments, cells may be transfected with two or more expression vectors. For example, cells may be transfected with a first vector encoding a retroviral Gag polypeptide and a second vector encoding an HCV envelope protein (e.g., El or E2) or an HCV envelope protein variant (e.g., E2-G). In some such embodiments, "monovalent" HCV VLPs comprising an HCV envelope protein (e.g., El or E2) or an HCV envelope protein variant (e.g., E2-G) are produced. In some embodiments, cells are transfected with a first vector encoding a retroviral Gag polypeptide, a second vector encoding an HCV envelope protein (e.g., El or E2) or an HCV envelope protein variant (e.g., E2-G) and a third vector encoding another HCV envelope protein (e.g., El or E2) or an HCV envelope protein variant (e.g., E2-G). In some such embodiments, "bivalent" HCV VLPs comprising two HCV envelope proteins (e.g., El and E2) or HCV envelope protein variants (e.g., E2-G) are produced.

[0112] In some embodiments, cells are transfected with a first vector encoding a fusion protein of a Gag polypeptide and one or more HCV interior non-structural protein described herein and a second vector encoding an HCV envelope protein (e.g., El or E2) or an HCV envelope protein variant (e.g., E2-G). In some such embodiments, "bivalent" HCV VLPs comprising an HCV interior non-structural protein (e.g., NS3 or NS4A) and an HCV envelope protein (e.g., El or E2) or an HCV envelope protein variant (e.g., E2-G) are produced. In some embodiments, cells are transfected with a first vector encoding a Gag/NS3-NS4A fusion polypeptide, and a second vector encoding an HCV envelope protein (e.g., El or E2) or an HCV envelope protein variant (e.g., E2-G). In some such embodiments, "trivalent" HCV VLPs comprising two HCV interior non-structural proteins (NS3 and NS4A) and an HCV envelope protein (e.g., El or E2) or an HCV envelope protein variant (e.g., E2-G) are produced. In some embodiments, cells are transfected with a first vector encoding a Gag/NS3-NS4A fusion polypeptide, a second vector encoding an HCV envelope protein (e.g., El or E2) or an HCV envelope protein variant (e.g., E2-G), and a third vector encoding another HCV envelope protein (e.g., El or E2) or an HCV envelope protein variant (e.g., E2-G). In some such embodiments, "quadrivalent" HCV VLPs comprising two HCV interior non-structural proteins (NS3 and NS4A) and two HCV envelope proteins (e.g., El and E2) or HCV envelope protein variants (e.g., E2-G) are produced.

[0113] In some embodiments, monovalent, bivalent, trivalent, and/or quadrivalent HCV

VLPs are admixed. For example, in some embodiments, monovalent and bivalent HCV VLPs are admixed to form a trivalent HCV VLP mixture. In some embodiments two bivalent HCV VLPs are admixed to form a trivalent HCV VLP mixture.

Pharmaceutical Compositions

[0114] The present invention provides pharmaceutical compositions comprising provided

VLPs and/or provided glycoprotein variants. In some embodiments, the present invention provides a VLP and at least one pharmaceutically acceptable excipient. Such pharmaceutical compositions may optionally comprise and/or be administered in combination with one or more additional therapeutically active substances. In some embodiments, provided pharmaceutical compositions are useful in medicine. In some embodiments, provided pharmaceutical compositions are useful as prophylactic agents (i.e., vaccines) in the treatment or prevention of HCV or of negative ramifications associated or correlated with HCV infection. In some embodiments, provided pharmaceutical compositions are useful in therapeutic applications, for example in individuals suffering from or susceptible to HCV infection. In some embodiments, pharmaceutical compositions are formulated for administration to humans.

[0115] For example, pharmaceutical compositions provided here may be provided in a sterile injectible form (e.g., a form that is suitable for subcutaneous injection or intravenous infusion). For example, in some embodiments, pharmaceutical compositions are provided in a liquid dosage form that is suitable for injection. In some embodiments, pharmaceutical compositions are provided as powders (e.g. lyophilized and/or sterilized), optionally under vacuum, which are reconstituted with an aqueous diluent (e.g., water, buffer, salt solution, etc.) prior to injection. In some embodiments, pharmaceutical compositions are diluted and/or reconstituted in water, sodium chloride solution, sodium acetate solution, benzyl alcohol solution, phosphate buffered saline, etc. In some embodiments, powder should be mixed gently with the aqueous diluent (e.g., not shaken).

[0116] In some embodiments, provided pharmaceutical compositions comprise one or more pharmaceutically acceptable excipients (e.g., preservative, inert diluent, dispersing agent, surface active agent and/or emulsifier, buffering agent, etc.). Suitable excipients include, for example, water, saline, dextrose, sucrose, trehalose, glycerol, ethanol, or similar, and

combinations thereof. In addition, if desired, the vaccine may contain auxiliary substances such as wetting or emulsifying agents, pH buffering agents, or adjuvants which enhance the effectiveness of the vaccines. In some embodiments, pharmaceutical compositions comprise one or more preservatives. In some embodiments, pharmaceutical compositions comprise no preservative.

[0117] In some embodiments, pharmaceutical compositions are provided in a form that can be refrigerated and/or frozen. In some embodiments, pharmaceutical compositions are provided in a form that cannot be refrigerated and/or frozen. In some embodiments, reconstituted solutions and/or liquid dosage forms may be stored for a certain period of time after reconstitution (e.g., 2 hours, 12 hours, 24 hours, 2 days, 5 days, 7 days, 10 days, 2 weeks, a month, two months, or longer). In some embodiments, storage of VLP formulations for longer than the specified time results in VLP degradation.

[0118] Liquid dosage forms and/or reconstituted solutions may comprise particulate matter and/or discoloration prior to administration. In some embodiments, a solution should not be used if discolored or cloudy and/or if particulate matter remains after filtration.

[0119] Formulations of the pharmaceutical compositions described herein may be prepared by any method known or hereafter developed in the art of pharmacology. In some embodiments, such preparatory methods include the step of bringing active ingredient into association with one or more excipients and/or one or more other accessory ingredients, and then, if necessary and/or desirable, shaping and/or packaging the product into a desired single- or multi-dose unit.

[0120] A pharmaceutical composition in accordance with the invention may be prepared, packaged, and/or sold in bulk, as a single unit dose, and/or as a plurality of single unit doses. As used herein, a "unit dose" is discrete amount of the pharmaceutical composition comprising a predetermined amount of the active ingredient. The amount of the active ingredient is generally equal to a dose which would be administered to a subject and/or a convenient fraction of such a dose such as, for example, one-half or one -third of such a dose.

[0121] Relative amounts of active ingredient, pharmaceutically acceptable excipient, and/or any additional ingredients in a pharmaceutical composition in accordance with the invention may vary, depending upon the identity, size, and/or condition of the subject treated and/or depending upon the route by which the composition is to be administered. By way of example, the composition may comprise between 0.1% and 100% (w/w) active ingredient.

[0122] Pharmaceutical compositions of the present invention may additionally comprise a pharmaceutically acceptable excipient, which, as used herein, may be or comprise solvents, dispersion media, diluents, or other liquid vehicles, dispersion or suspension aids, surface active agents, isotonic agents, thickening or emulsifying agents, preservatives, solid binders, lubricants and the like, as suited to the particular dosage form desired. Remington's The Science and Practice of Pharmacy, 21st Edition, A. R. Gennaro, (Lippincott, Williams & Wilkins, Baltimore, MD, 2006) discloses various excipients used in formulating pharmaceutical compositions and known techniques for the preparation thereof. Except insofar as any conventional excipient medium is incompatible with a substance or its derivatives, such as by producing any undesirable biological effect or otherwise interacting in a deleterious manner with any other component(s) of the pharmaceutical composition, its use is contemplated to be within the scope of this invention.

[0123] In some embodiments, a pharmaceutical composition is sufficiently immunogenic as a vaccine (e.g., in the absence of an adjuvant). In some embodiments, immunogenicity of a pharmaceutical composition is enhanced by including an adjuvant. Any adjuvant may be used in accordance with the present invention. A large number of adjuvants are known; a useful compendium of many such compounds is prepared by the National Institutes of Health and can be found (www.niaid.nih.gov/daids/vaccine/pdf/compendium.pdf). See also Allison (1998, Dev. Biol. Stand., 92:3-11; incorporated herein by reference), Unkeless et al. (1998, Annu. Rev.

Immunol., 6:251-281; incorporated herein by reference), and Phillips et al. (1992, Vaccine, 10: 151-158; incorporated herein by reference). Hundreds of different adjuvants are known in the art and may be employed in the practice of the present invention. Exemplary adjuvants that can be utilized in accordance with the invention include, but are not limited to, cytokines, gel-type adjuvants (e.g., aluminum hydroxide, aluminum phosphate, calcium phosphate, etc.); microbial adjuvants (e.g., immunomodulatory DNA sequences that include CpG motifs; endotoxins such as monophosphoryl lipid A; exotoxins such as cholera toxin, E. coli heat labile toxin, and pertussis toxin; muramyl dipeptide, etc.); oil-emulsion and emulsifier-based adjuvants (e.g., Freund's Adjuvant, MF59 [Novartis], SAF, etc.); particulate adjuvants (e.g., liposomes, biodegradable microspheres, saponins, etc.); synthetic adjuvants (e.g., nonionic block copolymers, muramyl peptide analogues, polyphosphazene, synthetic polynucleotides, etc.); and/or combinations thereof. Other exemplary adjuvants include some polymers (e.g., polyphosphazenes; described in U.S. Patent 5,500,161, which is incorporated herein by reference), Q57, QS21, squalene, tetrachlorodecaoxide, etc. Pharmaceutically acceptable excipients have been previously described in further detail in the above section entitled "Pharmaceutical Compositions." Administration

[0124] Provided compositions and methods of the present disclosure are useful for prophylaxis of HCV and/or therapeutic treatment of HCV infection in a subject, including human adults and children. In general however they may be used with any animal. In certain embodiments, the methods herein may be used for veterinary applications, e.g., canine and feline applications. If desired, the methods herein may also be used with farm animals, such as ovine, avian, bovine, porcine and equine breeds.

[0125] As used herein, the terms "subject," "individual" or "patient" refer to a human or a non-human mammalian subject. The individual (also referred to as "patient" or "subject") being treated is an individual (fetus, infant, child, adolescent, or adult) suffering from a disease, for example, HCV infection. In some embodiments, the subject is at risk for HCV infection. In some embodiments, the subject is an immunosuppressed subject. For example, in some embodiments, the immunosuppressed subject is selected from the group consisting of an HIV- infected subject, an AIDS patient, a transplant recipient, a pediatric subject, and a pregnant subject. In some embodiments, the subject has been exposed to HCV infection. In some embodiments, the subject is a human.

[0126] Compositions described herein will generally be administered in such amounts and for such a time as is necessary or sufficient to induce an immune response. Dosing regimens may consist of a single dose or a plurality of doses over a period of time. The exact amount of an immunogenic composition (e.g., VLP) to be administered may vary from subject to subject and may depend on several factors. Thus, it will be appreciated that, in general, the precise dose used will be as determined by the prescribing physician and will depend not only on the weight of the subject and the route of administration, but also on the age of the subject and the severity of the symptoms and/or the risk of infection. In certain embodiments a particular amount of a VLP composition is administered as a single dose. In certain embodiments, a particular amount of a VLP composition is administered as more than one dose (e.g., 1-3 doses that are separated by 1-12 months). In certain embodiments a particular amount of a VLP composition is administered as a single dose on several occasions (e.g., 1-3 doses that are separated by 1-12 months). [0127] In some embodiments, a provided composition is administered in an initial dose and in at least one booster dose. In some embodiments, a provided composition is administered in an initial dose and two booster doses. In some embodiments, a provided composition is administered in an initial dose and three booster doses. In some embodiments, a provided composition is administered in an initial dose and four booster doses. In some embodiments, a provided composition is administered in an initial dose and in at least one booster dose about one month, about two months, about three months, about four months, about five months, or about six months following the initial dose. In some embodiments, a provided composition is administered in a second booster dose about six months, about seven months, about eight months, about nine months, about ten months, about eleven months, or about one year following the initial dose. In some embodiments, a provided composition is administered in a booster dose every 1 year, 2 years, 3 years, 4 years, 5 years, 6 years, 7 years, 8 years, 9 years, or 10 years.

[0128] In certain embodiments, provided compositions may be formulated for delivery parenterally, e.g., by injection. In such embodiments, administration may be, for example, intravenous, intramuscular, intradermal, or subcutaneous, or via by infusion or needleless injection techniques. In certain embodiments, the compositions may be formulated for peroral delivery, oral delivery, intranasal delivery, buccal delivery, sublingual delivery, transdermal delivery, transcutaneous delivery, intraperitoneal delivery, intravaginal delivery, rectal delivery or intracranial delivery.

Examples

[0129] The following examples describe some exemplary modes of making and practicing certain compositions that are described herein. It should be understood that these examples are for illustrative purposes only and are not meant to limit the scope of the compositions and methods described herein.

Example 1: Construction of DNA Expression Plasmids

[0130] This Example describes development of expression plasmids and constructs for expression of recombinant HCV gene sequences (e.g., E2-G and Gag/NS3-NS4A fusion gene sequences). A standard expression plasmid generally consists of a promoter sequence of mammalian origin, an intron sequence, a PolyAdenylation signal sequence (Poly A), a pUC origin of replication sequence (pUC - pBR322 is a colEl origin/site of replication initiation and is used to replicate plasmid in bacteria such as E Coli (DH5 )), and an antibiotic resistance gene as a selectable marker for plasmid plaque selection. Within the plasmid following the Intron are a variety of restriction enzyme sites that can be used to splice in a gene or partial gene sequence of interest.

[0131] The Propol II expression plasmid contains the pHCMV (early promoter for

HCMV), a Beta-Globin Intron (BGL Intron), a rabbit Globin polyAdenylation signal sequence (Poly A), a pUC origin of replication sequence (pUC - pBR322 is a colEl origin/site of replication initiation and is used to replicate plasmid in bacteria such as E. coli (DH5a)), and an ampicillin resistance gene β-lactamase (Amp R - selectable marker for plasmid confers resistance to ampicillin (100 μg/ml) (Figure 1A).

[0132] Figure IB depicts exemplary recombinant expression plasmids. For example, to develop a pHCMV-Gag/NS3-NS4A expression construct ("Gag/NS3-NS4A"), a sequence encoding the Gag polyprotein of MMLV (Gag without its C terminus Pol sequence) was fused with the truncated NS3 sequence corresponding to the helicase domain of HCV NS3 and HCV NS4A sequence, codon-optimized for human expression (GenScript) and cloned into a Propol II expression vector (Figure 2). Alternatively, to develop a pHCMV-Gag MMLV expression construct ("MLV-Gag"), a complementary DNA (cDNA) sequence encoding a Gag polyprotein of MMLV (Gag without its C terminus Pol sequence) was cloned into a Propol II (pHCMV) expression vector. To develop an E2-G expression construct ("E2-G"), the truncated sequence of E2 encoding only the extracellular portion, preceded by a truncated sequence of HCV Core acting as signal peptide, was fused together with transmembrane and cytoplasmic portions of VSV-G and codon-optimized for human expression (GenScript). A rabbit Globin

polyAdenylation signal sequence (Poly A) was synthesized directly after the fused sequence, and the final sequence was cloned into a Propol II expression vector (Figure 3).

[0133] DNA plasmids were amplified in competent E. coli (DH5a) and purified with endotoxin- free preparation kits according to standard protocols. Description of the Gag/NS3-NS4A Fusion Gene Sequence:

[0134] The different sequences comprising the Gag/NS3-NS4A fusion nucleotide sequence (SEQ ID NO: 8) are shown in Table 1. The Gag_is a sequence corresponding to the full length sequence of the Moloney Murine Leukemia Virus Gag without its C terminus Pol sequence, corresponding to base pairs 357-1971 from GenBank accession number AF033811.1. The HCV NS3 helicase is the HCV NS3 helicase sequence, corresponding to base pairs 3989- 5323 from the JFHl isolate sequence, GenBank AB047639. The HCV NS4A is the HCV NS4A domain, corresponding to base pairs 5324-5485 from the JFHl isolate sequence, GenBank

AB047639

Table 1

[0135] The Gag/NS3-NS4A sequence was codon optimized (SEQ ID NO:9) to maximize protein expression in human cells. For subcloning purposes, additional 3 '(GAATTCCACGTGGGATCC) and 5'(CTCGAGGTTTAAACGAATTCCGCCACC) sequences containing restriction sites were added. The Gag/NS3-NS4A fusion sequence was subcloned into the expression plasmid Propol II, in cloning sites XhoI-BamHI (Figure 2).

Description of the E2-G Gene Sequence:

[0136] The different sequences comprising the E2-G nucleotide sequence (SEQ ID

NO:5) are shown in Table 2. The HCV deltaCorejs a sequence corresponding to a fragment of the core of hepatitis C virus, corresponding to base pairs 740-913 from JFHl isolate, GenBank accession number AB047639. The HCV E2 extracellular (without TM/Cyt) is an E2 sequence deprived of transmembrane and cytoplasmic domains, corresponding to JFHl isolate sequence base pairs 1489-2344. The VSV-G TM/Cyt is the transmembrane and cytoplasmic domain of the glycoprotein G from the vesicular stomatitis virus, strain Indiana, GenBank accession number J02428, corresponding to base pairs 2821-2955.

Table 2

[0137] The E2-G gene sequence was codon optimized (SEQ ID NO:6) to maximize protein expression in human cells. For subcloning purposes, A rabbit Globin polyAdenylation signal sequence (poly A) was synthesized directly after the optimized sequence for HCV E2-G and additional 3 ' (G AATTCC ACGTGGGATCC) and

5 '(CTCGAGGTTTAAACGAATTCCGCCACC) sequences containing restriction sites were added. The E2-G-polyA sequence was then subcloned into the expression plasmid Propol II, in cloning sites XhoI-BamHI (Figure 3).

Example 2: Production of Virus-Like Particles

[0138] This Example describes methods for production of virus-like particles containing various recombinant HCV antigens described in Example 1.

[0139] HEK 293T cells (ATCC, CRL-11268) were transiently transfected using calcium phosphate methods with an MMLV-Gag DNA expression plasmid and co-transfected with an E2-G DNA expression plasmid. Alternatively cells were transfected with a Gag/NS3-NS4A DNA expression plasmid and co-transfected with an E2-G DNA expression plasmid (Table 3).

Table 3

[0140] Surface expression of E2-G HCV antigens by the HEK 293 cells was confirmed with FACS analysis by flow cytometry (Figure 4). After 48 hours of transfection, supernatants containing the eVLPs were harvested and filtered through 0.45 μιη pore size membranes and further concentrated and purified by ultracentrifugation through a 20% sucrose cushion in a JA17 Beckman rotor (17,000 rpm, 3.5 hours, 4°C). Pellets were resuspended in sterile endotoxin-free PBS (HyClone) to obtain 500 times concentrated eVLP stocks. Total protein was determined on an aliquot by a Bradford assay quantification kit (BioRad). MMLV-Gag content in different eVLP preparations was quantified using a commercially available Quick Titer MuLV Core Antigen ELISA kit (MuLV p30) (Cell Biolabs, Cat# VPK-156) according to the manufacturer's instructions. All monovalent E2-G VLPs and bivalent E2-G and Gag/NS3-NS4A VLPs had significant Gag content and post transfection HEK 293 cell preparations exhibited surface- staining for E2 providing indirect evidence that E2-G was being expressed and directed to the VLP envelope [see Table 4].

Table 4

[0141] Purified eVLPs were stored at -20°C until used. Each lot of purified eVLPs was analyzed for the expression of MMLV-Gag, E2-G and/or MMLV-Gag/NS3-NS4A fusion protein by SDS-Page (Figure 5) and Western Blot with specific antibodies to Gag (Figure 6; Primary antibody Anti-MuLV p30 rat monoclonal antibody , R187, ATCC CRL-1912; Secondary antibody Goat anti-rat alkaline phosphatase ), E2-G (Figure 7; Primary antibody mouse monoclonal antibody to Anti-VSV-G tag antibody P5D4, Sigma V5507; Secondary antibody Goat anti-mouse alkaline phosphatase). For E2-G detection on western blots we also used specific monkey serum from monkeys primed with an Adenovirus expressing E1E2 followed by a boost with E1E2 VLPs which should result in an increased titer of neutralizing antibodies to both El and E2 in the treated monkeys sera which could then be used to detect portions of the native E2 sequence of E2-G in a western blot, data not shown) . To visualize the western blots, secondary antibodies with alkaline phosphatase were detected by combination with NBT and BCIP as chromogenic substrates.

[0142] In figure 7 there is evidence for expression of E2-G protein on bivalent Gag/NS3-

NS4, E2-G eVLPs. In figure 6 there is evidence for expression of Gag/NS3-NS4 in the bivalent eVLPs, though the production of these bivalent eVLPs was approximately 10 fold less than monovalent E2-G eVLPs produced with the native Gag sequence (based on Gag ELISA). Also there appeared to be some cleavage of the Gag/NS3-NS4A protein by SDS-PAGE (figure 5), giving rise to a major band around 65kDa; however, the anti-Gag western blot in figure 6 clearly shows Gag/NS3-NS4A at the higher molecular weight, and no staining of a 65kD Gag sequence. Data not shown provided evidence for monovalent expression of E2-G with the native Gag sequence.

Other Embodiments

[0143] Other embodiments of the disclosure will be apparent to those skilled in the art from a consideration of the specification or practice of the disclosure disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope of the disclosure being indicated by the following claims. The contents of any reference that is referred to herein are hereby incorporated by reference in their entirety. SEQUENCE LISTING

MMLV Gag Amino Acid Sequence (SEP ID NO:l)

MGQTVTTPLSLTLGHWKJJVEPJAHNQSVDVKKRRWVTFCSAEWPTFNVGWPRDGTFN

RDLITQVKIKVFSPGPHGHPDQVPYIVTWEALAFDPPPWVKPFVHPKPPPPLPPSAPSLPL

EPPRSTPPRSSLYPALTPSLGAKPKPQVLSDSGGPLIDLLTEDPPPYRDPRPPPSDRDGNGG

EATPAGEAPDPSPMASRLRGRREPPVADSTTSQAFPLRAGGNGQLQYWPFSSSDLYNW

KNNNPSFSEDPGKLTALIESVLITHQPTWDDCQQLLGTLLTGEEKQRVLLEARKAVRGD

DGRPTQLPNEVDAAFPLERPDWDYTTQAGRNHLVHYRQLLLAGLQNAGRSPTNLAKV

KGITQGPNESPSAFLERLKEAYRRYTPYDPEDPGQETNVSMSFIWQSAPDIGRKLERLED

LKNKTLGDLVREAEKIFNKRETPEEREERIRRETEEKEERRRTEDEQKEKERDRRRHREM

SKLLATVVSGQKQDRQGGERRRSQLDRDQCAYCKEKGHWAKDCPKKPRGPRGPRPQT

SLLTLDD

MMLV Gag Nucleotide Sequence (SEP ID NO:2)

ATGGGCCAGACTGTTACCACTCCCTTAAGTTTGACCTTAGGTCACTGGAAAGATGTC

GAGCGGATCGCTCACAACCAGTCGGTAGATGTCAAGAAGAGACGTTGGGTTACCTT

CTGCTCTGCAGAATGGCCAACCTTTAACGTCGGATGGCCGCGAGACGGCACCTTTAA

CCGAGACCTCATCACCCAGGTTAAGATCAAGGTCTTTTCACCTGGCCCGCATGGACA

CCCAGACCAGGTCCCCTACATCGTGACCTGGGAAGCCTTGGCTTTTGACCCCCCTCC

CTGGGTCAAGCCCTTTGTACACCCTAAGCCTCCGCCTCCTCTTCCTCCATCCGCCCCG

TCTCTCCCCCTTGAACCTCCTCGTTCGACCCCGCCTCGATCCTCCCTTTATCCAGCCC

TCACTCCTTCTCTAGGCGCCAAACCTAAACCTCAAGTTCTTTCTGACAGTGGGGGGC

CGCTCATCGACCTACTTACAGAAGACCCCCCGCCTTATAGGGACCCAAGACCACCCC

CTTCCGACAGGGACGGAAATGGTGGAGAAGCGACCCCTGCGGGAGAGGCACCGGA

CCCCTCCCCAATGGCATCTCGCCTACGTGGGAGACGGGAGCCCCCTGTGGCCGACTC

CACTACCTCGCAGGCATTCCCCCTCCGCGCAGGAGGAAACGGACAGCTTCAATACT

GGCCGTTCTCCTCTTCTGACCTTTACAACTGGAAAAATAATAACCCTTCTTTTTCTGA

AGATCCAGGTAAACTGACAGCTCTGATCGAGTCTGTTCTCATCACCCATCAGCCCAC

CTGGGACGACTGTCAGCAGCTGTTGGGGACTCTGCTGACCGGAGAAGAAAAACAAC

GGGTGCTCTTAGAGGCTAGAAAGGCGGTGCGGGGCGATGATGGGCGCCCCACTCAA

CTGCCCAATGAAGTCGATGCCGCTTTTCCCCTCGAGCGCCCAGACTGGGATTACACC

ACCCAGGCAGGTAGGAACCACCTAGTCCACTATCGCCAGTTGCTCCTAGCGGGTCTC

CAAAACGCGGGCAGAAGCCCCACCAATTTGGCCAAGGTAAAAGGAATAACACAAG

GGCCCAATGAGTCTCCCTCGGCCTTCCTAGAGAGACTTAAGGAAGCCTATCGCAGGT

ACACTCCTTATGACCCTGAGGACCCAGGGCAAGAAACTAATGTGTCTATGTCTTTCA

TTTGGCAGTCTGCCCCAGACATTGGGAGAAAGTTAGAGAGGTTAGAAGATTTAAAA

AACAAGACGCTTGGAGATTTGGTTAGAGAGGCAGAAAAGATCTTTAATAAACGAGA

AACCCCGGAAGAAAGAGAGGAACGTATCAGGAGAGAAACAGAGGAAAAAGAAGA

ACGCCGTAGGACAGAGGATGAGCAGAAAGAGAAAGAAAGAGATCGTAGGAGACAT

AGAGAGATGAGCAAGCTATTGGCCACTGTCGTTAGTGGACAGAAACAGGATAGACA

GGGAGGAGAACGAAGGAGGTCCCAACTCGATCGCGACCAGTGTGCCTACTGCAAAG

AAAAGGGGCACTGGGCTAAAGATTGTCCCAAGAAACCACGAGGACCTCGGGGACC

AAGACCCCAGACCTCCCTCCTGACCCTAGATGAC Codon Optimized MMLV Gag Nucleotide Sequence (SEP ID NO:3)

ATGGGACAGACCGTCACAACACCCCTGAGCCTGACCCTGGGACATTGGAAAGACGT

GGAGAGGATCGCACATAACCAGAGCGTGGACGTGAAGAAACGGAGATGGGTCACA

TTCTGCAGTGCTGAGTGGCCAACTTTTAATGTGGGATGGCCCCGAGACGGCACTTTC

AACAGGGATCTGATCACCCAGGTGAAGATCAAGGTCTTTAGCCCAGGACCTCACGG

ACATCCAGACCAGGTGCCTTATATCGTCACCTGGGAGGCACTGGCCTTCGATCCCCC

TCCATGGGTGAAGCCATTTGTCCACCCAAAACCACCTCCACCACTGCCTCCAAGTGC

CCCTTCACTGCCACTGGAACCACCCCGGAGCACACCACCCCGCAGCTCCCTGTATCC

TGCTCTGACTCCATCTCTGGGCGCAAAGCCAAAACCACAGGTGCTGAGCGACTCCG

GAGGACCACTGATTGACCTGCTGACAGAGGACCCCCCACCATACCGAGATCCTCGG

CCTCCACCAAGCGACCGCGATGGAAATGGAGGAGAGGCTACTCCTGCCGGCGAAGC

CCCTGACCCATCTCCAATGGCTAGTAGGCTGCGCGGCAGGCGCGAGCCTCCAGTGG

CAGATAGCACCACATCCCAGGCCTTCCCTCTGAGGGCTGGGGGAAATGGGCAGCTC

CAGTATTGGCCATTTTCTAGTTCAGACCTGTACAACTGGAAGAACAATAACCCCTCT

TTCAGTGAGGACCCCGGCAAACTGACCGCCCTGATCGAATCCGTGCTGATTACCCAT

CAGCCCACATGGGACGATTGTCAGCAGCTCCTGGGCACCCTGCTGACCGGAGAGGA

AAAGCAGCGCGTGCTGCTGGAGGCTCGCAAAGCAGTCCGAGGGGACGATGGACGG

CCCACACAGCTCCCTAATGAGGTGGACGCCGCTTTTCCACTGGAAAGACCCGACTGG

GATTATACTACCCAGGCAGGGAGAAACCACCTGGTCCATTACAGGCAGCTCCTGCT

GGCAGGCCTGCAGAATGCCGGGAGATCCCCCACCAACCTGGCCAAGGTGAAAGGCA

TCACACAGGGGCCTAATGAGTCACCAAGCGCCTTTCTGGAGAGGCTGAAGGAAGCT

TACCGACGGTATACCCCATACGACCCTGAGGACCCCGGACAGGAAACAAACGTCTC

CATGTCTTTCATCTGGCAGTCTGCCCCAGACATTGGGCGGAAGCTGGAGAGACTGGA

AGACCTGAAGAACAAGACCCTGGGCGACCTGGTGCGGGAGGCTGAAAAGATCTTCA

ACAAACGGGAGACCCCCGAGGAAAGAGAGGAAAGGATTAGAAGGGAAACTGAGGA

AAAGGAGGAACGCCGACGGACCGAGGACGAACAGAAGGAGAAAGAACGAGATCG

GCGGCGGCACCGGGAGATGTCAAAGCTGCTGGCCACCGTGGTCAGCGGACAGAAAC

AGGACAGACAGGGAGGAGAGCGACGGAGAAGCCAGCTCGACAGGGATCAGTGCGC

ATACTGTAAGGAAAAAGGCCATTGGGCCAAGGATTGCCCCAAAAAGCCAAGAGGAC

CAAGAGGACCAAGACCACAGACATCACTGCTGACCCTGGACGAC

E2-G Amino Acid Sequence (SEP ID NO:4)

MGYIPVVGAPLSGAARAVAHGVRVLEDGVNYATGNLPGFPFSIFLLALLSCITVPVSAGT

TTVGGAVARSTNVIAGVFSHGPQQNIQLINTNGSWHINRTALNCNDSLNTGFLAALFYT

NRFNSSGCPGRLSACRNIEAFRIGWGTLQYEDNVTNPEDMRPYCWHYPPKPCGVVPARS

VCGPVYCFTPSPVVVGTTDRRGVPTYTWGENETDVFLLNSTRPPQGSWFGCTWMNSTG

FTKTCGAPPCRTRADFNASTDLLCPTDCFRKHPDATYIKCGSGPWLTPKCLVHYPYRLW

HYPCTVNFTIFKIRMYVGGVEHRLTAACNFTRGDRCDLEDRDRSQLSPFFFIIGLIIGLFLV

LRVGIHLCIKLKHTKKRQIYTDIEMNRLGK* E2-G Nucleotide Sequence (SEP ID NO:5)

ATGGGGTACATCCCCGTCGTAGGCGCCCCGCTTAGTGGCGCCGCCAGAGCTGTCGCG

CACGGCGTGAGAGTCCTGGAGGACGGGGTTAATTATGCAACAGGGAACCTACCCGG

TTTCCCCTTTTCTATCTTCTTGCTGGCCCTGTTGTCCTGCATCACCGTTCCGGTCTCTG

CTGGCACCACCACCGTTGGAGGCGCTGTTGCACGTTCCACCAACGTGATTGCCGGCG

TGTTCAGCCATGGCCCTCAGCAGAACATTCAGCTCATTAACACCAACGGCAGTTGGC

ACATCAACCGTACTGCCTTGAATTGCAATGACTCCTTGAACACCGGCTTTCTCGCGG

CCTTGTTCTACACCAACCGCTTTAACTCGTCAGGGTGTCCAGGGCGCCTGTCCGCCT

GCCGCAACATCGAGGCTTTCCGGATAGGGTGGGGCACCCTACAGTACGAGGATAAT

GTCACCAATCCAGAGGATATGAGGCCGTACTGCTGGCACTACCCCCCAAAGCCGTG

TGGCGTAGTCCCCGCGAGGTCTGTGTGTGGCCCAGTGTACTGTTTCACCCCCAGCCC

GGTAGTAGTGGGCACGACCGACAGACGTGGAGTGCCCACCTACACATGGGGAGAGA

ATGAGACAGATGTCTTCCTACTGAACAGCACCCGACCGCCGCAGGGCTCATGGTTCG

GCTGCACGTGGATGAACTCCACTGGTTTCACCAAGACTTGTGGCGCGCCACCTTGCC

GCACCAGAGCTGACTTCAACGCCAGCACGGACTTGTTGTGCCCTACGGATTGTTTTA

GGAAGCATCCTGATGCCACTTATATTAAGTGTGGTTCTGGGCCCTGGCTCACACCAA

AGTGCCTGGTCCACTACCCTTACAGACTCTGGCATTACCCCTGCACAGTCAATTTTA

CCATCTTCAAGATAAGAATGTATGTAGGGGGGGTTGAGCACAGGCTCACGGCCGCA

TGCAACTTCACTCGTGGGGATCGCTGCGACTTGGAGGACAGGGACAGGAGTCAGCT

GTCTCCTTTTTTCTTTATCATAGGGTTAATCATTGGACTATTCTTGGTTCTCCGAGTTG

GTATCCATCTTTGCATTAAATTAAAGCACACCAAGAAAAGACAGATTTATACAGACA

TAGAGATGAACCGACTTGGAAAGTAA

Codon Optimized E2-G Nucleotide Sequence (SEP ID NP:6)

ATGGGCTACATCCCTGTCGTCGGGGCACCACTGTCTGGGGCTGCACGGGCTGTCGCA

CACGGGGTCCGGGTCCTGGAAGATGGAGTCAACTACGCCACCGGGAATCTGCCAGG

ATTTCCCTTCTCCATCTTCCTGCTGGCTCTGCTGTCATGCATTACAGTCCCTGTGAGC

GCAGGCACCACAACTGTCGGAGGGGCTGTGGCAAGGAGTACCAACGTCATCGCCGG

GGTGTTTTCACACGGACCACAGCAGAATATCCAGCTCATCAACACCAATGGCTCTTG

GCATATTAACCGCACAGCTCTGAACTGTAATGATAGTCTGAATACTGGGTTTCTGGC

CGCTCTGTTCTACACCAACCGGTTCAACAGCAGCGGATGCCCCGGCAGACTGTCTGC

ATGTCGAAACATCGAGGCCTTCCGCATTGGGTGGGGAACTCTGCAGTATGAGGATA

ACGTGACCAATCCCGAAGACATGAGGCCTTACTGCTGGCACTATCCACCTAAGCCAT

GTGGAGTGGTCCCCGCACGCAGCGTCTGCGGACCAGTGTACTGTTTCACACCCTCCC

CTGTGGTCGTGGGCACCACAGATCGGAGAGGGGTGCCCACTTATACCTGGGGCGAG

AACGAAACAGACGTGTTCCTGCTGAACAGCACTAGGCCACCCCAGGGCTCTTGGTTC

GGGTGCACTTGGATGAACTCAACCGGCTTCACCAAAACTTGCGGCGCACCTCCATGT

AGGACCCGCGCCGACTTCAATGCTAGTACAGATCTGCTGTGCCCCACTGACTGTTTT

CGGAAGCATCCTGACGCTACATATATCAAATGCGGCAGCGGGCCTTGGCTGACTCC

AAAGTGTCTGGTGCACTACCCTTATAGACTGTGGCATTACCCATGCACCGTGAACTT

TACAATCTTCAAAATCCGGATGTACGTCGGAGGCGTGGAGCACAGACTGACCGCAG

CCTGCAATTTCACAAGAGGCGACAGGTGTGATCTGGAAGACCGAGATCGGTCTCAG

CTCAGTCCTTTCTTTTTCATCATTGGACTGATCATTGGCCTGTTTCTGGTCCTGAGAG TGGGCATCCACCTGTGCATTAAGCTGAAACATACCAAAAAACGACAGATCTACACC GACATCGAAATGAACAGACTGGGCAAATAA

Gag/NS3-NS4 Amino Acid Sequence (SEP ID NO:7)

MGQTVTTPLSLTLGHWKOVEPJAHNQSVDVKKRRWVTFCSAEWPTFNVGWPRDGTFN

RDLITQVKIKVFSPGPHGHPDQVPYIVTWEALAFDPPPWVKPFVHPKPPPPLPPSAPSLPL

EPPRSTPPRSSLYPALTPSLGAKPKPQVLSDSGGPLIDLLTEDPPPYRDPRPPPSDRDGNGG

EATPAGEAPDPSPMASRLRGRREPPVADSTTSQAFPLRAGGNGQLQYWPFSSSDLYNW

KNNNPSFSEDPGKLTALIESVLITHQPTWDDCQQLLGTLLTGEEKQRVLLEARKAVRGD

DGRPTQLPNEVDAAFPLERPDWDYTTQAGRNHLVHYRQLLLAGLQNAGRSPTNLAKV

KGITQGPNESPSAFLERLKEAYRRYTPYDPEDPGQETNVSMSFIWQSAPDIGRKLERLED

LK KTLGDLVREAEKIFNKRETPEEREERIRRETEEKEERRRTEDEQKEKERDRRRHREM

SKLLATVVSGQKQDRQGGERRRSQLDRDQCAYCKEKGHWAKDCPKKPRGPRGPRPQT

SLLTLDDPAVPQTYQVGYLHAPTGSGKSTKVPVAYAAQGYKVLVLNPSVAATLGFGAY

LSKAHGINPNIRTGVRTVMTGEAITYSTYGKFLADGGCASGAYDIIICDECHAVDATSILG

IGTVLDQAETAGVRLTVLATATPPGSVTTPHPDIEEVGLGREGEIPFYGRAIPLSCIKGGR

HLIFCHSKK CDELAAALRGMGLNAVAYYRGLDVSIIPAQGDVVVVATDALMTGYTG

DFDSVIDCNVAVTQAVDFSLDPTFTITTQTVPQDAVSRSQRRGRTGRGRQGTYRYVSTG

ERASGMFDSVVLCECYDAGAAWYDLTPAETTVRLRAYFNTPGLPVCQDHLEFWEAVF

TGLTHIDAHFLSQTKQAGENFAYLVAYQATVCARAKAPPPSWDAMWKCLARLKPTLA

GPTPLLYRLGPITNEVTLTHPGTKYIATCMQADLEVMTSTWVLAGGVLAAVAAYCLAT

GCVSIIGRLHVNQRVVVAPDKEVLYEAFDEMEEC*

Gag/NS3-NS4 Nucleotide Sequence (SEP ID NO:8)

ATGGGCCAGACTGTTACCACTCCCTTAAGTTTGACCTTAGGTCACTGGAAAGATGTC

GAGCGGATCGCTCACAACCAGTCGGTAGATGTCAAGAAGAGACGTTGGGTTACCTT

CTGCTCTGCAGAATGGCCAACCTTTAACGTCGGATGGCCGCGAGACGGCACCTTTAA

CCGAGACCTCATCACCCAGGTTAAGATCAAGGTCTTTTCACCTGGCCCGCATGGACA

CCCAGACCAGGTCCCCTACATCGTGACCTGGGAAGCCTTGGCTTTTGACCCCCCTCC

CTGGGTCAAGCCCTTTGTACACCCTAAGCCTCCGCCTCCTCTTCCTCCATCCGCCCCG

TCTCTCCCCCTTGAACCTCCTCGTTCGACCCCGCCTCGATCCTCCCTTTATCCAGCCC

TCACTCCTTCTCTAGGCGCCAAACCTAAACCTCAAGTTCTTTCTGACAGTGGGGGGC

CGCTCATCGACCTACTTACAGAAGACCCCCCGCCTTATAGGGACCCAAGACCACCCC

CTTCCGACAGGGACGGAAATGGTGGAGAAGCGACCCCTGCGGGAGAGGCACCGGA

CCCCTCCCCAATGGCATCTCGCCTACGTGGGAGACGGGAGCCCCCTGTGGCCGACTC

CACTACCTCGCAGGCATTCCCCCTCCGCGCAGGAGGAAACGGACAGCTTCAATACT

GGCCGTTCTCCTCTTCTGACCTTTACAACTGGAAAAATAATAACCCTTCTTTTTCTGA

AGATCCAGGTAAACTGACAGCTCTGATCGAGTCTGTTCTCATCACCCATCAGCCCAC

CTGGGACGACTGTCAGCAGCTGTTGGGGACTCTGCTGACCGGAGAAGAAAAACAAC

GGGTGCTCTTAGAGGCTAGAAAGGCGGTGCGGGGCGATGATGGGCGCCCCACTCAA

CTGCCCAATGAAGTCGATGCCGCTTTTCCCCTCGAGCGCCCAGACTGGGATTACACC

ACCCAGGCAGGTAGGAACCACCTAGTCCACTATCGCCAGTTGCTCCTAGCGGGTCTC CAAAACGCGGGCAGAAGCCCCACCAATTTGGCCAAGGTAAAAGGAATAACACAAG

GGCCCAATGAGTCTCCCTCGGCCTTCCTAGAGAGACTTAAGGAAGCCTATCGCAGGT

ACACTCCTTATGACCCTGAGGACCCAGGGCAAGAAACTAATGTGTCTATGTCTTTCA

TTTGGCAGTCTGCCCCAGACATTGGGAGAAAGTTAGAGAGGTTAGAAGATTTAAAA

AACAAGACGCTTGGAGATTTGGTTAGAGAGGCAGAAAAGATCTTTAATAAACGAGA

AACCCCGGAAGAAAGAGAGGAACGTATCAGGAGAGAAACAGAGGAAAAAGAAGA

ACGCCGTAGGACAGAGGATGAGCAGAAAGAGAAAGAAAGAGATCGTAGGAGACAT

AGAGAGATGAGCAAGCTATTGGCCACTGTCGTTAGTGGACAGAAACAGGATAGACA

GGGAGGAGAACGAAGGAGGTCCCAACTCGATCGCGACCAGTGTGCCTACTGCAAAG

AAAAGGGGCACTGGGCTAAAGATTGTCCCAAGAAACCACGAGGACCTCGGGGACC

AAGACCCCAGACCTCCCTCCTGACCCTAGATGACCCGGCTGTGCCCCAGACCTATCA

GGTCGGGTACTTGCATGCTCCAACTGGCAGTGGAAAGAGCACCAAGGTCCCTGTCG

CGTATGCCGCCCAGGGGTACAAAGTACTAGTGCTTAACCCCTCGGTAGCTGCCACCC

TGGGGTTTGGGGCGTACCTATCCAAGGCACATGGCATCAATCCCAACATTAGGACTG

GAGTCAGGACCGTGATGACCGGGGAGGCCATCACGTACTCCACATATGGCAAATTT

CTCGCCGATGGGGGCTGCGCTAGCGGCGCCTATGACATCATCATATGCGATGAATGC

CACGCTGTGGATGCTACCTCCATTCTCGGCATCGGAACGGTCCTTGATCAAGCAGAG

ACAGCCGGGGTCAGACTAACTGTGCTGGCTACGGCCACACCCCCCGGGTCAGTGAC

AACCCCCCATCCCGATATAGAAGAGGTAGGCCTCGGGCGGGAGGGTGAGATCCCCT

TCTATGGGAGGGCGATTCCCCTATCCTGCATCAAGGGAGGGAGACACCTGATTTTCT

GCCACTCAAAGAAAAAGTGTGACGAGCTCGCGGCGGCCCTTCGGGGCATGGGCTTG

AATGCCGTGGCATACTATAGAGGGTTGGACGTCTCCATAATACCAGCTCAGGGAGA

TGTGGTGGTCGTCGCCACCGACGCCCTCATGACGGGGTACACTGGAGACTTTGACTC

CGTGATCGACTGCAATGTAGCGGTCACCCAAGCTGTCGACTTCAGCCTGGACCCCAC

CTTCACTATAACCACACAGACTGTCCCACAAGACGCTGTCTCACGCAGTCAGCGCCG

CGGGCGCACAGGTAGAGGAAGACAGGGCACTTATAGGTATGTTTCCACTGGTGAAC

GAGCCTCAGGAATGTTTGACAGTGTAGTGCTTTGTGAGTGCTACGACGCAGGGGCTG

CGTGGTACGATCTCACACCAGCGGAGACCACCGTCAGGCTTAGAGCGTATTTCAAC

ACGCCCGGCCTACCCGTGTGTCAAGACCATCTTGAATTTTGGGAGGCAGTTTTCACC

GGCCTCACACACATAGACGCCCACTTCCTCTCCCAAACAAAGCAAGCGGGGGAGAA

CTTCGCGTACCTAGTAGCCTACCAAGCTACGGTGTGCGCCAGAGCCAAGGCCCCTCC

CCCGTCCTGGGACGCCATGTGGAAGTGCCTGGCCCGACTCAAGCCTACGCTTGCGGG

CCCCACACCTCTCCTGTACCGTTTGGGCCCTATTACCAATGAGGTCACCCTCACACA

CCCTGGGACGAAGTACATCGCCACATGCATGCAAGCTGACCTTGAGGTCATGACCA

GCACGTGGGTCCTAGCTGGAGGAGTCCTGGCAGCCGTCGCCGCATATTGCCTGGCG

ACTGGATGCGTTTCCATCATCGGCCGCTTGCACGTCAACCAGCGAGTCGTCGTTGCG

CCGGATAAGGAGGTCCTGTATGAGGCTTTTGATGAGATGGAGGAATGCTAA

Codon Optimized Gag/NS3-NS4 Nucleotide Sequence (SEP ID NO:9)

ATGGGGCAGACCGTGACTACACCACTGTCCCTGACCCTGGGGCATTGGAAGGATGT

CGAAAGGATTGCTCATAACCAGAGCGTGGATGTGAAGAAACGGAGATGGGTCACAT

TCTGCAGTGCCGAGTGGCCAACTTTTAATGTGGGATGGCCCCGGGACGGGACCTTCA

ACAGAGATCTGATTACACAGGTGAAAATCAAGGTCTTTAGCCCAGGACCACACGGA

CATCCAGACCAGGTGCCTTACATTGTCACCTGGGAGGCCCTGGCTTTCGATCCCCCT CCATGGGTGAAACCATTTGTCCACCCAAAGCCACCTCCACCACTGCCTCCAAGCGCC

CCCTCCCTGCCTCTGGAACCACCTCGCAGTACACCACCCCGAAGCTCCCTGTATCCT

GCACTGACTCCAAGCCTGGGGGCCAAACCTAAGCCACAGGTGCTGAGCGACTCCGG

AGGACCACTGATCGACCTGCTGACCGAGGACCCCCCACCATACCGGGACCCCCGGC

CCCCACCCAGCGACAGGGATGGAAATGGAGGAGAGGCAACACCTGCCGGCGAAGC

ACCCGACCCTTCCCCAATGGCATCTCGACTGCGGGGAAGGCGCGAACCTCCAGTGG

CAGATTCTACCACAAGTCAGGCATTCCCACTGCGAGCAGGAGGAAATGGACAGCTC

CAGTATTGGCCTTTTTCTAGTTCAGACCTGTACAACTGGAAAAACAATAACCCCTCT

TTCAGTGAGGACCCCGGCAAGCTGACCGCCCTGATTGAATCCGTGCTGATCACACAC

CAGCCCACTTGGGACGATTGCCAGCAGCTCCTGGGCACCCTGCTGACCGGCGAGGA

AAAACAGAGGGTGCTGCTGGAGGCAAGGAAGGCTGTCCGCGGGGACGATGGACGC

CCCACCCAGCTCCCTAATGAGGTGGACGCCGCTTTTCCACTGGAAAGACCCGACTGG

GATTATACTACCCAGGCCGGCAGAAACCACCTGGTGCATTACAGACAGCTCCTGCTG

GCTGGGCTGCAGAATGCAGGACGGAGCCCCACCAACCTGGCCAAAGTGAAGGGGAT

CACACAGGGACCTAATGAGTCACCAAGCGCCTTCCTGGAGCGGCTGAAGGAAGCAT

ACCGACGGTATACCCCATACGACCCAGAGGACCCCGGACAGGAAACAAACGTGTCC

ATGTCTTTCATTTGGCAGAGCGCCCCCGACATCGGACGAAAGCTGGAGCGGCTGGA

AGACCTGAAAAATAAGACTCTGGGCGATCTGGTGCGGGAGGCCGAAAAAATTTTCA

ACAAGAGAGAGACCCCTGAGGAAAGGGAGGAACGCATCAGAAGGGAAACTGAGGA

AAAGGAGGAACGCCGACGGACCGAGGACGAACAGAAAGAGAAGGAAAGGGATCG

GCGGCGGCACCGGGAGATGAGCAAACTGCTGGCCACCGTGGTCTCCGGACAGAAGC

AGGACAGGCAGGGAGGAGAGCGACGGAGATCCCAGCTCGACCGCGATCAGTGCGC

ATACTGTAAAGAAAAGGGCCACTGGGCCAAGGATTGCCCAAAGAAACCCCGAGGCC

CTCGGGGGCCCAGACCTCAGACCTCTCTGCTGACACTGGACGATCCCGCCGTGCCCC

AGACCTATCAGGTCGGCTACCTGCATGCCCCCACCGGATCAGGCAAAAGCACAAAG

GTGCCTGTCGCCTATGCAGCCCAGGGGTACAAAGTGCTGGTCCTGAACCCTTCTGTG

GCTGCAACACTGGGGTTTGGAGCCTATCTGAGTAAGGCTCATGGCATTAATCCAAAC

ATCAGAACTGGCGTGAGGACTGTCATGACCGGGGAGGCCATCACATATTCAACTTA

CGGGAAGTTCCTGGCTGACGGAGGCTGTGCAAGCGGAGCCTACGACATCATTATCT

GCGATGAGTGTCACGCTGTGGACGCAACTTCAATTCTGGGCATCGGGACCGTGCTGG

ATCAGGCCGAAACTGCTGGCGTGCGGCTGACCGTCCTGGCAACAGCAACTCCCCCT

GGGAGCGTGACAACTCCACATCCCGATATTGAGGAAGTCGGACTGGGCAGGGAGGG

AGAAATCCCTTTTTATGGCCGCGCCATTCCACTGTCCTGCATCAAGGGGGGAAGACA

CCTGATCTTCTGCCATTCTAAGAAAAAGTGTGACGAGCTGGCCGCTGCACTGCGAGG

AATGGGACTGAATGCTGTGGCATACTATAGAGGACTGGATGTCTCCATTATCCCAGC

ACAGGGCGACGTGGTCGTGGTCGCAACCGATGCCCTGATGACCGGATACACAGGCG

ACTTCGATAGCGTGATTGACTGTAACGTGGCCGTCACACAGGCTGTGGACTTCAGCC

TGGACCCCACCTTCACCATCACCACACAGACAGTGCCCCAGGATGCCGTCAGTCGAT

CACAGAGGCGCGGAAGAACTGGCAGAGGGAGGCAGGGCACATACAGATACGTGAG

CACTGGCGAGCGCGCTAGTGGGATGTTTGACTCAGTGGTCCTGTGCGAATGTTATGA

CGCCGGAGCCGCTTGGTACGATCTGACTCCTGCCGAGACTACCGTGCGCCTGCGAGC

TTATTTCAATACCCCTGGACTGCCAGTGTGCCAGGACCACCTGGAGTTCTGGGAAGC

CGTGTTCACCGGGCTGACCCACATCGATGCACATTTCCTGTCCCAGACCAAACAGGC

AGGAGAGAACTTTGCCTATCTGGTGGCTTACCAGGCAACAGTCTGCGCCAGGGCTA

AGGCACCACCCCCTTCTTGGGACGCCATGTGGAAATGTCTGGCTCGGCTGAAGCCCA

CTCTGGCCGGACCTACCCCACTGCTGTATAGACTGGGGCCTATTACCAATGAAGTGA CTCTGACCCACCCAGGCACAAAGTACATCGCTACTTGTATGCAGGCAGATCTGGAA

GTGATGACATCTACTTGGGTCCTGGCTGGAGGGGTGCTGGCAGCCGTCGCTGCATAC

TGCCTGGCCACAGGGTGCGTGAGCATTATCGGAAGGCTGCATGTGAACCAGCGCGT

CGTCGTCGCCCCCGATAAAGAGGTGCTGTATGAGGCATTTGATGAGATGGAGGAGT

GCTGA

Propol II Expression Plasmid (SEP ID NO: 10)

CTAGAGAGCTTGGCCCATTGCATACGTTGTATCCATATCATAATATGTACATTTATAT

TGGCTCATGTCCAACATTACCGCCATGTTGACATTGATTATTGACTAGTTATTAATAG

TAATCAATTACGGGGTCATTAGTTCATAGCCCATATATGGAGTTCCGCGTTACATAA

CTTACGGTAAATGGCCCGCCTGGCTGACCGCCCAACGACCCCCGCCCATTGACGTCA

ATAATGACGTATGTTCCCATAGTAACGCCAATAGGGACTTTCCATTGACGTCAATGG

GTGGAGTATTTACGGTAAACTGCCCACTTGGCAGTACATCAAGTGTATCATATGCCA

AGTACGCCCCCTATTGACGTCAATGACGGTAAATGGCCCGCCTGGCATTATGCCCAG

TACATGACCTTATGGGACTTTCCTACTTGGCAGTACATCTACGTATTAGTCATCGCTA

TTACCATGGTGATGCGGTTTTGGCAGTACATCAATGGGCGTGGATAGCGGTTTGACT

CACGGGGATTTCCAAGTCTCCACCCCATTGACGTCAATGGGAGTTTGTTTTGGCACC

AAAATCAACGGGACTTTCCAAAATGTCGTAACAACTCCGCCCCATTGACGCAAATG

GGCGGTAGGCGTGTACGGTGGGAGGTCTATATAAGCAGAGCTCGTTTAGTGAACCG

TCAGATCGCCTGGAGACGCCATCCACGCTGTTTTGACCTCCATAGAAGACACCGGGA

CCGATCCAGCCTCCGGTCGACCGATCCTGAGAACTTCAGGGTGAGTTTGGGGACCCT

TGATTGTTCTTTCTTTTTCGCTATTGTAAAATTCATGTTATATGGAGGGGGCAAAGTT

TTCAGGGTGTTGTTTAGAATGGGAAGATGTCCCTTGTATCACCATGGACCCTCATGA

TAATTTTGTTTCTTTCACTTTCTACTCTGTTGACAACCATTGTCTCCTCTTATTTTCTTT

TCATTTTCTTGTAACTTTTTCGTTAAACTTTAGCTTGCATTTGTAACGAATTTTTAAAT

TCACTTTTGTTTATTTGTCAGATTGTAAGTACTTTCTCTAATCACTTTTTTTTCAAGGC

AATCAGGGTATATTATATTGTACTTCAGCACAGTTTTAGAGAACAATTGTTATAATT

AAATGATAAGGTAGAATATTTCTGCATATAAATTCTGGCTGGCGTGGAAATATTCTT

ATTGGTAGAAACAACTACATCCTGGTCATCATCCTGCCTTTCTCTTTATGGTTACAAT

GATATACACTGTTTGAGATGAGGATAAAATACTCTGAGTCCAAACCGGGCCCCTCTG

CTAACCATGTTCATGCCTTCTTCTTTTTCCTACAGCTCCTGGGCAACGTGCTGGTTAT

TGTGCTGTCTCATCATTTTGGCAAAGAATTCCTCGAGCGTACGCCTAGGGGATCCAG

CGCTATTTAAATGCTAGCATGCATGTTAACCCTGCAGGGGTACCGCGGCCGCAAGCT

TAGATCCGTCGAGGAATTCACTCCTCAGGTGCAGGCTGCCTATCAGAAGGTGGTGGC

TGGTGTGGCCAATGCCCTGGCTCACAAATACCACTGAGATCTTTTTCCCTCTGCCAA

AAATTATGGGGACATCATGAAGCCCCTTGAGCATCTGACTTCTGGCTAATAAAGGAA

ATTTATTTTCATTGCAATAGTGTGTTGGAATTTTTTGTGTCTCTCACTCGGAAGGACA

TATGGGAGGGCAAATCATTTAAAACATCAGAATGAGTATTTGGTTTAGAGTTTGGCA

ACATATGCCCATATGCTGGCTGCCATGAACAAAGGTTGGCTATAAAGAGGTCATCA

GTATATGAAACAGCCCCCTGCTGTCCATTCCTTATTCCATAGAAAAGCCTTGACTTG

AGGTTAGATTTTTTTTATATTTTGTTTTGTGTTATTTTTTTCTTTAACATCCCTAAAAT

TTTCCTTACATGTTTTACTAGCCAGATTTTTCCTCCTCTCCTGACTACTCCCAGTCATA

GCTGTCCCTCTTCTCTTATGGAGATCCCTCGACGGATCGGCCGCAATTCGTAATCATG

TCATAGCTGTTTCCTGTGTGAAATTGTTATCCGCTCACAATTCCACACAACATACGA GCCGGAAGCATAAAGTGTAAAGCCTGGGGTGCCTAATGAGTGAGCTAACTCACATT

AATTGCGTTGCGCTCACTGCCCGCTTTCCAGTCGGGAAACCTGTCGTGCCAGCTGCA

TTAATGAATCGGCCAACGCGCGGGGAGAGGCGGTTTGCGTATTGGGCGCTCTTCCGC

TTCCTCGCTCACTGACTCGCTGCGCTCGGTCGTTCGGCTGCGGCGAGCGGTATCAGC

TC ACTC AAAGGC GGT AAT AC GGTT ATC C AC AG AATC AGGGG AT AAC GC AGG A AAG A

ACATGTGAGCAAAAGGCCAGCAAAAGGCCAGGAACCGTAAAAAGGCCGCGTTGCT

GGCGTTTTTCCATAGGCTCCGCCCCCCTGACGAGCATCACAAAAATCGACGCTCAAG

TCAGAGGTGGCGAAACCCGACAGGACTATAAAGATACCAGGCGTTTCCCCCTGGAA

GCTCCCTCGTGCGCTCTCCTGTTCCGACCCTGCCGCTTACCGGATACCTGTCCGCCTT

TCTCCCTTCGGGAAGCGTGGCGCTTTCTCATAGCTCACGCTGTAGGTATCTCAGTTCG

GTGTAGGTCGTTCGCTCCAAGCTGGGCTGTGTGCACGAACCCCCCGTTCAGCCCGAC

CGCTGCGCCTTATCCGGTAACTATCGTCTTGAGTCCAACCCGGTAAGACACGACTTA

TCGCCACTGGCAGCAGCCACTGGTAACAGGATTAGCAGAGCGAGGTATGTAGGCGG

TGCTACAGAGTTCTTGAAGTGGTGGCCTAACTACGGCTACACTAGAAGAACAGTATT

TGGTATCTGCGCTCTGCTGAAGCCAGTTACCTTCGGAAAAAGAGTTGGTAGCTCTTG

ATCCGGCAAACAAACCACCGCTGGTAGCGGTGGTTTTTTTGTTTGCAAGCAGCAGAT

TACGCGCAGAAAAAAAGGATCTCAAGAAGATCCTTTGATCTTTTCTACGGGGTCTGA

CGCTCAGTGGAACGAAAACTCACGTTAAGGGATTTTGGTCATGAGATTATCAAAAA

GGATCTTCACCTAGATCCTTTTAAATTAAAAATGAAGTTTTAAATCAATCTAAAGTA

TATATGAGTAAACTTGGTCTGACAGTTACCAATGCTTAATCAGTGAGGCACCTATCT

CAGCGATCTGTCTATTTCGTTCATCCATAGTTGCCTGACTCCCCGTCGTGTAGATAAC

TACGATACGGGAGGGCTTACCATCTGGCCCCAGTGCTGCAATGATACCGCGAGACC

CACGCTCACCGGCTCCAGATTTATCAGCAATAAACCAGCCAGCCGGAAGGGCCGAG

CGCAGAAGTGGTCCTGCAACTTTATCCGCCTCCATCCAGTCTATTAATTGTTGCCGG

GAAGCTAGAGTAAGTAGTTCGCCAGTTAATAGTTTGCGCAACGTTGTTGCCATTGCT

ACAGGCATCGTGGTGTCACGCTCGTCGTTTGGTATGGCTTCATTCAGCTCCGGTTCCC

AACGATCAAGGCGAGTTACATGATCCCCCATGTTGTGCAAAAAAGCGGGTTAGCTC

CTTCGGTCCTCCGATCGTTGTCAGAAGTAAGTTGGCCGCAGTGTTATCACTCATGGTT

ATGGCAGCACTGCATAATTCTCTTACTGTCATGCCATCCGTAAGATGCTTTTCTGTGA

CTGGTGAGTACTCAACCAAGTCATTCTGAGAATAGTGTATGCGGCGACCGAGTTGCT

CTTGCCCGGCGTCAATACGGGATAATACCGCGCCACATAGCAGAACTTTAAAAGTG

CTCATCATTGGAAAACGTTCTTCGGGGCGAAAACTCTCAAGGATCTTACCGCTGTTG

AGATCCAGTTCGATGTAACCCACTCGTGCACCCAACTGATCTTCAGCATCTTTTACTT

TCACCAGCGTTTCTGGGTGAGCAAAAACAGGAAGGCAAAATGCCGCAAAAAAGGG

AATAAGGGCGACACGGAAATGTTGAATACTCATACTCTTCCTTTTTCAATATTATTG

AAGCATTTATCAGGGTTATTGTCTCATGAGCGGATACATATTTGAATGTATTTAGAA

AAATAAACAAATAGGGGTTCCGCGCACATTTCCCCGAAAAGTGCCACCTAAATTGT

AAGCGTTAATATTTTGTTAAAATTCGCGTTAAATTTTTGTTAAATCAGCTCATTTTTT

AACCAATAGGCCGAAATCGGCAAAATCCCTTATAAATCAAAAGAATAGACCGAGAT

AGGGTTGAGTGTTGTTCCAGTTTGGAACAAGAGTCCACTATTAAAGAACGTGGACTC

CAACGTCAAAGGGCGAAAAACCGTCTATCAGGGCGATGGCCCACTACGTGAACCAT

CACCCTAATCAAGTTTTTTGGGGTCGAGGTGCCGTAAAGCACTAAATCGGAACCCTA

AAGGGAGCCCCCGATTTAGAGCTTGACGGGGAAAGCCGGCGAACGTGGCGAGAAA

GGAAGGGAAGAAAGCGAAAGGAGCGGGCGCTAGGGCGCTGGCAAGTGTAGCGGTC

ACGCTGCGCGTAACCACCACACCCGCCGCGCTTAATGCGCCGCTACAGGGCGCGTC

CCATTCGCCATTCAGGCTGCGCAACTGTTGGGAAGGGCGATCGGTGCGGGCCTCTTC GCTATTACGCCAGCTGGCGAAAGGGGGATGTGCTGCAAGGCGATTAAGTTGGGTAA CGCCAGGGTTTTCCCAGTCACGACGTTGTAAAACGACGGCCAGTGAGCGCGCGTAA TACGACTCACTATAGGGCGAATTGGAGCTCCACCGCGGTGGCGGCCGCT

Claims

Claims What is claimed is:

1. A virus-like particle (VLP) comprising:

a retroviral gag polypeptide comprising at least 100, 200, 300 or more amino acids that are at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99% or 100% identical to a self-assembling portion of a reference gag protein, wherein the reference gag protein comprises the amino acid sequence of SEQ ID NO: l; and

a hepatitis C virus (HCV) E2 polypeptide, or a portion thereof, that induces an immune response.

2. The VLP of claim 1, wherein the E2 polypeptide comprises an extracellular domain, a transmembrane domain, and a cytoplasmic domain.

3. The VLP of claim 2, wherein the extracellular domain comprises or consists of amino acid residues 59-343 of SEQ ID NO:4.

4. The VLP of claim 3, wherein the transmembrane domain, the cytoplasmic domain, or both, is not found in nature in the E2 protein.

5. The VLP of claim 3, wherein the transmembrane domain, the cytoplasmic domain, or both, is found in nature in a vesicular stomatitis virus (VSV) protein.

6. The VLP of any one of claims 1-5, wherein the E2 polypeptide, or portion thereof, is fused to a heterologous polypeptide .

7. The VLP of any one of claims 1-6, wherein the E2 polypeptide comprises or consists of the amino acid sequence of SEQ ID NO:4, or a portion thereof.

The VLP of any one of claims 1-7, wherein the E2 polypeptide is positioned on the VLP

9. A virus-like particle (VLP) comprising:

a fusion protein comprising:

a) a retroviral gag polypeptide comprising at least 100, 200, 300 or more amino acids that are at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99% or 100% identical to a self-assembling portion of a reference gag protein, wherein the reference gag protein comprises the amino acid sequence of SEQ ID NO: l; b) a second polypeptide comprising or consisting of at least 100, 200, 300 or more amino acids that are at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99% or 100% identical to amino acid residues 539-978 of SEQ ID NO:7; and

c) a third polypeptide comprising or consisting of at least 10, 20, 30, 40 or more amino acids that are at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99% or 100% identical to amino acid residues 980-1033 of SEQ ID NO:7.

10. A virus-like particle (VLP) comprising:

a fusion protein comprising:

a) a retroviral gag polypeptide comprising at least 100, 200, 300 or more amino acids that are at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99% or 100% identical to a self-assembling portion of a reference gag protein, wherein the reference gag protein comprises the amino acid sequence of SEQ ID NO: l; and

b) a second polypeptide comprising or consisting of at least 100, 200, 300 or more amino acids that are at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99% or 100% identical to amino acid residues 539-1033 of SEQ ID NO:7.

11. The VLP of claim 9 or claim 10, wherein the fusion protein is arranged and constructed such that it self-assembles to form the VLP such that at least a portion of the second and third polypeptides are positioned in the VLP interior.

12. The VLP of any one of claims 9-11, wherein the fusion protein comprises or consists of the amino acid sequence of SEQ ID NO:7.

13. A virus-like particle (VLP) comprising:

a fusion protein comprising:

c) a third polypeptide comprising or consisting of at least 10, 20, 30, 40 or more amino acids that are at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99% or 100% identical to amino acid residues 980-1033 of SEQ ID NO:7; and an HCV E2 polypeptide, or portion thereof.

14. The VLP of claim 13, wherein the N-terminal portion of the gag protein does not comprise a C-terminal polymerase sequence found in MLV.

15. The VLP of claim 13 or claim 14, wherein the N-terminal portion of the gag protein comprises residues 1-538 of the full length protein.

16. The VLP of any one of claims 13-15, wherein the HCV E2 polypeptide comprises an extracellular domain, a transmembrane domain, and a cytoplasmic domain.

17. The VLP of claim 16, wherein the extracellular domain comprises or consists of amino acid residues 59-343 of SEQ ID NO:4.

18. The VLP of claim 16, wherein the transmembrane domain, the cytoplasmic domain, or both, is not found in nature in the E2 protein.

19. The VLP of claim 16, wherein the transmembrane domain, the cytoplasmic domain, or both, is found in nature in a vesicular stomatitis virus (VSV) protein.

20. The VLP of any one of claims 13-19, wherein the E2 polypeptide, or portion thereof, is fused to a heterologous polypeptide.

21. The VLP of any one of claims 13-20, wherein the E2 polypeptide comprises or consists of the amino acid sequence of SEQ ID NO:4, or a portion thereof.

22. The VLP of any one of claims 13-21, wherein the fusion protein comprises or consists of the amino acid sequence of SEQ ID NO:7, or a portion thereof.

23. The VLP of any one of claims 13-22, wherein the fusion protein is arranged and constructed such that it self-assembles to form the VLP such that at least a portion of the second and third polypeptides are positioned in the VLP interior.

24. The VLP of any one of claims 13-23, wherein the E2 polypeptide is positioned on the VLP surface.

25. A vector comprising :

a polynucleotide coding for a fusion protein, the fusion protein comprising:

an N-terminal portion of a retroviral gag protein;

an HCV NS3 polypeptide, or a portion thereof; and

an HCV NS4A polypeptide, or a portion thereof;

wherein the polynucleotide coding for the fusion protein is under the control of a single promoter; and

wherein the vector comprises a polyadenylation signal downstream of the polynucleotide coding for the fusion protein.

26. The vector of claim 25, wherein the N-terminal portion of the gag protein does not comprise a C-terminal polymerase sequence found in murine leukemia virus (MLV).

27. The vector of claim 25 or claim 26, wherein the N-terminal portion of the gag protein comprises residues 1-538 of the full length protein.

28. The vector of any one of claims 24-26, comprising or consisting of the nucleotide sequence of SEQ ID NO:8 or 9.

29. A vector comprising:

a polynucleotide coding for a fusion protein, the fusion protein comprising:

an extracellular region of an HCV E2 polypeptide;

a transmembrane domain of a VSV-G polypeptide; and

a cytoplasmic domain of a VSV-G polypeptide;

30. The vector of claim 29, wherein the extracellular region of the E2 polypeptide comprises or consists of amino acid residues 59-343 of SEQ ID NO:4.

31. The vector of claim 29 or claim 30, wherein the transmembrane and cytoplasmic domains comprise or consist of amino acid residues 344-387 of SEQ ID NO:4.

32. The vector of any one of claims 29-31 , comprising or consisting of the nucleotide sequence of SEQ ID NO:5 or 6.

33. The VLP of any one of claims 1-24, wherein the retroviral gag protein is a murine leukemia virus (MLV) gag polypeptide.

34. The vector of any one of claims 25-32, wherein the retroviral gag protein is a murine leukemia virus (MLV) gag polypeptide.

35. The VLP of any one of claims 1-24, wherein the VLP is characterized in that it has a diameter within a range bounded by a lower limit of 20, 30, 40, 50, 60, 70, 80, 90, or 100 nm and bounded by an upper limit of 300, 290, 280, 270, 260, 250, 240, 230, 220, 210, 200, 190, 180, or 170 nm.

36. A population of VLPs according to any one of claims 1-24, wherein the VLPs within the population show an average diameter within a range bounded by a lower limit of 20, 30, 40, 50, 60, 70, 80, 90, or 100 nm and bounded by an upper limit of 300, 290, 280, 270, 260, 250, 240, 230, 220, 210, 200, 190, 180, or 170 nm.

37. The population of VLPs according to claim 36, wherein the VLPs in the population have a polydispersity index that is less than 0.5.

38. The VLP of any one of claims 1-24, wherein the VLP is characterized in that the E2 polypeptide, or portion thereof, is exposed on the surface of the VLP and the Gag fusion protein is located in the tegument/lumen of the VLP.

39. An immunogenic composition comprising the VLP of any one of claims 1-24.

40. An immunogenic composition comprising the vector of any one of claims 25-32.

41. The immunogenic composition of claim 39 or claim 40, wherein the composition is characterized in that it induces both humoral and cellular immune responses when administered to a subject.

42. The immunogenic composition of claim 41, wherein the humoral immune response in a subject is sustained for at least about 1 month, at least about 2 months, at least about 3 months, at least about 4 months, at least about 5 months, at least about 6 months, at least about 7 months, at least about 8 months, at least about 9 months, at least about 10 months, at least about 11 months, or at least 12 months.

43. The immunogenic composition of claim 41, wherein the cellular immune response in a subject is sustained for at least about 1 month, at least about 2 months, at least about 3 months, at least about 4 months, at least about 5 months, at least about 6 months, at least about 7 months, at least about 8 months, at least about 9 months, at least about 10 months, at least about 11 months, or at least 12 months.

44. A cell comprising one or more vectors of any one of claims 25-32.

45. The cell of claim 44, wherein the cell is transiently transfected with one or more of the vectors.

46. The cell of claim 44, wherein the cell is stably transfected with one or more of the vectors.

47. A pharmaceutical composition comprising the VLP of any one of claims 1-24 and a pharmaceutically acceptable carrier.

48. A pharmaceutical composition comprising the vector of any one of claims 25-32 and a pharmaceutically acceptable carrier.

49. The pharmaceutical composition of claim 47 or claim 48, further comprising an adjuvant.

50. The pharmaceutical composition of claim 49, wherein the adjuvant is selected from the group consisting of cytokines, gel-type adjuvants, microbial adjuvants, oil-emulsion and emulsifier-based adjuvants, particulate adjuvants, synthetic adjuvants, polymer adjuvants, and/or combinations thereof.

51. A method for reducing frequency or severity or delaying onset of symptoms of HCV infection in a subject, the method comprising administering to the subject an effective amount of the pharmaceutical composition of any one of claims 47-50.

52. The method of claim 51 , wherein the subject is at risk for HCV infection.

53. The method of claim 51 , wherein the subject is an immunosuppressed subject.

54. The method of claim 53, wherein the immunosuppressed subject is selected from the group consisting of an HIV-infected subject, an AIDS patient, a transplant recipient, a pediatric subject, and a pregnant subject.

55. The method of any one of claims 51-54, wherein the subject has been exposed to HCV infection.

56. The method of any one of claims 51-54, wherein the subject is a human.

57. The method of claim 51 , wherein the frequency, severity or onset of symptoms of HCV infection in a subject are reduced by about 50% or more as compared to the frequency, severity or onset of symptoms of HCV infection in the subject prior to administration of the

pharmaceutical composition.

58. The method of claim 57, wherein the frequency, severity or onset of symptoms of HCV infection in a subject are reduced by about 60%> or more, about 70%> or more, or about 75% or more as compared to the frequency, severity or onset of symptoms of HCV infection in the subject prior to administration of the pharmaceutical composition.

59. The method of any one of claims 51-58, wherein the pharmaceutical composition is administered in an initial dose and in at least one booster dose.

60. The method of claim 59, wherein the pharmaceutical composition is administered in an initial dose and two booster doses.

61. The method of claim 59, wherein the pharmaceutical composition is administered in an initial dose and three booster doses.

62. The method of claim 59, wherein the pharmaceutical composition is administered in an initial dose and four booster doses.

63. The method of claim 59, wherein the pharmaceutical composition is administered in an initial dose and in at least one booster dose about one month, about two months, about three months, about four months, about five months, or about six months following the initial dose.

64. The method of claim 63, wherein the pharmaceutical composition is administered in a second booster dose about six months, about seven months, about eight months, about nine months, about ten months, about eleven months, or about one year following the initial dose.

65. The method of any one of claims 51-64, wherein the pharmaceutical composition is administered in a booster dose every 1 year, 2 years, 3 years, 4 years, 5 years, 6 years, 7 years, 8 years, 9 years, or 10 years.

66. A VLP comprising a fusion protein comprising or consisting of an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:4.

67. A VLP comprising a fusion protein comprising or consisting of an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:7.

68. A VLP comprising a first fusion protein comprising or consisting of an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:4, and a second fusion protein comprising or consisting of an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:7.

69. The VLP of any one of claims 1-24 and 66-68, wherein the VLP does not comprise viral DNA.

70. The VLP of claim 69, wherein the VLP is not infectious.