AVIPOX RECOMBINANTS EXPRESSING FOOT AND MOUTH DISEASE VIRUS GENES

Abstract

The present invention relates to modified poxyiral vectors and to methods of making and using the same. In particular, the invention relates to recombinant avipox that expresses gene products of foot and mouth disease virus (FMDV), and to compositions or vaccines that elicit immune responses directed to FMDV gene products and which can confer protective immunity against infection by FMDV.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 11/110,480, filed Apr. 20, 2005, which claims priority to provisional U.S. application Ser. No. 60/563,786 filed on Apr. 20, 2004.

This application makes reference to U.S. application Ser. No. 10/327,481, filed on Dec. 20, 2002, which is a continuation of International application No. PCT/FR01/02042, filed on Jun. 27, 2001, published on Jan. 3, 2002 as WO 02/00251, and claiming priority to French application No. 00/08437, filed on Jun. 29, 2000.

All of the foregoing applications, as well as all documents cited in the foregoing applications (“application documents”) and all documents cited or referenced in the application documents are incorporated herein by reference. Also, all documents cited in this application (“herein-cited documents”) and all documents cited or referenced in herein-cited documents are incorporated herein by reference. In addition, any manufacturer's instructions or catalogues for any products cited or mentioned in each of the application documents or herein-cited documents are incorporated by reference. Documents incorporated by reference into this text or any teachings therein can be used in the practice of the invention. Documents incorporated by reference into this text are not admitted to be prior art.

FIELD OF THE INVENTION

The present invention relates to vectors, such as viruses, e.g., modified viruses such as poxviruses, and to methods of making and using the same. In particular, the invention relates to recombinant avipox vectors and viruses that express antigens of foot and mouth disease virus (FMDV), and to methods of making and using the same. The invention further relates to methods of eliciting an immune response to FMDV in a subject.

BACKGROUND OF THE INVENTION

Foot-and-mouth disease (FMD) is one of the most virulent and contagious diseases affecting farm animals. This disease is endemic in numerous countries in the world, especially in Africa, Asia and South America. In addition, epidemic outbreaks can occur periodically. The presence of this disease in a country may have very severe economic consequences resulting from loss of productivity, loss of weight and milk production in infected herds, and from trade embargoes imposed on these countries. The measures taken against this disease consist of strict application of import restrictions, hygiene controls and quarantine, slaughtering sick animals and vaccination programs using inactivated vaccines, either as a preventive measure at the national or regional level, or periodically when an epidemic outbreak occurs.

FMD is characterized by its short incubation period, its highly contagious nature, the formation of ulcers in the mouth and on the feet and sometimes, the death of young animals. FMD affects a number of animal species, in particular cattle, pigs, sheep and goats. The agent responsible for this disease is a ribonucleic acid (RNA) virus belonging to the Aphthovirus genus of the Picornaviridae family (Cooper et al., Intervirology, 1978, 10, 165-180). At present, at least seven types of foot-and-mouth disease virus (FMDV) are known: the European types (A, O and C), the African types (SAT1, SAT2 and SAT3) and an Asiatic type (Asia 1). Numerous sub-types have also been distinguished (Kleid et al. Science (1981), 214, 1125-1129).

FMDV is a naked icosahedral virus of about 25 nm in diameter, containing a single-stranded RNA molecule consisting of about 8500 nucleotides, with a positive polarity. This RNA molecule comprises a single open reading frame (ORF), encoding a single polyprotein containing, inter alia, the capsid precursor also known as protein P1 or P88. The protein P1 is myristylated at its amino-terminal end. During the maturation process, the protein P1 is cleaved by the protease 3C into three proteins known as VP0, VP1 and VP3 (or 1AB, 1D and 1C respectively; Belsham G. J., Progress in Biophysics and Molecular Biology, 1993, 60, 241-261). In the virion, the protein VP0 is then cleaved into two proteins, VP4 and VP2 (or 1A and 1B respectively). The mechanism for the conversion of the proteins VP0 into VP 1 and VP3, and for the formation of mature virions is not known. The proteins VP1, VP2 and VP3 have a molecular weight of about 26,000 Da, while the protein VP4 is smaller at about 8,000 Da.

The simple combination of the capsid proteins forms the protomer or 5S molecule, which is the elementary constituent of the FMDV capsid. This protomer is then complexed into a pentamer to form the 12S molecule. The virion results from the encapsidation of a genomic RNA molecule by assembly of twelve 12S pentamers, thus constituting the 146S particles. The viral capsid may also be formed without the presence of an RNA molecule inside it (hereinafter “empty capsid”). The empty capsid is also designated as particle 70S. The formation of empty capsids may occur naturally during viral replication or may be produced artificially by chemical treatment.

Many hypotheses, research routes, and proposals have been developed in an attempt to design effective vaccines against FMD. Currently, the only vaccines on the market comprise inactivated virus. Concerns about safety of the FMDV vaccine exist, as outbreaks of FMD in Europe have been associated with shortcomings in vaccine manufacture (King, A. M. Q. et al, (1981) Nature 293: 479-480). The inactivated vaccines do not confer long-term immunity, thus requiring booster injections given every year, or more often in the event of epidemic outbreaks. In addition, there are risks linked to incomplete inactivation and/or to the escape of virus during the production of inactivated vaccines (King, A. M. Q., ibid). A goal in the art has been to construct conformationally correct immunogens lacking the infective FMDV genome to make effective and safe vaccines.

Vaccinia virus has been used successfully to immunize against smallpox, culminating in the worldwide eradication of smallpox in 1980. Thus, a new role for poxviruses became important, that of a genetically engineered vector for the expression of foreign genes (Panicali and Paoletti, 1982; Paoletti et al., 1984). Genes encoding heterologous antigens have been expressed in vaccinia, often resulting in protective immunity against challenge by the corresponding pathogen (reviewed in Tartaglia et al., 1990). A highly attenuated strain of vaccines, designated MVA, has also been used as a vector for poxvirus-based vaccines. Use of MVA is described in U.S. Pat. No. 5,185,146.

Additional vaccine vector systems involve the use of avipox viruses, which are naturally host-restricted poxviruses. Both fowlpoxvirus (FPV; Taylor et al. 1988a, b) and canarypoxvirus (CPV; Taylor et al., 1991 & 1992) have been engineered to express foreign gene products. Fowlpox virus (FPV) is the prototypic virus of the Avipox genus of the Poxvirus family. The virus causes an economically important disease of poultry that has been well controlled since the 1920's by the use of live attenuated vaccines. Replication of the avipox viruses is limited to avian species (Matthews, 1982) and there are no reports in the literature of avipox virus causing a productive infection in any non-avian species including man. This host restriction provides an inherent safety barrier against transmission of the virus to other species and makes the use of avipox virus based vaccine vectors in veterinary and human applications an attractive proposition.

Other attenuated poxvirus vectors have been prepared by genetic modifications of wild type strains of virus. The NYVAC vector, derived by deletion of specific virulence and host-range genes from the Copenhagen strain of vaccinia (Tartaglia et al., 1992) has proven useful as a recombinant vector in eliciting a protective immune response against an expressed foreign antigen. Another engineered poxvirus vector is ALVAC, derived from canarypox virus (see U.S. Pat. No. 5,756,103). ALVAC does not productively replicate in non-avian hosts, a characteristic thought to improve its safety profile (Taylor et al., 1991 & 1992). ALVAC was deposited under the terms of the Budapest Treaty with the American Type Culture Collection under accession number VR-2547. Yet another engineered poxvirus vector is TROVAC, derived from fowlpox virus (see U.S. Pat. No. 5,766,599).

Recombinant poxviruses can be constructed in two steps known in the art and analogous to the methods for creating synthetic recombinants of poxviruses such as the vaccinia virus and avipox virus described in U.S. Pat. Nos. 4,769,330; 4,722,848; 4,603,112; 5,110,587; 5,174,993; 5,494,807; and 5,505,941, the disclosures of which are incorporated herein by reference. It can thus be appreciated that provision of a FMDV recombinant poxvirus, and of compositions and products therefrom, particularly ALVAC or TROVAC-based FMDV recombinants and compositions and products therefrom, especially such recombinants containing the P1 genes and/or C3 protease gene of FMDV, and compositions and products therefrom, would be a highly desirable advance over the current state of technology.

SUMMARY OF THE INVENTION

Accordingly, one aspect of the present invention provides a recombinant avipox vector comprising at least one nucleic acid molecule encoding one or more foot-and-mouth disease virus (FMDV) antigen(s). In advantageous embodiments, the avipox is ALVAC or TROVAC.

Advantageously, the FMDV antigen(s) can be VP1, VP2, VP3, VP4, 2A, 2B or 3C. Advantageously, the nucleic acid molecule encoding one or more foot-and-mouth disease virus (FMDV) antigen(s) is a cDNA encoding FMDV P1 region and a cDNA encoding FMDV 3C protease of FMDV.

In one embodiment, the FMDV antigens are operably linked to a promoter sequence, which can be the H6 vaccinia promoter, I3L vaccinia promoter, 42K vaccinia promoter, 7.5K vaccinia promoter, or Pi vaccinia promoter. In another embodiment, the promoter is the H6 vaccinia promoter, which is mutated such that the expression levels of the FMDV antigens are decreased compared with expression levels of the FMDV antigens under a wild type (i.e. unmutated) H6 vaccinia promoter.

In another embodiment, the avipox vector of the present invention comprises a C6 insertion locus, wherein flanking sequences of the C6 insertion locus promote homologous recombination of the FMDV antigens with the C6 insertion locus. Advantageously, the flanking sequences comprise the C6L and C6R open reading frames of canarypox.

In a further embodiment, the avipox vector of the present invention comprises a F8 insertion locus, wherein the flanking sequences of the F8 insertion locus promote homologous recombination of the FMDV antigens with the F8 insertion locus. Advantageously, the flanking sequences comprise the F8L and F8R open reading frames of fowlpox.

A second aspect of the present invention provides a recombinant avipox virus, comprising at least one nucleic acid molecule encoding one or more FMDV antigens. The present invention also provides recombinant avipox viruses vCP2186, vCP2181, vCP2176, and vFP2215.

A further aspect of the invention relates to a method of eliciting an immune response to FMDV in a subject, comprising administering the avipox vector or avipox virus of the present invention to the subject.

In yet another aspect of the present invention, a method of producing a recombinant avipox vector comprising at least one nucleic acid molecule encoding one or more FMDV antigen(s), comprising the steps of: a) linearizing a donor plasmid with a restriction endonuclease, wherein the donor plasmid comprises restriction endonuclease cleavage sites or a multiple cloning site; and b) ligating at least one nucleic acid molecule comprising (i) a nucleic acid sequence encoding one or more FMDV antigen(s), (ii) a viral promoter sequence, and (iii) insertion sequences flanking (i) and (ii) that have complementary restriction endonuclease cleavage sites to the donor plasmid at FMDV antigens, thereby producing the recombinant avipox vector.

The method can further comprise the steps of c) introducing the vector into a cell permissive for replication of the vector; and d) isolating the vector from the cell. Advantageously, the cell permissive for replication of the vector is a chicken embryonic fibroblast.

In another embodiment, the vector further comprises a reporter gene, which is selected from the group consisting of the neomycin resistance gene, the ampicillin resistance gene, lacZ (β-galactosidase), luciferase, and green fluorescent protein (GFP).

These and other objects of the invention will be described in further detail in connection with the detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The following Detailed Description, given by way of example, but not intended to limit the invention to specific embodiments described, may be understood in conjunction with the accompanying drawings, incorporated herein by reference. Various preferred features and embodiments of the present invention will now be described by way of non-limiting examples and with reference to the accompanying drawings in which:

FIG. 1 shows the genome of foot and mouth disease virus (FMDV) and the genes inserted into the avipox recombinants.

FIG. 2 shows the oligonucleotide primers used to PCR-amplify the H6p FMDV gene cassette (SEQ ID NO:1-3), and the amino acids encoded by the nucleotides (SEQ ID NO:4 and 5).

FIGS. 3A and 3B show the construction of a pC5 H6p FMDV P1+3C donor plasmid for generating ALVAC recombinants, with inserts at the C5 loci.

FIGS. 4A-4E show the nucleotide (SEQ ID NO:6) and amino acid sequences (SEQ ID NO:7) of the C5 H6p FMDV gene cassette of the pC5 H6p FMDV P1+3C donor plasmid.

FIGS. 5A and 5B show the construction of a pF8 H6p FMDV P1+3C donor plasmid for generating fowlpox recombinants, with the insert at the unique F8 locus.

FIGS. 6A-6F show the nucleotide (SEQ ID NO:8) and amino acid sequences (SEQ ID NO:9) of the F8 H6p FMDV gene cassette of the pF8 H6p FMDV P1+3C donor plasmid.

FIG. 7 shows the oligonucleotide primers used to PCR amplify the 3′-end of the FMDV gene cassette (SEQ ID NO:10-12), and the amino acids encoded by the nucleotides (SEQ ID NO:13 and 14).

FIG. 8 shows the construction of a promoter-less pC6 FMDV P1+3C insertion plasmid for introduction of different promoters.

FIGS. 9A and 9B show the construction of a pC6 H6p FMDV P1+3C donor plasmid for generating ALVAC recombinants, with the insert at the unique C6 locus.

FIGS. 1A-10E show the nucleotide (SEQ ID NO:15) and amino acid sequences (SEQ ID NO:16) of the C6 H6p FMDV gene cassette of the pC6 H6p FMDV P1+3C donor plasmid.

FIG. 11 shows the nucleotide sequences of the wild-type early/late H6 promoter (H6p) (SEQ ID NO:17) and the mutant early H6 promoter (H6p*) (SEQ ID NO:18).

FIGS. 12A and 12B show the oligonucleotide primers used to amplify an H6p* 5′-FMDV fragment (SEQ ID NO:19-23) and the amino acids encoded by the nucleotides (SEQ ID NO:24 and 25).

FIGS. 13A and 13B show the construction of a pC6 H6p* FMDV P1+3C donor plasmid for generating ALVAC recombinants, with the insert at the unique C6 locus.

FIGS. 14A-14E show the nucleotide (SEQ ID NO:26) and amino acid sequences (SEQ ID NO:27) of the C6 H6p* FMDV gene cassette of the pC6 H6p* FMDV P1+3C donor plasmid.

FIGS. 15A and 15B show the oligonucleotide primers used to amplify the I3Lp 5′-FMDV fragment (SEQ ID NOS:28-33), and the amino acids encoded by the nucleotides (SEQ ID NO:34 and 35).

FIGS. 16A and 16B show the construction of a pC6 I3Lp FMDV P1+3C donor plasmid for generating ALVAC recombinants, with the insert at the unique C6 locus.

FIGS. 17A-17E show the nucleotide (SEQ ID NO:36) and amino acid sequences (SEQ ID NO:37) of the C6 I3Lp FMDV gene cassettes of the pC6 I3Lp FMDV P1+3C donor plasmid.

FIGS. 18A and 18B show the oligonucleotide primers used to amplify the 42Kp 5′-FMDV fragment (SEQ ID NO:38-43) and the amino acids encoded by the nucleotides (SEQ ID NO:44 and 45).

FIGS. 19A and 19B show the construction of a pC6 42Kp FMDV P1+3C donor plasmid for generating ALVAC recombinants, with the insert at the unique C6 locus.

FIGS. 20A-20E show the nucleotide (SEQ ID NO:46) and amino acid sequences (SEQ ID NO:47) of the C6 42Kp FMDV gene cassette of the pC6 42Kp FMDV P1+3C donor plasmid.

FIGS. 21A-21C show the oligonucleotide primers used to amplify and repair the 7.5Kp 5′-FMDV fragment (SEQ ID NO:48-54), and the amino acids encoded by the nucleotides (SEQ ID NO:55-57).

FIGS. 22A and 22B show the construction of a pC6 7.5K FMDV P1+3C donor plasmid for generating ALVAC recombinants, with the insert at the unique C6 locus.

FIGS. 23A-23E shows the nucleotide (SEQ ID NO:58) and amino acid sequences (SEQ ID NO:59) of the C6 7.5Kp FMDV gene cassette of the pC6 7.5Kp FMDV P1+3C donor plasmid.

FIGS. 24A-24E show the oligonucleotide primers used to amplify and repair the Pip 5′-FMDV fragment (SEQ ID NO:60-77), and the amino acids encoded by the nucleotides (SEQ ID NO:78-80).

FIGS. 25A and 25B show the construction of a pC6 Pip FMDV P1+3C donor plasmid for generating ALVAC recombinants, with the insert at the unique C6 locus.

FIGS. 26A-26E show the nucleotide (SEQ ID NO: 81) and amino acid sequences (SEQ ID NO:82) of the C6 Pip FMDV gene cassette of the pC6 Pip FMDV P1+3C donor plasmid.

FIG. 27 describes the oligonucleotide primers used to PCR amplify an H6p* 5′-FMDV fragment for insertion into a pF8 donor plasmid (SEQ ID NO:83-86).

FIGS. 28A and 28B illustrate the construction of a pF8 H6p* FMDV P1+3C donor plasmid for generating fowlpox recombinants.

FIGS. 29A-29F depict the nucleotide (SEQ ID NO:87) and amino acid (SEQ ID NO:88) sequences of the F8 H6p* FMDV P1+3C gene cassette of the pF8 H6p* FMDV P1+3C donor plasmid.

FIG. 30 shows the expression analysis of ALVAC recombinants containing the FMDV P1+3C gene cassette under the I3L or 42K promoters.

DETAILED DESCRIPTION OF THE INVENTION

In this disclosure, “comprises,” “comprising,” “containing” and “having” and the like can have the meaning ascribed to them in U.S. Patent law and can mean “includes,” “including,” and the like; “consisting essentially of” or “consists essentially” likewise has the meaning ascribed in U.S. Patent law and the term is open-ended, allowing for the presence of more than that which is recited so long as basic or novel characteristics of that which is recited is not changed by the presence of more than that which is recited, but excludes prior art embodiments.

As used herein, the term “operably linked” means that the components described are in a relationship permitting them to function in their intended manner.

An “antigen” is a substance that is recognized by the immune system and induces an immune response. A similar term used in this context is “immunogen”.

It is therefore an object of this invention to provide compositions and methods for treatment and prophylaxis of infection with FMDV. It is also an object to provide a means to treat or prevent foot and mouth disease.

In one aspect, the present invention relates to a modified recombinant avipox vector expressing at least one nucleic acid sequences encoding for one or more FMDV antigens. The viral vector according to the present invention is advantageously an avipox virus, such as fowlpox virus and canarypox virus and more particularly, ALVAC or TROVAC. The modified recombinant vector comprises a heterologous nucleic acid sequence, which encodes an antigenic protein, e.g., derived from FMDV ORFs that are encoded by the P1 (comprising VP1, VP2, VP3, VP4, and 2A), 2B, and/or 3C regions.

In another aspect, the present invention relates to a modified recombinant avipox virus that includes, in a non-essential region of the virus genome, at least one heterologous nucleic acid sequence that encodes one or more antigens from FMDV, such as gene products of the P1 gene (comprising VP1, VP2, VP3, VP4, 2A), 2B, and/or 3C.

In a still further aspect, the present invention relates to methods of eliciting an immune response to FMDV in a subject, comprising administering the recombinant avipox vector of the present invention. The present invention also relates to methods of eliciting an immune response to FMDV in a subject, comprising administering the recombinant avipox virus of the present invention. Advantageously, the avipox virus is selected from the group consisting of vCP2186, vCP2181, vCP2176, and vFP2215.

The virus used according to the present invention is advantageously a poxvirus, particularly an avipox virus, such as fowlpox virus or canarypox virus. TROVAC refers to an attenuated fowlpox that was a plaque-cloned isolate derived from the FP-1 vaccine strain of fowlpoxvirus that is licensed for vaccination of 1-day-old chicks. ALVAC is an attenuated canarypox virus-based vector that was a plaque-cloned derivative of the licensed canarypox vaccine, Kanapox (Tartaglia et al., 1992). ALVAC-based recombinant viruses expressing extrinsic immunogens have also been demonstrated efficacious as vaccine vectors (Tartaglia et al., 1993 a,b). This avipox vector is restricted to avian species for productive replication. On human cell cultures, canarypox virus replication is aborted early in the viral replication cycle prior to viral DNA synthesis. Nevertheless, when engineered to express extrinsic immunogens, authentic expression and processing is observed in vitro in mammalian cells and inoculation into numerous mammalian species induces antibody and cellular immune responses to the extrinsic immunogen and provides protection against challenge with the cognate pathogen (Taylor et al., 1992; Taylor et al., 1991).

ALVAC and TROVAC have also been recognized as unique among avipoxviruses in that the National Institutes of Health (“NIH”; U.S. Public Health Service), Recombinant DNA Advisory Committee, which issues guidelines for the physical containment of genetic material such as viruses and vectors, i.e., guidelines for safety procedures for the use of such viruses and vectors, which are based upon the pathogenicity of the particular virus or vector, granted a reduction in physical containment level: from BSL2 to BSL1. No other avipoxvirus has a BSL1 physical containment level. Even the Copenhagen strain of vaccinia virus—the common smallpox vaccine—has a higher physical containment level; namely, BSL2. Accordingly, the art has recognized that ALVAC and TROVAC have a lower pathogenicity than other avipox viruses.

Advantageously, the avipox virus vector is an ALVAC or a canarypox virus (Rentschler vaccine strain), which was attenuated through 200 or more serial passages on chick embryo fibroblasts, after which a master seed therefrom was subjected to four successive plaque purifications under agar, from which a clone was amplified through five additional passages. The avipox virus vector can also be a fowlpox virus, or an attenuated fowlpox virus such as TROVAC.

The invention further relates to the product of expression of the inventive recombinant avipox virus and uses therefor, such as to form antigenic, immunological or vaccine compositions for treatment, prevention, diagnosis or testing; and, to DNA from the recombinant avipox virus which are useful in constructing DNA probes and PCR primers.

In one aspect, the present invention relates to recombinant avipox viruses containing at least one nucleic acid sequence expressing one or more antigens from FMDV, advantageously in a non-essential region of the avipox virus genome. The avipox virus can be a fowlpox virus, especially an attenuated fowlpox virus such as TROVAC, or a canarypox virus, especially an attenuated canarypox virus, such as ALVAC.

According to the present invention, the recombinant avipox virus and avipox viral vectors express at least one nucleic acid sequence encoding one or more FMDV antigens. In particular, any or all genes or open reading frames (ORFs) encoding FMDV antigens can be isolated, characterized and inserted into ALVAC recombinants. The resulting recombinant avipox virus is used to infect an animal. Expression in the animal of FMDV antigens results in an immune response in the animal to FMDV. Thus, the recombinant avipox virus of the present invention may be used in an immunological composition or vaccine to provide a means to induce an immune response, which may, but need not be, protective. The molecular biology techniques used are described by Sambrook et al. (1989).

The invention also contemplates FMDV antigens that can be delivered as a naked DNA plasmid or vector, or DNA vaccine or immunological or immunogenic compositions comprising nucleic acid molecules encoding and expressing in vivo an FMDV antigen(s).

The FMDV antigen of interest can be obtained from FMDV or can be obtained from in vitro and/or in vivo recombinant expression of FMDV gene(s) or portions thereof. The FMDV antigen of interest can also be provided using synthetic FMDV sequences. The FMDV antigen of interest can be, but are not limited to: L_b, L_ab, P1-2A (comprising VP1, VP2, VP3, VP4, and 2A); P2 (comprising 2B and 2C), and P3 (comprising 3A, 3B, VPg, 3C, and 3D), or portions thereof. In an advantageous embodiment, the FMDV antigens are P1 and 3C. In a particularly preferred embodiment, the FMDV antigens are P1-2A or P1-2A, 2B. Reference is made herein to U.S. patent application Ser. No. 10/327,481, relating to isolation of FMDV genome sequences, the contents of which are incorporated by reference.

Non-essential regions have been defined in the art (Johnson et al., (1993) Virology 196: 381-401) for vaccinia virus. These sites, also referred to herein as “insertion loci”, are described in U.S. Pat. Nos. 6,340,462, and 5,756,103 for ALVAC, the contents of which are incorporated herein by reference, and include, but are not limited to, thymidine kinase (TK), hemagglutinin (HA), M2L, C6, and other loci. In one embodiment, where canarypox is used, the insertion locus is C6. In another embodiment, where fowlpox is used, the insertion locus is F8.

Insertion of nucleic acid sequences encoding FMDV antigens can be facilitated by homologous recombination, wherein the FMDV sequence of interest is flanked by sequences corresponding to avipox viral open reading frames immediately adjacent to the insertion locus (hereinafter referred to as “flanking sequences” or “insertion sequences”). Homologous recombination is facilitated by recognition of homologous flanking sequences, which promotes integration of the FMDV sequences into the insertion locus of interest. By way of example, insertion of FMDV sequences into the C6 locus requires the presence of the C6L and C6R ORFs on either side of the nucleic acid sequence encoding the FMDV antigen of interest in the viral vector. Thus, advantageously the insertion loci is C6 and the flanking sequences comprise C6L and C6R. Where the F8 insertion locus is used, the flanking sequences comprise F8L and F8R.

The recombinant viral vectors of the invention expressing FMDV antigens can be replicated or produced in cells or cell lines, or in vivo in a host or subject. One alternative embodiment consists of replicating the vector in cells permissive for replication of the vector.

It must be noted that avipox viruses can only productively replicate in or be passaged through avian species or avian cell lines such as, for example, chicken embryonic fibroblasts or QT35. The recombinant avipox viruses harvested from avian host cells, when inoculated into a non-avian vertebrate, such as a mammal, in a manner analogous to the inoculation of mammals by vaccinia virus, without productive replication of the avipox virus. Despite the failure of the avipox virus to productively replicate in such an inoculated non-avian vertebrate, sufficient expression of the virus occurs so that the inoculated animal responds immunologically to the antigenic determinants of the recombinant avipox virus and also to the antigenic determinants encoded in exogenous genes therein. Thus, in an advantageous embodiment, when avipox viruses or viral vectors are used, chicken embryonic fibroblasts or QT35 are preferred as the cells permissive for viral vector replication.

The recombinant viral vectors and recombinant viruses can contain promoters that are operably linked to the FMDV antigens of the present invention. The promoter is advantageously of poxyiral origin and advantageously early or early-late promoters, which may be, in particular, the promoter P11K of the vaccinia virus, I3L poxyiral promoter, 42K poxyiral promoter, H6 poxyiral promoter, Pi poxyiral promoter, P28K of the vaccinia virus, P160K ATI of the cowpox virus. In particular, the sequence driving the early transcription of an early-late promoter can be used instead of the full-length promoter (Moss, B. (1990) Ann. Rev. Biochem. 59: 661-688; Mars, M. et al, (1987) J. Mol. Biol. 198: 619-631; Davison, A. et al (1989) J. Mol. Biol. 210: 749-769; Vassef, A. (1987) Nucl. Acid. Res. 15: 1427-1443). The promoter is advantageously a weak promoter. The terms “strong promoter” and “weak promoter” are known in the art and are defined by the relative frequency of transcription initiation (times per minute) at the promoter.

The invention also provides for poxyiral promoters that are mutated. The present inventors have found that expression of certain FMDV antigens is not possible from strong poxyiral promoters. Without being bound by theory, it is believed that high levels of expression of potentially toxic FMDV antigens can preclude formation of stable poxyiral recombinants. Therefore, the present invention also comprehends the use of a mutated poxyiral promoter, such as, for example, a mutated H6 promoter, such that the expression levels of the FMDV antigens are decreased compared with expression levels of the FMDV antigens under a wild type promoter (Davison, A. et al (1989) J. Mol. Biol. 210: 749-769). The mutated H6 promoter of the instant invention can be considered a weak promoter.

The mutated H6 promoter taught herein contains a point mutation. The invention can also employ promoters other than H6, which contain point mutations that reduce their frequency of transcription initiation compared with the wild type promoter. In addition, other types of mutated promoters are suitable for use in the instant invention. For example, U.S. application Ser. No. 10/679,520, incorporated herein by reference, describes a truncated form of the H6 promoter (see also Davison, A. et al (1989) J. Mol. Biol. 210: 749-769; Taylor J. et al., Vaccine, 1988, 6, 504-508; Guo P. et al. J. Virol., 1989, 63, 4189-4198; Perkus M. et al., J. Virol., 1989, 63, 3829-3836).

The present invention also relates to a method of producing a recombinant avipox vector comprising FMDV antigens, comprising the steps of linearizing a donor plasmid with a restriction endonuclease, wherein the donor plasmid comprises restriction endonuclease cleavage sites or a multiple cloning site, and ligating at least one nucleic acid sequence comprising (i) a nucleic acid sequence encoding one or more FMDV antigen(s), (ii) a viral promoter sequence, and (iii) insertion sequences flanking (i) and (ii) that have complementary restriction endonuclease cleavage sites to the donor plasmid at FMDV antigens, thereby producing the recombinant avipox vector. Advantageously, the method further comprises the steps of introducing the vector into a cell permissive for replication of the vector, and isolating the vector from the cell.

By definition, a donor plasmid expression vector (or donor plasmid) includes a DNA transcription unit comprising a polynucleotide sequence containing the cDNA to be expressed and the elements necessary for its expression in vivo. The donor plasmid can also include a poxyiral early termination signal at the 3′ terminus of the foreign gene (Moss, B. (1990) Ann. Rev. Biochem. 59: 661-688). The circular, super-coiled or uncoiled plasmid form is preferred. The linear form also comes under the scope of this invention.

Methods for making and/or using vectors (or recombinants) for expression and uses of expression products and products therefrom (such as antibodies) can be by or analogous to the methods disclosed in herein cited documents and documents referenced or cited in herein cited documents. See, for example, Sambrook et al. Molecular Cloning (1999). The invention also includes the use of the avipox vectors expressing FMDV antigens in the research setting. The recombinant avipox vectors and recombinant avipox viruses can be used to transfect or infect cells or cell lines of interest to study, for example, cellular responses to FMDV antigens, or signal transduction pathways mediated by FMDV antigens.

In the research setting, it is often advantageous to design recombinant vectors or viruses that comprise reporter genes that can be easily detected by laboratory assays and techniques. Reporter genes are well known in the art and can comprise resistance genes to antibiotics such as, but not limited to, ampicillin, neomycin, zeocin, kanamycin, bleomycin, hygromycin, chloramphenicol, among others. Reporter genes can also comprise green fluorescent protein, the lacZ gene (which encodes β-galactosidase), luciferase, and β-glucuronidase.

The invention also relates to a method of eliciting an immune response against foot-and-mouth disease in a subject comprising administering the recombinant avipox vectors or recombinant avipox viruses according to the present invention to the subject. The subject can be any animal which can become infected with FMDV, in particular, bovine, ovine, porcine or caprine species. Methods of administration and doses are defined herein.

The recombinant avipox vectors and viruses expressing FMDV antigens or an expression product thereof, immunological, antigenic or vaccine compositions or therapeutic compositions, can be administered via a parenteral route (intradermal, intramuscular or subcutaneous). Such an administration enables a systemic immune response, or humoral or cell-mediated responses.

As used herein, the terms “immunogenic composition” and “immunological composition” and “immunogenic or immunological composition” cover any composition that elicits an immune response against the targeted FMDV antigen; for instance, after administration of injection into the animal, elicits an immune response against the targeted FMDV antigen. The terms “vaccinal composition” and “vaccine” and “vaccine composition” covers any composition that induces a protective immune response against the FMDV antigen or which efficaciously protects against the antigen after administration or injection into the animal. The invention also comprehends recombinant avipox viral vectors administered as a plasmid DNA vector or vaccine.

More generally, the inventive recombinant avipox viral vectors and recombinant avipox viruses expressing FMDV antigens, antigenic, immunogenic, immunological or vaccine avipox virus-FMDV compositions or therapeutic compositions, can be prepared in accordance with standard techniques well known to those skilled in the pharmaceutical or veterinary arts. Such compositions can be administered in dosages and by techniques well known to those skilled in the medical or veterinary arts taking into consideration such factors as the age, sex, weight, species and condition of the particular patient, and the route of administration.

The compositions can be administered alone, or can be co-administered or sequentially administered with compositions, e.g., with “other” immunological, antigenic or vaccine or therapeutic compositions thereby providing multivalent or “cocktail” or combination compositions of the invention and methods of employing them. Again, the ingredients and manner (sequential or co-administration) of administration, as well as dosages can be determined taking into consideration such factors as the age, sex, weight, species and condition of the particular subject, and the route of administration. In this regard, reference is made to U.S. Pat. No. 5,843,456, incorporated herein by reference, and directed to rabies compositions and combination compositions and uses thereof.

Examples of compositions of the invention include liquid preparations for orifice, or mucosal, e.g., oral, nasal, anal, vaginal, peroral, intragastric, etc., administration such as suspensions, solutions, sprays, syrups or elixirs; and, preparations for parenteral, subcutaneous, intradermal, intramuscular or intravenous administration (e.g., injectable administration) such as sterile suspensions or emulsions. In such compositions, the recombinant avipox virus or recombinant avipox viral vectors may be in admixture with a suitable carrier, diluent, or excipient such as sterile water, physiological saline, glucose or the like. The compositions can also be lyophilized. The compositions can contain auxiliary substances, such as wetting or emulsifying agents, pH buffering agents, adjuvants, gelling or viscosity enhancing additives, preservatives, flavoring agents, colors, and the like, depending upon the route of administration and the preparation desired. Standard texts, such as “REMINGTON'S PHARMACEUTICAL SCIENCE”, 17th edition, 1985, incorporated herein by reference, may be consulted to prepare suitable preparations, without undue experimentation.

Compositions in forms for various administration routes are envisioned by the invention. And again, the effective dosage and route of administration are determined by known factors, such as age, sex, weight, condition and nature of the animal, as well as LD₅₀ and other screening procedures which are known and do not require undue experimentation. Dosages of each active agent can be as in herein cited documents (or documents referenced or cited in herein cited documents) and/or can range from one or a few to a few hundred or thousand micrograms, e.g., 1 μg to 1 mg, for an immunogenic, immunological or vaccine composition; and, 10⁴ to 10¹⁰ TCID₅₀ advantageously 10⁶ to 10³ TCID₅₀ for an immunogenic, immunological or vaccine composition.

Recombinants or vectors can be administered in a suitable amount to obtain in vivo expression corresponding to the dosages described herein and/or in herein cited documents. For instance, suitable ranges for viral suspensions can be determined empirically. The viral vector or recombinant in the invention can be administered to an animal or infected or transfected into cells in an amount of about at least 10³ pfu; more advantageously about 10⁴ pfu to about 10¹⁰ pfu, e.g., about 10⁵ pfu to about 10⁹ pfu, for instance about 10⁶ pfu to about 10⁸ pfu, with doses generally ranging from about 10⁶ to about 10¹⁰, advantageously about 10⁸ pfu/dose, and advantageously about 10⁷ pfu per dose of 2 ml. And, if more than one gene product is expressed by more than one recombinant, each recombinant can be administered in these amounts; or, each recombinant can be administered such that there is, in combination, a sum of recombinants comprising these amounts.

In vector or plasmid compositions employed in the invention, dosages can be as described in documents cited herein or as described herein or as in documents referenced or cited in herein cited documents. Advantageously, the dosage should be a sufficient amount of plasmid to elicit a response analogous to compositions wherein the antigen(s) of FMDV are directly present; or to have expression analogous to dosages in such compositions; or to have expression analogous to expression obtained in vivo by recombinant compositions. For instance, where DNA vaccines are administered, suitable quantities of each plasmid DNA in plasmid compositions can be 1 μg to 2 mg, advantageously 50 μg to 1 mg. Documents cited herein (or documents cited or referenced in herein cited documents) regarding DNA plasmid vectors may be consulted by the skilled artisan to ascertain other suitable dosages for DNA plasmid vector compositions of the invention, without undue experimentation.

However, the dosage of the composition(s), concentration of components therein and timing of administering the composition(s), which elicit a suitable immunological response, can be determined by methods such as by antibody titrations of sera, e.g., by ELISA and/or seroneutralization assay analysis. Such determinations do not require undue experimentation from the knowledge of the skilled artisan, this disclosure and the documents cited herein. And, the time for sequential administrations can be likewise ascertained with methods ascertainable from this disclosure, and the knowledge in the art, without undue experimentation.

The immunogenic or immunological compositions contemplated by the invention can also contain an adjuvant. Particularly suitable adjuvants for use in the practice of the present invention are (1) polymers of acrylic or methacrylic acid, maleic anhydride and alkenyl derivative polymers, (2) immunostimulating sequences (ISS), such as oligodeoxyribonucleotide sequences having one or more non-methylated CpG units (Klinman D. M. et al., Proc. Natl. Acad. Sci., USA, 1996, 93, 2879-2883; WO98/16247), (3) an oil in water emulsion, such as the SPT emulsion described on p 147 of “Vaccine Design, The Subunit and Adjuvant Approach” published by M. Powell, M. Newman, Plenum Press 1995, and the emulsion MF59 described on p 183 of the same work, (4) cationic lipids containing a quaternary ammonium salt, (5) cytokines, (6) aluminum hydroxide or aluminum phosphate or (7) other adjuvants discussed in any document cited and incorporated by reference into the instant application, or (8) any combinations or mixtures thereof. The DNA vaccines or immunogenic or immunological compositions encompassed by the invention can be formulated with a liposome, in the presence or absence of an adjuvant as described above.

Other suitable adjuvants include FMLP (N-formyl-methionyl-leucyl-phenylalanine; U.S. Pat. No. 6,017,537) and/or acrylic acid or methacrylic acid polymer and/or a copolymer of maleic anhydride and of alkenyl derivative. The acrylic acid or methacrylic acid polymers can be cross-linked, e.g., with polyalkenyl ethers of sugars or of polyalcohols. These compounds are known under the term “carbomer” (Pharmeuropa, Vol. 8, No. 2, June 1996). A person skilled in the art may also refer to U.S. Pat. No. 2,909,462 (incorporated by reference), which discusses such acrylic polymers cross-linked with a polyhydroxylated compound containing at least 3 hydroxyl groups: in one embodiment, a polyhydroxylated compound contains not more than 8 hydroxyl groups; in another embodiment, the hydrogen atoms of at least 3 hydroxyls are replaced with unsaturated aliphatic radicals containing at least 2 carbon atoms; in other embodiments, radicals contain from about 2 to about 4 carbon atoms, e.g., vinyls, allyls and other ethylenically unsaturated groups. The unsaturated radicals can themselves contain other substituents, such as methyl. The products sold under the name Carbopol® (Noveon Inc., Ohio, USA) are particularly suitable for use as an adjuvant. They are cross-linked with an allyl sucrose or with allylpentaerythritol, as to which, mention is made of the products Carbopol® 974P, 934P, and 971P.

As to the copolymers of maleic anhydride and of alkenyl derivative, mention is made of the EMA® products (Monsanto), which are copolymers of maleic anhydride and of ethylene, which may be linear or cross-linked, for example cross-linked with divinyl ether. Also, reference may be made to J. Fields et al., Nature 186:778-780, 1960 (incorporated by reference).

With regard to structure, the acrylic or methacrylic acid polymers and EMA are advantageously formed by basic units having the following formula:

in which:

• • R₁ and R₂, which can be the same or different, represent H or CH₃
  • x=0 or 1, advantageously x=1
  • y=1 or 2, withx+y=2.

For EMA, x=0 and y=2 and for carbomers x=y=1.

These polymers are soluble in water or physiological salt solution (20 g/l NaCl) and the pH can be adjusted to 7.3 to 7.4, e.g., by soda (NaOH), to provide the adjuvant solution in which the expression vector(s) can be incorporated. The polymer concentration in the final vaccine composition can range between 0.01 and 1.5% w/v, advantageously 0.05 to 1% w/v and advantageously 0.1 to 0.4% w/v.

The cationic lipids containing a quaternary ammonium salt which are advantageously but not exclusively suitable for plasmids, are advantageously those having the following formula:

in which R₁ is a saturated or unsaturated straight-chain aliphatic radical having 12 to 18 carbon atoms, R₂ is another aliphatic radical containing 2 or 3 carbon atoms and X is an amine or hydroxyl group.

Among these cationic lipids, preference is given to DMRIE (N-(2-hydroxyethyl)-N,N-dimethyl-2,3-bis(tetradecyloxy)-1-propane ammonium; WO96/34109), advantageously associated with a neutral lipid, advantageously DOPE (dioleoyl-phosphatidyl-ethanol amine; Behr J. P., 1994, Bioconjugate Chemistry, 5, 382-389), to form DMRIE-DOPE.

Advantageously, the plasmid mixture with the adjuvant is formed extemporaneously or contemporaneously with administration of the preparation or shortly before administration of the preparation; for instance, shortly before or prior to administration, the plasmid-adjuvant mixture is formed, advantageously so as to give enough time prior to administration for the mixture to form a complex, e.g. between about 10 and about 60 minutes prior to administration, such as approximately 30 minutes prior to administration.

When DOPE is present, the DMRIE:DOPE molar ratio is advantageously about 95:about 5 to about 5:about 95, more advantageously about 1:about 1, e.g., 1:1.

The DMRIE or DMRIE-DOPE adjuvant:plasmid weight ratio can be between about 50:about 1 and about 1:about 10, such as about 10:about 1 and about 1:about 5, and advantageously about 1:about 1 and about 1:about 2, e.g., 1:1 and 1:2.

A recombinant vaccine or immunogenic or immunological composition can also be formulated in the form of an oil-in-water emulsion. The oil-in-water emulsion can be based, for example, on light liquid paraffin oil (European Pharmacopea type); isoprenoid oil such as squalane, squalene, EICOSANE™ or tetratetracontane; oil resulting from the oligomerization of alkene(s), e.g., isobutene or decene; esters of acids or of alcohols containing a linear alkyl group, such as plant oils, ethyl oleate, propylene glycol di(caprylate/caprate), glyceryl tri(caprylate/caprate) or propylene glycol dioleate; esters of branched fatty acids or alcohols, e.g., isostearic acid esters. The oil advantageously is used in combination with emulsifiers to form the emulsion. The emulsifiers can be nonionic surfactants, such as esters of sorbitan, mannide (e.g., anhydromannitol oleate), glycerol, polyglycerol, propylene glycol, and oleic, isostearic, ricinoleic, or hydroxystearic acid, which are optionally ethoxylated, and polyoxypropylene-polyoxyethylene copolymer blocks, such as the Pluronic® products, e.g., L121. The adjuvant can be a mixture of emulsifier(s), micelle-forming agent, and oil such as that which is available under the name Provax® (IDEC Pharmaceuticals, San Diego, Calif.).

The term “prime-boost” refers to the successive administrations of two different types of vaccine or immunogenic or immunological compositions having at least one antigen in common. The priming administration (priming) is the administration of a first vaccine or immunogenic or immunological composition type and may comprise one, two or more administrations. The boost administration is the administration of a second vaccine or immunogenic or immunological composition type and may comprise one, two or more administrations, and, for instance, may comprise or consist essentially of annual administrations.

Thus, the invention encompasses prime-boost immunization or vaccination method of an animal against at least one FMDV antigen comprising administering to the animal a priming DNA vaccine or immunological or immunogenic composition comprising nucleic acid molecule(s) encoding and expressing in vivo an antigen(s) from FMDV, and thereafter administering a boosting composition that comprises the FMDV antigen expressed by the DNA vaccine or immunogenic or immunological composition, or a recombinant or modified vector, e.g., virus, such as an avipox virus (such as ALVAC, canarypox, TROVAC, or fowlpox virus) that contains and expresses in an animal host cell a nucleotide sequence encoding the antigen of FMDV expressed by the DNA vaccine or immunogenic or immunological composition. The boosting vaccine or immunogenic or immunological composition can be the same as or different than the priming vaccine or immunogenic or immunological composition.

For instance, the boosting vaccine or immunogenic or immunological composition can be advantageously the FMDV antigen expressed by the DNA vaccine (or immunogenic or immunological composition) and/or a recombinant or modified avipox vector, e.g., virus, vaccine or immunogenic or immunological composition. A recombinant or modified vector is advantageously an in vivo expression vector, such as a modified or recombinant bacteria, yeast, virus, e.g. avipox virus, comprising nucleic acid molecule(s) encoding and expressing in vivo the antigen(s) from FMDV expressed by the DNA vaccine or immunogenic or immunological composition. The boost is advantageously performed with an inactivated vaccine or immunogenic or immunological composition, or with a vaccine or immunogenic or immunological composition comprising a recombinant live viral vector, such as a recombinant avipox virus, that comprises nucleic acid molecule(s) encoding and expressing in vivo the antigen(s) from the FMDV antigen expressed by the DNA vaccine or immunogenic or immunological composition. Thus, it is advantageous that the boost either comprises the antigen expressed by the DNA vaccine or immunogenic or immunological composition or expresses in vivo the same FMDV antigen expressed by the DNA vaccine or immunogenic or immunological composition. Advantageously, the boost comprises the recombinant avipox virus expressing FMDV antigens described herein.

Alternatively, the prime-boost immunization or vaccination method can comprise administering to the animal a priming vaccine comprising the recombinant avipox viruses of the present invention, and boosting thereafter with the DNA vaccine.

The DNA plasmid, or recombinant avipox vector expressing one or more nucleic acid sequences encoding at least one FMDV antigen, e.g., vector according to this disclosure, can be preserved and/or conserved and stored either in liquid form, at about 5° C., or in lyophilised or freeze-dried form, in the presence of a stabilizer. Freeze-drying can be according to well-known standard freeze-drying procedures. The pharmaceutically acceptable stabilizers may be SPGA (sucrose phosphate glutamate albumin; Bovarnik et al., J. Bacteriology 59:509, 1950), carbohydrates (e.g., sorbitol, mannitol, lactose, sucrose, glucose, dextran, trehalose), sodium glutamate (Tsvetkov T et al, Cryobiology 20(3): 318-23, 1983; Israeli E et al., Cryobiology 30(5): 519-23, 1993), proteins such as peptone, albumin or casein, protein containing agents such as skimmed milk (Mills C K et al, Cryobiology 25(2): 148-52, 1988; Wolff E et al., Cryobiology 27(5):569-75, 1990), and buffers (e.g., phosphate buffer, alkaline metal phosphate buffer). An adjuvant and/or a vehicle or excipient may be used to make soluble the freeze-dried preparations.

The invention will now be further described by way of the following non-limiting Examples, given by way of illustration.

EXAMPLES

Example 1

Construction of a pC5 H6p FMDV P1+3C Donor Plasmid for Introduction of FMDV Genes into the C5 Loci of ALVAC

Plasmid pAd5-A24 was used as the donor plasmid to generate the adenovirus Ad5A24 recombinant. It is a ˜39 kb plasmid containing the strain A24 P1 genes and the strain A12 3C protease. Several deletions of the FMDV genome were made for safety reasons and are indicated in FIG. 1.

Plasmid pAd5-A24 was digested with EcoRI and XbaT and the ˜3.4 kb fragment containing the FMDV genes was inserted in pUC8:2 (pUC8 with BglII and XbaI sites added to the multiple cloning site). The resulting 6 kb pUC FMDV plasmid (designated pHM-1119-1) was used as the source of the FMDV genes in all future constructs.

The H6 promoter (H6p) is an early/late promoter derived from the vaccinia H6 gene (Perkus, M. E. et al, (1989) J. Virol. 63: 3829-3836), which is designated as the H5 gene in the Copenhagen vaccinia strain. The H6p is a strong promoter that has been used extensively in avipox recombinants for foreign gene expression.

Plasmid pHM-1119-1 was used as the template for PCR amplification with primers 11277.SL and 11282.SL. These primers introduced the 3′ end of the vaccinia H6 promoter, as well as translation and transcription stop signals, and XbaI or BamHI restriction sites for cloning. The primer sequences are shown in FIG. 2. The 3.4 kb PCR product was cloned into pCR2.1 to generate plasmid pHM-1151-4, pCR2.1 H6p FMDV.

Plasmid pCXL-148-2 is an ALVAC insertion plasmid for the C5 loci, which contains the vaccinia virus H6 promoter. The 3.4 kb NruI-XbaI fragment from pHM-1151-4 was inserted into pCXL-148-2, to generate pC5 H6p FMDV P1+3C (pHM-1175-1). The construction of pHM-1175-1 is illustrated in FIGS. 3A and 3B and the sequence of the C5 H6p FMDV gene cassette is shown in FIGS. 4A-4E.

Despite multiple attempts, no ALVAC recombinants were generated from pC5 H6p FMDV P1+3C, pHM-1175-1.

Example 2

Construction of a pF8 H6p FMDV P1+3C Donor Plasmid for Introduction of FMDV Genes into the F8 Locus of Fowlpox

Plasmid pSL-6427-2-1 (pF8 H6p) is a fowlpox insertion plasmid, which contains the vaccinia virus H6 promoter. The 3.4 kb NruI-BamHI fragment from pHM-1151-4 (pCR2.1 H6p FMDV; see Example 1) was inserted into pSL-6427-2-1, generating vector pHM-1180-11 (pF8 H6p FMDV P1+3C). The construction of pHM-1180-11 is illustrated in FIGS. 5A and 5B and the sequence of the F8 H6p FMDV gene cassette is shown in FIGS. 6A-6F.

Despite multiple attempts, no fowlpox recombinants could be generated from pF8 H6p FMDV P1+3C, pHM-1180-1.

Example 3

Construction of a Promoter-Less pC6 FMDV P1+3C Insertion Plasmid

The failure to generate avipox recombinants expressing FMDV genes could be due to the use of the strong vaccinia virus H6 promoter in the pC5 H6p FMDV P1+3C and pF8 H6p FMDV P1+3C plasmids described in Examples 1 and 2. In addition, the ALVAC donor plasmid results in the insertion of gene cassettes at the two C5 loci. For ALVAC, different viral promoters and the unique C6 insertion locus was used.

Plasmid pHM-1119-1 (pUC FMDV, see Example 1) was used as the template for PCR amplification of a 3′-fragment of FMDV, with primers 11280.SL and 11352.CXL. The ˜900 bp PCR fragment contains the 3′-end of FMDV from the XhoI site and introduces translational and transcriptional stops and a PstI cloning site. The primers are illustrated in FIG. 7. The PCR fragment was cloned into pCR2.1, generating plasmid pHM-1240-2, pCR2.1 3′-FMDV.

Plasmid pC6L is an ALVAC insertion plasmid for the unique ALVAC C6 site. The ˜2.6 kb EcoRI-Xho 5′-FMDV fragment from pHM-1119-1 was inserted into pC6L, generating plasmid pCXL-1008-1, pC6 5′-FMDV. The ˜900 bp XhoI-PstI fragment from pHM-1240-2 was inserted into pCXL-1008-1, generating pCXL-1013-2, pC6 FMDV. The construction of pC6 FMDV is illustrated in FIG. 8.

Example 4

Construction of a pC6 H6p FMDV P1+3C Donor Plasmid for Insertion of the FMDV Gene Cassette at the Unique C6 Locus of ALVAC

Plasmid pSL-6407-7 is a pC6 H6p insertion plasmid for the ALVAC C6 locus, which contains the vaccinia virus H6 promoter. The H6 promoter is in the opposite orientation to the C6 arms. The ˜2.6 kb NruI-Xho 5′-FMDV fragment from pHM-1151-4 (pCR2.1 FMDV, see Example 1) was inserted into pSL-6407-7, generating pC6 H6p 5′-FMDV, pCXL-1008-3. The ˜900 bp Xho-PstI 3′-FMDV fragment from pHM-1240-2 (pCR2.1 3′-FMDV, see Example 3) was inserted into pCXL-1008-3, generating pC6 H6p FMDV P1+3C, pCXL-1013-4. The construction of pC6 H6p FMDV P1+3C is illustrated in FIGS. 9A and 9B and the sequence of the C6 H6p FMDV gene cassette is shown in FIGS. 10A-10E.

Despite multiple attempts, ALVAC recombinants could not be generated using the pC6 H6p FMDV P1+3C donor plasmid, suggesting that insertion at a single site with a strong promoter was not feasible.

Example 5

Construction of a pC6 H6p* FMDV P1+3C Donor Plasmid for Insertion of the FMDV Gene Cassette at the Unique C6 Locus of ALVAC

Based upon studies with the vaccinia virus 7.5K early promoter (Davison, A. J. and Moss, B. (1989) J. Mol. Biol. 210: 749-769), a point mutation was introduced into the vaccinia virus H6 early promoter region, generating a mutant H6 promoter, H6p*. The wild-type early/late H6p and mutant early H6p* sequences are shown in FIG. 11.

Plasmid pHM-1119-1 (pUC FMDV, see Example 1) was used as the template to PCR amplify the H6p* 5′-FMDV fragment, with primers 11353.CXL and 11358.CXL. The ˜1.2 kb fragment contained the H6p* and the 5′-FMDV genes up to a unique NdeI site. The fragment was cloned into pCR2.1, generating plasmid pHM-1249-1-3. This clone was missing a nucleotide in VP4, so site-directed mutagenesis was performed with primers 11410.HM and 11411.HM to repair the PCR error. Clone pHM-1260-2, pCR2.1 H6p* 5′-FMDV, was confirmed by sequence analysis. FIG. 12A describes the PCR amplification primers and FIG. 12B describes the mutagenesis primers.

The ˜1.2 kb EcoR I-Nde I H6p* 5′-FMDV fragment from pHM-1260-2 was inserted into pCXL-1013-2 (pC6 FMDV P1+3C, see Example 3), generating plasmid pHM-1273-1, pC6 H6p* FMDV P1+3C. The construction of pC6 H6p* FMDV P1+3C is illustrated in FIGS. 13A and 13B and the sequence of the C6 H6p* FMDV gene cassette is shown in FIGS. 14A-14E.

To generate an ALVAC recombinant, primary chicken embryonic fibroblasts (CEF) were transfected with SapI-linearized pHM-1273-1 donor plasmid, in the presence of FuGENE-6® reagent (Roche). The transfected cells were subsequently infected with ALVAC as rescue virus at an MOI of 10 and after 24 hours, the transfected-infected cells were harvested, sonicated, and used for recombinant virus screening. Recombinant plaques were screened based on the plaque lift hybridization method using a 1.7 kb FMDV-specific probe labeled with horseradish peroxidase (HRP) according to the manufacturer's protocol (Amersham). ALVAC recombinants were generated and designated as vCP2176.

Example 6

Construction of a pC6 T3Lp FMDV P1+3C Donor Plasmid for Introduction of the FMDV Genes into the Unique C6 Locus of ALVAC

The early/intermediate I3L promoter (I3Lp) from vaccinia virus (Schmitt, J. F. and Stunnenberg, H. G. (1988) J. Virol. 62: 1889-1897) has been used previously in avipox recombinants.

Plasmid pCXL-1-4 is pC5 H6p EHV-1 gB (−TM)/42Kp EHV-1gD (−TM)/I3Lp EHV-1 gC (−TM), a donor plasmid used to introduce the EHV-1 gB, gC, and gD genes into ALVAC (described in U.S. Pat. No. 5,756,103). Each gene utilizes a different viral promoter, so pCXL-1-4 was used as the template to PCR amplify the I3L promoter. Primers 11407.CXL and 11423.CXL were used to amplify a 75 bp fragment containing the I3 L promoter and the 5′-end of the FMDV genes. The PCR primers are described in FIG. 15A.

A 648 bp PCR fragment, which contains a 20 bp overlap with the 75 bp I3Lp fragment, was amplified using primers 11425.CXL and 11407.CXL, with pHM-1119-1 (pUC FMDV, see Example 1) as template. This fragment contained the 5′-FMDV genes up to the unique KpnI site. The PCR primers are described in FIG. 15B.

The two PCR fragments were mixed at a 1:1 molar ratio and PCR amplified using primers 11423.CXL and 11407.CXL. The resultant 703 bp fragment was cloned into pCR2.1, generating pCXL-1068-1 (pCR2.1 I3Lp 5′-FMDV).

The ˜700 bp EcoRI-KpnI I3Lp 5′-FMDV fragment from pCXL-1068-1 was inserted into pHM1119-1, generating pCXL-1072-2 (pUC I3Lp FMDV P1+3C).

The ˜1.2 kb EcoRI-NdeI I3Lp 5′-FMDV fragment from pCXL-1072-2 was inserted into pCXL-1013-2 (pC6 FMDV P1+3C). The construction of pC6 I3Lp FMDV P1+3C is illustrated in FIGS. 16A and 16B and the sequence of the C6 I3Lp FMDV gene cassette is shown in FIGS. 17A-17E.

To generate an ALVAC recombinant, primary CEFs were transfected with 20 μg of SapI-linearized donor plasmid pCXL-1079-1 using FuGENE-6® reagent (Roche). The transfected cells were subsequently infected with ALVAC as rescue virus at an MOI of 10 and after 24 hours, the transfected-infected cells were harvested, sonicated, and used for recombinant virus screening. Recombinant plaques were screened based on the plaque lift hybridization method using a 1.7 kb FMDV-specific probe labeled with horseradish peroxidase (HRP) according to the manufacturer's protocol (Amersham). After four sequential rounds of plaque purification, the recombinants designated as vCP2181.4.1.1.1 and vCP2181.5.1.1.1 were generated and confirmed by hybridization as 100% positive for the FMDV insert and 100% negative for the C6 ORF.

Single plaques were selected from the 4^th round of plaque purification and expanded to obtain P1 (1×T25 flask per sister), P2 (1×T75 flask per sister) and P3 (4×roller bottles per sister) amplified stocks of the vCP2181 recombinants. The infected cells from the roller bottles were harvested and concentrated to produce virus stock. The viral concentrate was re-confirmed by hybridization of plaque lifts with the FMDV- and C6-specific probes. Viral DNA was prepared and the correct insertion of the FMDV gene cassette at the ALVAC C6 locus was confirmed by Southern blot and sequence analyses. Immunoblot and immunoplaque assays were performed using specific antibodies as described in Example 7 (see FIG. 30).

Example 7

Construction of a pC6 42 kDp FMDV P1+3C Donor Plasmid for the Introduction of the FMDV Genes into the Unique C6 Locus of ALVAC

A 42K promoter (42Kp) derived from the AMV091 gene (vaccinia virus A23R homolog) of the insect poxvirus Amsacta moorei (Bawden, A. L. et al, (2000) Virology 274: 120-139) has been used previously in avipox recombinants (U.S. Pat. No. 5,756,103).

Plasmid pCXL-1-4 is pC5 H6p EHV-1 gB (−TM)/42Kp EHV-1 gD (−TM)/I3Lp EHV-1 gC (−TM), a donor plasmid used to introduce the EHV-1 gB, gC, and gD genes into ALVAC (see Example 6). Each gene uses a different viral promoter, so pCXL-1-4 was used as the template to PCR amplify the 42K promoter. Primers 11426.CXL and 11427.CXL were used to amplify a 48 bp fragment containing the 42K promoter and the 5′-end of the FMDV genes. The PCR primers are described in FIG. 18A.

A 647 bp PCR fragment, which contains a 20-bp overlap with the 48 bp 42Kp fragment, was amplified using primers 11428.CXL and 11407.CXL, with pHM-1119-1 (pUC FMDV, see Example 1) as a template. This fragment contains the 5′-FMDV genes up to the unique KpnI site. The PCR primers are described in FIG. 18B.

The two PCR fragments were mixed at a 1:1 molar ratio and PCR amplified using primers 11426.CXL and 11407.CXL. The resultant 676 bp fragment was cloned into pCR2.1, generating pCXL-1080-2-2 (pCR2.1 42Kp 5′-FMDV).

The 676 bp EcoRI-KpnI 42Kp 5′-FMDV fragment from pCXL-1080-2-2 was inserted into pHM-1119-1, generating pCXL-1089-1 (pUC 42Kp FMDV P1+3C).

The ˜1.2 kb EcoRI-NdeI 42Kp 5′-FMDV fragment from pCXL-1089-1 was inserted into pCXL-1013-2 (pC6 FMDV P1+3C, see Example 3), generating pCXL-1095-1 (pC6 42Kp FMDV P1+3C). The construction of pC6 42Kp FMDV P1+3C is illustrated in FIGS. 19A and 19B and the sequence of the C6 42Kp FMDV gene cassette is shown in FIGS. 20A-20E.

To generate an ALVAC recombinant, primary CEFs were transfected with 20 μg of SapI-linearized donor plasmid pCXL-1095-1, using FuGENE-6® reagent (Roche). The transfected cells were subsequently infected with ALVAC as rescue virus at an MOI of 10 and after 29 hours, the transfected-infected cells were harvested, sonicated, and used for recombinant virus screening. Recombinant plaques were screened based on the plaque lift hybridization method using the 1.7 kb FMDV-specific probe labeled with horseradish peroxidase (HRP) according to the manufacturer's protocol (Amersham). After four sequential rounds of plaque purification, the recombinant designated as vCP2186.6.2.1.1 was generated and confirmed by hybridization as 100% positive for the FMDV insert and 100% negative for the C6 ORF.

Single plaques were selected from the 4^th round of plaque purification, and expanded to obtain P1 (1×T25 flask), P2 (1×T75 flask) and P3 (8×roller bottles) amplified stocks. The infected cells from the roller bottles were harvested and concentrated to produce virus stock. The virl concentrate was characterized by performing hybridization of plaque lifts with the FMDV- and C6-specific probes to confirm 100% genetic purity. Viral DNA was extracted and Southern blotting and sequence analyses confirmed the correct insertion of the FMDV gene cassette.

For expression analysis, CEFs were infected at an MOI of 10 with vCP2181 (ALVAC C6 I3Lp FMDV P1+3C; see Example 6) or vCP2186 (ALVAC C6 42Kp FMDV P1+3C) and grown at 37° C., in the presence of 5% CO₂, for 24 hours. The supernatant was harvested and clarified and the cell monolayer was resuspended in PBS, and then pelleted. The pellets were resuspended in water, and then SDS PAGE sample buffer was added to the supernatants. The protein samples were separated on a 10% SDS PAGE gel, then electrotransferred to a nylon membrane. The membrane was blocked, and then probed with rabbit anti-FMDV VP1, VP2, and VP3 antisera. Secondary antibody and colorimetric analysis revealed that both recombinants expressed specific proteins of sizes consistent with VP0, VP1 and VP3 in both the pellets and supernatants. These data are illustrated in FIG. 30.

Example 8

Construction of a pC6 7.5Kp FMDV P1+3C Donor Plasmid for the Introduction of the FMDV Genes into the Unique C6 Locus of ALVAC

The early 7.5K promoter (7.5Kp) of vaccinia virus (Davison, A. J. and Moss, B. (1989) J. Mol. Biol. 210: 749-769) has been used previously in avipox recombinants.

Plasmid pHM-1119-1 (pUC FMDV, see Example 1) was used as the template for PCr amplification of the 7.5K promoter and FMDV genes, up to the unique NdeI site. Primers 11357.CXL and 11358.CXL were used to amplify a 1214 bp 7.5Kp 5′-FMDV fragment, which was cloned into pCR2.1, generating pHM-1249-5-3. The PCR amplification primers are describe in FIG. 21A.

Sequence analysis revealed that three base pair deletions in pHM-1249-5-3. Oligonucleotide primers 11429.HM and 11430.HM were designed to re-introduce the missing ucleotides by site-directed mutagenesis. The mutagenesis primers are described I FIG. 21B. The resultant clones contained 2 of the 3 re-introduced nucleotides, so clone pHM-1267-4 was subjected to a further round of site-directed mutagenesis with primers 11445.HM and 11446.HM. The mutagenesis primers are described in FIG. 21C. Clone pHM-1299-2 (pCR2.1 7.5Kp 5′-FMDV) was confirmed to be correct by sequence analysis.

The ˜1.2 kb EcoRI-NdeI fragment from pHM-1299-2 was inserted into pCXL-1013-2 (pC6 FMDV, see Example 3), generating plasmid pHM-1310-4 (pC6 7.5Kp FMDV P1+3C). The construction of pHM-1310-4 is illustrated in FIGS. 22A and 22B and the sequence of the C6 7.5Kp FMDV gene cassette is shown in FIGS. 23A-23E.

ALVAC recombinant vCP2189 was obtained after two rounds of screening, but could not be purified/amplified and was lost, suggesting that it was unstable and/or toxic.

Example 9

Construction of a pC6 Pip FMDV P1+3C Donor Plasmid for the Insertion of the FMDV Genes into the Unique C6 Locus of ALVAC

The early Pi promoter (Pip) from vaccinia virus (Wachsman, M. et al, (1987) J. Infect. Dis. 155: 1188-1197) has been used previously in avipox recombinants. It is 81 nucleotides in length and is thought to be a relatively weak promoter.

Plasmid pHM-1119-1 (pUC FMDV, see Example 1) was used as a template to PCR-amplify the Pip 5′-FMDV fragment, with primers 11356.CXL and 11358.CXL (FIG. 24A). The amplified fragment was cloned into pCR2.1 and several clones were screened by sequence analysis. The clone with the fewest PCR errors (pHM-1249-4-4, pCR2.1 Pip* 5′-FMDV) was missing 28 nucleotides randomly throughout the Pi promoter region, including the EcoRI cloning site.

Oligonucleotides 11395.CXL and 11399.CXL (FIG. 24B) were used to assemble the correct Pi promoter. The Pip was PCR amplified with primers 11400.CXL and 11401.CXL (FIG. 24C) and cloned into pCR2.1 to generate pHM-1263-1 (pCR2.1 Pip). Plasmid pHM-1263-1 was used as a template to PCR-amplify a 97 bp Pip 5′-FMDV fragment, using primers 11402.CXL and 1140.CXL (FIG. 24D). This fragment contains the EcoRI cloning site, the full-length Pip and 10 bp of FMDV.

Using pHM-1249-4-4 as template, a 648 bp fragment was PCR-amplified using primers 11406.CXL and 11407.CXL (FIG. 24E). This fragment contains 10 bp of the 3′ end of Pip and the 5′-FMDV genes up to a unique KpnI site.

Equimolar amounts of the 97 bp Pip 5′-FMDV and 648 bp 3′-Pip 5′-FMDV PCR fragments were mixed and amplified using primers 11402.CXL and 11407.CXL. The resulting 745 bp Pip 5′-FMDV (EcoRI-KpnI) fragment was cloned into pCR2.1 to generate pHM-1268-1 (pCR2.1 Pip 5′-FMDV, EcoRI-KpnI). The EcoRI-KpnI fragment from pHM-1268-1 was inserted into pHM-1119-1, generating pHM-1277-6 (pUC Pip FMDV).

The 1252 bp EcoRI-NdeI Pip 5′-FMDV fragment from pHM-1277-6 was inserted into plasmid pCXL-1013-2 (pC6 FMDV P1+3C, see Example 3), generating plasmid pHM-1284-25 (pC6 Pip FMDV P1+3C). The construction of pC6 Pip FMDV P1+3C is illustrated in FIG. 25 and the sequence of the C6 Pip FMDV gene cassette is shown in FIGS. 26A-26E.

ALVAC recombinant vCP2184 was obtained after two rounds of purification, but was lost at the third round of screening/amplification, suggesting that it was toxic and/or unstable.

Example 10

Construction of a pF8 H6p* FMDV P1+3C Donor Plasmid for Insertion of the FMDV Gene Cassette at the Unique F8 Locus of Fowlpox

Plasmid pHM-1260-2 (pCR2.1 H6p* 5′-FMDV (Nde); see Example 5) was used as the template to PCR amplify an H6p* 5′-FMDV fragment, with primers 11506.HM and 11279.5L. Primer 11506.HM was designed to introduce a Hind III site in front of H6p* and primer 11279.5L was designed to amplify the FMDV genes up to the unique KpnI site in the VP2 gene. The ˜700 bp fragment was cloned into pCR2.1, generating pHM-1341-7 (pCR2.1 H6p* 5′-FMDV KpnI), which was confirmed as correct by sequence analysis. FIG. 27 describes the PCR primers.

Plasmid pHM-1180-11 is pF8 H6p FMDV P1+3C, containing the wild-type H6 promoter (see Example 2 and FIGS. 5A and 5B). Plasmid pSL-6427-1-1 (pF8 MCS) is a promoter-less plasmid used for insertion into the fowlpox F8 site. The 0.7 kb HindIII-KpnI H6p* 5′-FMDV fragment from pHM-1341-7 and the 2.7 kb KpnI-BamH I 3′-FMDV fragment from pHM-1180-11 were ligated into plasmid pSL-6427-1-1 that had been digested with HindIII and BamHI, generating pHM-1354-1 (pF8 H6p* FMDV P1+3C). The construction ofpHM-1354-1 is illustrated in FIGS. 28A and 28B and the sequence of the F8 H6p* FMDV P1+3C gene cassette is shown in FIGS. 29A-29F.

To generate a fowlpox recombinant, primary CEFs were transfected with NotI-linearized pHM-1354-1, in the presence of Fugene-6® reagent (Roche). The transfected cells were subsequently infected with fowlpox as rescue virus at MOI of 10 and after 51 hours, the transfected-infected cells were harvested, sonicated and used for recombinant virus screening. Recombinant plaques were screened based on the plaque lift hybridization method using a 1.7 kb FMDV-specific probe labelled with horseradish peroxidase (HRP) according to the manufacturer's protocol (Amersham Cat# RPN3001). After five sequential rounds of plaque purification, a fowlpox recombinant designated as vFP2215.1.3.1.1.1 was generated and confirmed by hybridization as 100% positive for the FMDV insert and 100% negative for the F8 ORF.

Single plaques were selected from the 5^th round of plaque purification, and expanded to obtain P1 (1×T25 flask), P2 (2×T75 flask) and P3 (10×roller bottles) stocks to amplify vFP2215. The infected cells from the roller bottles was harvested and concentrated to produce virus stock. The viral concentrate was re-confirmed by hybridization of plaque lifts with the FMDV- and F8-specific probes. Viral DNA was prepared and the correct insertion of the FMDV gene cassette at the fowlpox F8 locus was confirmed by Southern blot and sequence analyses.

Example 11

Preparation and Purification of Plasmids

For the preparation of the plasmids intended for the vaccination of animals, any technique may be used which makes it possible to obtain a suspension of purified plasmids predominantly in a supercoiled form. These techniques are well known to persons skilled in the art. There may be mentioned in particular the alkaline lysis technique followed by two successive ultracentrifugations on a caesium chloride gradient in the presence of ethidium bromide as described in J. Sambrook et al. (Molecular Cloning: A Laboratory Manual, 2nd edition, Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y., 1989). Reference may also be made to Patent Applications PCT WO 95/21250 and PCT WO 96/02658, which describe methods for producing, on an industrial scale, plasmids which can be used for vaccination. For the purposes of the manufacture of vaccines (see Example 11), the purified plasmids are resuspended so as to obtain solutions at a high concentration (>2 mg/ml), which are compatible with storage. To do this, the plasmids are resuspended either in ultrapure water or in TE buffer (10 mM Tris-HC 1; 1 mM EDTA, pH 8.0).

Example 12

Manufacture of the Associated Vaccine

The various plasmids necessary for the manufacture of an associated vaccine are mixed starting with their concentrated solutions (Example 10). The mixtures are prepared such that the final concentration of each plasmid corresponds to the effective dose of each plasmid. The solutions, which can be used to adjust the final concentration of the vaccine may be either a 0.9M NaCl solution, or PBS buffer.

Specific formulations such as liposomes or cationic lipids may also be used for the manufacture of the vaccines.

Example 13

Vaccination of Animals

The animals are vaccinated with doses of 100 pg, 250 μg or 500 μg per plasmid. The injections are performed with a needle by the intramuscular route either at the level of the gluteus muscle, or at the level of the neck muscles. The vaccinal doses are administered in volumes of between 1 and 5 ml.

Having thus described in detail preferred embodiments of the present invention, it is to be understood that the invention defined by the appended claims is not to be limited to particular details set forth in the above description as many apparent variations thereof are possible without departing from the spirit or scope of the present invention.

Claims

1-30. (canceled)

31. A method of producing a recombinant avipox vector comprising at least one nucleic acid molecule encoding one or more foot-and-mouth disease virus (FMDV) antigen(s), comprising the steps of:

(a) linearizing a donor plasmid with a restriction endonuclease, wherein the donor plasmid comprises restriction endonuclease cleavage sites or a multiple cloning site; and

(b) ligating at least one nucleic acid molecule comprising

(i) a nucleic acid sequence encoding one or more FMDV antigen(s),

(ii) a viral promoter sequence, and

(iii) insertion sequences flanking (i) and (ii) that have complementary restriction endonuclease cleavage sites to the donor plasmid at FMDV antigens,

thereby producing the recombinant avipox vector.

32. The method of claim 31, further comprising the steps of:

(c) introducing the vector into a cell permissive for replication of the vector; and

(d) isolating the vector from the cell.

33. The method of claim 31, wherein the avipox is ALVAC.

34. The method of claim 31, wherein the avipox is fowlpox.

35. The method of claim 31, wherein the antigen comprises at least one of FMDV VP1, VP2, VP3, VP4, 2A, 2B, and 3C.

36. The method of claim 31, wherein the nucleic acid sequence encoding one or more FMDV antigen(s) is a cDNA encoding FMDV P1 region and a cDNA encoding FMDV 3C protease.

37. The method of claim 31, wherein the promoter sequence is selected from the group consisting of H6 vaccinia promoter, I3L vaccinia promoter, 42K poxyiral promoter, 7.5K vaccinia promoter and Pi vaccinia promoter.

38. The method of claim 37, wherein the promoter is the H6 vaccinia promoter, which is mutated such that expression levels of the FMDV antigens are decreased compared with expression levels of the FMDV antigens under a wild type H6 vaccinia promoter.

39. The method of claim 31, wherein the vector comprises a C6 insertion locus, and wherein flanking sequences of the C6 insertion locus promote homologous recombination of the FMDV antigens with the C6 insertion locus.

40. The method of claim 39, wherein the flanking sequences comprise C6L and C6R open reading frames of avipox.

41. The method of claim 31, wherein the vector comprises a F8 insertion locus, and wherein flanking sequences of the F8 insertion locus promote homologous recombination of the FMDV antigens with the F8 insertion locus.

42. The method of claim 41, wherein the flanking sequences comprise F8L and F8R open reading frames of avipox.

43. The method of claim 31, wherein the vector further comprises a reporter gene.

44. The method of claim 43, wherein the reporter gene is selected from the group consisting of neomycin resistance gene, ampicillin resistance gene, lacZ (□-galactosidase), luciferase, and green fluorescent protein (GFP).

45. The method of claim 32, wherein the cell permissive for growth of the vector is a chicken embryonic fibroblast.