Patent Application
20130101619
The present invention relates to novel recombinant multivalent non-pathogenic Marek's Disease virus constructs encoding and expressing Infectious Laryngotracheitis Virus and Newcastle Disease virus protein antigens, and methods of their use in poultry vaccines.
Pathogenic poultry viruses are not only debilitating to chickens, but they also are costly to chicken breeders because most of the resulting diseases are contagious and the poultry industry relies heavily on confined, large-scale breeding facilities. Vaccinating young chicks is often the only viable means to combat these viruses. Although attenuated or killed poultry viral vaccines remain important in the market place, in recent years significant resources have been expended on developing vaccines containing recombinant viral constructs which express pathogenic viral protein antigens. Furthermore, substantial efforts have been made to construct stable and efficacious multivalent recombinant non-pathogenic Marek's Disease virus (rMDVnp) vectors that express foreign genes from multiple viral pathogens. Such multivalent vaccines would serve to minimize the number of injections given to the chicks and thereby, reduce discomfort and stress on the vaccinated chick, as well as significantly reduce costs in labor and materials. Vaccinating with such single multivalent constructs also would be preferable to alternative multivalent rMDVnp vaccines that contain multiple recombinant monovalent rMDVnp constructs, because these alternative vaccines have, at least to date, resulted in protection against only a single viral pathogen. The failure of such alternative vaccines is presumably due to one of the monovalent rMDVnp constructs overgrowing the other monovalent rMDVnp constructs thereby, preventing these other monovalent rMDVnp constructs from inducing a significant immune response. In any case, despite substantial efforts in the past to construct stable and efficacious multivalent recombinant rMDVnp vectors that express foreign genes from multiple viral pathogens heretofore, such efforts have proved unsuccessful.
One poultry virus disease that can be controlled through vaccination is Marek's disease. Marek's disease is a pathogenic disease that adversely affects chickens, worldwide. Marek's disease occurs predominantly in young chickens between 2 and 5 months of age. Clinical signs include: progressive paralysis of one or more of the extremities, incoordination due to paralysis of legs, drooping of the limb due to wing involvement, and a lowered head position due to involvement of the neck muscles. In acute cases, severe depression may result. Bursal and thymic atrophy may also develop.
The etiological agent for Marek's disease is Marek's disease virus serotype 1 (MDV1), a cell-associated virus having a double-stranded DNA genome. MDV1 is a lymphotropic avian alphaherpesvirus that both: (i) infects B cells, which can result in cytolysis, and (ii) latently infects T cells, which can induce T-cell lymphoma. Closely related to the virulent MDV1 strain, Marek's disease virus serotype 2 (MDV2), previously known as Gallid herpes virus 3, is a naturally attenuated MDV strain that has been shown to have little to no pathogenicity in chickens [Petherbridge et al., J. Virological Methods 158:11-17 (2009)]. SB-1 is a specific MDV2 strain that has been shown to be useful in vaccines against MDV1 [see e.g., Murthy and Calnek, Infection and Immunity 26(2) 547-553 (1979)].
Another closely related alphaherpesvirus, Marek's disease virus serotype 3 (MDV3), more widely known as herpesvirus of turkeys (HVT), is a nonpathogenic virus of domestic turkeys [see e.g., Kingham et al., J. of General Virology 82:1123-1135 (2001)]. Two commonly used strains of HVT are the PB1 strain and the FC126 strain. Whereas, HVT is also nonpathogenic in chickens, it does induce a long-lasting protective immune response in chickens against MDV1. Accordingly, HVT has been used in poultry vaccines against virulent MDV1 for many years, generally in combination with SB-1, which is more viraemic than HVT, but considered less safe. Alternatively, when flocks are challenged with particularly virulent MDV1 strains, HVT can be combined with the Rispen's vaccine. The Rispen's vaccine is an isolate that originated from a mildly virulent MDV1 strain that was subsequently further weakened by cell passaging. The Rispen's strain however, retains some virulence towards highly susceptible lines of chickens.
The sequence of the complete genome of HVT has been disclosed [Afonso et al., J. Virology 75(2):971-978 (2001)], and as most alphaherpesviruses, HVT possesses a significant number of potential nonessential insertion sites [see e.g., U.S. Pat. No. 5,187,087; U.S. Pat. No. 5,830,745; U.S. Pat. No. 5,834,305; U.S. Pat. No. 5,853,733; U.S. Pat. No. 5,928,648; U.S. Pat. No. 5,961,982; U.S. Pat. No. 6,121,043; U.S. Pat. No. 6,299,882 B1]. HVT also has been shown to be amenable to genetic modification and thus, has been used as a recombinant vector for many years [WO 87/04463]. Accordingly, recombinant HVT vectors have been reported to express foreign genes that encode antigens from e.g., Newcastle Disease Virus (NDV), [Sondermeijer et al., Vaccine, 11:349-358 (1993); Reddy et al., Vaccine, 14:469-477 (1996)], Infectious Bursal Disease Virus (IBDV), [Darteil et al., Virology, 211:481-490 (1995); Tsukamoto et al., J. of Virology 76(11):5637-5645 (2002)], and Infectious Laryngotracheitis Virus (ILTV) [Johnson et al., Avian Disease, 54(4):1251-1259 (2010); WO 92/03554; U.S. Pat. No. 6,875,856]. The entire genomic sequence of MDV2 is also known [see, GenBank acc. nr: AB049735.1, and Petherbridge et al., supra]. The genomic organization of the MDV2 is very similar to that of HVT, with the US region in particular, being identical to that of HVT [see, Kingham et al., supra].
In addition a recombinant chimeric virus, known as the novel avian herpesvirus (NAHV), has been constructed in which specific regions of the HVT genome have been replaced by the corresponding regions of the MDV1 genome. The NAHV also has been used to express foreign genes that encode antigens from other poultry viruses [U.S. Pat. No. 5,965,138; U.S. Pat. No. 6,913,751].
Like MDV, infectious laryngotracheitis virus (ILTV) is an alphaherpesvirus that adversely affects chickens, worldwide [Fuchs et al., Veterinary Research 38:261-279 (2007)]. ILTV causes acute respiratory disease in chickens, which is characterized by respiratory depression, gasping, and expectoration of bloody exudate. Viral replication is limited to cells of the respiratory tract, where in the trachea the infection gives rise to tissue erosion and hemorrhage.
Newcastle disease is another highly contagious and debilitating disease of chickens. The etiological agent for Newcastle disease is the Newcastle disease virus (NDV). NDV belongs to the order of the Mononegavirales and is in the family of Paramyxoviridae. Newcastle disease viruses have a non-segmented, negative sense, single-stranded RNA genome. NDV has been grouped into three distinct pathotypes according to their virulence. Infection of poultry by the non-pathogenic lentogenic strains of NDV is essentially asymptomatic. In direct contrast, the mesogenic (medium pathogenic) and velogenic (highly pathogenic) NDV strains cause extensive disease that can be fatal. Most types of NDV infect the respiratory system and/or the nervous system, and can result in gasping and torticollis.
Infectious bursal disease virus (IBDV), also called Gumboro disease virus, is the causative agent of infectious bursal disease. IBDV causes an acute, highly-contagious, viral infection of a chicken's lymphoid tissue, with its primary target being the bird's essential immunological organ: the bursa of Fabricius. The morbidity rate in susceptible flocks is high, with rapid weight loss and moderate to high mortality rates. Chicks that recover from the disease may have immune deficiencies because of destruction of (or parts of) the bursa of Fabricius. This makes them particularly vulnerable to secondary infections.
IBDV is a member of the Birnaviridae family. The viruses in this family have a genome consisting of two segments (A and B) of double-stranded RNA. Two serotypes of IBDV exist, serotype 1 and 2, which can be differentiated by virus neutralization (VN) tests. Serotype 1 viruses have been shown to be pathogenic to chickens, while serotype 2 viruses cause only sub-acute disease in turkeys. Historically, IBDV serotype 1 viruses consisted of only one type that is now known as “classic” IBD virus. More recently, so-called “variant” IBDV strains have emerged. Classic and variant strains of IBDV can be identified and distinguished by a virus neutralisation test using a panel of monoclonal antibodies, or by RT-PCR [Wu et al., Avian Diseases, 51:515-526 (2007)]. Well-known classic IBDV strains include, D78, Faragher 52/70, and STC, whereas 89/03 is a well-known variant strain. Many live or inactivated IBDV vaccines are commercially available, e.g. a live vaccine such as NOBILIS® Gumboro D78 (MSD Animal Health).
As indicated above, because HVT can act as both an antigen that provides significant protection against Marek's Disease and as a recombinant vector, it is presently used as a platform vector for such multivalent vaccines as Innovax®-ILT (sold by Merck Animal Health), which protects against ILTV; and Innovax®-ND-SB (sold by Merck Animal Health) and Vectormune® HVT-NDV (sold by Ceva), both of which protect against NDV. Notably, however, heretofore, no multivalent vaccine comprising a recombinant HVT encoding antigens from more than one pathogen has been shown to be stable and efficacious, even though such vaccines had been suggested more than fifteen years ago [see e.g., U.S. Pat. No. 5,965,138]. Indeed, Innovax®-ILT contains the only recombinant HVT that comprises two foreign genes, i.e., ILTV gD and ILTV gI, which has proved to be safe, effective, and stable. However, these two foreign genes are from the same pathogen and moreover, they naturally overlap and need to be co-expressed in order to allow proper immunization against ILTV.
Accordingly, despite the clear advantages of stable, multivalent, recombinant MDVnp constructs that can efficaciously express foreign antigens from two or more different pathogens, and the substantial efforts to design them, heretofore, none have been forthcoming. Therefore, there is a clear need to overcome the collective industry failure, by constructing novel, stable, recombinant MDVnp vectors that can be used in multivalent vaccines as the sole active to protect against two or more different non-MDV1 poultry virus pathogens.
The citation of any reference herein should not be construed as an admission that such reference is available as “prior art” to the instant application.
Accordingly, the present invention provides a novel, stable, and efficacious multivalent recombinant nonpathogenic Marek's Disease virus (rMDVnp) for use as a vector to express foreign genes from multiple viral pathogens. In particular embodiments, the rMDVnp is a recombinant herpesvirus of turkeys (rHVT). In alternative embodiments, the rMDVnp is a recombinant Marek's disease virus serotype 2 (rMDV2). An rMDVnp, e.g., an rHVT or an rMDV2, can be used in vaccines against pathogenic poulty viruses.
In particular embodiments, an rMDVnp comprises a first nucleic acid inserted in a first nonessential site in the rMDVnp genome and a second nucleic acid inserted in a second nonessential site in the rMDVnp genome. The first nucleic acid comprises both a nucleotide sequence that encodes an Infectious Laryngotracheitis Virus (ILTV) gD protein and a nucleotide sequence that encodes an Infectious Laryngotracheitis Virus (ILTV) gI protein. The second nucleic acid comprises a nucleotide sequence that encodes a Newcastle Disease Virus (NDV) F protein. In specific embodiments of this type, the first nucleic acid comprises the nucleotide sequence of SEQ ID NO: 16 and the second nucleic acid comprises the nucleotide sequence of SEQ ID NO: 15. In specific embodiments, the rMDVnp is an rHVT. In alternative embodiments, the rMDVnp is an rMDV2.
In certain embodiments, the first nonessential site of the rMDVnp is the US2 site, while the second nonessential site is a nonessential site of the rMDVnp other than the US2 site. In related embodiments, the first nonessential site of the rMDVnp is the US2 site and the second nonessential site of the rMDVnp is the UL7/8 site. In yet other embodiments, the first nonessential site of the rMDVnp is the US2 site and the second nonessential site of the rMDVnp is the US10 site. In still other embodiments, the first nonessential site of the rMDVnp is the US2 site and the second nonessential site of the rMDVnp is the UL 54.5 site. In specific embodiments, the rMDVnp is an rHVT. In alternative embodiments, the rMDVnp is an rMDV2.
In other embodiments, the first nonessential site and the second nonessential site of the rMDVnp are the same. In specific embodiments of this type, the first nucleic acid and the second nucleic acid are actually constructed as part of the same DNA molecule, which is inserted into a nonessential site of the rMDVnp. Such a DNA molecule can be an expression cassette that encodes an Infectious Laryngotracheitis Virus (ILTV) gD protein, an Infectious Laryngotracheitis Virus (ILTV) gI protein, and a Newcastle Disease Virus (NDV) F protein. In particular embodiments of this type, the DNA molecule comprises the nucleotide sequence of SEQ ID NO: 17. In specific embodiments, the rMDVnp is an rHVT. In alternative embodiments, the rMDVnp is an rMDV2.
Accordingly, in particular embodiments, the first nonessential site and the second nonessential site of the rMDVnp are the US2 site. In other embodiments, the first nonessential site and the second nonessential site of the rMDVnp are the UL54.5 site. In yet other embodiments, the first nonessential site and the second nonessential site of the rMDVnp are the UL7/8 site. In still other embodiments, the first nonessential site and the second nonessential site of the rMDVnp are the US10 site. In specific embodiments, the rMDVnp is an rHVT. In alternative embodiments, the rMDVnp is an rMDV2.
The nucleotide sequences encoding the ILTV gD protein, the ILTV gI protein, and the NDV F protein can be operatively under the control of exogenous promoters, i.e., promoters that are not naturally found in the MDVnp. In certain embodiments, these three nucleotide sequences are operatively under the control of different promoters, i.e., the nucleotide sequence encoding the ILTV gD protein is operatively under the control of a first promoter, the nucleotide sequence encoding the ILTV gI protein is operatively under the control of a second promoter, and the nucleotide sequence encoding the NDV F protein is operatively under the control of a third promoter, with the first promoter, the second promoter, and the third promoter all being different. In particular embodiments, the promoter for the nucleotide sequence encoding the ILTV gD protein is the endogenous ILTV gD promoter. In certain embodiments, the promoter for the nucleotide sequence encoding the ILTV gI protein is the endogenous ILTV gI promoter. In particular embodiments of this type, the promoter for the nucleotide sequence encoding the ILTV gD protein is the endogenous ILTV gD promoter and the promoter for the nucleotide sequence encoding the ILTV gI protein is the endogenous ILTV gI promoter. In specific embodiments, the rMDVnp is an rHVT. In alternative embodiments, the rMDVnp is an rMDV2.
In certain embodiments, at least one of the promoters operably linked to a nucleotide sequence encoding the ILTV gD protein, the ILTV gI protein, or the NDV F protein is the human cytomegalovirus immediate early (hCMV IE) promoter. In particular embodiments of this type, the promoter for the nucleotide sequence encoding the NDV F protein is the hCMV IE promoter. In specific embodiments, at least one of the promoters operably linked to a nucleotide sequence encoding the ILTV gD protein, the ILTV gI protein or the NDV F protein is the pseudorabies virus (PRV) gpX promoter. In related embodiments, at least one of the promoters operably linked to a nucleotide sequence encoding the ILTV gD protein, the ILTV gI protein or the NDV F protein is the chicken beta-actin gene promoter. In specific embodiments, the promoter for the nucleotide sequence encoding the NDV F protein is the hCMV IE promoter, the promoter for the nucleotide sequence encoding the ILTV gD protein is the endogenous ILTV gD promoter, and the promoter for the nucleotide sequence encoding the ILTV gI protein is the endogenous ILTV gI promoter.
In certain embodiments, an rMDVnp of the present invention that includes insertions of nucleotide sequences encoding the ILTV gD protein, the ILTV gI protein, and the NDV F protein also includes one or more exogenous transcription terminator sequences. In specific embodiments of this type, a transcription terminator sequence is downstream from the nucleotide sequence encoding the NDV F protein. In particular embodiments, the nucleotide sequences encoding the ILTV gD protein and the ILTV gI protein share one transcription terminator sequence and the nucleotide sequence encoding the NDV F protein has another. In particular embodiments, at least one of the transcription terminator sequences comprises a synthetic polyadenylation sequence. In related embodiments at least one of the transcription terminator sequences comprises a Herpes Simplex Virus thymidine kinase (HSV TK) polyadenylation sequence. In specific embodiments, the rMDVnp is an rHVT. In alternative embodiments, the rMDVnp is an rMDV2.
The present invention also provides a recombinant nucleic acid comprising in 5′ to 3′ direction in the following order (i) an Infectious Laryngotracheitis Virus (ILTV) gD promoter, (ii) a coding sequence for the ILTV gD protein, (iii) an ILTV gI promoter, (iv) a coding sequence for the ILTV gI protein, (v) a human cytomegalovirus immediate early (hCMV IE) promoter, (vi) a coding sequence for the NDV F protein, and (viii) a transcription terminator sequence. In a particular embodiment of this type, the recombinant nucleic acid comprises the nucleotide sequence of SEQ ID NO: 17.
The present invention further provides an rMDVnp in which a recombinant nucleic acid of the present invention has been inserted into a nonessential insertion site of the rMDVnp. In certain embodiments of this type, the rMDVnp includes an insert in a nonessential site that comprises a recombinant nucleic acid comprising in 5′ to 3′ direction in the following order (i) an Infectious Laryngotracheitis Virus (ILTV) gD promoter, (ii) a coding sequence for the ILTV gD protein, (iii) an ILTV gI promoter, (iv) a coding sequence for the ILTV gI protein, (v) a human cytomegalovirus immediate early (hCMV IE) promoter, (vi) a coding sequence for the NDV F protein, and (vii) a transcription terminator sequence. In specific embodiments, intervening nucleotide sequences, such as linkers, spacer sequences, and/or extraneous coding sequences, can also be included, see Example 1 below. In a particular embodiment, the rHVT comprises the nucleotide sequence of SEQ ID NO: 17 inserted into a nonessential site. In particular embodiments of these types, the nonessential site is the US2 site. In other such embodiments, the nonessential site is the UL54.5 site. In still other such embodiments, the nonessential site is the UL7/8 site. In yet other such embodiments, the nonessential site is the US10 site. In specific embodiments, the rMDVnp is an rHVT. In alternative embodiments, the rMDVnp is an rMDV2.
The present invention also provides methods of making an rMDVnp of the present invention. In certain embodiments, a heterologous nucleic acid is constructed that comprises a nucleotide sequence that encodes an ILTV gD protein, a nucleotide sequence that encodes an ILTV gI protein, and a nucleotide sequence that encodes an NDV F protein. The heterologous nucleic acid is then inserted into a nonessential site of an rMDVnp of the present invention. In certain embodiments, the heterologous nucleic acid is an expression cassette. In particular embodiments of this type, the expression cassette comprises the nucleotide sequence of SEQ ID NO: 17. In other embodiments, a first heterologous nucleic acid is constructed that comprises a nucleotide sequence that encodes an ILTV gD protein and a nucleotide sequence that encodes an ILTV gI protein; and a second heterologous nucleic acid is constructed that comprises a nucleotide sequence that encodes an NDV F protein. The first heterologous nucleic acid is inserted into a US2 site of an rMDVnp and the second heterologous nucleic acid is inserted into an alternative nonessential site of the rMDVnp. In certain embodiments, such heterologous nucleic acids are expression cassettes. In particular embodiments of this type, the first heterologous nucleic acid comprises the nucleotide sequence of SEQ ID NO: 16, and the second heterologous nucleic acid comprises the nucleotide sequence of SEQ ID NO: 15. In specific embodiments, the method of making an rMDVnp is a method of making an rHVT. In alternative embodiments, the method of making an rMDVnp is a method of making an rMDV2.
The present invention further provides immunogenic compositions and/or vaccines that comprise any rMDVnp of the present invention. In specific embodiments, the rMDVnp is an rHVT. In alternative embodiments, the rMDVnp is an rMDV2. In addition, the present invention provides methods for aiding in the protection of poultry against a disease caused by ILTV and/or NDV and/or MDV1 by administering such a vaccine and/or immunogenic composition of the present invention. In specific embodiments, such methods aid in the protection of a chicken. In particular embodiments of this type, a vaccine of the present invention is administered subcutaneously. In other embodiments, a vaccine of the present invention is administered in ovo.
Accordingly in one aspect, the present invention provides stable, safe, and efficacious immunogenic compositions and/or vaccines that comprise an rMDVnp of the present invention. The present invention also provides immunogenic compositions and/or vaccines that comprise any rMDVnp of the present invention that is further combined with an additional NDV, ILTV, and/or MDV antigen to improve and expand the immunogenicity provided. In addition, the present invention also provides immunogenic compositions and/or vaccines that comprise any rMDVnp of the present invention that is further combined with an antigen for a pathogen other than MDV, ILTV, or NDV. In a particular embodiment of this type, the antigen is an Infectious Bursal Disease Virus (IBDV) antigen. In a more particular embodiment the IBDV antigen is a mild live IBDV. In certain embodiments the mild live IBDV is a variant IBDV. The present invention also provides methods for aiding in the protection of poultry against a disease caused by ILTV and/or NDV and/or MDV1 and/or IBDV by administering such a vaccine and/or immunogenic composition to the poultry (e.g., chicken). In particular embodiments of this type, a vaccine of the present invention is administered subcutaneously. In other embodiments, a vaccine of the present invention is administered in ovo.
In certain embodiments the immunogenic compositions and/or vaccines of the present invention comprise an rHVT that comprises as an insertion into its US2 site of a recombinant nucleic acid comprising 5′ to 3′: (i) an Infectious Laryngotracheitis Virus (ILTV) gD promoter; (ii) a coding sequence for the ILTV gD protein; (iii) an ILTV gI promoter; (iv) a coding sequence for the ILTV gI protein; (v) a human cytomegalovirus immediate early (hCMV IE) promoter; (vi) a coding sequence for the Newcastle Disease Virus fusion protein (NDV F); and (vii) a transcription terminator sequence. In particular embodiments of this type the immunogenic compositions and/or vaccines further comprise a mild live infectious bursal disease virus (IBDV). In certain embodiments the mild live IBDV is a variant IBDV. In more particular embodiments, the IBDV is 89/03. In even more particular embodiments of this type, the recombinant nucleic acid has the nucleotide sequence of SEQ ID NO: 17.
The present invention further provides immunogenic compositions and/or vaccines that comprise any rMDVnp of the present invention combined with an additional NDV, ILTV, and/or MDV antigen, and a pathogen other than MDV, ILTV, or NDV.
These and other aspects of the present invention will be better appreciated by reference to the following Figures and the Detailed Description.
The present invention overcomes the prior industry failure to be able to construct rMDVnp vectors that both contain foreign antigens and can protect against two or more different poultry virus pathogens by providing unique recombinant MDVnp vectors that encode and express antigens from ILTV and NDV, and that protect against Mareks disease, Newcastle disease, and Infectious Laryngotraceitis virus. In particular embodiments, an rMDVnp of the present invention encodes and expresses foreign antigens from only ILTV and NDV, and can aid in the protection against Mareks disease, Newcastle disease, and Infectious Laryngotraceitis virus. In specific embodiments, the rMDVnp is an rHVT. In alternative embodiments, the rMDVnp is an rMDV2.
Prior to the present invention, an HVT vector already had been constructed containing an NDV gene inserted into the US10 region. This HVT-NDV vector was shown to be stable and to express sufficient levels of the corresponding NDV gene product, the NDV F protein, to protect vaccinated chickens against a virulent NDV challenge. In addition, an HVT vector already had been constructed containing a pair of ILTV genes inserted in the HVT UL54.5 region. This HVT-ILTV vector was shown to be stable and to express sufficient levels of the corresponding ILTV gene products, the ILTV gI and gD proteins, to protect vaccinated chickens against a virulent ILTV challenge virus.
Accordingly, a multivalent HVT construct to protect against both NDV and ILTV was designed based on the successful constructs above, i.e., inserting the NDV-F gene in the US10 site and inserting the ILTV gD and gI genes in UL54.5 site [see, 1348-34C in
The present invention therefore, provides recombinant rMDVnp vectors in which two genes from ILTV and one gene from NDV have been inserted. In a particular embodiment of the present invention all three genes were inserted in the US2 region of the HVT genome. Upon vaccination of a chicken or a chicken egg with this rHVT, the cells of the immunized host expressed the proteins encoded by the inserted genes. Furthermore, the NDV and ILTV proteins expressed by the rHVT stimulated an immune response that protected the vaccinated chicken against the disease caused by NDV and ILTV. Accordingly, such rMDVnp vectors can be used to provide protection against both NDV and ILTV infections. Previously, two separate rHVT vectors were necessary to protect against these two viruses, namely one for protection against ILTV and the other for protection against NDV.
The present invention therefore, is advantageous over current methods because it provides simultaneous protection against ILTV and NDV by inoculation of poultry and/or poultry eggs with only a single recombinant MDVnp. In particular, this allows for additional vaccines to be administered via the in ovo route, because there is a limit on how much volume can be injected into an egg, and further saves on manufacturing costs because only one rather than two vectors is needed. Moreover, this can allow an additional antigen to be included in the vaccine such as a live IBDV, e.g., strain 89/03.
Moreover, the present invention further includes embodiments that comprise different rMDVnp constructs in the same vaccine and/or immunogenic compositions. In certain embodiments of this type, the vaccine and/or immunogenic composition comprise both an rMDV2 and an rHVT, each of which encode one or more foreign antigens. Indeed, unlike the combination of two rHVTs, which inevitably lead to one construct significantly overgrowing the other, combining an rHVT with an rMDV2 leads to no such significant overgrowth. Therefore, in specific embodiments, a vaccine of the present invention comprises an rHVT that encodes an ILTVgD protein, an ILTVgI protein, and an NDV F protein with an rMDV2 that encodes yet another poultry viral antigen.
In order to more fully appreciate the instant invention, the following definitions are provided.
The use of singular terms for convenience in description is in no way intended to be so limiting. Thus, for example, reference to a composition comprising “a polypeptide” includes reference to one or more of such polypeptides.
As used herein a “nonpathogenic Marek's Disease Virus” or “MDVnp” or “npMDV” is a virus in the MDV family that shows little to no pathogenicity in poultry. The term “MDVnp” includes naturally occurring MDVs that have been passaged or otherwise similarly manipulated, but does not include viral constructs in which a specific region of the genome of one MDV serotype is replaced by the corresponding region of a different MDV serotype to form a chimeric virus, such as the novel avian herpesvirus (NAHV). In certain embodiments, the MDVnp is an HVT. In other embodiments, the MDVnp is an MDV2. In particular embodiments of this type, the MDV2 is SB1.
As used herein, an MDVnp that has been genetically modified to encode a heterologous nucleotide sequence (e.g., a foreign gene) is defined as a “recombinant MDVnp” or “rMDVnp”.
As used herein, a “nonessential site” is a site in the MDVnp genome in which an insertion of a heterologous nucleotide sequence into that site does not prevent the MDVnp from replicating in a host cell. Nonessential sites are generally identified by the gene in which they reside, e.g., the US2 site, or a region between two genes, e.g., the UL7/8 site.
As used herein the term “poultry” can include chickens, turkeys, ducks, geese, quail, and pheasants.
As used herein, a “vaccine” is a composition that is suitable for application to an animal (including, in certain embodiments, humans, while in other embodiments being specifically not for humans) comprising one or more antigens typically combined with a pharmaceutically acceptable carrier such as a liquid containing water, which upon administration to the animal induces an immune response strong enough to minimally aid in the protection from a clinical disease arising from an infection with a wild-type micro-organism, i.e., strong enough for aiding in the prevention of the clinical disease, and/or preventing, ameliorating or curing the clinical disease.
As used herein, a “multivalent vaccine” is a vaccine that comprises two or more different antigens. In a particular embodiment of this type, the multivalent vaccine stimulates the immune system of the recipient against two or more different pathogens.
As used herein, the term “aids in the protection” does not require complete protection from any indication of infection. For example, “aids in the protection” can mean that the protection is sufficient such that, after challenge, symptoms of the underlying infection are at least reduced, and/or that one or more of the underlying cellular, physiological, or biochemical causes or mechanisms causing the symptoms are reduced and/or eliminated. It is understood that “reduced,” as used in this context, means relative to the state of the infection, including the molecular state of the infection, not just the physiological state of the infection.
As used herein, an “adjuvant” is a substance that is able to favor or amplify the cascade of immunological events, ultimately leading to a better immunological response, i.e., the integrated bodily response to an antigen. An adjuvant is in general not required for the immunological response to occur, but favors or amplifies this response.
As used herein, the term “pharmaceutically acceptable” is used adjectivally to mean that the modified noun is appropriate for use in a pharmaceutical product. When it is used, for example, to describe an excipient in a pharmaceutical vaccine, it characterizes the excipient as being compatible with the other ingredients of the composition and not disadvantageously deleterious to the intended recipient.
As used herein, “systemic administration” is administration into the circulatory system of the body (comprising the cardiovascular and lymphatic system), thus affecting the body as a whole rather than a specific locus such as the gastro-intestinal tract (via e.g., oral or rectal administration) and the respiratory system (via e.g., intranasal administration). Systemic administration can be performed e.g., by administering into muscle tissue (intramuscular), into the dermis (intradermal or transdermal), underneath the skin (subcutaneous), underneath the mucosa (submucosal), in the veins (intravenous) etc.
As used herein the term “parenteral administration” includes subcutaneous injections, submucosal injections, intravenous injections, intramuscular injections, intradermal injections, and infusion.
The term “approximately” is used interchangeably with the term “about” and signifies that a value is within twenty-five percent of the indicated value i.e., a peptide containing “approximately” 100 amino acid residues can contain between 75 and 125 amino acid residues.
As used herein, the term, “polypeptide” is used interchangeably with the terms “protein” and “peptide” and denotes a polymer comprising two or more amino acids connected by peptide bonds. The term “polypeptide” as used herein includes a significant fragment or segment, and encompasses a stretch of amino acid residues of at least about 8 amino acids, generally at least about 12 amino acids, typically at least about 16 amino acids, preferably at least about 20 amino acids, and, in particularly preferred embodiments, at least about 30 or more amino acids, e.g., 35, 40, 45, 50, etc. Such fragments may have ends which begin and/or end at virtually all positions, e.g., beginning at residues 1, 2, 3, etc., and ending at, e.g., 155, 154, 153, etc., in all practical combinations.
Optionally, a polypeptide may lack certain amino acid residues that are encoded by a gene or by an mRNA. For example, a gene or mRNA molecule may encode a sequence of amino acid residues on the N-terminus of a polypeptide (i.e., a signal sequence) that is cleaved from, and therefore, may not be part of the final protein.
As used herein the term “antigenic fragment” in regard to a particular protein (e.g., a protein antigen) is a fragment of that protein (including large fragments that are missing as little as a single amino acid from the full-length protein) that is antigenic, i.e., capable of specifically interacting with an antigen recognition molecule of the immune system, such as an immunoglobulin (antibody) or T cell antigen receptor. For example, an antigenic fragment of an NDV fusion protein, is a fragment of that fusion protein that is antigenic. Preferably, an antigenic fragment of the present invention is immunodominant for antibody and/or T cell receptor recognition.
As used herein an amino acid sequence is 100% “homologous” to a second amino acid sequence if the two amino acid sequences are identical, and/or differ only by neutral or conservative substitutions as defined below. Accordingly, an amino acid sequence is about 80% “homologous” to a second amino acid sequence if about 80% of the two amino acid sequences are identical, and/or differ only by neutral or conservative substitutions.
Functionally equivalent amino acid residues often can be substituted for residues within the sequence resulting in a conservative amino acid substitution. Such alterations define the term “a conservative substitution” as used herein. For example, one or more amino acid residues within the sequence can be substituted by another amino acid of a similar polarity, which acts as a functional equivalent, resulting in a silent alteration. Substitutions for an amino acid within the sequence may be selected from other members of the class to which the amino acid belongs. For example, the nonpolar (hydrophobic) amino acids include alanine, leucine, isoleucine, valine, proline, phenylalanine, tryptophan and methionine. Amino acids containing aromatic ring structures are phenylalanine, tryptophan, and tyrosine. The polar neutral amino acids include glycine, serine, threonine, cysteine, tyrosine, asparagine, and glutamine. The positively charged (basic) amino acids include arginine, lysine and histidine. The negatively charged (acidic) amino acids include aspartic acid and glutamic acid. Such alterations will not be expected to affect apparent molecular weight as determined by polyacrylamide gel electrophoresis, or isoelectric point.
Particularly preferred conservative substitutions are: Lys for Arg and vice versa such that a positive charge may be maintained; Glu for Asp and vice versa such that a negative charge may be maintained; Ser for Thr such that a free—OH can be maintained; and Gln for Asn such that a free NH2 can be maintained. The amino acids also can be placed in the following similarity groups: (1) proline, alanine, glycine, serine, and threonine; (2) glutamine, asparagine, glutamic acid, and aspartic acid; (3) histidine, lysine, and arginine; (4) cysteine; (5) valine, leucine, isoleucine, methionine; and (6) phenylalanine, tyrosine, and tryptophan.
In a related embodiment, two highly homologous DNA sequences can be identified by their own homology, or the homology of the amino acids they encode. Such comparison of the sequences can be performed using standard software available in sequence data banks. In a particular embodiment two highly homologous DNA sequences encode amino acid sequences having about 80% identity, more preferably about 90% identity and even more preferably about 95% identity. More particularly, two highly homologous amino acid sequences have about 80% identity, even more preferably about 90% identity and even more preferably about 95% identity.
As used herein, protein and DNA sequence percent identity can be determined using software such as MacVector v9, commercially available from Accelrys (Burlington, Mass.) and the Clustal W algorithm with the alignment default parameters, and default parameters for identity. See, e.g., Thompson, et al., 1994. Nucleic Acids Res. 22:4673-4680. ClustalW is freely downloadable for Dos, Macintosh and Unix platforms from, e.g., EMBLI, the European Bioinformatics Institute. The present download link is found at http://www.ebi.ac.uk/clustalw/. These and other available programs can also be used to determine sequence similarity using the same or analogous default parameters.
As used herein the terms “polynucleotide”, or a “nucleic acid” or a “nucleic acid molecule” are used interchangeably and denote a molecule comprising nucleotides including, but is not limited to, RNA, cDNA, genomic DNA and even synthetic DNA sequences. The terms are also contemplated to encompass nucleic acid molecules that include any of the art-known base analogs of DNA and RNA.
A nucleic acid “coding sequence” or a “sequence encoding” a particular protein or peptide, is a nucleotide sequence which is transcribed and translated into a polypeptide in vitro or in vivo when placed under the control of appropriate regulatory elements.
The boundaries of the coding sequence are determined by a start codon at the 5′-terminus and a translation stop codon at the 3′-terminus. A coding sequence can include, but is not limited to, prokaryotic sequences, cDNA from eukaryotic mRNA, genomic DNA sequences from eukaryotic (e.g., avian) DNA, and even synthetic DNA sequences. A transcription termination sequence can be located 3′ to the coding sequence.
“Operably linked” refers to an arrangement of elements wherein the components so described are configured so as to perform their usual function. Thus, control elements operably linked to a coding sequence are capable of effecting the expression of the coding sequence. The control elements need not be contiguous with the coding sequence, so long as they function to direct the expression thereof. Thus, for example, intervening untranslated yet transcribed sequences can be present between a promoter and the coding sequence and the promoter can still be considered “operably linked” to the coding sequence.
As used herein, the term “transcription terminator sequence” is used interchangeably with the term “polyadenylation regulatory element” and is a sequence that is generally downstream from a DNA coding region and that may be required for the complete termination of the transcription of that DNA coding sequence.
As used herein an “expression cassette” is a recombinant nucleic acid that minimally comprises a promoter and a heterologous coding sequence operably linked to that promoter. In many such embodiments, the expression cassette further comprises a transcription terminator sequence. Accordingly, the insertion of an expression cassette into a nonessential site of the rMDVnp genome can lead to the expression of the heterologous coding sequence by the rMDVnp. In specific embodiments, the rMDVnp is an rHVT. In alternative embodiments, the rMDVnp is an rMDV2.
A “heterologous nucleotide sequence” as used herein is a nucleotide sequence that is added to a nucleotide sequence of the present invention by recombinant methods to form a nucleic acid that is not naturally formed in nature. In specific embodiments, a “heterologous nucleotide sequence” of the present invention can encode a protein antigen such as the NDV F protein, the ILTV gI protein, or the ILTV gD protein. Heterologous nucleotide sequences can also encode fusion (e.g., chimeric) proteins. In addition, a heterologous nucleotide sequence can encode peptides and/or proteins that contain regulatory and/or structural properties. In other such embodiments, a heterologous nucleotide sequence can encode a protein or peptide that functions as a means of detecting the protein or peptide encoded by the nucleotide sequence of the present invention after the recombinant nucleic acid is expressed. In still another embodiment, the heterologous nucleotide sequence can function as a means of detecting a nucleotide sequence of the present invention. A heterologous nucleotide sequence can comprise non-coding sequences including restriction sites, regulatory sites, promoters and the like.
Insertion of a nucleic acid encoding an antigen of the present invention into a rMDVnp vector is easily accomplished when the termini of both the nucleic acid and the vector comprise compatible restriction sites. If this cannot be done, it may be necessary to modify the termini of the nucleotide sequence and/or vector by digesting back single-stranded nucleic acid overhangs (e.g., DNA overhangs) generated by restriction endonuclease cleavage to produce blunt ends, or to achieve the same result by filling in the single-stranded termini with an appropriate polymerase. Alternatively, desired sites may be produced, e.g., by ligating nucleotide sequences (linkers) onto the termini. Such linkers may comprise specific oligonucleotide sequences that define desired restriction sites. Restriction sites can also be generated through the use of the polymerase chain reaction (PCR). [See, e.g., Saiki et al., Science 239:487-491 (1988)]. The cleaved vector and the DNA fragments may also be modified, if required, by homopolymeric tailing.
The ILTV gD gene appears to encode a glycoprotein of 434 amino acids in length having a molecular weight of 48,477 daltons, although others have suggested that a downstream start codon, which leads to an ILTV gD protein comprising only 377 amino acid residues, is the actual start codon [Wild et al., Virus Genes 12:104-116 (1996)]. The ILTV gI gene encodes a glycoprotein of 362 amino acids in length having a molecular weight of 39,753 daltons [U.S. Pat. No. 6,875,856, hereby incorporated by reference]. Nucleic acids encoding natural and/or laboratory derived variants of the ILTV gD and ILTV gI may be substituted for those presently exemplified.
In particular embodiments of the present invention, an rMDVnp comprises a recombinant nucleic acid (e.g., an expression cassette) that encodes an ILTV gD protein comprising the amino acid sequence of SEQ ID NO: 2 or an antigenic fragment thereof. In related embodiments the rMDVnp comprises a recombinant nucleic acid that encodes an ILTV gD protein comprising an amino acid sequence that has greater than 90%, and/or greater than 95%, and/or greater than 98%, and/or greater than 99% identity to the amino acid sequence of SEQ ID NO: 2. In particular embodiments, the ILTV gD protein is encoded by the nucleotide sequence of SEQ ID NO: 1. In specific embodiments, the rMDVnp is an rHVT. In alternative embodiments, the rMDVnp is an rMDV2.
In certain embodiments of the present invention, an rMDVnp comprises a recombinant nucleic acid (e.g., an expression cassette) that encodes an ILTV gI protein comprising the amino acid sequence of SEQ ID NO: 4 or an antigenic fragment thereof. In related embodiments, the rMDVnp comprises a recombinant nucleic acid that encodes an ILTV gI protein comprising an amino acid sequence that has greater than 90%, and/or greater than 95%, and/or greater than 98%, and/or greater than 99% identity to the amino acid sequence of SEQ ID NO: 4. In particular embodiments, the ILTV gI protein is encoded by the nucleotide sequence of SEQ ID NO: 3. In specific embodiments, the rMDVnp is an rHVT. In alternative embodiments, the rMDVnp is an rMDV2.
The NDV F protein gene encodes the so-called “fusion” protein. One NDV F protein gene exemplified by the present invention was derived from NDV Clone 30, a common lentogenic NDV vaccine strain. Nucleic acids encoding natural and/or laboratory derived variants of the F protein gene would equally be applicable, either from lentogenic, mesogenic or velogenic NDV, as the F protein gene sequence itself is highly conserved in these different NDV pathotypes. In particular embodiments of the present invention, an rMDVnp comprises a recombinant nucleic acid (e.g., an expression cassette) that encodes an NDV fusion protein comprising the amino acid sequence of SEQ ID NO: 6 or an antigenic fragment thereof. In related embodiments, the rMDVnp comprises a recombinant nucleic acid that encodes an NDF F protein comprising an amino acid sequence that has greater than 90%, and/or greater than 95%, and/or greater than 98%, and/or greater than 99% identity to the amino acid sequence of SEQ ID NO: 6. In specific embodiments, the NDV fusion protein is encoded by the nucleotide sequence of SEQ ID NO: 5. In certain embodiments of the present invention, an rMDVnp comprises a recombinant nucleic acid (e.g., an expression cassette) that encodes an NDV fusion protein comprising the amino acid sequence of SEQ ID NO: 8 or an antigenic fragment thereof. In related embodiments, an rMDVnp comprises a recombinant nucleic acid that encodes an NDF F protein comprising an amino acid sequence that has greater than 90%, and/or greater than 95%, and/or greater than 98%, and/or greater than 99% identity to the amino acid sequence of SEQ ID 8. In particular embodiments, the NDV fusion protein is encoded by the nucleotide sequence of SEQ ID NO: 7. In specific embodiments, the rMDVnp is an rHVT. In alternative embodiments, the rMDVnp is an rMDV2.
Many alternative promoters can be used to drive the expression of a heterologous gene encoding a protein antigen or antigenic fragment thereof in an rMDVnp of the present invention. Examples include the pseudorabies virus (PRV) gpX promoter [see, WO 87/04463], the Rous sarcoma virus LTR promoter, the SV40 early gene promoter, the ILTV gD promoter, the ILTV gI promoter [see e.g., U.S. Pat. No. 6,183,753 B1], the human cytomegalovirus immediate early1 (hCMV IE1) gene promoter [U.S. Pat. No. 5,830,745; U.S. Pat. No. 5,980,906], and the chicken beta-actin gene promoter [EP 1 298 139 B1]. More specific examples, as exemplified herein, include the Towne Strain hCMV IE promoter comprising the nucleotide sequence of SEQ ID NO: 12, a truncated hCMV IE promoter comprising the nucleotide sequence of SEQ ID NO: 11, an ILTV gD promoter comprising the nucleotide sequence of SEQ ID NO: 9, and an ILTV gI promoter comprising the nucleotide sequence of SEQ ID NO: 10.
The inclusion of a polyadenylation regulatory element downstream from a DNA coding region is oftentimes required to terminate the transcription of the coding DNA sequence. Accordingly, many genes comprise a polyadenylation regulatory element at the downstream end of their coding sequence. Many such regulatory elements have been identified and can be used in an rMDVnp of the present invention. Specific examples of polyadenylation regulatory elements as exemplified herein, include a synthetic polyadenylation signal comprising the nucleotide sequence of SEQ ID NO: 13, and the HSV thymidine kinase polyadenylation signal comprising the nucleotide sequence of SEQ ID NO: 14.
The present invention relates to the use of the recombinant MDVnp, the nucleic acid molecules used to construct the MDVnp, or the host cells to grow them, or any combination thereof, all according to the present invention for the manufacture of a vaccine for poultry. Accordingly, the present invention provides vaccines and/or immunogenic compositions that include a multivalent recombinant MDVnp of the present invention. Such vaccines can be used to aid in the prevention and/or prevent Newcastle disease, and/or Marek's disease, and/or maladies associated with ILTV infections. A vaccine according to the present invention can be used for prophylactic and/or for therapeutic treatment, and thus can interfere with the establishment and/or with the progression of an infection and/or its clinical symptoms of disease.
A recombinant MDVnp of the present invention can be grown by any number of means currently practiced in the field. For example, a recombinant MDVnp of the present invention can be grown through the use of in vitro cultures of primary chicken cells, see e.g., the Examples below where chicken embryo fibroblast cells (CEFs) were used. The CEFs can be prepared by trypsinization of chicken embryos. The CEFs also can be plated in monolayers and then infected with the MDVnp. This particular process can be readily scaled up to industrial-sized production.
Therefore, a further aspect of the invention relates to a method for the preparation of the vaccine according to the invention comprising the steps of infecting host cells with a recombinant MDVnp of the present invention, harvesting the infected host cells, and then admixing the harvested infected host cells with a pharmaceutically acceptable carrier. Suitable methods for infection, culture and harvesting are well known in the art and are described and exemplified herein.
Typically, the infected host cells are harvested while still intact to obtain the recombinant MDVnp in its cell-associated form. These cells can be taken up in an appropriate carrier composition to provide stabilization for storage and freezing. The infected cells can be filled into glass ampoules, which are sealed, frozen and stored in liquid nitrogen. Accordingly, in certain embodiments of the present invention, the vaccines and/or immunogenic compositions of the present invention are stored frozen and accordingly, comprise a cryropreservative, such as dimethyl sulfoxide (DMSO), to preserve the frozen infected cells.
Alternatively, when the recombinant MDVnp is a recombinant HVT, it can be isolated from its host cell, for instance through sonication at the end of culturing, and then taken up into a stabilizer, and freeze-dried (lyophilized) for stable storage or otherwise reduced in liquid volume, for storage, and then reconstituted in a liquid diluent before or at the time of administration. Such reconstitution may be achieved using, for example, vaccine-grade water. In certain embodiments, a lyophilized portion of a multivalent vaccine can comprise one or more antigens and the diluent can comprise one or more other antigens.
In particular embodiments a vaccine of the present invention (or a portion thereof) can be in a freeze-dried form, e.g., as tablets and/or spheres that are produced by a method described in WO 2010/125084, hereby incorporated by reference in its entirety. In particular, reference is made to the examples, from page 15, line 28 to page 27, line 9 of WO 2010/125084, describing a method to produce such fast disintegrating tablets/spheres. Such freeze-dried forms can be readily dissolved in a diluent, to enable systemic administration of the vaccine.
Vaccines and immunogenic compositions can, but do not necessarily include, physiologically compatible buffers and saline and the like, as well as pharmaceutically acceptable adjuvants. Adjuvants can be useful for improving the immune response and/or increasing the stability of vaccine preparations. Adjuvants are typically described as non-specific stimulators of the immune system, but also can be useful for targeting specific arms of the immune system. One or more compounds which have this activity may be added to the vaccine. Therefore, particular vaccines of the present invention can further comprise an adjuvant. Examples of chemical compounds that can be used as adjuvants include, but are not limited to aluminum compounds (e.g., aluminum hydroxide), metabolizable and non-metabolizable oils, mineral oils including mannide oleate derivatives in mineral oil solution (e.g., MONTANIDE ISA 70 from Seppic SA, France), and light mineral oils such as DRAKEOL 6VR, block polymers, ISCOM's (immune stimulating complexes), vitamins and minerals (including but not limited to: vitamin E, vitamin A, selenium, and vitamin B12) and CARBOPOL®.
Other suitable adjuvants, which sometimes have been referred to as immune stimulants, include, but are not limited to: cytokines, growth factors, chemokines, supernatants from cell cultures of lymphocytes, monocytes, cells from lymphoid organs, cell preparations and/or extracts from plants, bacteria or parasites (Staphylococcus aureus or lipopolysaccharide preparations) or mitogens. Generally, an adjuvant is administered at the same time as an antigen of the present invention. However, adjuvants can also or alternatively be administered within a two-week period prior to the vaccination, and/or for a period of time after vaccination, i.e., so long as the antigen, e.g., a recombinant MDVnp of the present invention persists in the tissues.
The vaccines and/or immunogenic compositions of the present invention may be administered by any route such as in ovo, by parenteral administration, including intramuscular injection, subcutaneous injection, intravenous injection, intradermal injection, by scarification, by oral administration, or by any combination thereof. Furthermore, the multivalent recombinant MDVnp of the present invention can be used and/or combined with additional NDV, ILTV, and/or MDV antigens to improve and expand the immunogenicity provided, and/or antigens for other pathogens in order to provide immune protection against such other pathogens. These additional antigens can be either live or killed whole microorganisms, other recombinant vectors, cell homogenates, extracts, proteins, or any other such derivative, provided that they do not negatively interfere with the safety, stability, and efficacy of the vaccine according to the present invention.
The combination of a multivalent recombinant MDVnp of the present invention with an additional MDV, NDV, and/or ILTV antigen can be advantageous in those cases in which very virulent field strains of MDV, NDV, or ILTV are prevalent, e.g., in a particular geographic region. In this regard, the combination of a multivalent recombinant MDVnp of the present invention with an MDV1, MDV2, or HVT includes the Rispens (MDV1) strain, the SB1 (MDV2) strain, the FC-126 (HVT) strain and/or PB1 (HVT) strain. To improve the response against NDV, multivalent recombinant MDVnp may be combined with an NDV vaccine strain, such as the mild live NDV vaccine strain C2.
Examples of other microorganisms that can be used as antigens together with the multivalent recombinant MDVnp of the present invention include: (i) viruses such as infectious bronchitis virus, adenovirus, egg drop syndrome virus, infectious bursal disease virus, chicken anaemia virus, avian encephalo-myelitis virus, fowl pox virus, turkey rhinotracheitis virus, duck plague virus (duck viral enteritis), pigeon pox virus, avian leucosis virus, avian pneumovirus, and reovirus, (ii) bacteria, such as Escherichia coli, Salmonella spec., Ornitobacterium rhinotracheale, Haemophilis paragallinarum, Pasteurella multocida, Erysipelothrix rhusiopathiae, Erysipelas spec., Mycoplasma spec., and Clostridium spec., (iii) parasites such as Eimeria spec., and (iv) fungi, such as Aspergillus spec. In particular embodiments of the present invention, a recombinant MDVnp of the present invention can be combined with a mild live IBDV vaccine strain such as D78 (cloned intermediate strain), PBG98, Cu-1, ST-12 (an intermediate strain), or 89-03 (a live Delaware variant strain) in a multivalent vaccine. Many of such strains are used in commercial vaccines.
The combination vaccine can be made in a variety of ways including by combining the recombinant MDVnp of the present invention with preparations of virus, or bacteria, or fungi, or parasites, or host cells, or a mixture of any and/or all of these. In particular embodiments, the components for such a combination vaccine are conveniently produced separately and then combined and filled into the same vaccine container.
As described above, a vaccine according to the invention can be used advantageously to provide safe and effective immune protection in poultry to a multiple diseases, by a single inoculation at very young age or in ovo. Alternatively, as would be apparent to anyone skilled in the art of poultry vaccines the combinations described above also could include vaccination schedules in which the multivalent recombinant MDVnp of the present invention and the additional antigen are not applied simultaneously; e.g., the recombinant MDVnp may be applied in ovo, and the NDV C2 and/or the IBDV strain (e.g., 89/03) could be applied at a subsequent time/date.
Accordingly, the vaccines of the present invention can be administered to the avian subject in a single dose or in multiple doses. For example, a vaccine of the present invention may be applied at the day of hatch and/or in ovo at day 16-18 (Embryonation Day) ED. When multiple doses are administered, they may be given either at the same time or sequentially, in a manner and time compatible with the formulation of the vaccine, and in such an amount as will be immunologically effective. Therefore, a vaccine of the present invention may effectively serve as a priming vaccination, which later can be followed and amplified by a booster vaccination of the identical vaccine, or with a different vaccine preparation e.g., a classical inactivated, adjuvanted whole-virus vaccine.
The volume per dose of a vaccine of the present invention can be optimized according to the intended route of application: in ovo inoculation is commonly applied with a volume between 0.05 and 0.5 ml/egg, and parenteral injection is commonly done with a volume between 0.1 and 1 ml/avian. In any case, optimization of the vaccine dose volume is well within the capabilities of the skilled artisan.
The present invention may be better understood by reference to the following non-limiting examples, which are provided as exemplary of the invention. The following examples are presented in order to more fully illustrate embodiments of the invention and should in no way be construed as limiting the broad scope of the invention.
The ability to generate herpesviruses by cotransfection of cloned overlapping subgenomic fragments was first demonstrated for pseudorabies virus [van Zijl et al., J. Virology 62:2191-2195 (1988)]. This procedure subsequently was employed to construct recombinant HVT vectors [see, U.S. Pat. No. 5,853,733, hereby incorporated by reference with respect to the methodology disclosed regarding the construction of recombinant HVT vectors] and was used to construct the recombinant HVT/NDV/ILTV vectors of the present invention. In this method, the entire HVT genome is cloned into bacterial vectors as several large overlapping subgenomic fragments constructed utilizing standard recombinant DNA techniques [Maniatis et al., (1982) Molecular Cloning, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York (1982); and Sambrook et al., Molecular Cloning, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. (1989)]. An HVT strain FC126 cosmid library was derived from sheared viral DNA cloned into the cosmid vector, pWE15 (Stratagene, now Agilent Technologies of Santa Clara, Calif.). In addition, several large genomic DNA fragments were isolated by restriction digestion with the enzyme, BamHI, and cloned into either pWE15 or the plasmid vector pSP64 (Promega, Madison Wis.). As described in U.S. Pat. No. 5,853,733, cotransfection of these fragments into chicken embryo fibroblast (CEF) cells results in the regeneration of the HVT genome mediated by homologous recombination across the overlapping regions of the fragments. If an insertion is engineered directly into one or more of the subgenomic fragments prior to the cotransfection, this procedure results in a high frequency of viruses containing the insertion. Five overlapping subgenomic clones are required to generate FC126 HVT, and served as the basis for creating all HVT/NDV/ILTV recombinant viruses.
Construction of HVT/NDV/ILTV 1332-62.E1:
The cosmid regeneration for HVT/NDV/ILTV 1332-62.E1 was performed essentially as described in U.S. Pat. No. 5,853,733 [e.g. FIG. 8 of U.S. Pat. No. 5,853,733; redrawn, at least in part, in
The set of seven linearized constructs: 3 cosmids and 4 plasmids are transfected all together into CEFs, using a standard CaCl2 transfection protocol and the resulting virus stock was plaque purified one time.
Construction of HVT/NDV/ILTV 1332-70.B1:
The cosmid regeneration for HVT/NDV/ILTV 1332-70.B1 was performed essentially as described in U.S. Pat. No. 5,853,733 [e.g., FIG. 8 of U.S. Pat. No. 5,853,733; redrawn, at least in part, in
The set of seven linearized constructs: 4 cosmids and 3 plasmids are transfected all together into CEFs, using a standard CaCl2 transfection protocol, and the resulting virus stock was plaque purified one time.
Construction of HVT/NDV/ILTV 1317-46.A1-1:
The cosmid regeneration for HVT/NDV/ILTV 1317-46.A1-1 was performed essentially as described in U.S. Pat. No. 5,853,733 [e.g., FIG. 8 of U.S. Pat. No. 5,853,733; redrawn, at least in part, in
The set of seven constructs: 1 uncut cosmid (1196-05.1), the remaining 2 linearized cosmids, and 4 linearized plasmids were transfected all together into CEFs, using a standard CaCl2 transfection protocol, and the resulting virus stock was plaque purified one time.
Description of Subgenomic Fragments for Generating FC126 HVT:
Subgenomic Clone 407-32.2C3.
Cosmid 407-32.2C3 contains an approximately 40,170 base pair region of genomic HVT DNA [Left terminus—pos. 39,754; Afonso et al., 2001, supra; Acc. #AF291866]. This region includes HVT BamHI fragments F′, L, P, N1, E, D, and 2,092 base pairs of fragment B.
Subgenomic Clone 172-07.BA2.
Plasmid 172-07.BA2 contains a 25,931 base pair region of genomic HVT DNA. It was constructed by cloning the HVT BamHI B fragment [pos. 37,663 to 63,593; Afonso et al., 2001, supra; Acc. #AF291866] into the plasmid pSP64 (Promega, Madison Wis.).
Subgenomic Clone 407-32.5G6.
Cosmid 407-32.5G6 contains a 39,404 base pair region of genomic HVT DNA [pos. 61,852-101,255; Afonso et al., 2001, supra; Acc. #AF291866]. This region includes HVT BamHI fragments H, C, Q, K1, M, K2, plus 1,742 base pairs of fragment B, and 3,880 base pairs of fragment J.
Subgenomic Clone 407-32.1C1.
Cosmid 407-32.1C1 contains a 37,444 base pair region of genomic HVT DNA [pos. 96,095-133,538; Afonso et al., 2001, supra; Acc. #AF291866]. This region includes HVT BamHI fragments J, G, I, F, O, plus 1,281 base pairs of fragment K2, and 6,691 base pairs of fragment A.
Subgenomic Clone 378-50.
Cosmid 378-50 contains a 28,897 base pair region of genomic HVT DNA [see FIG. 8 of U.S. Pat. No. 5,853,733; redrawn, at least in part, in
Additional Insertion Fragments for Generating HVT/NDV/ILTV 1332-62.E1:
Subgenomic Clone 1332-47.A2.
The insertion plasmid 1332-47.A2 contains a 7311 base pair EcoRI fragment of the HVT unique short region [pos. 136880-144190; Afonso et al., 2001, supra; Acc. #AF291866], cloned into the plasmid pSP64 (Promega, Madison Wis.). Inserted into a unique StuI site within the HVT US2 gene [pos. 140540/140541, Afonso et al., 2001, supra; Acc. #AF291866, between amino acid residues 124 and 125] are 2 elements: a 3563 base pair SalI-HindIII fragment from ILTV, NVSL Challenge Strain, Lot #83-2 [pos. 10532-14094; Wild et al., Virus Genes 12:104-116 (1996); Acc.#U28832], encoding the full length genes for glycoprotein D (gD) and glycoprotein I (gI), plus partial coding regions from glycoprotein E (amino acids 1-101), and ORF5 (amino acids 734-985); and an expression cassette consisting of the HCMV IE promoter, the NDV, clone 30 strain, fusion gene (F), followed by a synthetic poly-adenylation signal. The ILTV gD, ILTV gI, and NDV F genes are transcribed in the opposite direction relative to the HVT US2 gene.
Subgenomic Clone pSY640.
Plasmid pSY640 contains an approximately 13,600 base pair region of genomic HVT DNA [pos. 126848-140540; Afonso et al., 2001, supra; Acc. #AF291866] derived from BamHI fragment A. To generate this plasmid the region of DNA located upstream of the US2 gene, beginning at the StuI site located in the US2 gene and continuing to the end of the BamHI A fragment, was cloned into the plasmid pSP64 (Promega, Madison Wis.).
Subgenomic Clone 556-60.6.
Plasmid 556-60.6 contains an approximately 12,500 base pair region of genomic HVT DNA derived from BamHI fragment A [approximate pos. 143300 to pos. 155744, Afonso et al., 2001, supra; Acc. #AF291866]. To generate this plasmid the region of DNA located downstream of the US2 gene beginning at the StuI site located in the US2 gene and continuing to the end of the BamHI A fragment was cloned into the plasmid pSP64 (Promega, Madison Wis.), and then treated with exonucleasse to “chewed back” from StuI site—150 bp, and recloned into pBR322 plasmid vector.
Additional Insertion Fragments for Generating HVT/NDV/ILTV 1332-70.B1:
Subgenomic Clone 1332-29.4
Plasmid 1332-29.4 contains a 8,636 base pair region of genomic HVT DNA derived from the unique long region [pos. 109489-118124; Afonso et al., 2001, supra; Acc. #AF291866], cloned into a derivative of plasmid pNEB193 (deleted AatII-PvuII). It is flanked by AscI sites and includes HVT BamHI fragments I, S, plus 1337 base pairs of fragment G and 1177 base pairs of fragment F. Inserted into an XhoI site within the HVT UL54.5 open reading frame [pos. 111240/111241, Afonso et al., 2001, supra; Acc. #AF291866, between amino acid residues 21 and 22] are 2 elements: a 3563 base pair SalI-HindIII fragment from ILTV, NVSL Challenge Strain, Lot #83-2 [pos. 10532-14094; Wild et al. 1996, supra; Acc.#U28832], encoding the full length genes for glycoprotein D (gD) and glycoprotein I (gI), plus partial coding regions from glycoprotein E (amino acids 1-101), and ORF5 (amino acids 734-985); and an expression cassette consisting of the HCMV IE promoter, the NDV, clone 30 strain, fusion gene (F), followed by a synthetic poly-adenylation signal. The ILTV gD, ILTV gI and NDV F genes are transcribed in the opposite direction relative to the HVT UL54.5 gene.
Subgenomic Clone 672-01.A40
Plasmid 672-01.A40 contains a 14,731 base pair region of genomic HVT DNA derived from the unique long region [pos. 96095-110825; Afonso et al., 2001, supra; Acc. #AF291866], cloned into a derivative of plasmid pNEB193. This region includes HVT BamHI fragments G, J and 1281 base pairs of K2.
Subgenomic Clone 672-07.C40
Plasmid 672-07.C40 contains a 12,520 base pair region of genomic HVT DNA derived from the unique long region [pos. 116948-129467; Afonso et al., 2001, supra; Acc. #AF291866], cloned into a derivative of plasmid pNEB193. This region includes HVT BamHI fragments F, O and 2620 base pairs of A.
Additional Insertion Fragments for Generating HVT/NDV/ILTV 1317-46.A1-1:
Subgenomic Clone 1196-05.1.
Cosmid 1196-05.1 contains an approximately 40, 170 base pair region of genomic HVT DNA [Left terminus—pos. 39,754; Afonso et al., 2001, supra; Acc. #AF291866] cloned into cosmid pWE15. This region includes HVT BamHI fragments F′, L, P, N1, E, D, and 2,092 base pairs of fragment B. In addition an expression cassette encoding the NDV Fusion (F) gene, including the HCMV IE promoter and HSV TK poly-adenylation regulatory elements was inserted into a non-coding region between HVT UL7 and UL8 genes within BamHI fragment E [pos. 20030-20035; Afonso et al., 2001, supra; Acc. #AF291866]. The NDV F gene is transcribed the same direction as HVT UL7.
Subgenomic Clone 1317-15.1-1.
Plasmid 1317-15.1-1 contains a 7311 base pair EcoRI fragment of the HVT unique short region [pos. 136880-144190; Afonso et al., 2001, supra; Acc. #AF291866], cloned into the plasmid pSP64 (Promega, Madison Wis.). In addition, a 3563 base pair SalI-HindIII fragment from ILTV, NVSL Challenge Strain, Lot #83-2 [pos. 10532-14094; Wild et al., 1996, supra; Acc.#U28832], encoding the full length genes for glycoprotein D (gD) and glycoprotein I (gI), plus partial coding regions from glycoprotein E (amino acids 1-101), and ORF5 (amino acids 734-985) were cloned into a unique StuI site within the HVT US2 gene [pos. 140540/140541, Afonso et al., 2001, supra; Acc. #AF291866, between amino acid residues 124 and 125]. The ILTV gD and gI genes are transcribed in the opposite direction relative to the HVT US2 gene.
Subgenomic Clone pSY640.
Plasmid pSY640 contains an approximately 13,600 base pair region of genomic HVT DNA [pos. 126848-140540; Afonso et al., 2001, supra; Acc. #AF291866] derived from BamHI fragment A. To generate this plasmid the region of DNA located upstream of the US2 gene, beginning at the StuI site located in the US2 gene and continuing to the end of the BamHI A fragment, was cloned into the plasmid pSP64 (Promega, Madison Wis.).
Subgenomic Clone 556-60.6.
Plasmid 556-60.6 contains an approximately 12,500 base pair region of genomic HVT DNA derived from BamHI fragment A [approximate pos. 143300 to pos. 155744, Afonso et al., 2001, supra; Acc. #AF291866]. To generate this plasmid the region of DNA located downstream of the US2 gene beginning at the StuI site located in the US2 gene and continuing to the end of the BamHI A fragment was cloned into the plasmid pSP64 (Promega, Madison Wis.), and then treated with exonucleasse to “chewed back” from StuI site ˜150 bp, and recloned into pBR322 plasmid vector.
Standard CaCl2 Transfection Protocol:
Secondary CEF's are seeded on 6 well culture plates and incubated at 38° C. with 5% CO2 for 24 hours and confluent monolayers form. For each well a total amount of 0.25 μg DNA of cosmids and plasmids were mixed in Hepes buffer and 125 mM CaCl2 was added dropwise until precipitation was imminent. This mixture was added to the CEF cell monolayer, and incubated for 2 to 3 hrs. Supernatant was removed and an overlay of 15% Glycerol was added, and kept on the cells for 1 minute. Then this was removed, washed with PBS, and fresh culture medium was added and cells were incubated for 5 days. Next, cells were harvested by trypsinization and cells from individual plates were each seeded on fresh monolayers of CEF cells in 10 cm plates and incubated until 50-90% CPE was achieved. Next, the amplified transfected cells were harvested by trypsinization, and dilutions of 10−2 to 10−4 were plated on 10 cm plates with CEF monolayers and incubated. The following day, the plates were covered with agar, and a number of individual plaques of HVT/NDV/ILTV were isolated and amplified on CEFs.
Two vaccines, one comprising HVT/NDV/ILTV-1332-62E1 and the other, comprising 1332-70B1, were evaluated for efficacy in protecting chickens from an Infectious Laryngotracheitis Virus challenge. HVT/NDV/ILTV-1332-62E1 is an rHVT in which the FC126 HVT backbone comprises the nucleic acid sequence of SEQ ID NO: 17 inserted in the US2 site (see, Example 1 above). HVT/NDV/ILTV-1332-70B1 is an rHVT in which the FC126 HVT backbone comprises the nucleic acid sequence of SEQ ID NO: 17 inserted in the UL54.5 site (see, Example 1 above).
The vaccine preparations for both stocks of virus were prepared from stocks passaged through chicken embryo fibroblast tissue culture cells, at least 8 times, and an additional preparation of 11 tissue culture passages was prepared and tested for 1332-62E1.
The vaccines were administered to newly hatched, specific-antigen free (SPF) chicks by the subcutaneous route. Birds were then challenged at four weeks of age with virulent ILTV challenge virus by the intra-tracheal route and observed for 10 days for the clinical signs of the disease. The incidence of disease in these chicks was compared with controls that either received a commercial recombinant HVT/ILTV vaccine (Innovax®-ILT, from Merck Animal Health) or no vaccine. The Federal Code of Registry (9CFR) requires that at least 80% of the unvaccinated control birds must show clinical signs for a test to be valid, and at least 90% of the vaccinated birds must remain free of clinical signs to be considered to provide satisfactory protection. The results of this study are provided in Table 1 below. Both dual recombinant vaccines provided satisfactory protection against a virulent ILTV challenge.
Day-old specific-antigen free (SPF) chicks, or 19-day old embryos were vaccinated with a recombinant vaccine, HVT/NDV/ILTV-1332-62E1, tissue culture passage level 11, or a commercial recombinant HVT/NDV vaccine (Innovax®-ND, sold by Merck Animal Health) and then challenged at four weeks of age with virulent Newcastle Disease (ND) challenge virus, Texas-GB strain, by the intra-muscular route. Following a 14-day observation period, where birds were scored for clinical signs of Newcastle disease, the incidence of disease in each group of chicks was compared with unvaccinated controls. The Federal Code of Registry (9CFR) requires that at least 80% of the unvaccinated control birds must show clinical signs for a test to be valid, and at least 90% of the vaccinated birds must remain free of clinical signs for a vaccine to be considered to provide satisfactory protection. The results of this study indicate the recombinant HVT/NDV/ILTV 1332-62E1 vaccine provided satisfactory ND protection by both routes of administration.
A vaccine, HVT/NDV/ILT-1317-46.1-1, was evaluated for efficacy in protecting chickens from either Infectious Laryngotracheitis Virus challenge or Newcastle Disease Virus Challenge. HVT/NDV/ILTV-1317-46.1-1 is an rHVT in which the FC126 HVT backbone comprises the nucleic acid sequence of SEQ ID NO: 16 inserted into the US2 site, and the nucleic acid sequence of SEQ ID NO: 15 inserted into the UL7/8 site, i.e., in between the UL7 and UL8 genes of HVT, (see, Example 1 above). The vaccine preparation was prepared from a stock passaged through chicken embryo fibroblast tissue culture cells 15 times.
The vaccine was administered to newly hatched, specific-antigen free (SPF) chicks by the subcutaneous route. Birds were then challenged at four weeks of age with virulent Infectious Laryngotracheitis (ILT) challenge virus by the intra-tracheal route and observed for 10 days for the clinical signs of the disease, or challenged with virulent Newcastle Disease virus, Texas-GB strain, by the intra-muscular route and observed for 14 days. The incidence of disease in these chicks was compared with controls that either received a commercial recombinant HVT/ILT vaccine, HVT/ND vaccine, or no vaccine. The Federal Code of Registry (9CFR) requires that at least 80% of the unvaccinated control birds must show clinical signs for a test to be valid, and at least 90% of the vaccinated birds must remain free of clinical signs to be considered to provide satisfactory protection. The results of this study are provided in the Table 3 below. The HVT/NDV/ILT vaccine provided satisfactory protection against NDV challenge. Although, in this preliminary study the protection provided by this construct against a virulent ILTV challenge fell just short of the federal requirements, it did provide substantial protection.
Groups of one-day-old chicks (SPF Leghorn) were inoculated with HVT/NDV/ILTV-1332-62E1 combined with IBDV 89/03 vaccine at the time of use. A separate group of chicks were vaccinated with only the IBDV vaccine at 3.5 log10 TCID50 per dose. Chickens were challenged at 4 weeks of age with Variant E IBDV challenge. At 10 days post-challenge, birds were euthanized and examined for body/bursa weights and gross lesions consistent with bursal disease. The results were analyzed for acceptability per the applicable 9CFR 113.331 requirements.
IBDV 89/03 is a licensed product used in the poultry industry to protect flocks against both the classical and variant strains of Infectious Bursal Disease virus. The target dose for IBDV 89/03 vaccine was 3.5 log10 TCID50 per 0.2 mL dose. The target dose for HVT/NDV/ILT was 3000 PFU per 0.2 mL dose. To achieve the target doses in the final vaccine diluent volume the HVT/NDV/ILTV-1332-62E1 vaccine was diluted to contain 6000 PFU in 0.2 mL, which is double the target dose. The 89/03 vaccine was diluted to contain 3.8 log10 TCID50, which is double the target dose. For Group 1 the combination vaccine was prepared by combining equal volumes of the HVT/NDV/ILTV-1332-62E1 vaccine and the 89/03 vaccine. For Group 2, which received only the 89/03 vaccine, an equal volume of diluent was added. One day old chickens in each treatment group received 0.2 mL of the respective vaccine or placebo by the subcutaneous (SC) route (see, Table 4).
At hatch, chicks in each of the vaccine treatment groups were tagged with a set of randomized tag numbers assigned using the randomization program of EXCEL. In addition, birds removed from each pen at 7 days post-challenge for histological examination of bursas were randomly determined using the randomization program of EXCEL.
The chickens were challenged at four weeks of age with IBDV-Variant E challenge virus. Each chicken received 0.06 mL containing approximately 102.2 EID50 per dose via the eyedrop route. At seven days post-challenge, 6-9 birds from each group were removed for histological evaluation of individual bursae (see, Table 5). Bursa samples were collected from each challenged chicken using care to collect tissue which had not been crushed or squeezed by the forceps. The tissue sample was placed in an individual container of 10% formalin.
Bursa from each chicken challenged with IBD-Var E virus was recorded as negative or positive for bursal atrophy, gross macroscopic lesions and/or lymphocyte depletion as determined by histological examination. Bursal lesions included macroscopic hemorrhage, edema/exudates, cream/yellow color, striations, or gross atrophy. Bursal atrophy was measured by individually weighing each chicken to the nearest gram. Bursae were individually weighed to the nearest hundredth of a gram. Bursa/body weight ratios were computed for each bird employing the formula, BW ratio: (Bursa Weight ÷ Body Weight) X 1000. A bursa to body weight ratio of more than 2 standard deviations from the challenged control is considered negative for and protective from infectious bursal disease. The results of this study showed that vaccine treatment Groups 1 and 2 were negative for IBD (i.e., not statistically different from the placebo non-challenged control) indicating that both vaccines were efficacious and further demonstrating that there was no interference of the protection provided by the 89/03 strain of the vaccine against the IBDV challenge due to the recombinant HVT/NDV/ILT construct also being present in the multivalent vaccine (see, Table 5).
The following sequences have been used in the exemplary rHVT constructs. The coding sequences provided below include individual stop codons, which can be readily replaced with alternative stop codons without modifying the properties of the protein antigens that the coding sequences encode.
The present invention is not to be limited in scope by the specific embodiments described herein. Indeed, various modifications of the invention in addition to those described herein will become apparent to those skilled in the art from the foregoing description. Such modifications are intended to fall within the scope of the appended claims.
It is further to be understood that all base sizes or amino acid sizes, and all molecular weight or molecular mass values, given for nucleic acids or polypeptides are approximate, and are provided for description.
This application claims priority under 35 U.S.C. §119(e) of provisional application U.S. Ser. No. 61/549,844 filed Oct. 21, 2011, the contents of which are hereby incorporated by reference in their entireties.
| Number | Date | Country | |
|---|---|---|---|
| 61549844 | Oct 2011 | US |
