Patent Application
20140147465
The invention relates to recombinant viral vectors for the insertion and expression of foreign genes for use as safe immunization vehicles to protect against a variety of pathogens. It also relates to multivalent composition or vaccine comprising one or more recombinant viral vectors for protection against a variety of pathogens. The present invention relates to methods of making and using the recombinant viral vectors.
Poultry vaccination is widely used to protect poultry flocks against devastating diseases including Newcastle disease (ND), infectious bursal disease (IBD), Marek's disease (MD), infectious bronchitis (IB), infectious laryngotracheitis (ILT) and avian influenza (AI). ND is caused by the avian paramyxovirus 1 (APMV-1) also designated ND virus (NDV) belonging to the Paramyxoviridae family. MD is caused by Gallid herpesvirus 2 (Herpesviridae family) also designated as MD virus serotype 1 (MDV1). IB is caused by IB virus (IBV) belonging to the Coronaviridae family, ILT is caused by Gallid herpesvirus 1 (Herpesviridae family) also designated ILT virus (ILTV) and AI is caused by AI virus (AIV) belonging to the Orthomyxoviridae family.
A number of recombinant avian viral vectors have been proposed with a view to vaccinating birds against these avian pathogens. The viral vectors used comprise avipox viruses, especially fowlpox (EP-A-0,517,292), Marek's virus, such as serotypes 2 and 3 (HVT) (WO-A-87/04463), or alternatively the ITLV, NDV and avian adenovirus. When some of these recombinant avian viral vectors were used for vaccination, they display variable levels of protection.
Several recombinant herpesvirus of turkeys (HVT, also designated Meleagrid herpesvirus 1 or MDV serotype 3) vectors expressing antigens from various pathogens (U.S. Pat. Nos. 5,980,906, 5,853,733, 6,183,753, 5,187,087) including IBDV, NDV, ILTV and AIV have been developed and licensed. Of particular interest is a HVT vector-expressing IBDV VP2 protective gene that has shown clear advantages over classical IBD vaccines (Bublot et al J. Comp. Path.2007, Vol. 137, S81-S84). Other HVT vectors of interest are those expressing either NDV (Morgan et al 1992, Avian dis. 36, 858-70) or ILTV (Johnson et al, 2010 Avian Dis 54, 1251-1259) protective gene(s). One of the practical problems of using several HVT-based recombinant vaccines together is their interference. Lower protection is induced at least against one of the disease when two HVT recombinants expressing different antigens are mixed (Rudolf Heine 2011; Issues of the Poultry Recombinant Viral Vector Vaccines which May Cause an Effect on the Economic Benefits of those Vaccines; paper presented at the XVII World Veterinary Poultry Association (WVPA) Congress in Cancun, Mexico, Aug. 14-18, 2011; Slacum G, Hein R. and Lynch P., 2009, The compatibility of HVT recombinants with other Marek's disease vaccines, 58th Western Poultry Disease Conference, Sacramento, Calif., USA, March 23th-25th, p 84).
The combination of HVT and SB-1, a Gallid herpesvirus 3 (MDV serotype 2 or MDV-2) vaccine strain, has shown a synergistic effect on MD protection (Witter and Lee, 1984, Avian Pathology 13, 75-92). To address the interference problem, it is of interest to evaluate the SB-1 virus as a vaccine vector to express protective antigen(s) that could be compatible with HVT vector and improve MD protection.
The SB-1 genome was cloned and characterized in bacterial artificial chromosome (BAC) (Petherbridge, et al., J. Virol. Methods 158, 11-17, 2009; Singh et al., Research in Veterinary Science 89, 140-145, 2010). The MDV2 SB-1 sequence was recently obtained and analyzed (Spatz and Schat, Virus Gene 42, 331-338, 2011). A glycoprotein E deletion of SB-1 virus was described by Petherbridge et al. (J. Virol. Methods 158, 11-17, 2009). However, no research has been reported using SB-1 as a viral vector expressing foreign protective genes.
It has been shown that both UL13 protein kinase and glycoprotein C (UL44) genes individually are essential for horizontal transmission of MDV in chickens (Jarosinski, et al., J. of Virology 81, 10575-10587, 2007; Jarosinski, et al., J. of Virology 84, 7911-7916, 2010).
Considering the potential effect of animal pathogens, such as NDV and IBDV on veterinary public health and the economy, efficient methods of preventing infection and protecting animals are needed. There is a need for a solution of combined effective vector vaccines and a suitable method for making the vaccine that could alleviate the problem of interference observed between 2 HVT-based vector vaccines.
The present invention demonstrated for the first time a recombinant Gallid Herpesvirus-3 (MDV-2) viral vector protecting against a poultry pathogen beyond Marek's disease virus.
The present invention showed surprising result when multivalent vaccines were used to protect animals against a variety of avian pathogens.
The present invention relates to a recombinant Gallid Herpesvirus-3 (MDV-2) vector comprising one or more heterologous polynucleotides coding for and expressing at least one antigen of an avian pathogen. The present invention further relates to a recombinant Gallid Herpesvirus-3 (MDV-2) vector comprising a mutated glycoprotein C (gC) gene.
The present invention provides a composition or vaccine comprising one or more recombinant Gallid Herpesvirus-3 (MDV-2) vectors comprising one or more heterologous polynucleotides coding for and expressing at least one antigen of an avian pathogen. The present invention further provides a composition for vaccine comprising one or more Gallid Herpesvirus-3 (MDV-2) vectors comprising a mutated glycoprotein C (gC) gene.
The present invention provides a polyvalent composition or vaccine comprising: i) a recombinant Gallid Herpesvirus-3 (MDV-2) vector comprising heterologous polynucleotides coding for and expressing at least one antigen of an avian pathogen, or comprising a mutated glycoprotein C (gC) gene; and ii) at least one of: a recombinant HVT vector (or MDV-3 or Meleagrid herpesvirus-1) comprising heterologous polynucleotides coding for and expressing at least one antigen of an avian pathogen; or wild type HVT (MDV-3); or recombinant MDV serotype 1 vector (i.e., MDV-1, Gallid herpesvirus-2) comprising heterologous polynucleotides coding for and expressing at least one antigen of an avian pathogen; or any wild type MDV-1.
The present invention relates to a method of vaccinating an animal, or inducing an immunogenic or protective response in an animal, comprising at least one administration of the composition or vector of the present invention.
The present invention further provides specific insertion loci for the introduction of one or more isolated polynucleotide into nonessential regions of the SB-1 genome.
The following detailed description, given by way of example, and which is not intended to limit the invention to specific embodiments described, may be understood in conjunction with the accompanying figures, incorporated herein by reference, in which:
It is noted that in this disclosure and particularly in the claims, terms such as “comprises”, “comprised”, “comprising” and the like can have the meaning attributed to it in U.S. Patent law; e.g., they can mean “includes”, “included”, “including”, and the like; and that terms such as “consisting essentially of” and “consists essentially of” have the meaning ascribed to them in U.S. Patent law, e.g., they allow for elements not explicitly recited, but exclude elements that are found in the prior art or that affect a basic or novel characteristic of the invention.
Unless otherwise noted, technical terms are used according to conventional usage. Definitions of common terms in molecular biology may be found in Benjamin Lewin, Genes V. published by Oxford University Press, 1994 (ISBN 0-19-854287-9); Kendrew et al. (eds.), The Encyclopedia of Molecular Biology, published by Blackwell Science Ltd., 1994 (ISBN 0-632-02182-9); and Robert A. Meyers (ed.), Molecular Biology and Biotechnology: a Comprehensive Desk Reference, published by VCH Publishers, Inc., 1995 (ISBN 1-56081-569-8). The singular terms “a,” “an,” and “the” include plural referents unless context clearly indicates otherwise. Similarly, the word “or” is intended to include “and” unless the context clearly indicate otherwise. The word “or” means any one member of a particular list and also includes any combination of members of that list.
The term “animal” is used herein to include all mammals, birds and fish. The animal as used herein may be selected from the group consisting of equine (e.g., horse), canine (e.g., dogs, wolves, foxes, coyotes, jackals), feline (e.g., lions, tigers, domestic cats, wild cats, other big cats, and other felines including cheetahs and lynx), bovine (e.g., cattle), porcine (e.g., pig), ovine (e.g., sheep, goats, lamas, bisons), avian (e.g., chicken, duck, goose, turkey, quail, pheasant, parrot, finches, hawk, crow, ostrich, emu and cassowary), primate (e.g., prosimian, tarsier, monkey, gibbon, ape), humans, and fish. The term “animal” also includes an individual animal in all stages of development, including embryonic and fetal stages.
The terms “polypeptide” and “protein” are used interchangeably herein to refer to a polymer of consecutive amino acid residues.
The term “nucleic acid”, “nucleotide”, and “polynucleotide” are used interchangeably and refer to RNA, DNA, cDNA, or cRNA and derivatives thereof, such as those containing modified backbones. It should be appreciated that the invention provides polynucleotides comprising sequences complementary to those described herein. The “polynucleotide” contemplated in the present invention includes both the forward strand (5′ to 3′) and reverse complementary strand (3′ to 5′). Polynucleotides according to the invention can be prepared in different ways (e.g. by chemical synthesis, by gene cloning etc.) and can take various forms (e.g. linear or branched, single or double stranded, or a hybrid thereof, primers, probes etc.).
The term “genomic DNA”, or “genome” is used interchangeably and refers to the heritable genetic information of a host organism. The genomic DNA comprises the DNA of the nucleus (also referred to as chromosomal DNA) but also the DNA of the plastids (e.g., chloroplasts) and other cellular organelles (e.g., mitochondria). The genomic DNA or genome contemplated in the present invention also refers to the RNA of a virus. The RNA may be a positive strand or a negative strand RNA. The term “genomic DNA” contemplated in the present invention includes the genomic DNA containing sequences complementary to those described herein. The term “genomic DNA” also refers to messenger RNA (mRNA), complementary DNA (cDNA), and complementary RNA (cRNA).
The term “gene” is used broadly to refer to any segment of polynucleotide associated with a biological function. Thus, genes or polynucleotides include introns and exons as in genomic sequence, or just the coding sequences as in cDNAs, such as an open reading frame (ORF), starting from the start codon (methionine codon) and ending with a termination signal (stop codon). Genes and polynucleotides can also include regions that regulate their expression, such as transcription initiation, translation and transcription termination. Thus, also included are promoters and ribosome binding regions (in general these regulatory elements lie approximately between 60 and 250 nucleotides upstream of the start codon of the coding sequence or gene; Doree S M et al.; Pandher K et al.; Chung J Y et al.), transcription terminators (in general the terminator is located within approximately 50 nucleotides downstream of the stop codon of the coding sequence or gene; Ward C K et al.). Gene or polynucleotide also refers to a nucleic acid fragment that expresses mRNA or functional RNA, or encodes a specific protein, and which includes regulatory sequences.
The term “heterologous DNA” as used herein refers to the DNA derived from a different organism, such as a different cell type or a different species from the recipient. The term also refers to a DNA or fragment thereof on the same genome of the host DNA wherein the heterologous DNA is inserted into a region of the genome which is different from its original location.
As used herein, the term “antigen” or “immunogen” means a substance that induces a specific immune response in a host animal. The antigen may comprise a whole organism, killed, attenuated or live; a subunit or portion of an organism; a recombinant vector containing an insert with immunogenic properties; a piece or fragment of DNA capable of inducing an immune response upon presentation to a host animal; a polypeptide, an epitope, a hapten, or any combination thereof. Alternately, the immunogen or antigen may comprise a toxin or antitoxin.
The term “immunogenic protein or peptide” as used herein includes polypeptides that are immunologically active in the sense that once administered to the host, it is able to evoke an immune response of the humoral and/or cellular type directed against the protein. Preferably the protein fragment is such that it has substantially the same immunological activity as the total protein. Thus, a protein fragment according to the invention comprises or consists essentially of or consists of at least one epitope or antigenic determinant. An “immunogenic” protein or polypeptide, as used herein, includes the full-length sequence of the protein, analogs thereof, or immunogenic fragments thereof. By “immunogenic fragment” is meant a fragment of a protein which includes one or more epitopes and thus elicits the immunological response described above. Such fragments can be identified using any number of epitope mapping techniques, well known in the art. See, e.g., Epitope Mapping Protocols in Methods in Molecular Biology, Vol. 66 (Glenn E. Morris, Ed., 1996). For example, linear epitopes may be determined by e.g., concurrently synthesizing large numbers of peptides on solid supports, the peptides corresponding to portions of the protein molecule, and reacting the peptides with antibodies while the peptides are still attached to the supports. Such techniques are known in the art and described in, e.g., U.S. Pat. No. 4,708,871. Similarly, conformational epitopes are readily identified by determining spatial conformation of amino acids such as by, e.g., x-ray crystallography and 2-dimensional nuclear magnetic resonance. See, e.g., Epitope Mapping Protocols, supra.
The term “immunogenic protein or peptide” further contemplates deletions, additions and substitutions to the sequence, so long as the polypeptide functions to produce an immunological response as defined herein. The term “conservative variation” denotes the replacement of an amino acid residue by another biologically similar residue, or the replacement of a nucleotide in a nucleic acid sequence such that the encoded amino acid residue does not change or is another biologically similar residue. In this regard, particularly preferred substitutions will generally be conservative in nature, i.e., those substitutions that take place within a family of amino acids. For example, amino acids are generally divided into four families: (1) acidic—aspartate and glutamate; (2) basic—lysine, arginine, histidine; (3) non-polar—alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, tryptophan; and (4) uncharged polar—glycine, asparagine, glutamine, cysteine, serine, threonine, tyrosine. Phenylalanine, tryptophan, and tyrosine are sometimes classified as aromatic amino acids. Examples of conservative variations include the substitution of one hydrophobic residue such as isoleucine, valine, leucine or methionine for another hydrophobic residue, or the substitution of one polar residue for another polar residue, such as the substitution of arginine for lysine, glutamic acid for aspartic acid, or glutamine for asparagine, and the like; or a similar conservative replacement of an amino acid with a structurally related amino acid that will not have a major effect on the biological activity. Proteins having substantially the same amino acid sequence as the reference molecule but possessing minor amino acid substitutions that do not substantially affect the immunogenicity of the protein are, therefore, within the definition of the reference polypeptide. All of the polypeptides produced by these modifications are included herein. The term “conservative variation” also includes the use of a substituted amino acid in place of an unsubstituted parent amino acid provided that antibodies raised to the substituted polypeptide also immunoreact with the unsubstituted polypeptide.
The term “epitope” refers to the site on an antigen or hapten to which specific B cells and/or T cells respond. The term is also used interchangeably with “antigenic determinant” or “antigenic determinant site”. Antibodies that recognize the same epitope can be identified in a simple immunoassay showing the ability of one antibody to block the binding of another antibody to a target antigen.
An “immunological response” to a composition or vaccine is the development in the host of a cellular and/or antibody-mediated immune response to a composition or vaccine of interest. Usually, an “immunological response” includes but is not limited to one or more of the following effects: the production of antibodies, B cells, helper T cells, and/or cytotoxic T cells, directed specifically to an antigen or antigens included in the composition or vaccine of interest. Preferably, the host will display either a therapeutic or protective immunological response such that resistance to new infection will be enhanced and/or the clinical severity of the disease reduced. Such protection will be demonstrated by either a reduction or lack of symptoms normally displayed by an infected host, a quicker recovery time and/or a lowered viral titer in the infected host.
The terms “recombinant” and “genetically modified” are used interchangeably and refer to any modification, alteration or engineering of a polynucleotide or protein in its native form or structure, or any modification, alteration or engineering of a polynucleotide or protein in its native environment or surrounding. The modification, alteration or engineering of a polynucleotide or protein may include, but is not limited to, deletion of one or more nucleotides or amino acids, deletion of an entire gene, codon-optimization of a gene, conservative substitution of amino acids, insertion of one or more heterologous polynucleotides.
The terms “polyvalent vaccine or composition”, “combination or combo vaccine or composition” and “multivalent vaccine or composition” are used interchangeably to refer to a composition or vaccine containing more than one composition or vaccines. The polyvalent vaccine or composition may contain two, three, four or more compositions or vaccines. The polyvalent vaccine or composition may comprise recombinant viral vectors, active or attenuated or killed wild-type viruses, or a mixture of recombinant viral vectors and wild-type viruses in active or attenuated or killed forms.
One embodiment of the present invention provides a recombinant Gallid herpesvirus 3 (MDV-2) vector that comprises a mutated Glycoprotein C (gC or UL44) gene. The term “mutated gC gene” refers to the gC gene of Gallid herpesvirus 3 (MDV-2) that is altered or engineered which results in a non-functional gC protein upon expression. The alteration or engineering of the gC gene includes mutation or deletion of a segment of the gC gene which is essential for the expression of a functional gC protein. The term “mutated gC gene” also includes deletion of the entire gC gene of Gallid herpesvirus 3 (MDV-2) wherein gC protein is not expressed. Another embodiment of the present invention provides a recombinant Gallid herpesvirus 3 (MDV-2) wherein the Glycoprotein C (gC) gene in the native (wild-type) Gallid herpesvirus 3 (MDV-2) genome encoding the gC protein is deleted. The term “Glycoprotein C (gC) gene” includes any gene or polynucleotide that encodes the Glycoprotein C (gC) of Gallid herpesvirus 3 (MDV-2), and homologs, fragments or variants thereof. The gC gene may encode a gC protein having at least 75%, 80%, 85%, 90%, 95%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8% or 99.9% sequence identity to SEQ ID NO: 35, or a variant thereof. The gC gene having at least 75%, 80%, 85%, 90%, 95%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8% or 99.9% sequence identity to SEQ ID NO:34 is also encompassed in the present invention.
Another embodiment of the invention provides a recombinant Gallid herpesvirus 3 (MDV-2) viral vector comprising one or more heterologous polynucleotides coding for and expressing at least one antigen or polypeptide of an avian pathogen. The Gallid herpesvirus 3 (MDV-2) strains used for the recombinant viral vector may be any SB-1 strains, including, but not limited to, the commercial Marek's Disease Vaccine (SB-1 vaccine) (Merial Select Inc., Gainesville, Ga. 30503, USA), the SB-1 strain having the genome sequence as defined by GenBank Accession Number HQ840738.1. The Gallid herpesvirus 3 (MDV-2) strains used for the recombinant viral vector may be any other Gallid herpesvirus 3 isolate including the HPRS24 strain having the genome sequence as defined by GenBank Accession Number AB049735.1, or the HPRS24 strain having the genome sequence as defined by GenBank Accession Number NC—002577.1. The genomes of HPRS24 and SB-1 share 98.4% sequence identity (Spatz and Schat, 2011; Virus Gene 42, 331-338). The Gallid herpesvirus 3 (MDV-2) strains used for the recombinant viral vector may be the 301B/1 isolate described by Witter (1987 Avian Dis 31, 752-765) or by Witter et al. (1987 Avian Dis 31, 829-840). The Gallid herpesvirus 3 (MDV-2) strains may be any Gallid herpesvirus 3 (MDV-2) strains comprising the genome sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to the sequence as defined in GenBank Accession Number HQ840738.1 (SEQ ID NO:14), AB049735.1, or NC—002577.1.
The genes coding for antigen or polypeptide may be those coding for Newcastle Disease Virus fusion protein (NDV-F), Newcastle Disease Virus hemagglutinin neuraminidase (NDV-HN), Marek's Disease Virus glycoprotein C (gC), Marek's Disease Virus glycoprotein B (gB), Marek's Disease Virus glycoprotein E (gE), Marek's Disease Virus glycoprotein I (gI), Marek's Disease Virus glycoprotein H (gH) or Marek's Disease Virus glycoprotein L (gL), IBDV VP2, IBDV VPX, IBDV VP3, IBDV VP4, ILTV glycoprotein B, ILTV glycoprotein I, ILTV UL32, ILTV glycoprotein D, ILTV glycoprotein E, ILTV glycoprotein C, influenza hemaglutinin (HA), influenza neuraminidase (NA), protective genes derived from Mycoplasma gallisepticum (MG), or Mycoplasma synoviae (MS), or combinations thereof. The antigen or polypeptide may be any antigen from the poultry pathogen selected form the group consisting of avian encephalomyelitis virus, avian reovirus, avian paramyxovirus, avian metapneumovirus, avian influenza virus, avian adenovirus, fowl pox virus, avian coronavirus, avian rotavirus, chick anemia virus, avian astrovirus, avian parvovirus, coccidiosis (Eimeria sp.), Campylobacter sp., Salmonella sp., Pasteurella sp., Avibacterium sp., Mycoplasma gallisepticum, Mycoplasma synoviae, Clostridium sp., and E. coli.
Moreover, homologs of aforementioned antigen or polynucleotides are intended to be within the scope of the present invention. As used herein, the term “homologs” includes orthologs, analogs and paralogs. The term “analogs” refers to two polynucleotides or polypeptides that have the same or similar function, but that have evolved separately in unrelated organisms. The term “orthologs” refers to two polynucleotides or polypeptides from different species, but that have evolved from a common ancestral gene by speciation. Normally, orthologs encode polypeptides having the same or similar functions. The term “paralogs” refers to two polynucleotides or polypeptides that are related by duplication within a genome. Paralogs usually have different functions, but these functions may be related. Analogs, orthologs, and paralogs of a wild-type polypeptide can differ from the wild-type polypeptide by post-translational modifications, by amino acid sequence differences, or by both. In particular, homologs of the invention will generally exhibit at least 80-85%, 85-90%, 90-95%, or 95%, 96%, 97%, 98%, 99% sequence identity, with all or part of the polynucleotide or polypeptide sequences of antigens described above, and will exhibit a similar function.
In one embodiment, the present invention provides a recombinant Gallid Herpesvirus-3 (MDV-2) viral vector comprising one, two or more heterologous polynucleotides coding for and expressing the NDV-F antigen or polypeptide. In one aspect of the embodiment, the NDV-F antigen or polypeptide has at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity to a polypeptide having the sequence as set forth in SEQ ID NO:2, 9, 50, 52, or 54, or a conservative variant, an allelic variant, a homolog or an immunogenic fragment comprising at least eight or at east ten consecutive amino acids of one of these polypeptides, or a combination of these polypeptides. In another aspect of the embodiment, the heterologous polynucleotide encoding an NDV-F antigen or polypeptide has at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity to a polypeptide having the sequence as set forth in SEQ ID NO:2, 9, 50, 52, or 54. In yet another aspect of the embodiment, the heterologous polynucleotide has at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity to a polynucleotide having the sequence as set forth in SEQ ID NO:1, 8, 49, 51, or 53.
Variants include allelic variants. The term “allelic variant” refers to a polynucleotide or a polypeptide containing polymorphisms that lead to changes in the amino acid sequences of a protein and that exist within a natural population (e.g., a virus species or variety). Such natural allelic variations can typically result in 1-5% variance in a polynucleotide or a polypeptide. Allelic variants can be identified by sequencing the nucleic acid sequence of interest in a number of different species, which can be readily carried out by using hybridization probes to identify the same gene genetic locus in those species. Any and all such nucleic acid variations and resulting amino acid polymorphisms or variations that are the result of natural allelic variation and that do not alter the functional activity of gene of interest, are intended to be within the scope of the invention.
The term “identity” with respect to sequences can refer to, for example, the number of positions with identical nucleotides or amino acids divided by the number of nucleotides or amino acids in the shorter of the two sequences wherein alignment of the two sequences can be determined in accordance with the Wilbur and Lipman algorithm (Wilbur and Lipman). The sequence identity or sequence similarity of two amino acid sequences, or the sequence identity between two nucleotide sequences can be determined using Vector NTI software package (Invitrogen, 1600 Faraday Ave., Carlsbad, Calif.). When RNA sequences are said to be similar, or have a degree of sequence identity or homology with DNA sequences, thymidine (T) in the DNA sequence is considered equal to uracil (U) in the RNA sequence. Thus, RNA sequences are within the scope of the invention and can be derived from DNA sequences, by thymidine (T) in the DNA sequence being considered equal to uracil (U) in RNA sequences.
The polynucleotides of the disclosure include sequences that are degenerate as a result of the genetic code, e.g., optimized codon usage for a specific host. As used herein, “optimized” refers to a polynucleotide that is genetically engineered to increase its expression in a given species. To provide optimized polynucleotides coding for NDV-F polypeptides, the DNA sequence of the NDV-F protein gene can be modified to 1) comprise codons preferred by highly expressed genes in a particular species; 2) comprise an A+T or G+C content in nucleotide base composition to that substantially found in said species; 3) form an initiation sequence of said species; or 4) eliminate sequences that cause destabilization, inappropriate polyadenylation, degradation and termination of RNA, or that form secondary structure hairpins or RNA splice sites. Increased expression of NDV F protein in said species can be achieved by utilizing the distribution frequency of codon usage in eukaryotes and prokaryotes, or in a particular species. The term “frequency of preferred codon usage” refers to the preference exhibited by a specific host cell in usage of nucleotide codons to specify a given amino acid. There are 20 natural amino acids, most of which are specified by more than one codon. Therefore, all degenerate nucleotide sequences are included in the disclosure as long as the amino acid sequence of the NDV-F polypeptide encoded by the nucleotide sequence is functionally unchanged.
In another embodiment, the present invention provides a method for producing a recombinant Gallid Herpesvirus-3 or SB-1 viral vector comprising the introduction into the SB-1 genome of one, two or more isolated polynucleotides in a nonessential region of the SB-1 genome. In yet another embodiment, the present invention provides a method for producing a recombinant Gallid Herpesvirus-3 or SB-1 viral vector comprising the steps of altering, engineering, or deleting the gC gene from the SB-1 genome. The term “nonessential region” refers to a region of a virus genome which is not essential for replication and propagation of the virus in tissue culture or in chickens. Any nonessential region or portion thereof can be deleted from the SB-1 genome or a foreign sequence can be inserted in it, and the viability and stability of the recombinant Gallid Herpesvirus-3 or SB-1 vector resulting from the deletion or insertion can be used to ascertain whether a deleted region or portion thereof is indeed nonessential. In one aspect of the embodiment, the non-essential regions are located in the unique long (UL) and unique short (US) regions of the SB-1 genome (see Spatz et al., Virus Genes 42:331-338, 2011). The UL region of SB-1 is about 109,744 bp to about 109,932 bp in length and may extend from positions 12,209 to 121,952 of SEQ ID NO:14 (GenBank accession No, HQ840738.1) or equivalent positions of other SB1-genomes, for example, from 11,826 bp to 121,757 bp of HPRS24 genome. The US region of SB-1 is about 12,109 bp to about 12,910 bp in length and may extend from positions 143,514 to 156,423 of SEQ ID NO:14 (GenBank accession No, HQ840738.1) or equivalent positions of other SB1-genomes, for example from 142,681 bp to 154,789 bp of HPRS24 genome (Spatz et al., 2011). In one aspect of the embodiment, the non-essential region is between ORF of UL55 and ORF of LORF5 in the unique long (UL) region of SB-1. In another aspect, the polynucleotide is inserted into or to replace SB-1 glycoprotein C gene (also designated UL44). The use of the gC locus may allow the generation of recombinant virus unable to produce a functional gC protein and unable to be transmitted horizontally. In yet another embodiment, the nonessential region may be in the intergenic regions between UL7 and UL8, between UL 21 and UL22, between UL40 and UL41, between UL50 and UL51, between UL54 and LORF4, between US10 and SORF4, or within the UL43, US2, US10 or US6 (coding for gD) gene (see GenBank accession No, HQ840738.1). In yet another embodiment, the nonessential regions may be in the region of nucleotide positions 118057-118306 (intergenic UL55-LORF5), 98595-100031 (gC or UL44), 25983-26038 (intergenic UL7-UL8), 49865-50033 (intergenic UL21-UL22), 75880-75948 (intergenic UL35-UL36), 93928-93990 (intergenic UL40-UL41), 109777-109847 (intergenic UL50-UL51), 116466-116571 (intergenic UL54-LORF4), 146548-146697 (intergenic US10-SORF4), 97141-98385 (UL43), 147857-148672 (US2), 145853.146548 (US10) or 150322-151479 (gD or US6) of SEQ ID NO:14.
Construction of recombinant virus is well known in the art as described in, e.g., U.S. Pat. Nos. 4,769,330, 4,722,848, 4,603, 112, 5,174, 993, and 5,756,103, 6,719,979. Specifically, a recombinant Gallid Herpesvirus-3 (MDV-2) viral vector may be constructed in two steps. First, the Gallid Herpesvirus-3 (MDV-2) or SB-1 genomic regions flanking the locus of insertion are cloned into an E. coli plasmid construct; unique(s) restriction site(s) is (are) placed between the two flanking regions (insertion plasmid) in order to allow the insertion of the donor expression cassette DNA. Separately, the cDNA or DNA gene sequence to be inserted is preceded by a promoter region (gene start region) and a terminator (or poly-adenylation, polyA) sequence which is specific for the Gallid Herpesvirus-3 (MDV-2) or SB-1 vector and/or eukaryotic cells. The whole expression cassette (promoter-foreign gene-poly-A) is then cloned into the unique(s) restriction site(s) of the insertion plasmid to construct the “donor plasmid” which contains the expression cassette flanked by Gallid Herpesvirus-3 (MDV-2) or SB-1 “arms” flanking the insertion locus. The resulting donor plasmid construct is then amplified by growth within E. coli bacteria and plasmid DNA is extracted. This plasmid is then linearized using a restriction enzyme that cut the plasmid backbone (outside the Gallid Herpesvirus-3 (MDV-2) or SB-1 arms and expression cassette). Chicken embryo fibroblasts are then co-transfected with parental Gallid Herpesvirus-3 (MDV-2) or SB-1 DNA and linearized donor plasmid DNA. The resulting virus population is then cloned by multiple limiting dilution steps where viruses expressing the foreign gene are isolated from the non-expressing viral population. Similarly, another foreign cassette can be inserted in another locus of insertion to create a double Gallid Herpesvirus-3 (MDV-2) or SB-1 recombinant expressing two genes. The second cassette can also be inserted into the same locus. The Gallid Herpesvirus-3 (MDV-2) or SB-1 recombinant is produced in primary chicken embryo fibroblasts similarly to the parental Gallid Herpesvirus-3 (MDV-2) or SB-1 MD vaccine. After incubation, infected cells are harvested, mixed with a freezing medium allowing survival of infected cells, and frozen usually in cryovial or glass ampoules and stored in liquid nitrogen.
Successful expression of the inserted cDNA genetic sequence by the modified infectious virus requires two conditions. First, the insertion must be introduced into a region of the genome of the virus in order that the modified virus remains viable. The second condition for expression of inserted cDNA is the presence of a regulatory sequences allowing expression of the gene in the viral background (for instance: promoter, enhancer, donor and acceptor splicing sites and intron, Kozak translation initiation consensus sequence, polyadenylation signals, untranslated sequence elements).
In general, it is advantageous to employ a strong promoter functional in eukaryotic cells. The promoters include, but are not limited to, an immediate early cytomegalovirus (CMV) promoter, guinea pig CMV promoter, an SV40 promoter, Pseudorabies Virus promoters such as that of glycoprotein X promoter, Herpes Simplex Virus-1 such as the alpha 4 promoter, Marek's Disease Viruses (including MDV-1, MDV-2 and HVT) promoters such as those driving glycoproteins gC, gB, gE, or gI expression, Infectious Laryngotracheitis Virus promoters such as those of glycoprotein gB, gE, gI, gD genes, or other herpesvirus promoters. When the insertion locus consists of a SB-1 gene (for instance, gC, gD, US2 or US10 genes), the foreign gene can be inserted into the vector with no additional promoter sequence since the promoter of the deleted gene of the vector will drive the transcription of the inserted foreign gene.
In one embodiment, the present invention relates to a pharmaceutical composition or vaccine comprising one or more recombinant Gallid Herpesvirus-3 (MDV-2) rival vectors of the present invention and a pharmaceutically or veterinarily acceptable carrier, excipient, vehicle or adjuvant. The Gallid herpesvirus 3 (MDV-2) strains used for the recombinant Gallid Herpesvirus-3 viral vector may be any SB-1 strains, the HPSR24 strains, or the 301B/1 strains. The Gallid Herpesvirus-3 (MDV-2) strains may also include those described in Witter et al (Avian Diseases 34, 944-957; 1990), Witter (Avian Pathology 21, 601-614, 1992) and Witter (Avian Pathology 24, 665-678, 1995): 280-5/1, 281MI/1, 287C/1, 298B/1, 301A/1, 401/1, 437A/1, 437B/1, 468A/1, 468A/2, 468B/1, 471B/1, or HN-1/1.
In another embodiment, the present invention provides a composition or vaccine comprising: i) a recombinant Gallid Herpesvirus-3 vector (MDV-2) comprising heterologous polynucleotides coding for and expressing at least one antigen of an avian pathogen; and ii) at least one of: a recombinant HVT vector (or MDV-3 or Meleagrid Herpesvirus-1) comprising heterologous polynucleotides coding for and expressing at least one antigen of an avian pathogen; or wild type MDV-3; or recombinant MDV-1 vector (or Gallid herpesvirus-2) comprising heterologous polynucleotides coding for and expressing at least one antigen of an avian pathogen; or wild type MDV-1. The composition or vaccine may further comprise a pharmaceutically or veterinarily acceptable carrier, excipient, vehicle or adjuvant. This composition may further contain a recombinant fowlpox vector comprising heterologous polynucleotides coding for and expressing at least one antigen of an avian pathogen; or wild type fowlpox.
In one aspect of the embodiment, the composition or vaccine comprises one (or more) recombinant Gallid Herpesvirus-3 (MDV-2) vectors and one or more wild type HVT (MDV-3). In another aspect, the composition or vaccine comprises one (or more) recombinant Gallid Herpesvirus-3 (MDV-2) vectors and one or more recombinant HVT (MDV-3). In another aspect, the composition or vaccine comprises one or more recombinant Gallid Herpesvirus-3 (MDV-2) vectors and one or more wild type or genetically modified MDV-1. In another aspect, the composition or vaccine comprises one or more recombinant Gallid Herpesvirus-3 (MDV-2) vectors and one or more recombinant MDV-1. In another aspect, the composition or vaccine comprises one or more recombinant Gallid Herpesvirus-3 (MDV-2) vectors, one or more wild type HVT (MDV-3) and one or more wild type MDV-1. In another aspect, the composition or vaccine comprises one or more recombinant Gallid Herpesvirus-3 (MDV-2) vectors, one or more recombinant HVT (MDV-3) and one or more wild type MDV-1. In another aspect, the composition or vaccine comprises one or more recombinant Gallid Herpesvirus-3 (MDV-2) vectors, one or more wild type HVT (MDV-3) and one or more recombinant MDV-1. In yet another aspect, the composition or vaccine comprises one or more recombinant Gallid Herpesvirus-3 (MDV-2) vectors, one or more recombinant HVT (MDV-3) and one or more recombinant MDV-1. The wild type HVT (MDV-3) or wild type MDV-1 may be live, attenuated or genetically modified. The heterologous polynucleotides in recombinant Gallid Herpesvirus-3 (MDV-2) vectors, recombinant HVT (MDV-3) vectors, and recombinant MDV-1 vectors may encode same or different antigens from the same or different avian pathogens.
The pharmaceutically or veterinarily acceptable carriers or adjuvant or vehicles or excipients are well known to the one skilled in the art. For example, a pharmaceutically or veterinarily acceptable carrier or adjuvant or vehicle or excipient can be Marek's disease vaccine diluent used for MD vaccines. Other pharmaceutically or veterinarily acceptable carrier or adjuvant or vehicle or excipients that can be used for methods of this invention include, but are not limited to, 0.9% NaCl (e.g., saline) solution or a phosphate buffer, poly-(L-glutamate) or polyvinylpyrrolidone. The pharmaceutically or veterinarily acceptable carrier or vehicle or excipients may be any compound or combination of compounds facilitating the administration of the vector (or protein expressed from an inventive vector in vitro), or facilitating transfection or infection and/or improve preservation of the vector (or protein). Doses and dose volumes are herein discussed in the general description and can also be determined by the skilled artisan from this disclosure read in conjunction with the knowledge in the art, without any undue experimentation.
Optionally other compounds may be added as pharmaceutically or veterinarily acceptable carriers or adjuvant or vehicles or excipients, including, but not limited to, alum; CpG oligonucleotides (ODN), in particular ODN 2006, 2007, 2059, or 2135 (Pontarollo R. A. et al., Vet. Immunol. Immunopath, 2002, 84: 43-59; Wernette C. M. et al., Vet. Immunol. Immunopath, 2002, 84: 223-236; Mutwiri G. et al., Vet. Immunol. Immunopath, 2003, 91: 89-103); polyA-polyU, dimethyldioctadecylammonium bromide (DDA) (“Vaccine Design The Subunit and Adjuvant Approach”, edited by Michael F. Powell and Mark J. Newman, Pharmaceutical Biotechnology, 6: p. 03, p. 157); N,N-dioctadecyl-N′,N′-bis(2-hydroxyethyl) propanediamine (such as AVRIDINE®) (Ibid, p. 148); carbomer, chitosan (see U.S. Pat. No. 5,980,912 for example).
The pharmaceutical compositions and vaccines according to the invention may comprise or consist essentially of one or more adjuvants. 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 et al., 1996; 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) cation lipids containing a quaternary ammonium salt, e.g., DDA (5) cytokines, (6) aluminum hydroxide or aluminum phosphate, (7) saponin or (8) other adjuvants discussed in any document cited and incorporated by reference into the instant application, or (9) any combinations or mixtures thereof.
Another aspect of the invention relates to a method for inducing an immunological response in an animal against one or more antigens or a protective response in an animal against one or more avian pathogens, which method comprises inoculating the animal at least once with the vaccine or pharmaceutical composition of the present invention. Yet another aspect of the invention relates to a method for inducing an immunological response in an animal to one or more antigens or a protective response in an animal against one or more avian pathogens in a prime-boost administration regimen, which is comprised of at least one primary administration and at least one booster administration using at least one common polypeptide, antigen, epitope or immunogen. The immunological composition or vaccine used in primary administration may be same, may be different in nature from those used as a booster.
The avian pathogens may be Newcastle Disease Virus (NDV), Infectious Bursal Disease Virus (i.e., IBDV or Gumboro Disease virus), Marek's Disease Virus (MDV), Infectious Laryngotracheitis Virus (ILTV), avian encephalomyelitis virus and other picornavirus, avian reovirus, avian paramyxovirus, avian metapneumovirus, avian influenza virus, avian adenovirus, fowl pox virus, avian coronavirus, avian rotavirus, avian parvovirus, avian astrovirus and chick anemia virus, coccidiosis (Eimeria sp.), Campylobacter sp., Salmonella sp., Mycoplasma gallisepticum, Mycoplasma synoviae, Pasteurella sp., Avibacterium sp., E. coli or Clostridium sp.
Usually, one administration of the vaccine is performed either at one day-of-age by the subcutaneous or intramuscular route or in ovo in 17-19 day-old embryo. A second administration can be done within the first 10 days of age. The animals are preferably at least 17-day-embryo or one day old at the time of the first administration.
A variety of administration routes in day-old chicks may be used such as subcutaneously or intramuscularly, intradermally, transdermally. The in ovo vaccination can be performed in the amniotic sac and/or the embryo. Commercially available in ovo and SC administration devices can be used for vaccination.
The invention will now be further described by way of the following non-limiting examples.
Construction of DNA inserts, plasmids and recombinant viral vectors was carried out using the standard molecular biology techniques described by J. Sambrook et al. (Molecular Cloning: A Laboratory Manual, 2nd Edition, Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y., 1989).
The aim of the work is to construct a recombinant SB-1 virus in which an expression cassette containing mouse cytomegalovirus (mCMV) promoter, Newcastle disease virus fusion protein (NDV-F), and Simian virus 40 (SV40) poly A tail is inserted into the intergenic site between US10 and SORF4 site of SB-1 virus (Table 1 and
A Newcastle disease virus Fusion Protein (NDV-F) corresponding to genotype VIId sequence (SEQ ID NO:2 encoded by SEQ ID NO:3) was chemically synthesized (GenScript, Piscataway, N.J., USA). The F protein cleavage site of this synthetic gene was altered to match with a lentogenic F cleavage site sequence and the resultant NDV-F gene sequence has 99% nucleotide as well as 99% amino acid sequence identity to NDV-F sequence deposited in GenBank under accession number AY337464 (for DNA) and AAP97877.1 (for protein), respectively.
Donor Plasmid SB-1 US10mFwt SbfI Construction
A fragment containing the synthetic NDV-F gene was excised from pUC57 NDV-F VIId wt plasmid (synthesized by GeneScript) using NotI and inserted into the same site of pCD046 plasmid containing mCMV promoter and SV40 polyA tail. The resultant plasmid, pCD046+NDV-F wt was digested with EcoRI and SalI and blunt ended with Klenow. A 3.3 kb fragment was gel extracted and ligated to a SmaI digested and dephosphorylated (CIPed) vector (SB1 US10-SORF4 SbfI pUC57) containing flanking arms. Ligated material was transformed using Top10 Oneshot kit (Invitrogen, CA, USA). Bacterial colonies were grown in LBamp broth, plasmid extracted by using Qiagens MiniSpin Prep kit, and screened for insert orientation using PstI digestion. The correct donor plasmid was designated SB-1 10mFwt SbfI. Large scale cultures were grown and plasmid extraction was done using Qiagens Maxi Prep kit. Transient expression of the maxi preps was verified using Fugene Transfection Reagent in Chicken Embryo Fibroblast Cells (CEF's) and chicken polyclonal sera against NDV.
A standard homologous recombination procedure was followed by co-electroporation of secondary CEF cells using SB-1 US10 mFwt SbfI donor plasmid and viral DNA isolated from vaccine strain of SB-1 virus. Co-electroporation was performed using 1×107 2° CEF in 300 μl Opti-MEM and shocked at 150 volts with 950 capacitance in a 2 mm electroporation cuvette. The transfected cells were seeded into 96-well plate and incubated for 5-7 days. The cells grown in the 96-well plate were then treated with trypsin and transferred into two “sisters” 96-well plates and incubated for 5 more days. One set of 96-well plates was used for IFA using chicken polyclonal sera against NDV-F to identify positive wells containing recombinants and another set of 96-well plates was used for recovering the infected cells from the positive wells.
The recombinant viral purification methods were performed first by 96-well plate duplication and IFA selection for the wells containing the most IFA positive plaques with the least amount of IFA negative plaques. Wells matching those criteria were then harvested and adjusted to 1 ml in DMEM+2% FBS. From the 1 ml stock, 5-20 μl (depending on the number of visible plaques) were removed and mixed with 1×107 CEFs in 10 ml DMEM+2% FBS and aliquoted onto a new 96-well plate to have single SB-1 plaques per well. The 96-well plates were duplicated after 5 days of incubation and wells that contained plaques were tested for the presence of recombinant SB-1 and absence of parental virus by IFA and PCR. Again the wells that appeared to have more recombinant virus, by comparing the PCR banding results, were harvested and adjusted to 1 ml and aliquoted onto new 96-well plates. After three to five rounds of purification of virus infected cells, recombinant SB-1 expressing NDV-F protein was isolated and the purity of the recombinant virus was tested by IFA and PCR to confirm the absence of parental virus. Selected recombinant virus was then passed from one well of a 96-well plate (P0) to 2×T-25 flasks (P1), then 2×T-75 flasks (P2), 2×T-175 flasks (P3), and finally 2×850 cm2 roller bottles (pre-MSV stock or P4). Vials with 2 ml aliquot were stored in liquid nitrogen. Titrations were performed in triplicate on CEFs and a titer of 1×105 pfu/ml was obtained for SB1-004.
For immunofluorescence testing, the P3 material was diluted 1:100 in media. Approximately 50 μA of the diluted virus was added to 10 ml of DMEM+2% FBS with 1×107 CEFs and then aliquoted onto a 96 well plate (100 gl/well). The plates were incubated for 5 days at 37° C.+5% CO2 until viral plaques were visible. The plates were fixed with 95% ice-cold acetone for three minutes and washed three times with PBS. Chicken anti-sera against Newcastle Disease Virus (lot#C0139, Charles Rivers Laboratory) at 1:1000 was added and the plates were incubated at 37° C. for 1 hour. After one hour incubation, the plates were washed three times with PBS and FITC anti-chicken (cat# F8888, Sigma) was added at 1:500. Again the plates were incubated at 37° C. for 1 hour. After one hour incubation the cells were rinsed three times with PBS and visualized with a fluorescent microscope using fluorescein isothiocyanate (FITC) filter. All examined plaques of vSB1-004 were found to express NDV-F protein (
DNA was extracted from a stock virus by phenol/chloroform extraction, ethanol precipitated, and resuspended in 20 mM HEPES. PCR primers were designed to specifically identify the NDV-F VIId gene, the promoter, the SV40 poly A and the SB-1 flanking arms (see
The PCR reactions with all primer pairs resulted in the expected PCR products and banding patterns. The PCR results demonstrate that recombinant virus vSB1-004 carries the intended expression cassette and the virus stock is free from detectable amounts of parental SB-1 virus (
The nucleotide sequence of the donor plasmid SB-1 US10mFwt SbfI (SEQ ID NO:41) is shown in
Based on PCR testing and immunofluorescence analysis, vSB1-004 is a recombinant SB-1 expressing a NDV-F gene under the control of mCMV promoter. Recombinant vector vSB1-004 is free of any detectable parental SB-1 virus or potential HVT contaminant.
The aim of the work is to construct a recombinant SB-1 virus in which an expression cassette containing SV40 promoter, Newcastle disease virus fusion protein (NDV-F), and synthetic polyA tail is inserted between the UL55 and LORF5 site of SB-1 virus (Table 2).
A Newcastle disease virus Fusion Protein (NDV-F) corresponding to a consensus codon-optimized genotype VIId sequence (SEQ ID NO:2 encoded by SEQ ID NO:1) was chemically synthesized (GeneArt).
A synthetic SB-1 UL55-LOrf5 SbfI plasmid covering approximately 1 kb sequence on each side of the insertion site (GenScript) was digested with SbfI and dephosphorylated. A synthetic SV OptF syn tail pUC57 plasmid (Genscript) was digested with SbfI and a 2239 base pair fragment was gel extracted and ligated to the SbfI digested vector to create the new SB1 UL55 SVFopt syn tail SbfI donor plasmid.
A standard homologous recombination procedure was followed by co-electroporation of secondary CEF cells using donor plasmid SB1 UL55 SV Fopt syn tail SbfI and viral DNA isolated from vaccine strain of SB-1 virus. Essentially the procedure described in example 1 for vSB1-004 was followed to generate, plaque purify and characterize recombinants by immunofluorescence and PCR.
The nucleotide sequence of the donor plasmid SB1 UL55 SVFopt syn tail SbfI (SEQ ID NO:42) is shown in
Genomic DNA of SB-1 virus was co-electroporated with SB-1 UL55 SV Fopt syn tail SbfI donor plasmid to generate recombinant SB-1 using homologous recombination technique. Recombinant virus was separated from parental SB-1 virus by immunofluorescent positive well selection and PCR screening in multiple rounds of plaque purification. A plaque purified recombinant SB-1 virus expressing the NDV-F protein, designated vSB1-006, was scaled up from tissue culture flasks to 2×850 cm2 roller bottles. After about 72 hrs post infection in roller bottles, the infected CEFs were harvested. Aliquots were frozen in liquid nitrogen containing 10% FBS and 10% DMSO. Titrations were performed in triplicate on CEFs and a titer of 8×105 pfu/ml was obtained for SB1-006.
Immunofluorescence was preformed using chicken anti-sera (lot# C0139, Charles Rivers Laboratories) followed by a FITC labeled anti-chicken IgG (cat#02-24-06, KPL). All examined plaques of vSB1-006 were found to express NDV-F protein (
PCR Analysis of vSB1-006
Purity of recombinant virus was verified by PCR using primer pairs that are specific to the SB-1 flanking arms, codon-optimized NDV-F VIId, SV40 promoter as well as primer pairs specific to HVT (see
Based on PCR testing and immunofluorescence analysis, it is confirmed that vSB1-006 is a recombinant SB-1 expressing a codon-optimized NDV-F gene under the control of SV40 promoter. Recombinant vector vSB1-006 is free of any detectable amount of parental SB-1 virus and potential HVT contaminant.
The aim of the work is to construct a recombinant SB-1 virus in which an expression cassette containing SV40 promoter, NDV-F gene corresponding to the F sequence of genotype VIId of NDV is used to replace the coding sequence of glycoprotein C (gC or UL44) of SB-1 virus (Table 3).
A Newcastle disease virus Fusion Protein (NDV-F) corresponding to a consensus codon-optimized genotype VIId sequence (SEQ ID NO:2 encoded by SEQ ID NO:1) was chemically synthesized (GeneArt).
Donor Plasmid pSB1 44 Cds SVOptF Construction
A synthetic pSB 1 44 cds plasmid containing flanking arms was generated by gene synthesis (GenScript). The pSB1 44 cds was digested with SbfI, dephosphorylated. Another plasmid named SV-OptF-syn no polyA tail-pUC57 was digested with SbfI and 2.1 kb fragment containing SV40 promoter and NDV-F gene was gel extracted, ligated into the SbfI digested vector and transformed using the Top10 Oneshot kit (Invitrogen). Bacterial colonies were grown in LB-ampicillin media (100 ug/ml), and plasmids were extracted by using Qiagen Mini Spin Prep kit, and screened for insertions by EcoRI and NcoI digestion. The resultant donor plasmid was designated pSB1 44 cds SVOptF.
The synthetic plasmid pSB1 44 cds (SEQ ID NO:36 in
A standard homologous recombination procedure was followed by co-electroporation of secondary CEF cells using donor plasmid pSB1 44 cds SVOptF and viral DNA isolated from vaccine strain of SB-1 virus. Essentially the procedure described in example 1 for vSB1-004 was followed to generate, plaque purify and characterize recombinants by immunofluorescence. A plaque purified recombinant SB-1 virus expressing the NDV-F protein, designated vSB1-007, was scaled up from T-25 tissue culture flasks to 10×T-150 cm2 flasks. Infected CEF cells were harvested and aliquots were frozen in liquid nitrogen containing 10% FBS and 10% DMSO. Titrations were performed in triplicate on CEFs and a titer of 7.2×104 pfu/ml was obtained for SB1-007.
Immunofluorescents was performed using chicken anti-sera (lot# C0139, Charles Rivers Laboratories) followed by a FITC labeled anti-chicken IgG (cat#02-24-06, KPL). All examined plaques of vSB1-007 were found to express NDV-F protein (
PCR Analysis of vSB1-007
Viral DNA was extracted from SB1-007 from P.1 through P.6 by QIA DNeasy Blood & Tissue Kit (Qiagen). PCR primers were designed to specifically identify the presence of NDV F (codon-optimized), the SV40 promoter and the flanking arms of UL44 (see
Similarly, a standard homologous recombination procedure using synthetic plasmid pSB1 44 cds and viral DNA isolated from vaccine strain of SB-1 virus will generate a recombinant SB-1 in which the coding region of gC gene is deleted. Two PCR primers (SB1 43.F and SB1 45.R, Table 4) will produce a PCR product of 103 nucleotides for a gC-deleted recombinant SB-1 versus a 1540 nucleotides for the parent SB-1 virus.
Purity of recombinant virus was verified by PCR using primer pairs that are specific to the SB-1 flanking arms, codon-optimized NDV-F VIId, SV40 promoter as well as primer pairs (MB080 +MB081) specific to HVT. PCR reactions with all primer pairs resulted in the expected PCR products and banding patterns. In addition, there is no evidence of the parental SB-1 virus in vSB1-007 (Tables 4-5 and
Based on PCR testing and immunofluorescence analysis, it is confirmed that vSB1-007 is a recombinant SB-1 expressing a codon-optimized NDV-F gene under the control of SV40 promoter. The NDV-F expression cassette was successfully used to replace the gC gene of SB1, demonstrating that gC is dispensable for in vitro propagation of SB-1 virus. Recombinant vector vSB1-007 is free of any detectable amount of parental SB-1 virus or HVT.
The nucleotide sequence of the donor plasmid pSB1 44 cds SVOptF (SEQ ID NO:43) is shown in
The aim of the work is to construct a recombinant SB-1 virus in which an expression cassette containing SV40 promoter, NDV-F gene corresponding to the F sequence of CA02 strain of NDV, and synthetic polyA tail is inserted between the UL55 and LORF5 site of SB-1 virus (Table 6).
An NDV-F corresponding to a codon-optimized genotype V (CA02 strain) sequence (SEQ ID NO:9 encoded by SEQ ID NO:8) was chemically synthesized (GeneArt). The F protein cleavage site of this synthetic gene was altered to match a lentogenic F cleavage site sequence and the resultant NDV-F gene sequence has 99% amino acid sequence identity to NDV-F sequence deposited in GenBank (ABS84266).
A synthetic SB-1 UL55-LOrf5 SbfI plasmid (Genscript) containing approximately 1 kb sequence of each side of the insertion site was digested with SbfI and dephosphorylated. A synthetic SV OptF syn tail pUC57 plasmid (Genscript) was digested with SbfI and a 2239 base pair fragment containing syn tail was gel extracted and ligated to the SbfI digested vector to create the new SB1 UL55 SVFopt syn tail SbfI donor plasmid. This donor plasmid was then digested with NotI, CIPed, and a 5196 base pair fragment was gel extracted. A synthetic NDV-F CAO2 CSmut 0813005 pVR101 donor plasmid (GeneArt) was digested with NotI and a 1677 base pair fragment was gel extracted and ligated to the NotI digested and CIPed UL55 vector resulting in donor plasmid SB1 UL55 SV CaFopt syn tail SbfI.
A standard homologous recombination procedure was followed by co-electroporation of secondary CEF cells using donor plasmid SB-1 UL55 SV CaFopt syn tail SbfI and viral DNA isolated from vaccine strain of SB-1 virus. Essentially the procedure described in example 1 was followed to generate and characterize recombinants by immunofluorescence and PCR.
Recombinant virus was separated from parental SB-1 virus by immunofluorescent positive well selection and PCR screening in multiple rounds of plaque purification. A plaque purified recombinant SB-1 virus expressing the NDV-F protein, designated vSB1-008, was scaled up from tissue culture flasks to 2×850 cm2 roller bottles. After about 72 hrs post infection in roller bottles, the infected CEFs were harvested. Aliquots were frozen in liquid nitrogen containing 10% FBS and 10% DMSO.
Immunofluorescence was performed using chicken anti-sera (Charles Rivers Laboratories) followed by a FITC labeled anti-chicken IgG (KPL) (
PCR Analysis of vSB1-008
Purity of recombinant virus was verified by PCR using primer pairs that are specific to the SB-1 flanking arms, codon-optimized NDV-F VIId, SV40 promoter (see
The nucleotide sequence of the donor plasmid SB-1 UL55 CaFopt syn tail SbfI (SEQ ID NO:44) is shown in
Based on PCR testing and immunofluorescence analysis, it is confirmed that vSB1-008 is a recombinant SB-1 expressing a codon-optimized NDV-F gene under the control of SV40 promoter. Recombinant vector vSB1-008 is free of any detectable parental SB-1 virus or HVT.
The aim of the study is to construct a recombinant SB-1 viral vector vSB1-009 in which an expression cassette containing SV40 promoter and Newcastle disease virus fusion (NDV-F) gene is inserted to replace UL44 coding (gC) sequence of SB-1 and to construct a recombinant SB-1 viral vector vSB1-010 in which an additional expression cassette containing guinea pig CMV promoter and NDV-F gene is inserted in SORF-US2 locus of SB1-009 vector backbone.
A donor plasmid pSB1 44 cds SV FCAopt was constructed containing UL44 flanking arms of SB1 virus, SV40 promoter and NDV F codon optimized gene sequence (SEQ ID NO:8, coding for SEQ ID NO:9) (Table 7).
A standard homologous recombination procedure was followed by co-electroporation of secondary CEF cells using donor plasmid pSB 1 44 cds SV FCAopt and viral DNA isolated from SB-1 virus infected CEFs. Essentially the procedure described in example 1 was followed to generate, plaque purify and characterize recombinants by immunofluorescence.
After two rounds of plaque purification, pure recombinant virus (vSB1-009) was isolated and the purity of vSB1-009 was tested by IFA and PCR to validate the appropriate insertion as well as no remnant parental virus.
Viral DNA was extracted from vSB1-009 pre-master seed virus (pre-MSV) stock by QIA DNeasy Blood & Tissue Kit (Qiagen). PCR primers were designed to identify the presence of the NDV F optimized, the NDV F wild type, the SV40 promoter, the mCMV promoter, the UL44 flanking arms of SB-1 virus and HVT virus. PCR amplifications were performed using approximately 200 ng of DNA template along with the primer pairs.
PCR amplification with various primers confirmed that the vSB1-009 has the expected amplification patterns and amplicons.
Indirect immunofluorescent assay (IFA) was performed on the vSB1-009 pre-MSV stock to examine the expression of NDV F gene and SB-1 virus antigen. The CEFs that were inoculated with vSB1-009 were fixed with ice-cold 95% acetone for three minutes at room temperature and air-dried for 10 min. The plates were washed with PBS, then two primary antibodies, chicken anti-Newcastle Disease Virus sera (Charles Rivers Laboratories cat#10100641, lot#C0117A) at 1:500 dilution and Y5.9 monoclonal antibody against SB-1 virus (Merial Select, Gainesville, Ga.) at 1:3000 dilution were added and the plates were incubated for 45 min at 37° C. After three washes with PBS, two secondary antibodies, goat anti-chicken IgG-fluorescein (KPL) at 1:500 dilution and donkey anti-mouse IgG-Alexa Fluor 568 (Molecular Probe) at 1:250 dilution were added. The plates were incubated at 37° C. for 45 min and followed by three washes with PBS. The wells were screened for IFA positive plaques with a fluorescent microscope using fluorescein isothiocyanate (FITC) and tetramethylrhodamine isothiocyanate (TRITC)-filters of Nikon Eclipse Ti inverted microscope. Similarly, reactivity of vSB1-009 with NDV F Mab was examined by Dual IFA using anti-MDV serum (Charles River Laboratories (1/300 dilution) and anti-NDV F monoclonal antibody (1/300 dilution) as primary antibody. The goat anti-chicken IgG-fluorescein (KPL) (1:500 dilution) and donkey anti-mouse IgG-Alexa Fluor 568 (Molecular Probe) (1:250 dilution) were used as secondary antibodies. The wells were observed to identify the IFA positive plaques with a fluorescent microscope using FITC- and TRITC-filters of Nikon Eclipse Ti inverted microscope.
IFA results indicate that vSB1-009 expresses the NDV F protein in virus-infected CEF. Over 500 vSB1-009 plaques were counted for NDV F protein expression as well as SB-1 virus specific protein expression with dual IFA. The expression of NDV F protein completely matched with SB-1 virus antigen expression in each virus plaque (Table 8).
NDV F Mab reactivity was confirmed by Dual IFA. Over 200 vSB1-009 plaques were examined for NDV F Mab reactivity as well as anti-MDV serum reactivity. The reactivity with NDV F Mab completely matched with anti-MDV serum reactivity in each virus plaque (Table 9).
Total genomic DNA was extracted from vSB1-009 pre-MSV stock infected CEFs. The genomic DNA of vSB1-009, SB-1 virus (negative control), pSB1 44 cds SV FCA opt donor plasmid were digested at 37° C. with EcoRI, NcoI, and KpnI restriction endonucleases separately. The restriction fragments were separated by a 0.8% agarose gel electrophoresis and transferred onto a positively charged Nylon membrane. After transfer, the membrane was treated with 0.4M NaOH and then neutralized with 2×SSC—HCl buffer. The membrane was then air dried and UV crosslinked.
Following the North2South Chemiluminescent Hybridization and Detection Kit (Thermo Scientific cat#89880) manufacturers' instructions, the membrane was pre-hybridized for 1 hr and then hybridized with the probe at 55° C. for overnight. For hybridization, two probes were used; 1) the SbfI fragment of pSB1 44 cds SV FCA opt as NDV F cassette probe, 2) the SmaI-EcoRI fragment of pUC57 SB1 44 arm (GenScript) as recombination arm probe. After the overnight hybridization, several stringency washes were conducted until the membrane was placed in blocking buffer with the addition of Streptavidin-HRP. After rinsing the membrane of any unbound Streptavidin-HRP, the substrate solution of Luminal and peroxide were added. The membrane was then exposed to X-ray film and the film was developed.
The Southern blot results were as expected based on Vector NTI map analysis. The NDV F cassette (SV40 promoter, NDV-F CA02 codon optimized gene) replaced the UL44 coding sequences of SB-1 virus.
The genomic DNA of vSB1-009 pre-MSV stock was conducted by nucleotide sequence determination of the region of recombination arm as well as inserted gene cassette. Primers were designed and used to amplify the entire NDV-F gene cassette including the recombination arms.
The vSB1-009 sequence (donor plasmid pSB1 44 cds SV FCAopt) containing the recombinant arms, SV40 promoter and NDV F codon-optimized gene was confirmed to be correct as shown in SEQ ID NO:37 (
The CEF monolayer was infected with vSB1-009 pre-MSV at MOI ˜0.1. After a 5-day incubation, the CEFs were pelleted and washed with PBS followed by lysis with IP Lysis/Wash buffer of Pierce Classic IP Kit (Thermo Scientific cat#26146) according to the manufacturers' protocols. The lysate was pre-cleared and incubated with 100 ul of anti-NDV F monoclonal antibody to make the immune complex. The immune complex was captured by Protein A/G Plus Agarose and after removing of the un-bounded immune complex by washing steps, the 50 ul of sample buffer was used to elute under non-reducing conditions. The uninfected CEFs were included as a control. The 20 ul of eluted samples were separated in 10% Bis-Tris gels by electrophoresis. After the electrophoresis, the separated proteins in a gel were transferred onto PVDF membrane. The Protein Detection TMB Western Blot Kit (KPL cat#54-11-50) was used to detect the NDV antigens onto PVDF membrane with chicken anti-NDV serum (Charles River Laboratories Laboratories cat#10100641, lot#C0117A), and goat anti-chicken IgG-peroxidase conjugate (KM, cat#14-24-06) following the manufacturers' protocols.
The NDV F protein expression of vSB1-009 was confirmed by two-step immunodetection. First, the expressed NDV F proteins from vSB1-009 infected CEF lysate were captured by the immunoprecipitation using anti-NDV F monoclonal antibody 001C3. Subsequently Western blot analysis using anti-NDV polyclonal serum (Charles River Laboratories cat#10100641, lot#C0117A) was applied to detect the NDV F protein in the captured samples (NDV F protein-monoclonal antibody complex) (
Donor Plasmid SB1US2 gpVIIdwtsyn Construction
Using the plasmid HVT SOrf3-US2 gpVar-Ewt Syn, the gpCMV, Varient E, Syn tail was removed by SbfI digestion. This fragment was ligated into the SB1 US2 donor plasmid. The Varient E gene was cut out by NotI and replaced by NDV-F VIId wt. The synthetic NDV-F VIId wild type gene (SEQ ID NO:3 encoding SEQ ID NO:2) was excised from pUC57 NDV-F VIId wt plasmid (synthesized by GeneScript) using NotI digestion. Ligated material was transformed using Top10 Oneshot kit (cat#C404002, Invitrogen). Bacterial colonies were grown in LBamp broth, plasmid extracted by using Qiagens MiniSpin Prep kit, and screened for insert orientation using NcoI+SalI digestion. The correct donor plasmid was designated pSB1 US2 gpVIIdwt Syn. Table 10.1 shows the features unique to the construct around the expression cassettes, including the respective sequences. Large scale cultures were grown and plasmid extraction was done by using Qiagens Maxi Prep kit. Transient expression of the maxi preps was verified using Fugene Transfection Reagent in Chicken Embryo Fibroblast Cells (CEF's) and chicken polyclonal sera against NDV-F.
A standard homologous recombination procedure was followed by co-electroporation of secondary CEF cells using pSB1 US2 gpVIIdWt Syn donor plasmid and viral DNA isolated from vSB1-009 (vSB1-009 is already a recombinant virus expressing CA02 F gene of NDV). Essentially the procedure described in example 1 for was followed to generate, plaque purify and characterize recombinants by immunofluorescence.
After five rounds of plaque purification, pure recombinant virus (vSB1-010) was isolated and the purity of vSB1-010 was tested by IFA and PCR to validate the appropriate insertion as well as no remnant parental virus.
Sequencing of the insert region confirmed that vSB1-010 contains the correct sequences of guinea pig CMV promoter and the NDV-F VIId wt gene as shown in the sequence of the donor plasmid SB1US2 gpVIIdwtsyn (SEQ ID NO:57).
DNA was extracted from a stock virus by phenol/chloroform extraction, ethanol precipitated, and resuspended in 20 mM HEPES. PCR primers were designed to specifically identify the NDV-F VIId wt gene, the promoter, the polyA, as well as, the purity of the recombinant virus from SB1 parental virus. PCR was performed using 200 μg of DNA template along with the specified primers pairs indicted in Table 1. PCR cycling conditions are as follows (unless otherwise noted): 94° C. −2 min; 30 cycles of 94° C. −30 sec, 55° C. −30 sec, 68° C. −3 min; 68° C. −5 min.
Purity of recombinant virus was verified by PCR using primer pairs that are specific to the SB1 flanking arms, the gpCMV promoter, the NDV-F VIId wt gene and the syn tail. Primers, specific to HVT, MDV serotype 3 (MB080 +MB081) were also included in the analysis. The PCR results demonstrate that recombinant virus vSB1-010 carries the intended expression cassette and the virus stock is free from detectable amounts of parental SB1-009 virus.
Immunofluorescent Staining of Recombinant vSB1-010 Virus Expressing Two NDV-F Proteins
For immunofluorescence testing, the P3 material was diluted 1:100 in media. Approximately 50 μl of the diluted virus was added to 10 ml of DMEM+2% FBS with 1×107 CEFs and then aliquoted onto a 96 well plate (100 μl/well). The plates were incubated for 5 days at 37° C.+5% CO2 until viral plaques were visible. The plates were fixed with 95% ice-cold acetone for three minutes and washed three times with PBS. Chicken anti-sera against Newcastle Disease Virus (lot#C0139, Charles Rivers Laboratory) at 1:1000 was added and the plates were incubated at 37° C. for 1 hour. After one hour incubation, the plates were washed three times with PBS and FITC anti-chicken (cat# F8888, Sigma) was added at 1:500. Again the plates were incubated at 37° C. for 1 hour. After one hour incubation the cells were rinsed three times with PBS and visualized with a fluorescent microscope using fluorescein isothiocyanate (FITC) filter.
The immunofluorescent staining results indicate that vSB1-010 exhibited a very strong expression of the NDV-F protein when the polyclonal sera against both CA02 and VIId F proteins of NDV were used.
Based on PCR testing and immunofluorescence analysis, vSB1-010 is a recombinant SB-1 in which VIId-F gene of NDV under the control of gpCMV promoter was successfully inserted into a vSB1-009, which already expresses the CA02-F gene of NDV. Consequently vSB1-010 carries both VIId and CA02 F genes of NDV genotypes and it is free of any detectable parental vSB1-009.
Preparation of Donor Plasmid pHM103+Fopt for vHVT114
The plasmid pHM103 (Merial Limited) containing the Intergenic I arms of HVT FC126, SV40 promoter and SV40 poly A was digested with NotI, dephosphorylated, and the 5.6 kb fragment was gel extracted. A NotI flanked 1.7 kb fragment of a chemically synthesized codon-optimized genotype VIId NDV-F gene (SEQ ID NO:1, coding for SEQ ID NO:2) was also NotI digested and the 1.7 kb fragment was gel extracted. The 5.6 and 1.7 kb fragments were ligated to create pHM103+Fopt (Table 10.2).
A standard homologous recombination procedure was followed by co-electroporation of secondary CEF cells using donor plasmid pHM103+Fopt and viral DNA isolated from the HVT strain FC126 (Igarashi T. et al., J. Gen. Virol. 70, 1789-1804, 1989). Essentially the procedure described in example 1 was followed to generate, plaque purify and characterize recombinants by immunofluorescence.
After five rounds of plaque purification, a recombinant virus designated as vHVT114 was isolated and the purity was tested by IFA and PCR to confirm NDV-F expression and the absence of parental virus.
PCR Analysis of Recombinant vHVT 114
DNA was extracted from vHVT114 by phenol/chloroform extraction, ethanol precipitated, and was resuspended in 20 mM HEPES. PCR primers were designed to specifically identify the presence of the codon optimized NDV-F, the SV40 promoter, as well as, the purity of the recombinant virus from FC126 CL2 parental virus.
The PCR results showed that the sizes of PCR products after gel electrophoresis correspond well with the expected sizes and the banding patterns.
Sequence Analysis of the Inserted Region in Recombinant vHVT114
Analysis of vHVT114 genomic DNA region was performed by PCR amplification. Total of 10 primers were used to amplify the entire cassette, as well as, beyond the flanking BamHI-I arms used in the donor plasmid. The 4.727 kb PCR product was gel purified and the entire fragment was sequenced using the sequencing primers. The sequence result confirmed that the vHVT114 contains the correct SV40 promoter, the codon-optimized NDV-F and the SV40 polyA sequences that match exactly the sequence described for the donor plasmid pHM103+Fopt in SEQ ID NO:38 (see
Western Blot Analysis of Recombinant vHVT114
Approximately 2×106 chicken fibroblast cells were infected at ˜0.1 MOI with vHVT114 Pre-MSV. After two days of incubation at 37° C., infected as well as uninfected cells were harvested using a cell scraper after removing the media and rinsing with PBS. The cells were harvested with 1 ml of PBS and centrifuged. The cell pellets were lysed by following the Pierce Classic IP Kit (Thermo Scientific). 100 μl of the anti-NDV-F monoclonal antibody 001C3 (Merial Limited) was used to form the immune complex. The antibody/lysate sample was added to Protein A/G Plus Agarose to capture the immune complex. The immune complex was washed three times to remove non-bound material and then eluted in 50 ul volume using sample buffer elution under non-reducing condition. After boiling for 5 minutes, 10 μl of the samples were loaded into a 10% Acrylamide gel (Invitrogen). The PAGE gel was run in MOPS buffer (Invitrogen) at 200 volts for 1 hour. Then the gel was transferred onto a PVDF membrane.
The Protein Detector Western Blot Kit TMB System (KPL, cat#54-11-50) was used for blotting the PVDF membrane by using the reagents and following manufacturer's directions. After blocking the membrane for 1 hour at room temperature, the membrane was then rinsed three times in 1× Wash Buffer, five minutes each and then soaked in blocking buffer containing 1:1000 dilution of chicken serum raised against NDV virus (Lot # C0139, Charles River Laboratories). After washing three times in a washing buffer, the membrane was incubated with a peroxidase labeled goat anti-chicken IgG (KPL, cat#14-24-06) at a dilution of 1:2000 for 1 hour at room temperature. The membrane was then rinsed three times in 1× Wash Buffer, five minutes each. 5 ml of TMB membrane peroxidase substrate was added to the membrane and gently rocked for about 1 minute. The developing reaction was stopped by placing the membrane into water.
The immunoprecipitation and Western blot technique detected an approximately 55 kD protein in vHVT114 sample that corresponds to the expected size of F1 component of the NDV-F protein (
Generation and characterization of other HVT recombinants, such as vHVT039, vHVT110, vHVT111, vHVT112, vHVT113, and vHVT116 were essentially done in the same way as for vHVT114 described above. The generation and characterization of recombinant HVT viral vectors were also described in U.S. patent application Ser. No. ______ filed on ______ (Merial limited), which is incorporated herein by reference in its entirety. Table 11 shows the features unique to each construct around the expression cassettes, including the respective sequences.
Preparation of Donor Plasmid pHVT US2 SV-Fopt-synPA for vHVT306
The donor plasmid pHVT US2 SV-Fopt-synPA was constructed containing SV40 promoter, synthetic NDV F codon optimized VII gene, synthetic polyA tail flanked by the SORF3 and US2 arm sequences of HVT FC126.
A standard homologous recombination procedure was followed by co-electroporation of secondary CEF cells using donor plasmid pHVT US2 SV-Fopt-synPA and viral DNA isolated from vHVT13 (an HVT vector expressing the IBDV VP2 gene, Merial Limited). Essentially the procedure described in example 1 was followed to generate, plaque purify and characterize recombinants by immunofluorescence.
After two rounds of plaque purification, pure recombinant virus (vHVT306) was isolated and the purity of vHVT306 was tested and confirmed by IFA and PCR.
Viral DNA was extracted from vHVT306 pre-master seed virus (pre-MSV) stock by QIA DNeasy Blood & Tissue Kit (Qiagen). PCR primers were designed to identify the presence of the NDV F optimized, the NDV F wild type, the SV40 promoter, the mCMV promoter, the flanking arms of US2 HVT virus and SB-1 virus.
PCR amplification with various primers confirmed that the vHVT306 had the expected amplification patterns and amplicons.
The genomic DNA of vHVT306 pre-MSV stock was sequenced to verify the sequence of the recombination arm region as well as inserted gene cassette.
Primers were designed to amplify the entire inserted gene cassette including recombination arm used in donor plasmid. Analysis of vHVT306 genomic DNA was performed by PCR amplification and followed by nucleotide sequence determination.
The vHVT306 (donor plasmid pHVT US2 SV-Fopt-synPA) containing the recombinant arms, SV40 promoter and NDV F codon-optimized gene was confirmed to be correct as shown in SEQ ID NO:45 (
The NDV F protein expression of vHVT306 was confirmed by two-step immunodetection. First, the expressed NDV F proteins from vHVT306 infected CEF were captured by the immunoprecipitation using anti-NDV F monoclonal antibody 001C3 (Merial Limited). Subsequently Western blot analysis using anti-NDV polyclonal serum (Charles River Laboratories) was applied to detect the NDV F protein in the captured samples (NDV F protein-monoclonal antibody complex). A 55 kDa protein in vHVT306 pre-MSV lysates was detected by anti-NDV serum which corresponds to the expected size of NDV F1 fusion protein.
Generation and characterization of double HVT recombinants, such as vHVT301, vHVT302, vHVT303, vHVT304, vHVT202, and vHVT307 were essentially done in the same way as for vHVT306 described above. The generation and characterization of recombinant HVT viral vectors were also described in U.S. patent application Ser. No. ______ filed on ______ (Merial limited), which is incorporated herein by reference in its entirety. Table 12 shows the features unique to each construct around the expression cassettes, including the respective sequences.
The objective of the study was to compare the level of viremia and horizontal transmission induced by the parental SB-1 with that of a recombinant SB-1 virus in which the gC gene was deleted (see example 3).
Two groups (A and B) of thirty one-day-old specific pathogen free (SPF) white Leghorn chicks were randomly constituted. Twenty birds from groups A were vaccinated (D0) by the subcutaneous route (nape of the neck; 0.2 ml/bird) with 2000 PFU of parental SB-1 and twenty from groups B with 2000 PFU of the SB-1 gC-deleted mutant. Ten birds were kept unvaccinated in the same isolator as the vaccinated birds (groups Ac and Bc). At 2-weeks-of-age (D14), the spleen as well as 2 feathers of twenty vaccinated birds of groups A and B were removed after euthanasia. At 4-weeks-of-age (D28) the spleen of the 10 contact birds of groups Ac and Bc were also removed for viral isolation. White blood cells were collected from the buffy coat of ground spleens which had added to lymphocyte separation medium and centrifuged. For each bird, 106 leucocytes were added to a 60 mm tissue culture dish that contained confluent monolayers of primary chicken embryo fibroblasts (CEF) prepared the day before. Five days post-infection, MDV plaques were counted on each dish and the number of positive birds and mean number of plaques was calculated. For feather follicles samples, the feather pulp was added to SPGA medium and sonicated for 10 seconds before placing on confluent monolayers of primary CEF from which the media had been removed. The pulp suspension was allowed to absorb for 45 minutes prior to adding fresh media with 1% calf serum.
Results of virus isolation from spleen and from feather follicles of vaccinated birds at D14 are reported in Table 13. All birds from both groups were positive for virus isolation from spleen with a similar mean number of plaques of 142.5 and 176.0 for groups A and B, respectively. Virus could be isolated from feather follicles of all birds in group A and from 90% of birds in group B.
Results of virus isolation from spleen of unvaccinated contact birds at D28 are reported in Table 14. Seven out of ten birds from group Ac were positive for virus isolation from spleen indicating that the parental SB-1 spread horizontally to contact birds. Virus could not be isolated from birds of group Bc suggesting that the gC-deleted mutant did not spread to contact birds.
This study indicates that the level of viremia of the gC-deleted SB-1 mutant measured at D14 post-vaccination was similar to that of the parental SB-1 virus suggesting that the gC deletion did not impair the ability of the SB-1 virus to replicate in vaccinated birds. The level of virus at the feather follicle was slightly lower with the gC-deleted mutant since 2/20 birds did not have detectable amount of virus. Horizontal transmission could be detected in 7/10 birds in contact with birds vaccinated with the parental SB-1. In contrast, no virus could be detected from the birds in contacts with birds vaccinated with the gC-deleted mutant indicating that the gC deletion severely impaired horizontal transmission.
The objective of the study was to evaluate the efficacy of the vSB1-004 recombinant expressing NDV F gene against an ND challenge performed at 4 week-of-age in SPF chicks vaccinated with vSB1-004 alone or in combination with an HVT-IBD vector vaccine.
Three groups (1, 2 and 3) of fifteen one-day-old specific pathogen free (SPF) white Leghorn chicks were randomly constituted. Two vectored vaccines were used: the vSB1-004 described in example 1 and vHVT13, an herpesvirus of turkey (HVT) vector expressing the VP2 gene of infectious bursal disease virus Faragher 52/70 strain (active ingredient of the Merial licensed VAXXITEK® HVT+IBD vaccine, U.S. Pat. No. 5,980,906 and EP 0 719 864). Birds from groups 1, 2 and 3 received vHVT13 only (control group), vSB1-004 only and a mix of vHVT13 and vSB1-004, respectively (see Table 6). All birds were vaccinated by the subcutaneous route (nape of the neck) with 2000 PFU of vSB1-004 and/or vHVT13 (D0). Twenty seven days after vaccination (D27), birds of each group were challenged with the genotype V Mexican Chimalhuacan (Mex V) velogenic NDV strain. The challenge was performed by the intramuscular (IM) route using 105 Egg Infectious Dose 50 (EID50) diluted in 0.2 ml of physiological sterile water. Birds were observed daily during 14 days after challenge for clinical signs and mortality. Oropharyngeal swabs were also sampled from 10 birds per group 5, 7 and 9 days after challenge. The viral RNA load was evaluated in these swabs after RNA extraction by using a quantitative reverse transcriptase real time polymerase chain reaction (qRT-PCR) based on the M gene and described by Wise et al. (2004; Development of a Real-Time Reverse-Transcription PCR for Detection of Newcastle Disease Virus RNA in Clinical Samples; J. Clin. Microbiol. 42, 328-338). Shedding levels were expressed as log 10 egg infectious dose 50% (EID50) per mL. Blood was also sampled at the time of challenge (D27). The serums were tested with the anti-IBD ELISA (Synbiotics ELISA ProFlok PLUS IBD) to evaluate the impact of vSBA-004 on the vHVT13-induced IBDV antibodies.
Results of protection and serology are summarized in Table 15. All control birds died within 5 days after ND challenge. The vSB1-004 recombinant virus induced full clinical protection either alone or when combined with vHVT13. The number of birds shedding detectable amount of challenge ND virus was very low in both vaccinated groups. The mean IBD ELISA titers in groups 1 and 3 were nearly identical indicating the lack of vSB1-004 interference on vHVT13-induced IBDV antibodies.
The ND challenge model with the genotype V Chimalhuacan velogenic NDV is very severe. In these severe challenge conditions, vSB1-004 induced full clinical protection and excellent protection against shedding of challenge virus by the oropharyngeal route. It is worth noting that the F gene inserted in vSB1-004 is from a genotype VIId NDV strain and the challenge strain used here is a genotype V. It shows therefore that the genotype VIId F gene inserted into the SB-1 vector is cross-protecting birds against a genotype V challenge. The addition of vHVT13 did not impair the ND protection induced by vSB1-004 and the vSB1-004 did not interfere on vHVT13-induced IBD antibody titers, demonstrating compatibility of SB-1 vector with HVT vector.
The objective of the study was to evaluate the efficacy of the vSB1-004 recombinant expressing NDV F gene against an early (D14) ND challenge in SPF chicks performed with two different NDV challenge strains.
Two groups (1 and 2) of twenty one-day-old specific pathogen free (SPF) white Leghorn chicks were randomly constituted. Birds from group 2 were vaccinated by the subcutaneous route (nape of the neck) with 2000 PFU of vSB1-004. Chicks from group 1 were not vaccinated and were kept as control birds. At 2 week-of-age, half of the birds of each group were challenged with the genotype V Mexican Chimalhuacan (Mex V) velogenic NDV strain and the other half with the genotype VIId Malaysia 04-1 (Mal VIId) velogenic NDV strain. The challenge was performed by the intramuscular (IM) route using 105 Egg Infectious Dose 50 (EID50) diluted in 0.2 ml of physiological sterile water. Birds were observed daily during 14 days after challenge for clinical signs and mortality.
Results of protection are summarized in Table 16. All control birds died within 5 days after ND challenges. The vSB1-004 recombinant virus induced partial protection against mortality (70% and 40% protection after challenge with Mal VIId and Mex V, respectively) and against morbidity (50% and 30% protection after challenge with Mal VIId and Mex V, respectively) in these severe early challenge conditions.
The early ND challenge model that was used to evaluate the efficacy of vSB1-004 recombinant was chosen because Marek's disease virus vectors expressing NDV F gene do not generally provide full protection in this model. Indeed, their onset of immunity is delayed compared to live NDV vaccines (Morgan et al. (1993) Avian Dis 37, 1032-40; Heckert et al. (1996) Avian Dis 40, 770-777). It is therefore a good model to evaluate and compare the vaccine candidates. In these severe early challenge conditions, vSB1-004 recombinant induced partial protection that was only slightly higher against the Malaysian genotype VIId challenge than against the Mexican Chimalhuacan genotype V one indicating a broad protection against the 2 most prevalent genotypes circulating in the Americas and Eurasia/Africa, respectively.
The objective of the study was to evaluate the efficacy of the vSB1-004 recombinant expressing NDV F gene against two ND challenges performed at 4 week of age in broiler chicks vaccinated with vSB1-004 alone or in combination with an HVT-IBD vector vaccine.
Six groups (1a, 1b, 2a, 2b, 3a, 3b) of twelve one-day-old broilers (Hubbard JA957 line) were randomly constituted. Two vectored vaccines were used: the vSB1-004 described in example 1 and vHVT13, an herpesvirus of turkey (HVT) vector expressing the VP2 gene of infectious bursal disease virus Faragher 52/70 strain (active ingredient of the Merial licensed VAXXITEK® HVT+IBD vaccine). Birds from groups 1 (1a & 1b) were vaccinated with vHVT13 only (control group); those from groups 2 with vSB1-004 only and those from groups 3 with a mix of vHVT13 and vSB1-004 (see Table 17). All birds were vaccinated by the subcutaneous route (nape of the neck) with 2000 PFU of vSB1-004 and/or vHVT13 (D0). Twenty eight days after vaccination (D28), all birds of each subgroup “a” were challenged with the genotype VIId Malaysia 04-1 (Mal VIId) velogenic NDV strain and all birds of each subgroup “b” with the genotype V Mexican Chimalhuacan (Mex V) velogenic NDV strain. The challenge was performed by the intramuscular (IM) route using 105 Egg Infectious Dose 50 (EID50) diluted in 0.2 ml of physiological sterile water. Birds were observed daily during 14 days after challenge for clinical signs and mortality. Blood was also sampled from 5 birds in each group at the time of challenge (D28). The serums were tested with the anti-IBD ELISA (Synbiotics ELISA ProFlok PLUS IBD) to evaluate the impact of vSB1-004 on the vHVT13-induced IBDV antibodies in broilers.
Results of protection and serology are summarized in Table 17. All control birds died within 5 days after ND challenges. The vSB1-004 recombinant virus induced significant level of clinical protection when combined or not with vHVT13. The number of birds shedding detectable amount of virus was very low in both vaccinated groups. The mean IBD antibody titers in groups 2 was still high (3 log 10) at D27 indicating a high level of maternally-derived IBD antibodies; nevertheless, vHVT13 induced a clear IBD antibody response which was not affected when mixed with vSB1-004.
Results of this study indicated significant levels of protection induced by vSB1-004 in broilers with NDV MDA. The addition of vHVT13 did not have negative impact on vSB1-004-induced ND protection indicating the lack of vHVT13 interference. Furthermore, vSB1-004 did not interfere on vHVT13-induced IBD antibodies, confirming in broilers the compatibility between these two vectors.
The objective of the study was to evaluate the potential interference of the vSB1-004 recombinant on the IBD efficacy induced by an HVT-IBD vector vaccine (vHVT13) in an early (D14) IBD challenge model in SPF chicks.
Three groups (1 to 3) of ten one-day-old specific pathogen free (SPF) white Leghorn chicks were randomly constituted. Birds from group 1 were vaccinated by the subcutaneous route (nape of the neck) with 2000 PFU of vSB1-004 (control group). Chicks from group 2 were vaccinated with 2000 PFU of vHVT13 and birds from group 3 were vaccinated with 2000 PFU of vHVT13 and 2000 PFU of vSB1-004. At 2 week of age, all birds of each group were challenged by the ocular route with 50 μL containing 2.5 log 10 EID50 of the IBDV classical strain Faragher 52/70. Birds were observed daily during 10 days after challenge for clinical signs and mortality. All birds were euthanized 10 days after challenge and body and bursa of Fabricius weights were recorded in order to evaluate the bursa/body weight ratio. Their bursa was also checked for histological lesions typical of IBD. A score was assigned to each bursa based on the severity of the lesions as shown in Table 18. The number of affected birds (non-protected) in each group was calculated. A bird was considered as affected if it died and/or showed notable sign of disease and/or intermediate or severe lesions of the bursa of Fabricius (i.e., histology score ≧3).
Results of protection are summarized in Table 19. All control birds became sick and one died after challenge whereas all vaccinated birds remained healthy. The bursal body weight ratios of groups 2 and 3 were similar and significantly higher than that of group 1. All 8 birds that survived challenge from group 1 had bursa lesion scores of 4 or 5
The early IBD challenge model that was used to evaluate the lack of interference of vSB1-004 recombinant on vHVT13-induced IBD protection was chosen because it is very sensitive to detect interference on vHVT13 protection. Results obtained with vSB1-004+vHVT13 indicated an excellent level of IBD protection (89%) indicating compatibility between vSB1-004 and vHVT13 even when measured in an early IBD challenge.
The aim of the study was to assess the efficacy of 2 single HVT recombinant constructs (vHVT 114 and vHVT 116), 2 SB1 recombinant constructs (vSB1-007 & vSB1-008) expressing the NDV F gene and a double HVT recombinant (vHVT304) against Newcastle disease challenge with NDV ZJ1 (genotype VIId) and California/02 (genotype V) performed at 21 days of age in SPF chickens.
The characteristics of these 5 vaccine candidates are described in Table 20 below.
On D0, 158 one-day-old SPF chickens were randomly allocated into 6 groups of 24 birds (vaccinated) and 1 group of 12 birds (non-vaccinated controls). The birds were injected by subcutaneous injection in the neck at D0 with 0.2 mL of recombinant vaccines containing a target dose of 1000 pfu as described in Table 21 below. The birds were then separated into two sub-groups, each sub-group being challenged by the intramuscular route on D21 with 5 log 10 EID50 of either NDV ZJ1 (genotype VIId) or California/02 (genotype V) velogenic strain.
Each group was monitored before and after challenge. Technical problems observed with isolators reduced the number of birds in group 2 (vHVT114: from 24 to 14) and in group 3 (vHVT116: from 24 to 20). NDV clinical signs were recorded after challenge. Serum was collected from blood samples taken from birds of groups 2 and 7 before challenge (D21) for NDV serology by HI test using each challenge strains as antigen.
Percentages of protection against mortality and morbidity are reported in the table above. Full susceptibility was observed in the non-vaccinated challenged control group G1 thus validating the high severity of both challenges. All vaccines induced high levels (≧75%) of protection against both challenges. Full clinical protection against both challenges was induced by vHVT114 and vSB1-008.
The shedding was evaluated after challenge by real time RT-PCR in oral and cloacal swabs taken 2 and 4 days post-challenge. Percentage of positive (Ct<40) birds are shown for both challenges in
In conclusion, the results of this study showed the very good ND protection at 3 weeks of age induced by tested Marek's disease vector vaccines.
The aim of the study was to assess the efficacy of combinations of different Marek's disease vector vaccines expressing the NDV F and/or the IBDV VP2 gene against Newcastle disease challenge (Texas GB strain, genotype II) performed at 28 days of age in SPF chickens.
The characteristics of the 5 recombinant vaccine candidates tested in this study are described in Table 22 below.
The Marek's disease virus serotype 1 (CVI988 (or Rispens) strain; Gallid herpesvirus 2) and serotype 2 (SB-1 strain; gallid herpesvirus 3) vaccines were used also in combination with recombinant viruses in some of the groups.
On D0, 135 one-day-old SPF chickens were randomly allocated into 9 groups of 15 birds. The birds were injected by subcutaneous injection in the neck at D0 with 0.2 mL containing a target dose of 2000 pfu for recombinant vaccines (vSB1-007, vSB1-009, vHVT13, vHVT306, vHVT307, vHVT114), and 1000 pfu for parental Marek's disease vaccine strains (SB-1 and CVI988). The design of the study is shown in Table 23 below. The birds were challenged by the intramuscular route on D28 with 4.0 log 10 EID50 velogenic ND Texas GB (genotype II) strain.
Each group was monitored before and after challenge. NDV clinical signs after challenge were recorded.
Percentages of protection against mortality and morbidity are reported in the table 23 above. Full susceptibility was observed in the non-vaccinated challenged control group G1 thus validating the high severity of challenge. Excellent levels of protection were observed in all vaccinated groups. Birds from G3, G6, G7 and G9 were fully protected. This study shows that the vSB1-ND candidates can be co-administered with vHVT13 and CVI988 and still provide a very good ND protection. Similarly, double HVT-IBD+ND are compatible with SB-1 and vHVT-ND (vHVT114) is compatible with vHVT13 and SB-1.
In conclusion, the results of this study showed the lack of interference on ND protection induced by the tested Marek's disease parental and vector vaccines.
The aim of the study was to assess the efficacy of one HVT recombinant construct (vHVT 114) and two SB1 recombinant constructs (vSB1-007 and vSB1-009) expressing the NDV F gene in combination with vHVT-IBD (vHVT13), as well as a double HVT vHVT307 expressing both NDV F and IBDV VP2 against Newcastle disease challenge (Chimalhuacan, genotype V) performed at 28 days of age in SPF chickens.
The characteristics of these 4 vaccine candidates are described in Table 24 below.
On D0, 45 one-day-old SPF chickens were randomly allocated into 4 groups of 10 birds and 1 group of 5 birds (unvaccinated control group). The birds were injected by subcutaneous injection in the neck at D0 with 0.2 mL of recombinant vaccines containing a target dose of 2000 pfu as described in Table 25 below. The birds were challenged by the intramuscular route on D28 with 5.0 log 10 EID50 velogenic Chimalhuacan (genotype V) strain.
Each group was monitored before and after challenge. NDV clinical signs were recorded after challenge. Oropharyngeal swabs were taken in the vaccinated groups at 5 and 7 days post-challenge to evaluate the viral load by real time RT-PCR.
Percentages of protection against mortality and morbidity are reported in the table above. Full susceptibility was observed in the non-vaccinated challenged control group G1 thus validating the high severity of challenge. Very good protection was observed in all 4 vaccinated groups, a full clinical protection being induced by vHVT114+vHVT13. The percentage of positive birds and the mean shedding titer (expressed as log 10 EID50 equivalent per mL) are shown in
In conclusion, this example further illustrates the excellent ND protection induced by double HVT-IBD+ND recombinant or a combination of SB1-ND or HVT-ND and HVT-IBD (vHVT13) recombinant viruses. Contrary to the general belief in the field that a second HVT vaccine (regular HVT vaccines or recombinant HVT vaccines) interferes with the immunity to the foreign genes inserted into the first recombinant HVT vaccine, the present invention showed surprising result that vHVT114 in combination with vHVT13 offered excellent protection against NDV and no interference effect was observed.
The aim of the study was to assess the efficacy of the vHVT306 double HVT expressing both NDV F and IBDV VP2 genes, and the vSB1-008 SB1 recombinant expressing the NDV F gene in combination with vHVT-IBD (vHVT13), administered by the in ovo or by the subcutaneous route against Newcastle disease challenge (Chimalhuacan, genotype V) performed at 28 days of age in SPF chickens.
The design of the groups is shown on Table 26. Sixty SPF embryonated eggs (after approximately 18 days and 18 hours of incubation; D-3) were used for the in ovo administration (20 per group for G1, G2 and G3). Fifty microliters of vaccine containing 2000 PFU were administered by the in ovo route using the IntelliLab System device from AviTech LLC (Salisbury, Md., USA). Hatchability and survival were recorded after in ovo administration. On D0, 20 one-day-old SPF chickens were randomly allocated into 2 groups of 10 birds (G4 and G5). The birds were injected by subcutaneous (SC) injection in the neck at D0 with 0.2 mL of recombinant vaccines containing a target dose of 2000 pfu as described in Table 26 below. Ten birds per group were challenged by the intramuscular route on D28 with 5.0 log 10 EID50 velogenic Chimalhuacan (genotype V) strain.
Each group was monitored before and after challenge. NDV clinical signs were recorded after challenge. Oropharyngeal swabs were taken in the vaccinated groups at 5 and 7 days post-challenge to evaluate the viral load by real time RT-PCR.
Full hatchability and viability were recorded up to D28 (challenge day) for birds of groups G1 and G2. Hatchability in G3 was 85% and one additional bird died after hatching in this group. The lower hatchability of that group may be due to egg incubator problems. Body weights of males and females in G1, G2 and G3 were similar at D1 and at D28.
Percentages of protection against mortality and morbidity are reported in the table 26. Full susceptibility was observed in the non-vaccinated challenged control group G1 thus validating the high severity of challenge. Very good protection was observed in all 4 vaccinated groups, a full clinical protection being induced by vHVT306 administered by both routes.
The percentage of positive birds and the mean shedding titer (expressed as log 10 EID50 equivalent per mL) are shown in Table 27. Absence of detectable or very low shedding was observed in G2 and G4 vaccinated with vHVT306. The shedding levels detected in the groups vaccinated with vSB1-008+vHVT13 were higher especially at 5 days post-infection (pi).
In conclusion, this example shows excellent ND protection induced by vHVT306 double HVT recombinant administered either by in ovo or by SC routes. The performance of vSB1-008+vHVT13 was slightly lower especially after in ovo administration, but it may be at least partially due to egg incubator problems. Indeed, the in ovo safety testing of another SB1-ND recombinant (vSB1-009) at 1000 or 4000 PFU associated with 6000 PFU of vHVT13 did not show any difference in hatchability and early survival with a group receiving 6000 PFU of vHVT13 only.
The aim of the study was to assess the efficacy of two double HVT (vHVT304 and vHVT306) expressing both NDV F and IBDV VP2 genes, and two SB1 recombinants (vSB1-007 and vSB1-008) expressing the NDV F gene in combination with vHVT-IBD (vHVT13) against Newcastle disease challenge (Chimalhuacan, genotype V) performed at 42 days of age in commercial broiler chickens.
The design of the groups is shown on Table 28. On D0, 55 one-day-old commercial broiler chickens were randomly allocated into 5 groups of 11 birds. The birds were injected by subcutaneous (SC) injection in the neck at D0 with 0.2 mL of recombinant vaccines containing a target dose of 2000 pfu as described in Table 28 below. Ten birds per group were challenged by the intramuscular route on D42 with 5.0 log 10 EID50 velogenic Chimalhuacan (genotype V) strain.
Each group was monitored before and after challenge. NDV clinical signs were recorded during 14 days after challenge. Oropharyngeal swabs were taken in the vaccinated groups at 5 and 7 days post-challenge to evaluate the viral load by real time RT-PCR.
Percentages of protection against mortality and morbidity are reported in the table 28. Full susceptibility was observed in the non-vaccinated challenged control group G1 thus validating the high severity of challenge. Very good protection was observed in all 4 vaccinated groups, a full clinical protection being induced by vHVT306 and by vSB1-007+vHVT13.
The percentage of positive birds and the mean shedding titer (expressed as log 10 EID50 equivalent per mL) are shown in Table 29. The best reduction of shedding was induced by vHVT306 and vSB1-007+vHVT13, which were also the best candidates for clinical protection.
The vSB1-007+vHVT13 performed better than vSB1-008+vHVT13. The vSB1-007 genomic structure differs from that of vSB1-008 in different aspects: locus of insertion, promoter, poly-adenylation signal and F gene origin. The combination of these foreign sequences and locus of insertion in vSB1-007 were likely responsible for its better ND protection performances.
In summary, this example illustrates the importance of the locus of insertion and other regulatory sequences of the NDV expression cassette in the ND protection induced by HVT and MDV serotype 2 vectors.
The aim of the study was to assess the early IBD efficacy of double HVT recombinants vHVT304 and vHVT306 as well as that of vHVT13 co-administered with a SB1-ND (vSB1-008) recombinant constructs against a virulent infectious bursal disease virus (vIBDV) challenge (Faragher 52/70 strain) performed at 14 days of age in SPF chickens.
On D0, 95 one-day-old SPF chickens were randomly allocated into 9 groups of 10 birds and 1 group of 5 birds (unvaccinated unchallenged control group). The birds were injected by subcutaneous injection in the neck at D0 with 0.2 mL of recombinant vaccines containing a target dose of 300 or 1000 pfu as described in the Table 30 below. On D14, blood sample was collected from 5 birds per group for serological testing with the Kit ProFLOK® plus IBD (Synbiotics Corp). The birds (10 birds per group except for group 7 in which 1 bird died before challenge) were challenged by the eye drop (0.05 mL per bird) with 2.5 log 10 EID50.
1Mean IBD+ ELISA titers expressed in log10 in the serum of 5 birds per group sampled at D 14 before challenge;
2Birds sick for more than 2 days or still sick on D 25 were considered as sick.
3Protection against clinical signs and severe bursal lesion (bursal score <3)
4The bursal/body weight ratio of the unvaccinated/unchallenged group was 0.0047.
Each group was monitored before and after challenge. IBDV clinical signs were recorded for 11 days after challenge (from D15 to D25). At the end of the post-challenge observation period (D25), all the surviving birds were euthanized and necropsied. Body and bursal weights were recorded. Each bursa of Fabricius (BF) was weighted then stored in individual recipients containing 4% formaldehyde for histology. Histological lesions of the bursa were scored according to the scale presented in Table 31.
A bird was considered as affected if it died and/or showed notable sign of disease and/or severe lesions of the bursa of Fabricius (i.e., histology score ≧3).
The mean ELISA IBD+ antibody titer expressed in log 10 before challenge is shown in Table 30. Significant titers were detected in all vaccinated groups that were significantly higher than that of the control group G1. The serology titer was not dose-dependent.
Severe clinical signs were observed after challenge in all birds of the control group G1. Seven out of 10 birds of that group died within the 11 days observation period indicating the high severity of challenge. None of the vaccinated birds showed severe clinical signs after challenge except 1 bird of G4 that died. Percentages of protection against severe bursal lesions are shown in the table 30 above. Significant IBD protection was observed in all groups, the best protection being observed in G2 and G3 (vHVT13 alone). The co-administration of vSB1-008+vHVT13 and the double vHVT304 and vHVT306 constructs induced similar levels of IBD protection. The protection was not dose-dependent at the tested doses. The mean bursal/body weight ratios are also shown in Table 30. Ratios in all vaccinated groups were higher than those of the challenged control group.
In conclusion, these data indicate that both the combination of a SB 1-ND vector with a single HVT-IBD or double HVT expressing both NDV-F and IBDV-VP2 induce IBD antibodies and early IBD protection in a severe IBDV challenge model.
The aim of the study was to assess the IBD efficacy of vHVT13 co-administered with an HVT-ND (vHVT114) or SB1-ND (vSB1-007 and vSB1-009) recombinant constructs against a very virulent infectious bursal disease virus (vvIBDV) challenge (91-168/980702 isolate) performed at 23 days of age in commercial broiler chickens.
On D0, 90 one-day-old broiler chickens were randomly allocated into 7 groups of 12 birds and 1 group of 6 birds (unvaccinated unchallenged control group). The birds were injected by subcutaneous injection in the neck at D0 with 0.2 mL of recombinant vaccines containing a target dose of 3000 pfu as described in the Table 32. On D14, blood sample was collected from 5 birds per group for serological testing with the Kit ProFLOK® plus IBD (Synbiotics Corp). The serum of 10 extra one-day-old broiler chickens was tested at D0 with the same kit to evaluate the level of IBDV maternal antibody. The birds (10 birds per group) were challenged by the eye drop (0.05 mL per bird) on D23 with 4.3 log 10 EID50 of the vvIBDV 91-168 isolate.
Each group was monitored before and after challenge. IBDV clinical signs were recorded for 11 days after challenge (from D23 to D33). At the end of the post-challenge observation period (D33), all the surviving birds were euthanized and necropsied. Body and bursal weights were recorded. Each bursa of Fabricius (BF) was weighted then stored in individual recipients containing 4% formaldehyde for histology. Histological lesions of the bursa were scored according to the scale presented in Table 31.
A bird was considered as affected if it died and/or showed notable signs of disease and/or severe lesions of the bursa of Fabricius (i.e., histology score ≧3).
1Mean IBD+ ELISA titers expressed in log10 in the serum of 5 birds per group sampled at D 23 before challenge;
2The bursal/body weight ratio of the unvaccinated/unchallenged group was 0.0047
The mean ELISA IBD+ serological titer at D0 was 4.36±0.01 log 10 indicating a very high level of IBD maternal antibody at hatch. At D23, the mean ELISA IBD+ titer was still high (3.9) in the control G1. ELISA mean titers in the vaccinated groups were not significantly different from those of the control group.
Neither morbidity nor mortality was observed in any of the groups after challenge. Percentages of protection against severe bursal lesions are shown in Table 32 above. The result showed that co-administration of vHVT114, vSB1-007 or vSB1-009 did not interfere with vHVT13-induced IBD protection indicating a lack of interference. Similarly, the mean bursal/body weight ratios of the vaccinated groups were similar and clearly higher than that of the control group, indicating IBD protection and no difference between the vaccination regimens.
In conclusion, the data indicate the compatibility between vHVT114, vSB1-007 or vSB1-009 and vHVT13 for IBD protection.
The aim of the study was to assess the efficacy of two double HVT (HVT-ND+IBD: vHVT304 and vHVT306) or two vSB-1-NDV in combination with vHVT13 (vSB1-007+vHVT13, vSB1-008+vHVT13) vectored vaccines administered subcutaneously (SC) to day-old SPF chicks and challenged with IBDV-Variant (VAR-E) 28 days post-vaccination.
On D0, 105 one-day-old SPF chickens were randomly allocated into 7 groups of 15 birds including a group of challenged controls (G6) and unchallenged controls (G7). The birds of groups G1 to G5 were injected by subcutaneous injection in the neck at D0 with 0.2 mL of recombinant and/or SB-1 vaccines containing each a target dose of 2000 pfu. The design of the study is shown in Table 33 below. On D28, all birds from groups G1 to G6 were challenged by the eye drop (0.03 mL containing 3 log 10 EID50 per bird) of the IBDV variant E isolate from University of Delaware (USA). Each group was monitored before and after challenge. Eleven days post-challenge, birds were weighed and necropsied. The bursa were collected and weighed. The bursal/body weight ratio (bursa weight/body weight ratio×100) was calculated.
The mean bursal/body weight ratios are shown in Table 33. The challenged control birds had a severe bursal atrophy compared to unchallenged ones. The vSB1-007 and vSB1-008 vaccines did not interfere on vHVT13-induced protection (G4 and G5). The bursal/body weight ratios of birds vaccinated with the double HVT (HVT-ND+IBD) were slightly lower than the unchallenged control group but were clearly higher than the challenged control groups. Furthermore, the SB-1 serotype 2 Marek's disease vaccine did not interfere with vHVT304-induced IBD protection.
In conclusion, these data indicate that both the combination of a SB1-ND vector with a single HVT-IBD or double HVT expressing both NDV-F and IBDV-VP2 induce IBD protection in a variant E IBDV challenge model.
The aim of the study was to assess the IBD efficacy of vHVT13 when administered by SC or in ovo route concomitantly with vHVT114, vSB1-009 and/or SB-1 in SPF chicks in an IBDV-Variant (VAR-E) at D28 challenge model.
75 one-day-old SPF chickens and 75 SPF 18 to 19 day-old chicken embryo were randomly allocated into 5 groups (G1 to G5 and G6 to G10, respectively) including a group of challenged controls (G4 and G9, respectively) and unchallenged controls (G5 and G10, respectively). The birds of groups G1 to G3 were injected by subcutaneous injection in the neck at D0 with 0.2 mL of vaccines containing each a target dose of 3000 pfu except for SB-1 which had a target dose of 1000 PFU. Birds from G6 to G8 received the same vaccine doses but in 0.05 mL volume by the in ovo route 2-3 days before hatch. The design of the study is shown in Table 34 below. At 28 days of age, all birds from groups G1 to G4 and G6 to G9 were challenged by the eye drop (0.03 mL containing 3 log 10 EID50 per bird) of the IBDV variant E isolate from University of Delaware (USA). Each group was monitored before and after challenge. Eleven days post-challenge, birds were weighed and necropsied. The bursa were collected and weighed. The bursal/body weight ratio (bursa weight/body weight ratio×100) was calculated.
The mean bursal/body weight ratios are shown in Table 34. The challenged control birds (G4 and G9) had a severe bursal atrophy compared to unchallenged ones. The bursal/body weight ratios of the vaccinated groups (G1 to G3 and G6 to G8) were similar to those of the unchallenged control groups (G5 and G10) and well above those of the challenged control groups (G4 and G9). The lack of interference of vHVT114 on vHVT13-induced IBD protection after both SC or in ovo routes was surprising and confirmed data obtained in examples 15 and 19.
In conclusion, these data indicate clearly the compatibility of vHVT114+vSB1-009 or +SB-1 and of vSB1-009 with vHVT13 when administered by SC or in ovo route in a variant E IBDV challenge model.
The aim of this study was to evaluate the Marek's disease efficacy induced by different combinations of vaccines including vHVT114, vHVT13, SB-1 and/or vSB1-009 administered by the SC route to one-day-old SPF chicks and challenged 4 days later with the very virulent plus Marek's disease virus (vv+MDV) T-King isolate.
On D0, 100 one-day-old SPF chickens were randomly allocated into 5 groups of 20 birds. The birds from groups 1 to 3 were injected by subcutaneous injection in the neck at D0 with 0.2 mL of vaccines containing a target dose of 2000 pfu for each vaccine except for SB-1 for which the target dose was 1000 pfu. Birds from groups 4 and 5 were non-vaccinated and were used as sham controls challenged (group 4) or unchallenged (group 5). The study design is shown in the Table 35. On D4, All birds from groups 1 to 4 were challenged with 0.2 mL of the vv+MDV T-King isolate using the intraperitoneal route of administration.
Each group was monitored daily for any unfavourable reactions before and after challenge. At day 49, all live birds were terminated and necropsied to examine for gross lesions associated with Marek's disease. Chickens were classified as positive for infection with Marek's disease if nervous signs, such as paralysis, locomotive signs attributable to the disease, and severe emaciation or depression are observed, if mortality directly attributable to Marek's Disease occurs, or if gross lesions are observed at necropsy. Lesions might include, but not be limited to, the following: liver, heart, spleen, gonads, kidneys, and muscle lesions
Results of protection are shown in the Table 35 above. All vaccinated groups (G1 to G3) performed equally, inducing a partial (65%) MD protection as expected in this very severe and early challenge model. These results indicated that the vector vaccine candidates retain their ability to protect against Marek's disease.
The synergy between parental HVT and SB-1 in inducing a protection against Marek's disease is well known. The SB-1 vector expressing a foreign gene can therefore be mixed with either parental HVT or vectored HVT expressing another foreign gene in order to get a bivalent or a trivalent vaccine solution, respectively. An example of evaluation of Marek's disease efficacy induced by a combination of vSB1-009 with vHVT114 and vHVT13 is shown above (example 22). Marek's disease (MD) efficacy is also demonstrated for Marek's disease vectored recombinants either alone or in combination in other MD challenge models including virulent Marek's disease (vMD) challenge such as GA22, very virulent Marek's disease (vvMD) challenge such as RB1B and/or very virulent plus Marek's disease (vv+MD) challenge such as the T. King virus. One-day-old chickens are inoculated subcutaneously or 18-19-day-old embryonated eggs are inoculated with a 0.2 ml dose or 0.05 ml dose, respectively, of the test viruses. At five days of age the vaccinated chickens and naïve controls are challenged with the relevant Marek's challenge virus (v, vv, or vv+MDV). The challenged birds are observed until seven weeks of age. All birds are terminated and necropsied to observe for grossly visible lesions associated with Marek's disease as described in Example 22.
The aim of the study was to assess the efficacy of combinations of different Marek's disease vector vaccines expressing the NDV F and/or the IBDV VP2 gene against Newcastle disease challenge (Texas GB strain, genotype II) performed at 14 and/or 28 days of age in SPF chickens.
The characteristics of the 6 NDV recombinant vaccine candidates tested in this study are described in the Table 36 below.
On D0, 225 one-day-old SPF chickens were randomly allocated into 9 groups of 15 birds (G1 to G9a challenged at D14) and 6 groups of 15 birds (G1b, G3b, G4b, G5b, G8b, G9b challenged at D28). The birds were injected by subcutaneous injection in the neck at D0 with 0.2 mL containing a target dose of 2000 pfu for recombinant vaccines. The design of the study is shown in Table 37 below. The birds were challenged by the intramuscular route on D14 or D28 with 4.3 and 4.2 log 10 EID50 (0.1 mL) velogenic ND Texas GB (genotype II) strain, respectively.
20%
14%
80%
Each group was monitored before and after challenge. NDV clinical signs after challenge were recorded. One bird died in G6 and G7 before challenge reducing the number of birds from 15 to 14 in these groups.
Percentages of clinical protection (including protection against both mortality and morbidity) are reported in Table 37 above. Full susceptibility was observed in the non-vaccinated challenged control group G1a and G1b thus validating the high severity of challenge. Partial protections ranging from 13.3 to 46.6% were observed after challenge at D14, the highest levels of protection being induced by vSB1-008, vSB1-007 and vHVT304. Protection levels after ND challenge at D28 were much higher for all vaccinated groups and were again slightly higher in the groups vaccinates with vSB1-008, vSB1-007 or vHVT304. These results indicated that ND protection levels were dependent on the date of challenge and on the construct. The vSB1-008 and vSB1-007 constructs performed slightly better than vSB1-004 and vSB1-006, and the vHVT304 performed slightly better than vHVT302, indicating that different characteristics of the constructs are playing a role in the performances of MDV-based vector vaccines.
In conclusion, the results of this study showed that ND protection levels induced by Marek's disease vectors expressing NDV F gene may depend on different parameters including the vector, the locus of insertion, the F gene, the promoter, the poly-adenylation site and the challenge conditions.
The aim of the study was to assess the efficacy of HVT-vectored vaccine expressing both NDV F and IBDV VP2 genes against Newcastle disease challenge (Texas GB strain, genotype II) performed at 14 and/or 28 days of age in SPF chickens.
The characteristics of the 2 recombinant vaccine candidates tested in this study are described in the Table 38 below.
On D0, 90 one-day-old SPF chickens were randomly allocated into 3 groups of 15 birds (G1a to G3a challenged at D14) and 3 groups of 15 birds (G1b to G3b challenged at D28). The birds were injected by subcutaneous injection in the neck at D0 with 0.2 mL containing a target dose of 2000 pfu for recombinant vaccines. The design of the study is shown in Table 39 below. The birds were challenged by the intramuscular route on D14 or D28 with a target dose of 4.0 log 10 EID50 (0.1 mL) velogenic ND Texas GB (genotype II) strain.
Each group was monitored before and after challenge. NDV clinical signs after challenge were recorded. One bird died in G2b before challenge reducing the number of birds from 15 to 14 in this group.
Percentages of clinical protection (including protection against both mortality and morbidity) are reported in Table 39 above. Full susceptibility was observed in the non-vaccinated challenged control group G1a and G1b thus validating the high severity of challenge. Protections levels after challenge at D14 were much lower than those obtained after challenge at D28. These vaccine candidates had the same NDV F expression cassette inserted into 2 different loci of vHVT13 genome. They performed equally in terms of ND protection in the tested conditions, indicating that both insertion loci (IG2 and SORF3-US2) are equally suitable for NDV F cassette insertion.
In conclusion, the results of this study showed that ND protection levels induced by Marek's disease vectors expressing NDV F gene depend on different parameters including the vector, the locus of insertion, the F gene, the promoter, the poly-adenylation site and the challenge conditions.
The objective of the study was to evaluate the efficacy of three double HVT-ND+IBD (vHVT302, vHVT303, and vHVT304) and two SB1-ND vectors (vSB1-006 and vSB1-007) in one day-old SPF chickens against a velogenic genotype V (Chimalhuacan) NDV challenge performed at D14.
The characteristics of the 5 recombinant vaccine candidates tested in this study are described in the Table 40 below.
Six groups (1 and 2) of ten one-day-old specific pathogen free (SPF) white Leghorn chicks were randomly constituted. Birds from groups 2 to 6 were vaccinated by the subcutaneous route (nape of the neck) with a target dose of 2000 PFU as shown in the Table 41 below. Chicks from group 1 were not vaccinated and were kept as control birds. At 2 week-of-age, all birds were challenged with the genotype V Mexican Chimalhuacan (Mex V) velogenic NDV strain. The challenge was performed by the intramuscular (IM) route using 105 Egg Infectious Dose 50 (EID50) diluted in 0.2 ml of physiological sterile water. All birds were monitored until 14 days post-challenge. After challenge, health status of each bird was scored daily as follows: healthy/with specific symptoms (ruffled feathers, prostration, torticollis, tremor)/dead. Any bird that showed specific symptoms for more than 2 days or was noted sick on D28 was taken into account for calculation of morbidity.
Results of protection are summarized in Table 41. All control birds died after ND challenge. Variable levels of ND protection were induced by the different tested vaccines ranging from 10% to 80% and from 0% and 60% in terms of protection against mortality and morbidity, respectively. The vHVT304 candidate induced a better protection than the vHVT303 and vHVT302 candidates; this may be due to the exogenous SV40 promoter placed in front of the NDV F gene. The vSB1-007 performed slightly better than the vSB1-006. Furthermore, performances obtained with vHVT304 were comparable to those obtained with vSB1-007 indicating that different Marek's disease vectors can reach the same level of ND protection.
In conclusion, this study demonstrates that both double HVT-ND+ IBD and SB1-ND vectored vaccines can reach significant levels of ND protection in a very severe and early NDV challenge model.
The objective of the study was to evaluate the efficacy of one double HVT-ND+IBD (vHVT306) administered by the in ovo or SC route to SPF chickens against a velogenic genotype V (Chimalhuacan) NDV challenge performed at 28 days of age.
The characteristics of the vHVT306 recombinant vaccine candidate tested in this study are described in Table 42 below. The single HVT-IBD vector vaccine vHVT13 was used as a control.
On day −3, 40 SPF embryonated eggs aged around 18 days and 18 hours of incubation were randomly allocated into 2 groups of 20 eggs each. On D0, one group of 12 day-old SPF chicks was added. The definition of groups is given in Table 43 below. The vaccination was performed on D-3 (in ovo route) or on D0 (SC route, in the back of the neck) and the target dose of vHVT306 and vHVT13 was 2000 PFU/bird. For the in ovo route, hatchability, viability (until D28) and growth of the birds (between hatching and D28) were monitored.
On D28, 10 birds per group were challenged with virulent ND Chimalhuacan strain. The challenge was performed by the intramuscular (IM) route using 105 Egg Infectious Dose 50 (EID50) diluted in 0.2 ml of physiological sterile water. Birds were monitored until 14 days post-challenge. Specific clinical signs and mortality were recorded. Any bird that showed specific symptoms for more than 2 days or was noted sick on D42 was taken into account for calculation of morbidity. Five and seven days post-challenge (i.e. on D33 and D35), oropharyngeal swab was taken from each surviving bird. All the swabs were analyzed by specific NDV qRT-PCR.
Full hatchability was recorded after in ovo vaccination in groups 1 and 2 and all hatched birds survived up to D28. No difference in body weights was detected between the two groups at both D0 and D28 confirming the perfect safety of vHVT306 when administered in ovo. Results of protection are summarized in Table 43. All vHVT13-vaccinated control birds died by 4 days after ND challenge. Full clinical ND protection was induced by vHVT306 administered by both routes. Furthermore, no shedding was detected after in ovo administration whereas only a few birds shed detectable amount of challenge virus after SC administration.
In conclusion, this study demonstrates that the double HVT-ND+IBD vHVT306 induce excellent level of ND protection by SC or in ovo administration routes in a very severe heterologous NDV challenge model.
The aim of the study was to assess the early IBD efficacy of double HVT recombinants vHVT302, vHVT303 and vHVT304 recombinant constructs against a virulent infectious bursal disease virus (vIBDV) challenge (Faragher 52/70 strain) performed at 15 days of age in SPF chickens.
The characteristics of the 3 double HVT-ND+IBD recombinant vaccine candidates tested in this study are described in the Table 44 below.
On D0, 40 one-day-old SPF chickens were randomly allocated into 4 groups of 10 birds including one control groups (G1) that was vaccinated with vSB1-004, a SB-1 vector expressing NDV F gene. Five other SPF birds were kept unvaccinated and unchallenged for bursal/body weights evaluation. The birds were injected by subcutaneous injection in the neck at D0 with 0.2 mL of recombinant vaccines containing a target dose of 2000 pfu as described in the Table 45 below. On D15, blood sample was collected from all birds per group (10 birds per group except for groups 1 and 3 in which 1 bird died before blood sampling) for serological testing with the Kit ProFLOK® plus IBD (Synbiotics Corp). On D15, birds from all 4 groups were challenged by the eye drop (0.05 mL per bird) with 2.5 log 10 EID50.
1Birds sick for more than 2 days or still sick on D 25 were considered as sick. The number in brackets is the total number of birds in the group that were challenged.
2Protection against clinical signs and severe bursal lesion (bursal score <3)
4The bursal/body weight ratio of the unvaccinated/unchallenged group was 0.0043.
Each group was monitored before and after challenge. IBDV clinical signs were recorded for 11 days after challenge (from D15 to D25). At the end of the post-challenge observation period (D25), all the surviving birds were euthanized and necropsied. Body and bursal weights were recorded. Each bursa of Fabricius (BF) was weighted then stored in individual recipients containing 4% formaldehyde for histology. Histological lesions of the bursa were scored according to the scale presented in Table 46.
A bird was considered as affected if it died and/or showed notable sign of disease and/or severe lesions of the bursa of Fabricius (i.e., histology score ≧3).
The mean ELISA IBD+ antibody titer expressed in log 10 before challenge is shown in Table 45. Significant titers were detected in all vaccinated groups that were significantly higher than that of the control group G1. The serology titer was slightly higher in G3 (vHVT303).
Severe clinical signs were observed after challenge in all 9 birds of the control group G1, which lead to the death of 1 bird. Only one vaccinated bird in G2 (vHVT302) showed clinical signs after challenge. Percentages of protection against severe bursal lesions are shown in Table 45 above. Significant IBD protection was observed in all vaccinated groups, a full protection being observed in G3 (vHVT303). The mean bursal/body weight ratios are also shown in Table 45. Ratios in all vaccinated groups were higher than those of the challenged control group G1 and not significantly different from the unvaccinated and unchallenged control group.
In conclusion, these data indicate that the three double HVT-IBD+ND tested in this study induced IBD antibodies and early IBD protection in a severe IBDV challenge model.
The aim of the study was to assess the efficacy of 5 single HVT recombinant constructs (vHVT39, vHVT110, vHVT111, vHVT112 and vHVT113) expressing the NDV F gene against Newcastle disease challenge with velogenic NDV ZJ1 (genotype VIId) isolate performed at 14 days of age in SPF chickens.
The characteristics of these 5 vaccine candidates are described in Table 47 below.
On D0, 72 one-day-old SPF chickens were randomly allocated into 5 groups of 12 birds (vaccinated) and 1 group of 12 birds (non-vaccinated controls). The birds were injected by subcutaneous injection in the neck at D0 with 0.2 mL of recombinant vaccines containing a target dose of 6000 pfu as described in Table 48 below. The birds were challenged by the intramuscular route on D14 with 5 log 10 EID50 of NDV ZJ1/2000 (genotype VIId) velogenic strain.
Each group was monitored before and after challenge. NDV clinical signs and mortality were recorded after challenge. Oropharyngeal swabs were taken at 2 and 4 days post-infection (dpi) for evaluation of viral load by real time RT-PCR using the method described by Wise et al. (2004; Development of a Real-Time Reverse-Transcription PCR for Detection of Newcastle Disease Virus RNA in Clinical Samples. J Clin Microbiol 42, 329-338).
Percentages of protection against mortality and morbidity are reported in Table 48 above. Full susceptibility was observed in the non-vaccinated challenged control group G1 thus validating the high severity of the challenge. Vaccines induced variable levels of protection against mortality (25-100%) or against morbidity (8%-83%). The best protection level was induced by vHVT110 whereas the lowest one was induced by vHVT039, the other candidates giving intermediate results. Results of oropharyngeal shedding at 2 and 4 dpi are also shown in Table 48 above and are in line with those of clinical protection. These vaccine candidates differ in their promoter and F gene sequence. These results show that both of these parameters are important for the design of optimal HVT-ND vaccine candidate.
In conclusion, the results of this study showed the importance of promoter and F gene sequence in the ND efficacy induced by HVT-vectored ND vaccine candidates.
The aim of the study is to assess the efficacy of double SB1 constructs expressing IBDV VP2 and NDV F against Newcastle disease challenge.
On D0, one-day-old SPF chickens are randomly allocated into several groups of 10-20 birds, including vaccinated and non-vaccinated groups. The birds of the vaccinated groups are injected by subcutaneous injection in the neck at D0 with 0.2 mL containing a target dose of 1000 to 5000 pfu of recombinant vaccines. Alternatively, the same dose in 0.05 mL may be administered in ovo 2 or 3 days before hatch. The birds (at least one vaccinated and one non vaccinated group) are challenged by the intramuscular route at different time after vaccination: for instance, D14, D28 or D42 with about 4.0 log 10 EID50 (0.1 mL) of a velogenic NDV strain such as Texas GB (genotype II), ZJ1 (genotype VIId), Chimalhuacan (genotype V) strain.
Each group is monitored clinically before and after challenge. NDV clinical signs (morbidity) and mortality are recorded after challenge. Percentages of clinical protection in all groups are calculated. At least 90% of non-vaccinated challenged SPF birds should die or be severely sick after challenge to validate the severity of challenge. Oropharyngeal and cloacal swabs can be samples at different times after challenge such as 3, 5, 7 and 9 days post-challenge and the viral load can be estimated by real-time RT-PCR. The best candidates will be those who induced the highest level of clinical protection and the lowest level of viral load in the swabs. A similar study can be performed in broilers containing NDV maternal antibodies; however, these maternal antibodies may potentially protect the non-vaccinated birds if the challenge is performed early. The double SB1 construct may also be tested in combination with other Marek's disease vaccine or vector vaccines.
The aim of the study is to assess the IBD efficacy of double SB 1 expressing both the IBDV VP2 and the NDV F.
One-day-old SPF chickens are randomly allocated into several groups of 10 to 20 birds including vaccinated and non-vaccinated controls. Non-vaccinated controls will be separated into 2 subgroups including challenged and unchallenged birds. The birds of vaccinated groups are injected by subcutaneous injection in the neck at D0 with 0.2 mL of vaccines containing each a target dose of 1000 to 5000 pfu. Alternatively, the same dose in 0.05 mL may be administered in ovo 2 or 3 days before hatch. At different times after vaccination such as 14, 21, 28 or 42 days post-vaccination, all birds from vaccinated groups and the challenged controls are challenged by the eye drop (0.03 mL containing 2 to 4 log 10 EID50 per bird) of a virulent IBDV (such as the Faragher or the US standard strain), a very virulent IBDV such as the 91-168 isolate or a variant IBDV isolate such as the US Delaware variant E isolate. Each group is clinically monitored before and after challenge. Birds can be necropsied 4 or 5 days post-challenge for bursal gross lesions evaluation. They can also be necropsied 10 to 11 days post-challenge. Gross and/or histological lesions can be evaluated. Furthermore, birds and bursa are weighed the bursal/body weight ratios (bursa weight/body weight ratio×100) are calculated compared to those of the non-vaccinated unchallenged group. Control SPF challenged birds must show clinical signs and/or have significant gross and/or histological lesions, and/or should have a bursal/body weight ratio significantly lower than the unvaccinated unchallenged control birds to validate the severity of challenge. The efficacy of the vaccine is evaluated by comparing these parameters with unvaccinated/challenged and unvaccinated/unchallenged groups. Such study may be performed in broiler chickens containing IBDV maternal antibodies; however, these maternal antibodies may potentially protect the non-vaccinated birds if the challenge is performed early. The double SB 1 construct may also be tested in combination with other Marek's disease vaccine or vector vaccines.
The aim of the study is to evaluate Marek's disease efficacy induced by the SB1 vectors expressing both IBDV VP2 and NDVF.
One-day-old SPF chickens are randomly allocated into several groups of 20 to 50 birds including vaccinated and non-vaccinated controls. Non-vaccinated controls may be separated into 2 subgroups including challenged and unchallenged birds. The birds of vaccinated groups are injected by subcutaneous injection in the neck at D0 with 0.2 mL of vaccines containing each a target dose of 1000 to 5000 pfu. Alternatively, the same dose in 0.05 mL may be administered in ovo 2 or 3 days before hatch. At different times after vaccination such as 3 to 10 days post-vaccination, all birds from vaccinated groups and the challenged controls are challenged by the intraperitoneal route with 0.2 mL of a Marek's disease virus (MDV) strain. MDV strain may be of several pathotypes such as virulent MDV (vMDV) including the JM or GA22 isolate, very virulent MDV (vvMDV) such as the RB-1B or Md5 isolate, very virulent plus (vv+MDV) such as the T-King or 648A isolate. MDV challenge strain inoculum are prepared by infecting chickens, harvesting and freezing their blood cells into liquid nitrogen in presence of a cryopreservative such as DMSO. The chicken infectious dose 50 (CID50) is established for each challenge batch before performing vaccination/challenge studies. Each group is clinically monitored before and after challenge. Birds are necropsied after at least 7 weeks post-vaccination and the presence Marek's disease gross lesions is checked in each bird. Lesions might include, but not be limited to, the following: liver, heart, spleen, gonads, kidneys, nerve and muscle lesions. Such study may be performed in broiler chickens containing MDV maternal antibodies. The double SB1 construct may also be tested in combination with other Marek's disease vaccine (for instance HVT and or CVI988 Rispens strains) or MD vector vaccines. MD challenge may also be performed by contact between vaccinated birds and MDV infected non-vaccinated SPF chicks.
Having thus described in detail preferred embodiments of the present invention, it is to be understood that the invention defined by the above examples 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.
All documents cited or referenced herein (“herein cited documents”), and all documents cited or referenced in herein cited documents, together with any manufacturer's instructions, descriptions, product specifications, and product sheets for any products mentioned herein or in any document incorporated by reference herein, are hereby incorporated herein by reference, and may be employed in the practice of the invention.
This application claims priority to U.S. provisional application 61/564,877 filed on Nov. 30, 2011 and U.S. provisional application 61/694,957 filed on Aug. 30, 2012.
