Patent Grant
9555098
The present invention relates generally to attenuated viral vaccines, particularly those providing broad, safe, and effective protection to palmipeds against infections or diseases. The invention further relates to methods of producing the attenuated virus, and to the identification of variations in the nucleotide sequence that are associated with decreased virulence of the attenuated virus.
Goose parvovirus (GPV; also called Derzsy's Disease) and Muscovy duck parvovirus (MDPV) are antigenically distinct viruses that affect palmipeds. GPV is highly contagious and is characterized by multiple clinical signs, including anorexia, prostration, weakness and polydipsia. GPV may present in acute, subacute or chronic forms; the acute form of the disease may cause 100% mortality in goslings under 10 days of age. GPV primarily affects geese and Muscovy ducks (Cairina moschata). Currently, goose and Muscovy duck producers may protect against GPV using an attenuated live vaccine.
MDPV is an acute systemic infection of Muscovy ducklings. The clinical signs of MDPV are similar to those of GPV and the mortality rate can be 80% or higher. MDPV is transmitted horizontally and can also be transmitted vertically when susceptible hens become infected during lay or if there is reactivation of latency. To date, MDPV is known to affect only Muscovy ducks while other avian species are not susceptible. No attenuated live vaccine currently exists for combatting MDPV although an inactivated vaccine is available.
Accordingly, Muscovy ducks are vulnerable to both GPV and MDPV. Given the similarity with which both diseases present, it is difficult to determine which vaccine to administer, as the vaccine for GPV is ineffective against MDPV and the MDPV vaccine is ineffective against GPV. Muscovy duck producers may then administer vaccines against both diseases or face the economic hardship associated with the above-mentioned mortality rates.
Administering two vaccinations is less than ideal for logistical and economic reasons.
In one embodiment, the invention is a composition comprising an attenuated palmiped parvovirus capable of providing a heterologous immune response in palmipeds against Muscovy duck parvovirus and goose parvovirus (Derzsy's Disease). In one aspect, the composition of the attenuated palmiped parvovirus comprises a polynucleotide encoding viral protein 1 (VP1) having the sequence as set forth in SEQ ID NO. 2. See
In another embodiment, the invention is an attenuated palmiped parvovirus capable of providing a heterologous immune response in palmipeds against Muscovy duck parvovirus and goose parvovirus (Derzsy's Disease). In one aspect, the attenuated palmiped parvovirus comprises a polynucleotide encoding viral protein 1 (VP1) having the sequence as set forth in SEQ ID NO. 2. In another aspect, the attenuated palmiped parvovirus comprises a polynucleotide having the sequence as set forth in SEQ ID NO. 1.
In yet another embodiment, the invention is a method of treating a palmiped against Muscovy duck parvovirus and goose parvovirus (Derzsy's Disease) comprising the step of administering a composition comprising an attenuated palmiped parvovirus capable of providing a heterologous immune response in palmipeds against Muscovy duck parvovirus and goose parvovirus (Derzsy's Disease). In one aspect, the composition comprises the attenuated palmiped parvovirus comprising a polynucleotide encoding viral protein 1 (VP1) having the sequence as set forth in SEQ ID NO. 2. In another aspect, the composition comprises the attenuated palmiped parvovirus comprising a polynucleotide having the sequence as set forth in SEQ ID NO. 1.
In yet another embodiment, the invention is an isolated polynucleotide encoding the polypeptide having the sequence as set forth in SEQ ID NO. 2. The invention is further an isolated polynucleotide having the sequence as set forth in SEQ ID NO. 1.
As defined herein, the term “gene” will be used in a broad sense, and shall encompass both coding and non-coding sequences (i.e. upstream and downstream regulatory sequences, promoters, 5′/3′ UTR, introns, and exons). Where reference to only a gene's coding sequence is intended, the term “gene's coding sequence” or “CDS” will be used interchangeably throughout this disclosure. When a specific sequence is discussed, for example, the sequence as set forth in SEQ ID NO. # (the DNA sequence equivalent of parental virus cRNA “sense” strand), the skilled person will instantly be in possession of all derivable forms of that sequence (mRNA, vRNA, cRNA, DNA, protein, etc.). A skilled person using the genetic code can routinely derive from a DNA sequence the vRNA, cRNA, and peptide sequences.
In a particular embodiment, the attenuated vaccine comprises an adjuvant. The adjuvant may be any substance which increases and/or augments the elicited immune response, as compared to attenuated vaccine alone. Mucosal adjuvants, including chitosans and derivatives thereof, are particularly useful for the disclosed oral attenuated vaccines.
The invention further provides methods for inducing an immunological (or immunogenic) or protective response against GPV and MDPV, as well as methods for preventing or treating GPV and MDPV, or disease state(s) caused by the same, comprising administering the attenuated virus, or a composition comprising the attenuated virus to animals in need thereof.
These and other embodiments are disclosed or are obvious from and encompassed by, the following Detailed Description.
A full and enabling disclosure of the present invention, including the best mode thereof, to one of ordinary skill in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, wherein:
The present invention provides nucleotide sequences and genes involved in the attenuation of a microorganism, such as virus, for instance, parvovirus, products (e.g., proteins, antigens, immunogens, epitopes) encoded by the nucleotide sequences, methods for producing such nucleotide sequences, products, micro-organisms, and uses therefor, such as for preparing vaccine or immunogenic compositions or for eliciting an immunological or immune response or as a vector, e.g., as an expression vector (for instance, an in vitro or in vivo expression vector).
Mutations introduced into nucleotide sequences and genes of micro-organisms produce novel and nonobvious attenuated mutants. These mutants are useful for the production of live attenuated immunogenic compositions or live attenuated vaccines having a high degree of immunogenicity.
Identification of the mutations provides novel and nonobvious nucleotide sequences and genes, as well as novel and nonobvious gene products encoded by the nucleotide sequences and genes.
In an embodiment, the invention provides an attenuated palmiped parvovirus capable of providing a heterologous immune response in palmipeds against Muscovy duck parvovirus and goose parvovirus.
In another aspect, the invention provides immunological composition comprising an attenuated MDPV strain that provides a heterologous immune response in palmipeds against Muscovy duck parvovirus and goose parvovirus. In one embodiment, the compositions may further comprise a pharmaceutically or veterinary acceptable vehicle, diluent or excipient.
In an embodiment, the invention provides methods of vaccinating an animal comprising at least one administration of the compositions comprising sequences encoding an attenuated MDPV strain that provides a heterologous immune response in palmipeds against Muscovy duck parvovirus and goose parvovirus.
The invention further encompasses gene products, which provide antigens, immunogens and epitopes, and are useful as isolated gene products.
Such isolated gene products, as well as epitopes thereof, are also useful for generating antibodies, which are useful in diagnostic applications.
Such gene products, which can provide or generate epitopes, antigens or immunogens, are also useful for immunogenic or immunological compositions, as well as vaccines.
In an aspect, the invention provides a virus containing attenuating mutations in a nucleotide sequence or a gene wherein the mutation modifies the biological activity of a polypeptide or protein encoded by a gene, resulting in attenuated virulence of the virus.
In particular, the present invention encompasses attenuated parvovirus strains and vaccines comprising the same, which elicit an immunogenic response in an animal, particularly a attenuated parvovirus strain that elicits, induces or stimulates a response in a Muscovy duck.
The particular MDPV attenuated strain of interest has mutations relative to the virulent parent strain.
In another aspect, the novel attenuated parvovirus strain is formulated into a safe, effective vaccine against GPV and MDPV.
In an embodiment, the attenuated parvovirus vaccine further comprises an adjuvant. In a particular embodiment, the adjuvant is a mucosal adjuvant, such as chitosan, methylated chitosan, trimethylated chitosan, or derivatives or combinations thereof. Other adjuvants are well known to those of skill in the art.
The terms “protein”, “peptide”, “polypeptide” and “polypeptide fragment” are used interchangeably herein to refer to polymers of amino acid residues of any length. The polymer can be linear or branched, it may comprise modified amino acids or amino acid analogs, and it may be interrupted by chemical moieties other than amino acids. The terms also encompass an amino acid polymer that has been modified naturally or by intervention; for example disulfide bond formation, glycosylation, lipidation, acetylation, phosphorylation, or any other manipulation or modification, such as conjugation with a labeling or bioactive component.
The term “immunogenic or antigenic polypeptide” 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; Geysen et al., 1984; Geysen et al., 1986. 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.
As discussed herein, the invention encompasses active fragments and variants of the antigenic polypeptide. Thus, the term “immunogenic or antigenic polypeptide” 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, cystine, 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 and/or clinical disease signs normally displayed by an infected host, a quicker recovery time and/or a lowered viral titer in the infected host.
By “animal” is intended palmipeds; specifically Muscovy ducks.
Unless otherwise explained, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. 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.
“Heterologous” with respect to the claimed invention means a composition that confers protective immunity against a pathogen that shares cross-reacting antigens with the microorganisms in the vaccine. For example, a vaccine made from the composition of the claimed invention confers immunity to palmipeds against Muscovy Duck Parvovirus (MDPV) and Goose Parvovirus (GPV or Derzsy Disease).
Methods of use and Article of Manufacture
The present invention includes the following method embodiments. In an embodiment, a method of vaccinating an animal comprising administering a composition comprising an attenuated palmiped parvovirus capable of providing a heterologous immune response in waterfowl against Muscovy duck parvovirus and goose parvovirus (Derzsy's Disease) and a pharmaceutical or veterinarily acceptable carrier, excipient, or vehicle to an animal is disclosed.
In one embodiment of the invention, a prime-boost regimen can be employed, 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. Typically the immunological composition or vaccine used in primary administration is different in nature from those used as a booster. However, it is noted that the same composition can be used as the primary administration and the booster administration. This administration protocol is called “prime-boost”.
A prime-boost regimen comprises at least one prime-administration and at least one boost administration using at least one common polypeptide and/or variants or fragments thereof. The vaccine used in prime-administration may be different in nature from those used as a later booster vaccine. The prime-administration may comprise one or more administrations. Similarly, the boost administration may comprise one or more administrations. By way of example, the “prime” could comprise the modified live virus of the invention alone while the “boost” could comprise the modified live virus of the invention with an adjuvant.
The dose volume of compositions for target species is generally between about 0.1 to about 2.0 ml, between about 0.1 to about 1.0 ml, and between about 0.5 ml to about 1.0 ml.
The efficacy of the vaccines may be tested after the last immunization by challenging animals with a virulent strain of GPV or MDPV. The animal may be challenged by IM or SC injection, spray, intra-nasally, intra-ocularly, intra-tracheally, and/or orally. Samples from joints, lungs, brain, and/or mouth may be collected before and post-challenge and may be analyzed for the presence of parvovirus-specific antibody.
The compositions comprising the attenuated viral strains of the invention used in the prime-boost protocols are contained in a pharmaceutically or veterinary acceptable vehicle, diluent or excipient. The protocols of the invention protect the animal from parvovirus and/or prevent disease progression in an infected animal.
It should be understood by one of skill in the art that the disclosure herein is provided by way of example and the present invention is not limited thereto. From the disclosure herein and the knowledge in the art, the skilled artisan can determine the number of administrations, the administration route, and the doses to be used for each injection protocol, without any undue experimentation.
Another embodiment of the invention is a kit for performing a method of eliciting or inducing an immunological or protective response against parvovirus in an animal comprising an attenuated MDPV immunological composition or vaccine and instructions for performing the method of delivery in an effective amount for eliciting an immune response in the animal.
Yet another aspect of the present invention relates to a kit for prime-boost vaccination according to the present invention as described above. The kit may comprise at least two vials: a first vial containing a vaccine or composition for the prime-vaccination according to the present invention, and a second vial containing a vaccine or composition for the boost-vaccination according to the present invention. The kit may advantageously contain additional first or second vials for additional prime-vaccinations or additional boost-vaccinations.
The pharmaceutically or veterinarily acceptable carriers or vehicles or excipients are well known to the one skilled in the art. For example, a pharmaceutically or veterinarily acceptable carrier or vehicle or excipient can be a 0.9% NaCl (e.g., saline) solution or a phosphate buffer. Other pharmaceutically or veterinarily acceptable carrier or vehicle or excipients that can be used for methods of this invention include, but are not limited to, 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); advantageously, the carrier, vehicle or excipient may facilitate transfection 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.
The immunological 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 page 147 of “Vaccine Design, The Subunit and Adjuvant Approach” published by M. Powell, M. Newman, Plenum Press 1995, and the emulsion MF59 described on page 183 of the same work, (4) cationic 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.
In an embodiment, adjuvants include those which promote improved absorption through mucosal linings. Some examples include MPL, LTK63, toxins, PLG microparticles and several others (Vajdy, M. Immunology and Cell Biology (2004) 82, 617-627). In an embodiment, the adjuvant may be a chitosan (Van der Lubben et al. 2001; Patel et al. 2005; Majithiya et al. 2008; U.S. Pat. No. 5,980,912).
Choice of Vaccine Strain
The viral strain was isolated from liver of ducks originating from SPF (specific pathogen-free) flocks. These ducks were introduced onto a farm of the Guyomarc′h company struck down by the “MMFC” syndrome (Mortality, Malnutrition, Featherlessing, Crawling syndrome). The isolated virus obtained was named GM and it was inoculated to 7 SPF ducklings aged one day. These ducklings died 5 to 9 days after inoculation. The livers, hearts and spleens of these ducklings were removed and ground. The ground product was propagated successively 20 times in SPF duck embryo primary cells, with 3 cloning in limit dilutions, at the seventeenth, the eighteenth and the nineteenth passages. Then, the harvest of the twentieth passage underwent 179 passages in duck embryo cells before establishing the Master Seed Virus. The GM strain has thus been attenuated by a large number of passages in duck embryo cells before being used for the production of the final vaccine product (i.e., Parvoduck vaccine). Its characteristics are those of the parvovirus but without the pathogenic properties of wild strains.
In addition, the wild parvovirus in ducks being deemed stable, this strain is perfectly suited to the production of a vaccine against both the MDPV and GPV.
Methodology
The GM strain was adapted for growth on primary duck embryo cells (PDEC) as mentioned above and then purified. Another 74 attenuation passages were then carried out on PDEC (until strain GM93, i.e. 93 passages after the initial isolate). From this level, the strain was attenuated on either TDF2A cell line, PDEC or Pekin duck cells. The safety of the passaged strains was tested in SPF ducklings by successive studies in order to determine the most appropriate attenuation level for use as live modified vaccine. The passages are diagrammed in
Strain: GM10, titrating 7.5 log 10 CCID50/ml.
Animals: 24 SPF ten-day-old ducklings, divided into 4 groups of 6 and inoculated at D0 as in Table 1:
Monitoring: Clinical follow-up, D0 to D21. Scoring: (0) healthy (1) locomotor problems (2) lameness (3) paresis (4) death.
Clinical signs observed appeared as from D8 in all the groups.
The conclusion is that GM10 passage was not sufficiently attenuated since it induced severe locomotor symptoms in a large majority of birds, whatever the dose used. Considering the results obtained, the LD50 was not calculated.
Strain: GM33 titrating 8.2 log 10 CCID50/ml.
Animals: 10 SPF one-day-old ducklings, subcutaneously inoculated on D0 with 6.0 log 10 CCID50 of strain GM33 under a volume of 0.5 ml.
Monitoring: Mortality follow-up, D0 to D21. Birds which died during the study were necropsied. Necropsy at D21 for lesions of Derzsy's disease (spleen and/or liver enlargement, ascitis, hydropericarditis). Blood sampling at D21 and search for specific duck parvovirus antibodies by SN (i.e., sereoneutralization assay to measure virus neutralizing antibody titers). Data shown in Table 2.
(a) post-mortem lesions: spleen and/or liver enlargement, ascitis, hydropericarditis
(b) ie bad general condition, anorexia, lameness
(c) clinical assessment (no weighing)
All the sera showed high GM antibody titres, ranging from 3.4 to 4.0 log 10 SN unit (positive reference serum: 2.8 log 10 SN unit). These results validated the inoculation. Inoculation of 6.0 log 10 CCID50 of GM33 strain induced 40% mortality and 100% morbidity (considering the growth retardation in all the birds) in one-day-old SPF ducklings.
Strain: GM48, titrating 8.0 log 10 CCID50/ml.
Animals: 10 SPF one-day-old ducklings, subcutaneously inoculated on D0 with 6.0 log 10 CCID50 of strain GM48 under a volume of 0.5 ml.
Monitoring: Mortality follow-up, D0 to D21. Birds which died during the study were necropsied. See Table 3. Necropsy at D21 for lesions of Derzsy's disease (spleen enlargement, hepatitis, ascitis, hydropericarditis, aerosacculitis).
(a) post-mortem lesions: spleen and/or liver enlargement, ascitis, hydropericarditis
(b) ie bad general condition, anorexia, lameness
(c) clinical assessment (no weighing)
Inoculation of 6.0 log 10 CCID50 of GM48 strain induced 10% mortality and 60% morbidity (considering growth retardation+post-mortem observations at D21) in one-day-old SPF ducklings.
Strain: GM61, titrating 8.6 log 10 CCID50/ml.
Animals: 16 SPF one-day-old ducklings, divided into 2 groups and inoculated at D0 as in Table 4.
Monitoring: Mortality follow-up, D0 to D21. Birds which died during the study were necropsied. Weighing and sexing at D21. Necropsy at D21 for lesions of Derzsy's disease. Histological examination of brain, heart, spleen, liver, tendon and leg muscle (G1: pooled samples; G2 individual samples). Blood sampling at D21 and search for specific duck parvovirus antibodies by SN. The results are summarized in Table 5. Positive reference serum: 2.8 log 10 SN unit.
These results validated the inoculation and confirmed the spread of the virus to contact birds G2. There was one non-specific death in G1 on D1. No other bird was found dead nor sick all through the trial. Further, no G1 bird showed any lesion at necropsy at D21. In G2, 2 ducks showed ascitis and perihepatitis, suggesting that the virus spread to contact birds G2.
Inoculation of 6.0 log 10 CCID50 of GM61 strain to one-day-old SPF ducklings induced no mortality and very low morbidity from the clinical standpoint. Histopathology suggested that the safety of the strain was not complete. The data obtained also indicated that GM61 had a high ability to spread between birds.
Strain: GM72, titrating 6.0 log 10 CCID50/ml (freeze-dried).
Animals: 26 SPF one-day-old ducklings, and 20 SPF 8-day-old ducks inoculated at D0 as shown in Table 6.
Monitoring: Mortality follow-up, D0 to D21, weighing at D0 and D21, sexing and necropsy for lesions of Derzsy's disease at D21. Histological examination of brain, heart, spleen, liver, tendon and leg muscle of 4 birds per group. Blood sampling at D21 and search for specific duck parvovirus antibodies by SN. Observation: The one-day-old ducklings were in bad general condition at delivery.
Within each age category, the same pattern was observed: homogeneous bodyweights at D0, discrepancy between the vaccinates and the controls 3 weeks post-inoculation, with a clear growth lag in the inoculated birds. As expected, the sexual dimorphism was more marked in the older birds (G3/G4).
Clinical and post-mortem findings: There were 3 non-specific deaths in G1 (GM72-inoculated at one-day-old) on D1. Two ducks also died in G3 (GM72-inoculated at 8-day-old) at D6 and D15 respectively. No other bird was found dead nor sick all through the trial. Necropsy results at D21 are summarized in Table 7.
(a)number of birds examined at D 21
(b) Some birds can show different types of lesions
Post-mortem observations in G2 and G4 controls suggested that there was a virus spread during the study. All the samples examined showed very discreet inflammatory lesions, generally consisting of congestion sometimes associated with small lymphoid infiltrates. The lesions observed were all of slight intensity and showed no specificity; no differences were seen between the 4 groups.
Serology results at D21 are summarized in Table 8. Positive reference serum: 2.8 log 10 SN unit.
Serology titres in the inoculated groups G1 and G3 confirmed the virus take. The antibody level in G4 controls confirmed the previous assumption of a virus spread based on the post-mortem results. On the contrary, there was no serological changes in G2 controls; the spleen lesions observed at necropsy in this group was probably due to a late virus spread with no seroconversion before the end of the study. In both cases, the virus spread had no major influence on the bodyweight gain in the controls.
Zootechnical problems (non-specific mortality due to bad general condition of the birds at delivery and viral spread) interfered with a reliable interpretation of the study. The results available suggested yet that even if there was no impact of GM72 strain from the histology standpoint, inoculation of the strain at either 1 or 8 days of age induced patent growth lag.
Strain: GM87.
Animals: 30 SPF one-day-old ducklings, divided into 2 groups and inoculated at D0 as shown in Table 9.
Monitoring: Mortality follow-up, D0 to D21 (not necropsied), weighing at D0 and D21. Euthanasia at D21, sexing and necropsy for lesions of Derzsy's disease. Histological examination of brain, heart, spleen, liver, tendon and leg muscle of 4 birds per group (individual samples). Blood sampling at D21 and search for specific duck parvovirus antibodies by SN.
Serology results are summarized in Table 10. Positive reference serum: 3.4 log 10 SN unit.
These results validated the inoculation in G1. The relatively high antibody titres in G2 suggested that a viral spread occurred during the study.
Clinical and post-mortem findings: there was a non-specific death in the controls at D2.
In the GM87-inoculated group G1, there were 6 deaths between D4 and D18. Necropsy results at D21 are summarized in Table 11.
(a)number of birds examined at D 21-NB: in G2, one bird was omitted at necropsy by mistake
(b) Most birds showed at least 2 different types of lesions
(c)Fibrinous pericarditis and/or myocarditis
(d)Fibrinous perihepatitis and/or necrosed hepatitis
The main lesions observed were at the hepatic level. Some of them, such as perihepatitis and necrosis, were rather evocative of a bacterial infection. Lesions of myocarditis, myositis and encephalitis—classically observed in parvovirus infection—were rare and of slight intensity. There were no differences in the histopathological observations in the 2 groups regarding frequency or intensity of the lesions. Zootechnical problems (viral spread and intercurrent bacterial infection) did not allow to interpret the safety data on a reliable basis. The higher mortality recorded in the inoculated birds and the bad growth data suggested that the GM87 strain was still not attenuated enough.
Strains: GM100 grown on PDEC (herein named GM100/PDEC)—8.7 log 10 CCID50/ml; GM105 grown on TDF2A cells (herein named GM105/TDF)—8.2 log 10 CCID50/ml.
Animals: 30 SPF one-day-old not-sexed ducklings inoculated at D0 as shown in Table 12.
Monitoring: Mortality follow-up, D0 to D21. Weighing at D0, D10 and D21.
There were 2 non-specific deaths during the study: one in G1 (GM100/PDEC) at D3 and one in G3 (controls) at D2. In G1, 2 other deaths were recorded at D10 and D18, and considered as related to the strain inoculation. Weighing results are shown in
Inoculation of 5.0 log 10 CCID50 of GM100/PDEC strain induced 30% mortality and 100% morbidity (considering growth retardation at D21) in one-day-old SPF ducklings.
Inoculation of 5.0 log 10 CCID50 of GM105/TDF strain to one-day-old SPF ducklings induced no mortality. The safety of the strain was yet not complete, since it induced a significant growth lag—even if less marked than for strain GM100/PDEC—as compared to the controls.
Strain: GM124 grown on TDF2A cells (herein named GM124/TDF)—8.7 log 10 CCID50/ml.
Animals: 24 SPF one-day-old ducklings inoculated at D0 as shown in Table 13.
Monitoring: Mortality follow-up, D0 to D21. Weighing at D0 (group randomisation), D10 and D21. Necropsy at D21 for lesions of Derzsy's disease and sexing.
Mortality follow-up and post-mortem lesions: there was only one non-specific death in G1 (GM124/TDF) at D3. No other death was recorded during the study. No specific lesions attributable to the virus strain was observed at necropsy. Weighing results are shown in
Even if strain GM124/TDF seems safe on a clinical and necropsy basis, the data suggest that it still has an adverse affect on bird growth.
Strains: GM143 grown on TDF2A cells (herein named GM143/TDF)—8.2 log 10 CCID50/ml.
GM114 grown on Pekin cells (herein named GM114/Pekin)—6.3 log 10 CCID50/ml.
Animals: 30 SPF one-day-old ducklings inoculated at D0 as shown in Table 14.
Monitoring: Mortality follow-up, D0 to D21. Weighing at D0 (group randomisation), D10 and D21. Necropsy at D21 for lesions of Derzsy's disease and sexing. Blood sampling at D21 and search for specific duck parvovirus antibodies by SN.
Mortality follow-up and post-mortem observations: There was one non-specific death in G1 (GM143/TDF) at D1. No other death occurred during the study. All the inoculated ducks from G1 and G2 showed lesions at necropsy at the beak and/or heart and/or liver and/or spleen level. There were no lesions observed in the controls (G3).
Weighing results are shown in
These results validated the inoculation.
Inoculation of 5.0 log 10 CCID50 of GM143/TDF strain and of GM114/Pekin to one-day-old SPF ducklings induced no mortality. Both strains resulted in high morbidity, considering the numerous post-mortem lesions observed and the growth retardation in inoculated birds as compared with control ducks.
Strains: GM143 grown on TDF2A cells (herein named GM143/TDF)—8.2 log 10 CCID50/ml.
GM114 grown on Pekin cells (herein named GM114/Pekin)—6.3 log 10 CCID50/ml.
PALMIVAX, batch 3PMX4B122 (herein named PMX)—5.6 log 10 CCID50 per vial.
Diluent: diluent for live duck vaccines, batch 3SPP250311.
Animals: 40 SPF 15-day-old ducklings inoculated at D0 as shown in Table 16.
Monitoring: Mortality follow-up, D0 to D21. Weighing at D0 (group randomisation), D9 and D21. Sexing at D21.
There was no death in any groups all through the study.
Inoculation of 5.0 log 10 CCID50 of GM143/TDF strain and of GM114/Pekin to 15-day-old SPF ducklings induced no mortality. Both strains yet resulted in growth retardation as compared with non-inoculated controls ducks and PALMIVAX vaccinates.
Strains: GM189 grown on TDF2A cells (herein named GM189/TDF)—7.8 log 10 CCID50/ml;
GM131 grown on Pekin cells (herein named GM131/Pekin)—6.2 log 10 CCID50/ml.
Diluent: Diluent for live duck vaccines, batch 3SPP250311.
Animals: 33 SPF one-day-old ducklings, and 29 SPF 15-day-old ducks inoculated at D0 as shown in Table 17.
Monitoring: Mortality follow-up, D0 to D21. Weighing at D0 (group randomisation), D10 and D21. Sexing and necropsy for lesions of Derzsy's disease at D21. Blood sampling at D21 and search for duck parvovirus (GM) and Derzsy's (H) antibodies by SN.
Mortality follow-up and post-mortem observations: There were no deaths in any group all through the study. No duck showed any organ lesions at D21 necropsy examination.
Weighing results (individual data are given in Table 22 below): G1, G2, G3: Ducks injected at one day of age (see
G4, G5, G6: Ducks injected at 15 days of age (see
The results observed with GM189/TDF and GM131/Pekin were very close to each other. There was no significant differences between the observations in the 3 groups (Multifactor ANOVA on bodyweights, factors group and sex—D0: p=0.19; D10: p=0.49; D21: p=0.44).
Serology results for GM antibodies (Table 20) and H antibodies (Table 21) at D21 are summarized below. Positive reference serum: 2.8 log 10 SN unit (Table 20) and ≧4.0 log 10 SN unit (Table 21).
The results validated the inoculations. The controls remained seronegative. As expected, the serological conversion obtained with respect to GM antibodies (homologous antibody response) was higher than that regarding H antibodies (heterologous response).
GM serology response was higher in ducks injected with strain GM189/TDF than with GM131/Pekin. The values recorded were similar whatever the age of injection, for each strain type. Mean H serology response was low with the 2 strains used. However, there was a trend to have a serological response in ducks inoculated with strain GM189/TDF, while there was almost no response in birds which received the Pekin-passed strain GM131. The results with respect to H antibodies tended to be better after inoculation of 15-day-old birds.
This study showed that strain GM189/TDF and strain GM131/Pekin were similar from the safety standpoint. Both strains were completely safe with respect to mortality and lesional analysis. They had no major impact on the birds bodyweight gain when administered at 15 days of age, but induced some growth retardation if inoculated at one day old. In addition, analysis of the serological results indicated that GM189/Pekin induced a better immune response (homologous and heterologous) than strain GM131/Pekin, in particular when administered to 15-day-old ducks.
Table 22 shows individual duck weighing data for Example 11.
According to these studies, the strain finally considered as satisfactorily attenuated was the 189th passage from the initial isolate, obtained as follows: 19 adaptation passages on PDEC (i.e., until GM19); 74 attenuation passages on PDEC (i.e., until GM93); 71 attenuation passages on TDF2A cells at 38° C. (i.e., until GM164) and 25 attenuation passages on TDF2A cells at 33° C. (i.e., until GM189).
Having thus described in detail preferred embodiments of the present invention, it is to be understood that the invention defined by the above paragraphs 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.
This application claims the benefit of U.S. Provisional Application No. 61/698,842, filed Sep. 10, 2012.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2013/058981 | 9/10/2013 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2014/040040 | 3/13/2014 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20040208886 | Daeffler | Oct 2004 | A1 |
| Entry |
|---|
| Gough and Spackman, Studies with a duck embryo adapted goose parvovirus vaccine, 1982, Avian Pathology, vol. 11, pp. 503-510. |
| Lee et al., CpG oligodeoxynucleotides containing GACGTT motifs enhance the immune responses elicited by a goose parvovirus vaccine in ducks, 2010, Vaccine, vol. 28, pp. 7956-7962. |
| Number | Date | Country | |
|---|---|---|---|
| 20150216964 A1 | Aug 2015 | US |
| Number | Date | Country | |
|---|---|---|---|
| 61698842 | Sep 2012 | US |
