Browsing by Author "Halbur, Patrick G."

Now showing 1 - 10 of 10
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    Chimeric infectious DNA clones, chimeric porcine circoviruses and uses thereof
    (United States Patent and Trademark Office, 2007-10-09)
    The present invention relates to infectious DNA clones, infectious chimeric DNA clones of porcine circovirus (PCV), vaccines and means of protecting pigs against viral infection or postweaning multisystemic wasting syndrome (PMWS) caused by PCV2. The new chimeric infectious DNA clone and its derived, avirulent chimeric virus are constructed from the nonpathogenic PCV1 in which the immunogenic ORF gene of the pathogenic PCV2 replaces a gene of the nonpathogenic PCV1, preferably in the same position. The chimeric virus advantageously retains the nonpathogenic phenotype of PCV1 but elicits specific immune responses against the pathogenic PCV2. The invention further embraces the immunogenic polypeptide expression products. In addition, the invention encompasses two mutations in the PCV2 immunogenic capsid gene and protein, and the introduction of the ORF2 mutations in the chimeric clones.
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    Chimeric infectious DNA clones, chimeric porcine circoviruses and uses thereof
    (United States Patent and Trademark Office, 2018-02-13)
    The present invention relates to infectious DNA clones, infectious chimeric DNA clones of porcine circovirus (PCV), vaccines and means of protecting pigs against viral infection or postweaning multisystemic wasting syndrome (PMWS) caused by PCV2. The new chimeric infectious DNA clone and its derived, avirulent chimeric virus are constructed from the nonpathogenic PCV1 in which the immunogenic ORF gene of the pathogenic PCV2 replaces a gene of the nonpathogenic PCV1, preferably in the same position. The chimeric virus advantageously retains the nonpathogenic phenotype of PCV1 but elicits specific immune responses against the pathogenic PCV2. The invention further embraces the immunogenic polypeptide expression products. In addition, the invention encompasses two mutations in the PCV2 immunogenic capsid gene and protein, and the introduction of the ORF2 mutations in the chimeric clones.
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    Chimeric infectious DNA clones, chimeric porcine circoviruses and uses thereof
    (United States Patent and Trademark Office, 2007-10-02)
    The present invention relates to infectious DNA clones, infectious chimeric DNA clones of porcine circovirus (PCV), vaccines and means of protecting pigs against viral infection or postweaning multisystemic wasting syndrome (PMWS) caused by PCV2. The new chimeric infectious DNA clone and its derived, avirulent chimeric virus are constructed from the nonpathogenic PCV1 in which the immunogenic ORF gene of the pathogenic PCV2 replaces a gene of the nonpathogenic PCV1, preferably in the same position. The chimeric virus advantageously retains the nonpathogenic phenotype of PCV1 but elicits specific immune responses against the pathogenic PCV2. The invention further embraces the immunogenic polypeptide expression products.
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    Chimeric infectious DNA clones, chimeric porcine circoviruses and uses thereof
    (United States Patent and Trademark Office, 2015-12-15)
    The present invention relates to infectious DNA clones, infectious chimeric DNA clones of porcine circovirus (PCV), vaccines and means of protecting pigs against viral infection or postweaning multisystemic wasting syndrome (PMWS) caused by PCV2. The new chimeric infectious DNA clone and its derived, avirulent chimeric virus are constructed from the nonpathogenic PCV1 in which the immunogenic ORF gene of the pathogenic PCV2 replaces a gene of the nonpathogenic PCV1, preferably in the same position. The chimeric virus advantageously retains the nonpathogenic phenotype of PCV1 but elicits specific immune responses against the pathogenic PCV2. The invention further embraces the immunogenic polypeptide expression products. In addition, the invention encompasses two mutations in the PCV2 immunogenic capsid gene and protein, and the introduction of the ORF2 mutations in the chimeric clones.
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    Chimeric infectious DNA clones, chimeric porcine circoviruses and uses thereof
    (United States Patent and Trademark Office, 2009-08-18)
    The present invention relates to infectious DNA clones, infectious chimeric DNA clones of porcine circovirus (PCV), vaccines and means of protecting pigs against viral infection or postweaning multisystemic wasting syndrome (PMWS) caused by PCV2. The new chimeric infectious DNA clone and its derived, avirulent chimeric virus are constructed from the nonpathogenic PCV1 in which the immunogenic ORF gene of the pathogenic PCV2 replaces a gene of the nonpathogenic PCV1, preferably in the same position. The chimeric virus advantageously retains the nonpathogenic phenotype of PCV1 but elicits specific immune responses against the pathogenic PCV2. The invention further embraces the immunogenic polypeptide expression products. In addition, the invention encompasses two mutations in the PCV2 immunogenic capsid gene and protein, and the introduction of the ORF2 mutations in the chimeric clones.
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    Chimeric infectious DNA clones, chimeric porcine circoviruses and uses thereof
    (United States Patent and Trademark Office, 2011-11-15)
    The present invention relates to infectious DNA clones, infectious chimeric DNA clones of porcine circovirus (PCV), vaccines and means of protecting pigs against viral infection or postweaning multisystemic wasting syndrome (PMWS) caused by PCV2. The new chimeric infectious DNA clone and its derived, avirulent chimeric virus are constructed from the nonpathogenic PCV1 in which the immunogenic ORF gene of the pathogenic PCV2 replaces a gene of the nonpathogenic PCV1, preferably in the same position. The chimeric virus advantageously retains the nonpathogenic phenotype of PCV1 but elicits specific immune responses against the pathogenic PCV2. The invention further embraces the immunogenic polypeptide expression products. In addition, the invention encompasses two mutations in the PCV2 immunogenic capsid gene and protein, and the introduction of the ORF2 mutations in the chimeric clones.
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    Chimeric infectious DNA clones, chimeric porcine circoviruses and uses thereof
    (United States Patent and Trademark Office, 2019-12-17)
    The present invention relates to infectious DNA clones, infectious chimeric DNA clones of porcine circovirus (PCV), vaccines and means of protecting pigs against viral infection or postweaning multisystemic wasting syndrome (PMWS) caused by PCV2. The new chimeric infectious DNA clone and its derived, avirulent chimeric virus are constructed from the nonpathogenic PCV1 in which the immunogenic ORF gene of the pathogenic PCV2 replaces a gene of the nonpathogenic PCV1, preferably in the same position. The chimeric virus advantageously retains the nonpathogenic phenotype of PCV1 but elicits specific immune responses against the pathogenic PCV2. The invention further embraces the immunogenic polypeptide expression products. In addition, the invention encompasses two mutations in the PCV2 immunogenic capsid gene and protein, and the introduction of the ORF2 mutations in the chimeric clones.
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    A commercial porcine circovirus (PCV) type 2a-based vaccine reduces PCV2d viremia and shedding and prevents PCV2d transmission to naive pigs under experimental conditions
    Opriessnig, Tanja; Xiao, Chao-Ting; Halbur, Patrick G.; Gerber, Priscilla F.; Matzinger, Shannon R.; Meng, Xiang-Jin (2017-01-05)
    Porcine circovirus type 2 (PCV2) vaccination has been effective in protecting pigs from clinical disease and today is used extensively. Recent studies in vaccinated populations indicate a major PCV2 genotype shift from the predominant PCV2 genotype 2b towards 2d. The aims of this study were to determine the ability of the commercial inactivated PCV2a vaccine Circovac (R) to protect pigs against experimental challenge with a 2013 PCV2d strain and prevent transmission. Thirty-eight pigs were randomly divided into four groups with 9-10 pigs per group: NEG (sham-vaccinated, sham-challenged), VAC (PCV2a-vaccinated, sham-challenged), VAC + CHAL (PCV2a-vaccinated and PCV2d-challenged), and CHAL (sham-vaccinated, PCV2d-challenged). Vaccination was done at 3 weeks of age using Circovac (R) according to label instructions. The CHAL and VAC + CHAL groups were challenged with PCV2d at 7 weeks of age and all pigs were necropsied 21 days post-challenge (dpc). The VAC-CHAL pigs seroconverted to PCV2 by 21 days post vaccination (dpv). At PCV2d challenge on 28 dpv, 3/9 VAC and 1/9 VAC + CHAL pigs were seropositive. NEG pigs remained seronegative for the duration of the study. Vaccination significantly reduced PCV2d viremia (VAC + CHAL) at dpc 14 and 21, PCV2d fecal shedding at dpc 14 and 21 and PCV2d nasal shedding at dpc 7, 14 and 21 compared to CHAL pigs. Vaccination significantly reduced mean PCV2 antigen load in lymph nodes in VAC + CHAL pigs compared to CHAL pigs. When pooled serum or feces collected from VAC + CHAL and CHAL pigs at dpc 21 were used to expose single-housed PCV2 naive pigs, a pooled fecal sample from CHAL pigs contained infectious PCV2 whereas this was not the case for VAC + CHAL pigs suggesting reduction of PCV2d transmission by vaccination. Under the study conditions, the PCV2a-based vaccine was effective in reducing PCV2d viremia, tissue loads, shedding and transmission indicating that PCV2a vaccination should be effective in PCV2d-infected herds. (C) 2016 The Author(s). Published by Elsevier Ltd.
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    Comparison of Commercial Real-Time Reverse Transcription-PCR Assays for Reliable, Early, and Rapid Detection of Heterologous Strains of Porcine Reproductive and Respiratory Syndrome Virus in Experimentally Infected or Noninfected Boars by Use of Different Sample Types
    Gerber, Priscilla F.; O'Neill, Kevin; Owolodun, Olajide; Wang, Chong; Harmon, Karen; Zhang, Jianqiang; Halbur, Patrick G.; Zhou, Lei; Meng, Xiang-Jin; Opriessnig, Tanja (American Society for Microbiology, 2012-12-05)
    The aims of this study were to compare three commercial porcine reproductive and respiratory syndrome virus (PRRSV) real-time reverse transcription-PCR (RT-PCR) assays for detection of genetically diverse PRRSV isolates in serum, semen, blood swabs, and oral fluids collected from experimentally infected boars and to evaluate the effects of sample pooling. Six groups of three boars negative for PRRSV were each inoculated with one of six PRRSV isolates (sharing 55 to 99% nucleotide sequence identity in ORF5). Samples were collected on days -2, 1, 3, 5, 7, 14, and 21 postinoculation (p.i.) and tested by one of three commercially available real-time RT-PCR assays(VetMax from Applied Biosystems, Foster City, CA [ abbreviated AB]; VetAlert from Tetracore, Rockville, MD[TC]; and AcuPig from AnDiaTec GmbH, Kornwestheim, Germany [ AD]). At day 1 p.i., all assays detected at least one positive sample in each group. The highest detection rates were on days 3 and 5 p.i. Between days 1 and 7 p.i., serum samples had the highest detection rate (90%) with 100% agreement between tests, followed by blood swabs (kappa value of 0.97) and semen (kappa value of 0.80). Oral fluids had the lowest detection rates (AB, 55%; TC, 41%; AD, 46%) and the highest disagreement between kits (kappa value of 0.63). Pools of five samples did not reduce the detection rates if there was one positive sample with a large amount (cycle threshold,< 30) of viral RNA in the pool. Serum and blood swab samples had shorter turnaround times for RNA extraction. The AB assay had a 1.6-times-shorter PCR time. In summary, serum and blood swabs had the best performance with highest detection rates and agreement between assays and the shortest turnaround times.
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    Markedly different immune responses and virus kinetics in littermates infected with porcine circovirus type 2 or porcine parvovirus type 1
    Opriessnig, Tanja; Gerber, Priscilla F.; Matzinger, Shannon R.; Meng, Xiang-Jin; Halbur, Patrick G. (2017-09)
    Porcine parvovirus type 1 (PPV1) and porcine circovirus type 2 (PCV2) are small single-stranded DNA viruses with high prevalence in the global pig population. The aim of this study was to compare and contrast PCV2 and PPV1 infections in high-health status pigs and to describe PCV2 long-term infection dynamics. Six caesarian derived colostrum-deprived pigs were randomly divided into two groups and were experimentally infected with PCV2 or PPV1 at 5 weeks of age. All pigs had detectable viremia by day (D) 3 post-infection. Pigs infected with PPV1 had a detectable INF-alpha response by D3 followed by a high IFN-gamma response by D6. The PPV1 pigs developed antibodies against PPV1 by D6 resulting in decreasing virus titers until PPV1 DNA became undetectable from D28 until D42. In contrast, PCV2-infected pigs had no detectable INF-alpha or IFN-gamma response after PCV2 infection. PCV2-infected pigs had no detectable anti-PCV2 humoral response until D49 and had a sustained high level of PCV2 DNA for the duration of the study. While PPV1-infected pigs were clinically normal, PCV2-infected pigs developed severe clinical illness including fatal systemic porcine circovirus associated disease (PCVAD) by D28, fatal enteric PCVAD by D56 and chronic PCVAD manifested as decreased weight gain and periods of diarrhea. Microscopically, all three PCV2-infected pigs had lymphoid lesions consistent with PCVAD and associated with low (chronic disease) to high (acute disease) levels of PCV2 antigen. Under the study conditions, there was a lack of early IFN-gamma and INF-alpha activation followed by a delayed and low humoral immune response and persisting viremia with PCV2 infection. In contrast, PPV1-infected pigs had IFN-gamma and INF-alpha activation and an effective immune response to the PPV1 infection.