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Damon Deming

Publications and source records attributed to Damon Deming.

5 recordsLinked to original sources
PubMed2007

A mouse-adapted SARS-coronavirus causes disease and mortality in BALB/c mice.

No single animal model for severe acute respiratory syndrome (SARS) reproduces all aspects of the human disease. Young inbred mice support SARS-coronavirus (SARS-CoV) replication in the respiratory tract and are available in sufficient numbers for statistical evaluation. They are relatively inexpensive and easily accessible, but their use in SARS research is limited because they do not develop illness following infection. Older (12- to 14-mo-old) BALB/c mice develop clinical illness and pneumonitis, but they can be hard to procure, and immune senescence complicates pathogenesis studies. We adapted the SARS-CoV (Urbani strain) by serial passage in the respiratory tract of young BALB/c mice. Fifteen passages resulted in a virus (MA15) that is lethal for mice following intranasal inoculation. Lethality is preceded by rapid and high titer viral replication in lungs, viremia, and dissemination of virus to extrapulmonary sites accompanied by lymphopenia, neutrophilia, and pathological changes in the lungs. Abundant viral antigen is extensively distributed in bronchial epithelial cells and alveolar pneumocytes, and necrotic cellular debris is present in airways and alveoli, with only mild and focal pneumonitis. These observations suggest that mice infected with MA15 die from an overwhelming viral infection with extensive, virally mediated destruction of pneumocytes and ciliated epithelial cells. The MA15 virus has six coding mutations associated with adaptation and increased virulence; when introduced into a recombinant SARS-CoV, these mutations result in a highly virulent and lethal virus (rMA15), duplicating the phenotype of the biologically derived MA15 virus. Intranasal inoculation with MA15 reproduces many aspects of disease seen in severe human cases of SARS. The availability of the MA15 virus will enhance the use of the mouse model for SARS because infection with MA15 causes morbidity, mortality, and pulmonary pathology. This virus will be of value as a stringent challenge in evaluation of the efficacy of vaccines and antivirals.

Animals↗
PubMed2006

Vaccine efficacy in senescent mice challenged with recombinant SARS-CoV bearing epidemic and zoonotic spike variants.

BACKGROUND: In 2003, severe acute respiratory syndrome coronavirus (SARS-CoV) was identified as the etiological agent of severe acute respiratory syndrome, a disease characterized by severe pneumonia that sometimes results in death. SARS-CoV is a zoonotic virus that crossed the species barrier, most likely originating from bats or from other species including civets, raccoon dogs, domestic cats, swine, and rodents. A SARS-CoV vaccine should confer long-term protection, especially in vulnerable senescent populations, against both the 2003 epidemic strains and zoonotic strains that may yet emerge from animal reservoirs. We report the comprehensive investigation of SARS vaccine efficacy in young and senescent mice following homologous and heterologous challenge. METHODS AND FINDINGS: Using Venezuelan equine encephalitis virus replicon particles (VRP) expressing the 2003 epidemic Urbani SARS-CoV strain spike (S) glycoprotein (VRP-S) or the nucleocapsid (N) protein from the same strain (VRP-N), we demonstrate that VRP-S, but not VRP-N vaccines provide complete short- and long-term protection against homologous strain challenge in young and senescent mice. To test VRP vaccine efficacy against a heterologous SARS-CoV, we used phylogenetic analyses, synthetic biology, and reverse genetics to construct a chimeric virus (icGDO3-S) encoding a synthetic S glycoprotein gene of the most genetically divergent human strain, GDO3, which clusters among the zoonotic SARS-CoV. icGD03-S replicated efficiently in human airway epithelial cells and in the lungs of young and senescent mice, and was highly resistant to neutralization with antisera directed against the Urbani strain. Although VRP-S vaccines provided complete short-term protection against heterologous icGD03-S challenge in young mice, only limited protection was seen in vaccinated senescent animals. VRP-N vaccines not only failed to protect from homologous or heterologous challenge, but resulted in enhanced immunopathology with eosinophilic infiltrates within the lungs of SARS-CoV-challenged mice. VRP-N-induced pathology presented at day 4, peaked around day 7, and persisted through day 14, and was likely mediated by cellular immune responses. CONCLUSIONS: This study identifies gaps and challenges in vaccine design for controlling future SARS-CoV zoonosis, especially in vulnerable elderly populations. The availability of a SARS-CoV virus bearing heterologous S glycoproteins provides a robust challenge inoculum for evaluating vaccine efficacy against zoonotic strains, the most likely source of future outbreaks.

Aging↗
PubMed2005

Severe acute respiratory syndrome coronavirus group-specific open reading frames encode nonessential functions for replication in cell cultures and mice.

SARS coronavirus (SARS-CoV) encodes several unique group-specific open reading frames (ORFs) relative to other known coronaviruses. To determine the significance of the SARS-CoV group-specific ORFs in virus replication in vitro and in mice, we systematically deleted five of the eight group-specific ORFs, ORF3a, OF3b, ORF6, ORF7a, and ORF7b, and characterized recombinant virus replication and gene expression in vitro. Deletion of the group-specific ORFs of SARS-CoV, either alone or in various combinations, did not dramatically influence replication efficiency in cell culture or in the levels of viral RNA synthesis. The greatest reduction in virus growth was noted following ORF3a deletion. SARS-CoV spike (S) glycoprotein does not encode a rough endoplasmic reticulum (rER)/Golgi retention signal, and it has been suggested that ORF3a interacts with and targets S glycoprotein retention in the rER/Golgi apparatus. Deletion of ORF3a did not alter subcellular localization of the S glycoprotein from distinct punctuate localization in the rER/Golgi apparatus. These data suggest that ORF3a plays little role in the targeting of S localization in the rER/Golgi apparatus. In addition, insertion of the 29-bp deletion fusing ORF8a/b into the single ORF8, noted in early-stage SARS-CoV human and civet cat isolates, had little if any impact on in vitro growth or RNA synthesis. All recombinant viruses replicated to wild-type levels in the murine model, suggesting that either the group-specific ORFs play little role in in vivo replication efficiency or that the mouse model is not of sufficient quality for discerning the role of the group-specific ORFs in disease origin and development.

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