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1.  Repurposing of Clinically Developed Drugs for Treatment of Middle East Respiratory Syndrome Coronavirus Infection 
Outbreaks of emerging infections present health professionals with the unique challenge of trying to select appropriate pharmacologic treatments in the clinic with little time available for drug testing and development. Typically, clinicians are left with general supportive care and often untested convalescent-phase plasma as available treatment options. Repurposing of approved pharmaceutical drugs for new indications presents an attractive alternative to clinicians, researchers, public health agencies, drug developers, and funding agencies. Given the development times and manufacturing requirements for new products, repurposing of existing drugs is likely the only solution for outbreaks due to emerging viruses. In the studies described here, a library of 290 compounds was screened for antiviral activity against Middle East respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus (SARS-CoV). Selection of compounds for inclusion in the library was dependent on current or previous FDA approval or advanced clinical development. Some drugs that had a well-defined cellular pathway as target were included. In total, 27 compounds with activity against both MERS-CoV and SARS-CoV were identified. The compounds belong to 13 different classes of pharmaceuticals, including inhibitors of estrogen receptors used for cancer treatment and inhibitors of dopamine receptor used as antipsychotics. The drugs identified in these screens provide new targets for in vivo studies as well as incorporation into ongoing clinical studies.
PMCID: PMC4136000  PMID: 24841273
2.  Second Generation Inactivated Eastern Equine Encephalitis Virus Vaccine Candidates Protect Mice against a Lethal Aerosol Challenge 
PLoS ONE  2014;9(8):e104708.
Currently, there are no FDA-licensed vaccines or therapeutics for eastern equine encephalitis virus (EEEV) for human use. We recently developed several methods to inactivate CVEV1219, a chimeric live-attenuated eastern equine encephalitis virus (EEEV). Dosage and schedule studies were conducted to evaluate the immunogenicity and protective efficacy of three potential second-generation inactivated EEEV (iEEEV) vaccine candidates in mice: formalin-inactivated CVEV1219 (fCVEV1219), INA-inactivated CVEV1219 (iCVEV1219) and gamma-irradiated CVEV1219 (gCVEV1219). Both fCVEV1219 and gCVEV1219 provided partial to complete protection against an aerosol challenge when administered by different routes and schedules at various doses, while iCVEV1219 was unable to provide substantial protection against an aerosol challenge by any route, dose, or schedule tested. When evaluating antibody responses, neutralizing antibody, not virus specific IgG or IgA, was the best correlate of protection. The results of these studies suggest that both fCVEV1219 and gCVEV1219 should be evaluated further and considered for advancement as potential second-generation inactivated vaccine candidates for EEEV.
PMCID: PMC4130539  PMID: 25116127
3.  Preserving Immunogenicity of Lethally Irradiated Viral and Bacterial Vaccine Epitopes Using a Radio-Protective Mn2+-Peptide Complex from Deinococcus 
Cell host & microbe  2012;12(1):117-124.
Sterilization of pathogens with γ-radiation is an attractive approach for development of inactivated whole-organism vaccines. However, the radiation doses required to ensure sterility also destroy immunogenic epitopes needed to mount a protective immune response. We report that genome damage and killing can be uncoupled from epitope damage using a reconstituted manganous peptide complex of Deinococcus radiodurans, a radiation-resistant bacterium. The Mn2+ complex preserved antigenic structures in aqueous preparations of bacteriophage lambda, Venezuelan equine encephalitis virus (VEEV), and Staphylococcus aureus during supralethal irradiation (25-40 kGy). An irradiated vaccine elicited both antibody and CD4 T cell IL-17 (Th17) responses, and induced B cell- and T cell-dependent protection against methicillin-resistant S. aureus (MRSA) in mice. We demonstrate that structural integrity of viruses and bacteria can be preserved at radiation doses far above those which abolish infectivity. This approach could expedite vaccine production for emerging and established pathogens for which no protective vaccines exist.
PMCID: PMC4073300  PMID: 22817993
4.  Antibody to the E3 Glycoprotein Protects Mice against Lethal Venezuelan Equine Encephalitis Virus Infection▿  
Journal of Virology  2010;84(24):12683-12690.
Six monoclonal antibodies were isolated that exhibited specificity for a furin cleavage site deletion mutant (V3526) of Venezuelan equine encephalitis virus (VEEV). These antibodies comprise a single competition group and bound the E3 glycoprotein of VEEV subtype I viruses but failed to bind the E3 glycoprotein of other alphaviruses. These antibodies neutralized V3526 virus infectivity but did not neutralize the parental strain of Trinidad donkey (TrD) VEEV. However, the E3-specific antibodies did inhibit the production of virus from VEEV TrD-infected cells. In addition, passive immunization of mice demonstrated that antibody to the E3 glycoprotein provided protection against lethal VEEV TrD challenge. This is the first recognition of a protective epitope in the E3 glycoprotein. Furthermore, these results indicate that E3 plays a critical role late in the morphogenesis of progeny virus after E3 appears on the surfaces of infected cells.
PMCID: PMC3004303  PMID: 20926570
7.  Eastern and Venezuelan Equine Encephalitis Viruses Differ in Their Ability To Infect Dendritic Cells and Macrophages: Impact of Altered Cell Tropism on Pathogenesis▿  
Journal of Virology  2008;82(21):10634-10646.
Eastern and Venezuelan equine encephalitis viruses (EEEV and VEEV, respectively) cause severe morbidity and mortality in equines and humans. Like other mosquito-borne viruses, VEEV infects dendritic cells (DCs) and macrophages in lymphoid tissues, fueling a serum viremia and facilitating neuroinvasion. In contrast, EEEV replicates poorly in lymphoid tissues, preferentially infecting osteoblasts. Here, we demonstrate that infectivity of EEEV for myeloid lineage cells including DCs and macrophages was dramatically reduced compared to that of VEEV, whereas both viruses replicated efficiently in mesenchymal lineage cells such as osteoblasts and fibroblasts. We determined that EEEV infection of myeloid lineage cells was restricted after attachment, entry, and uncoating of the genome. Using replicon particles and translation reporter RNAs, we found that translation of incoming EEEV genomes was almost completely inhibited in myeloid, but not mesenchymal, lineage cells. Alpha/beta interferon (IFN-α/β) responses did not mediate the restriction, as infectivity was not restored in the absence of double-stranded RNA-dependent protein kinase, RNase L, or IFN-α/β receptor-mediated signaling. We confirmed these observations in vivo, demonstrating that EEEV is compromised in its ability to replicate within lymphoid tissues, whereas VEEV does so efficiently. The altered tropism of EEEV correlated with an almost complete avoidance of serum IFN-α/β induction in vivo, which may allow EEEV to evade the host's innate immune responses and thereby enhance neurovirulence. Taken together, our data indicate that inhibition of genome translation restricts EEEV infectivity for myeloid but not mesenchymal lineage cells in vitro and in vivo. In this regard, the tropisms of EEEV and VEEV differ dramatically, likely contributing to observed differences in disease etiology.
PMCID: PMC2573165  PMID: 18768986
8.  Chikungunya Virus Strains, Reunion Island Outbreak 
Emerging Infectious Diseases  2006;12(10):1604-1605.
PMCID: PMC3290959  PMID: 17176585
Chikungunya Virus; Alphavirus; La Reunion; Indian Ocean; Arbovirus; letter
9.  Two Nonoverlapping Domains on the Norwalk Virus Open Reading Frame 3 (ORF3) Protein Are Involved in the Formation of the Phosphorylated 35K Protein and in ORF3-Capsid Protein Interactions 
Journal of Virology  2003;77(6):3569-3577.
Expression of the Norwalk virus open reading frame 3 (ORF3) in Spodoptera frugiperda (Sf9) cells yields two major forms, the predicted 23,000-molecular-weight (23K) form and a larger 35K form. The 23K form is able to interact with the ORF2 capsid protein and be incorporated into virus-like particles. In this paper, we provide mass spectrometry evidence that both the 23K and 35K forms are composed only of the ORF3 protein. Two-dimensional gel electrophoresis and phosphatase treatment showed that the 35K form results solely from phosphorylation and that the 35K band is composed of several different phosphorylated forms with distinct isoelectric points. Furthermore, we analyzed deletion and point mutants of the ORF3 protein. Mutants that lacked the C-terminal 33 amino acids (ORF31-179, ORF31-152, and ORF31-107) no longer produced the 35K form. An N-terminal truncation mutant (ORF351-212) and a site-directed mutant (ORF3T201V) were capable of producing the larger form, which was converted to the smaller form by treatment with protein phosphatase. These data suggest that the region between amino acids 180 and 212 is phosphorylated, and mass spectrometry showed that amino acids Arg196 to Arg211 are not phosphorylated; thus, phosphorylation of the serine-threonine-rich region from Thr181 to Ser193 must be involved in the generation of the 35K form. Studies of the interaction between the ORF2 protein and full-length and mutated ORF3 proteins showed that the full-length ORF3 protein (ORF3FL), ORF31-179, ORF31-152, and ORF351-212 interacted with the ORF2 protein, while an ORF31-107 protein did not. These results indicate that the region of the ORF3 protein between amino acids 108 and 152 is responsible for interaction with the ORF2 protein.
PMCID: PMC149496  PMID: 12610132
10.  Norwalk Virus Open Reading Frame 3 Encodes a Minor Structural Protein 
Journal of Virology  2000;74(14):6581-6591.
Norwalk virus (NV) is a causative agent of acute epidemic nonbacterial gastroenteritis in humans. The inability to cultivate NV has required the use of molecular techniques to examine the genome organization and functions of the viral proteins. The function of the NV protein encoded by open reading frame 3 (ORF 3) has been unknown. In this paper, we report the characterization of the NV ORF 3 protein expressed in a cell-free translation system and in insect cells and show its association with recombinant virus-like particles (VLPs) and NV virions. Expression of the ORF 3 coding region in rabbit reticulocyte lysates resulted in the production of a single protein with an apparent molecular weight of 23,000 (23K protein), which is not modified by N-linked glycosylation. The ORF 3 protein was expressed in insect cells by using two different baculovirus recombinants; one recombinant contained the entire 3′ end of the genome beginning with the ORF 2 coding sequences (ORFs 2+3), and the second recombinant contained ORF 3 alone. Expression from the construct containing both ORF 2 and ORF 3 resulted in the expression of a single protein (23K protein) detected by Western blot analysis with ORF 3-specific peptide antisera. However, expression from a construct containing only the ORF 3 coding sequences resulted in the production of multiple forms of the ORF 3 protein ranging in size from 23,000 to 35,000. Indirect-immunofluorescence studies using an ORF 3 peptide antiserum showed that the ORF 3 protein is localized to the cytoplasm of infected insect cells. The 23K ORF 3 protein was consistently associated with recombinant VLPs purified from the media of insect cells infected with a baculovirus recombinant containing the entire 3′ end of the NV genome. Western blot analysis of NV purified from the stools of NV-infected volunteers revealed the presence of a 35K protein as well as multiple higher-molecular-weight bands specifically recognized by an ORF 3 peptide antiserum. These results indicate that the ORF 3 protein is a minor structural protein of the virion.
PMCID: PMC112168  PMID: 10864672

Results 1-10 (10)