David H O'Connor

University of Wisconsin–Madison, Madison, Wisconsin, United States

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Publications (135)779.38 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: In 49 patients with known Ebolavirus (EBOV) outcomes during the ongoing outbreak in Sierra Leone, 13 were co-infected with the immunomodulatory pegivirus GB virus C (GBV-C). 53% of these GBV-C+ patients survived; in contrast, only 22% of GBV-C(-) patients survived. Both survival and GBV-C status were associated with age, with older patients having lower survival rates and intermediate-age patients (21-45 years) having the highest rate of GBV-C infection. Understanding the separate and combined effects of GBV-C and age on EBOV survival could lead to new treatment and prevention strategies, perhaps through age-related pathways of immune activation. Copyright © 2014, American Society for Microbiology. All Rights Reserved.
    Journal of Virology 12/2014; 89(4). DOI:10.1128/JVI.02752-14 · 4.65 Impact Factor
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    ABSTRACT: A small percentage of human immunodeficiency virus (HIV)-infected people and simian immunodeficiency virus (SIV)-infected macaques control virus replication without antiretroviral treatment. The major determinant of this control is host expression of certain major histocompatibility complex alleles. However, this association is incompletely penetrant, suggesting that additional loci modify the major histocompatibility complex's protective effect. Here, to identify candidate control-modifying loci, we sequence the genomes of 12 SIV-infected Mauritian cynomolgus macaques that experienced divergent viral load set points despite sharing the protective M1 major histocompatibility complex haplotype. Our genome-wide analysis of haplotype-level variation identifies seven candidate control-modifying loci on chromosomes 2, 3, 7, 8, 9, 10, and 14. The highest variant density marks the candidate on chromosome 7, which is the only control-modifying locus to comprise genes with known immunological function. Upon closer inspection, we found an allele for one of these genes, granzyme B, to be enriched in M1(+) controllers. Given its established role as a cytotoxic effector molecule that participates in CD8-mediated killing of virus-infected cells, we test the role of variation within gzmb in modifying SIV control by prospectively challenging M1(+) granzyme B-defined macaques. Our study establishes a framework for using whole genome sequencing to identify haplotypes that may contribute to complex clinical phenotypes. Further investigation into the immunogenetics underlying spontaneous HIV control may contribute to the rational design of a vaccine that prevents acquired immune deficiency syndrome.
    Genome Biology 11/2014; 15(11):478. DOI:10.1186/s13059-014-0478-z · 10.47 Impact Factor
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    ABSTRACT: Simian hemorrhagic fever virus (SHFV) causes a severe and almost uniformly fatal viral hemorrhagic fever in Asian macaques, but is thought to be nonpathogenic for humans. To date, the SHFV lifecycle is almost completely uncharacterized on the molecular level. Here we describe the first steps of the SHFV lifecycle. Our experiments indicate that SHFV enters target cells by low pH-dependent endocytosis. Dynamin inhibitors, chlorpromazine, methyl-β-cyclodextrin, chloroquine, and concanamycin A dramatically reduced SHFV entry efficiency, whereas the macropinocytosis inhibitors EIPA, blebbistatin, and wortmannin, and the caveolin-mediated endocytosis inhibitors nystatin and filipin III had no effect. Furthermore, overexpression and knock-out study and electron-microscopy results indicate that SHFV entry occurs by a dynamin-dependent clathrin-mediated endocytosis-like pathway. Experiments utilizing latrunculin B, cytochalasin B, and cytochalasin D indicate that SHFV does not hijack the actin polymerization pathway. Treatment of target cells with proteases (proteinase K, papain, α-chymotrypsin, trypsin) abrogated entry, indicating that the SHFV cell-surface receptor is a protein. Phospholipases A2 and D had no effect on SHFV entry. Finally, treatment of cells with antibodies targeting CD163, a cell surface molecule identified as an entry factor for the SHFV-related porcine reproductive and respiratory syndrome virus, diminished SHFV replication, identifying CD163 as an important SHFV entry component.
    Journal of Virology 10/2014; 89(1). DOI:10.1128/JVI.02697-14 · 4.65 Impact Factor
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    ABSTRACT: The influence of MHC-I alleles on HIV diversity has been well characterised in humans at the population level. MHC-I alleles likely affect viral diversity in the SIV-infected pig-tailed macaque (M. nemestrina) model, but this is poorly characterised. We studied the evolution of SIV in pig-tailed macaques with a range of MHC-I haplotypes. SIVmac251 genomes were amplified from the plasma of 44 pig-tailed macaques infected with SIVmac251 at 4-10 months after infection and characterized by Illumina deep sequencing. MHC-I typing was performed on cellular RNA using Roche/454 pyrosequencing. MHC-I haplotypes and viral sequence polymorphisms were linked using in-house bioinformatics pipelines, both at individual mutations and groups of mutations spanning 10 amino acid segments, since CTL escape can occur at different amino acids within the same epitope in different animals. The approach successfully identified 6 known CTL escape mutations within 3 Mane-A1*084-restricted epitopes. The approach also identified over 70 new SIV polymorphisms linked to a variety of MHC-I haplotypes. Using functional CD8 T cell assays we confirmed that one of these associations, a Mane-B028 haplotype-linked mutation in Nef, corresponded to a CTL epitope. We also identified mutations associated with the Mane-B017 haplotype that were previously described as CTL epitopes restricted by Mamu-B*017:01 in rhesus macaques. This detailed study of pig-tailed macaque MHC-I genetics and SIV polymorphisms will enable a refined level of analysis for future vaccine design and treatment strategies for HIV.
    Journal of Virology 10/2014; DOI:10.1128/JVI.02428-14 · 4.65 Impact Factor
  • AIDS Research and Human Retroviruses 10/2014; 30 Suppl 1:A41. DOI:10.1089/aid.2014.5067.abstract · 2.46 Impact Factor
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    ABSTRACT: Since the 1960s, simian hemorrhagic fever virus (SHFV; Nidovirales; Arteriviridae) has caused highly fatal outbreaks of viral hemorrhagic fever in captive Asian macaque colonies. However, the source(s) of these outbreaks and the natural reservoir(s) of this virus remain obscure. Here we report the identification of two novel, highly divergent simian arteriviruses related to SHFV - Mikumi yellow baboon virus 1 (MYBV-1) and Southwest baboon virus 1 (SWBV-1) - in wild and captive baboons, respectively, and demonstrate recent transmission of SWBV-1 among captive baboons. These findings extend our knowledge of the genetic and geographic diversity of the simian arteriviruses, identify baboons as a natural host of these viruses, and provide further evidence that baboons may have played a role in previous outbreaks of simian hemorrhagic fever in macaques, as has long been suspected. This knowledge should aid in the prevention of disease outbreaks in captive macaques and supports the growing body of evidence that suggests simian arterivirus infections are common in Old World monkeys of many different species throughout Africa.
    Journal of Virology 09/2014; 88(22). DOI:10.1128/JVI.02203-14 · 4.65 Impact Factor
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    ABSTRACT: Pig-tailed macaques (Macaca nemestrina) serve as important models for human infectious disease research. Major histocompatibility complex (MHC) class II molecules are important to this research since they present peptides to CD4+ T cells. Despite the importance of characterizing the MHC-II alleles expressed in model species like pig-tailed macaques, to date, less than 150 MHC-II alleles have been named for the six most common classical class II loci (DRA, DRB, DQA, DQB, DPA, and DPB) in this population. Additionally, only a small percentage of these alleles are full-length, making it impossible to use the known sequence for reagent development. To address this, we developed a fast, high-throughput method to discover full-length MHC-II alleles and used it to characterize alleles in 32 pig-tailed macaques. By this method, we identified 128 total alleles across all six loci. We also performed an exon 2-based genotyping assay to validate the full-length sequencing results; this genotyping assay could be optimized for use in determining MHC-II allele frequencies in large cohorts of pig-tailed macaques.
    Immunogenetics 08/2014; 66(11). DOI:10.1007/s00251-014-0797-y · 2.49 Impact Factor
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    ABSTRACT: Within the Flaviviridae, the recently designated genus Pegivirus has expanded greatly due to new discoveries in bats, horses, and rodents. Here we report the discovery and characterization of three simian pegiviruses (SPgV) that resemble human pegivirus (HPgV) and infect red colobus monkeys (Procolobus tephrosceles), red-tailed guenons (Cercopithecus ascanius) and an olive baboon (Papio anubis). We have designated these viruses SPgVkrc, SPgVkrtg and SPgVkbab, reflecting their host species' common names, which include reference to their location of origin in Kibale National Park, Uganda. SPgVkrc and SPgVkrtg were detected in 47% (28/60) of red colobus and 42% (5/12) red-tailed guenons, respectively, while SPgVkbab infection was observed in 1 of 23 olive baboons tested. Infections were not associated with any apparent disease, despite the generally high viral loads observed for each variant. These viruses were monophyletic and equally divergent from HPgV and pegiviruses previously identified in chimpanzees (SPgVcpz). Overall, the high degree of conservation of genetic features among the novel SPgVs, HPgV and SPgVcpz suggests conservation of function among these closely related viruses. Our study describes the first primate pegiviruses detected in Old World monkeys, expanding the known genetic diversity and host range of pegiviruses and providing insight into the natural history of this genus.
    PLoS ONE 06/2014; 9(6):e98569. DOI:10.1371/journal.pone.0098569 · 3.53 Impact Factor
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    ABSTRACT: Key biological properties such as high genetic diversity and high evolutionary rate enhance the potential of certain RNA viruses to adapt and emerge. Identifying viruses with these properties in their natural hosts could dramatically improve disease forecasting and surveillance. Recently, we discovered two novel members of the viral family Arteriviridae: simian hemorrhagic fever virus (SHFV)-krc1 and SHFV-krc2, infecting a single wild red colobus (Procolobus rufomitratus tephrosceles) in Kibale National Park, Uganda. Nearly nothing is known about the biological properties of SHFVs in nature, although the SHFV type strain, SHFV-LVR, has caused devastating outbreaks of viral hemorrhagic fever in captive macaques. Here we detected SHFV-krc1 and SHFV-krc2 in 40% and 47% of 60 wild red colobus tested, respectively. We found viral loads in excess of 106-107 RNA copies per milliliter of blood plasma for each of these viruses. SHFV-krc1 and SHFV-krc2 also showed high genetic diversity at both the inter- and intra-host levels. Analyses of synonymous and non-synonymous nucleotide diversity across viral genomes revealed patterns suggestive of positive selection in SHFV open reading frames (ORF) 5 (SHFV-krc2 only) and 7 (SHFV-krc1 and SHFV-krc2). Thus, these viruses share several important properties with some of the most rapidly evolving, emergent RNA viruses.
    PLoS ONE 03/2014; 9(3):e90714. DOI:10.1371/journal.pone.0090714 · 3.53 Impact Factor
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    ABSTRACT: The identification of MHC class I ligands for rhesus macaque killer cell Ig-like receptors (KIRs) is fundamental to our basic understanding of KIR and MHC class I coevolution and to the study of NK cell responses in this nonhuman primate model for AIDS and other viral diseases. In this study, we show that Mamu-KIR3DL01, which is expressed by ∼90% of rhesus macaques, recognizes MHC class I molecules with a Bw4 motif. Primary NK cells expressing Mamu-KIR3DL01 were identified by staining with a mAb which, in this study, was shown to bind Mamu-KIR3DL01 allotypes with an aspartic acid at position 233. The cytolytic activity of Mamu-KIR3DL01(+) NK cells was suppressed by cell lines expressing the Bw4 molecules Mamu-B*007:01, -B*041:01, -B*058:02, and -B*065:01. The Bw4 motif was necessary for Mamu-KIR3DL01 recognition because substitutions in this region abrogated Mamu-KIR3DL01(+) NK cell inhibition. However, the presence of a Bw4 motif was not sufficient for recognition because another Bw4 molecule, Mamu-B*017:01, failed to suppress the cytolytic activity of these NK cells. Replacement of three residues in Mamu-B*017:01, predicted to be KIR contacts based on the three-dimensional structure of the human KIR3DL1-HLA-Bw4 complex, with the corresponding residues at these positions for the other Mamu-Bw4 ligands restored Mamu-KIR3DL01(+) NK cell inhibition. These results define the ligand specificity of one of the most polymorphic and commonly expressed KIRs in the rhesus macaque and reveal similarities in Bw4 recognition by Mamu-KIR3DL01 and human KIR3DL1, despite the absence of an orthologous relationship between these two KIRs or conservation of surface residues predicted to interact with MHC class I ligands.
    The Journal of Immunology 01/2014; 192(4). DOI:10.4049/jimmunol.1302883 · 5.36 Impact Factor
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    ABSTRACT: Simian hemorrhagic fever virus (SHFV) variant NIH LVR42-0/M6941 is the only remaining SHFV in culture, and only a single genome sequence record exists in GenBank/RefSeq. We compared the genomic sequence of NIH LVR42-0/M6941 acquired from the ATCC in 2011 to NIH LVR42-0/M6941 genomes sequenced directly from nonhuman primates experimentally infected in 1989.
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    ABSTRACT: A captive juvenile Bornean orangutan (Pongo pygmaeus) died from an unknown disseminated parasitic infection. Deep sequencing of DNA from infected tissues, followed by gene-specific PCR and sequencing, revealed a divergent species within the newly proposed genus Versteria (Cestoda: Taeniidae). Versteria may represent a previously unrecognized risk to primate health.
    Emerging Infectious Diseases 01/2014; 20(1):109-13. DOI:10.3201/eid2001.131191 · 7.33 Impact Factor
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    ABSTRACT: Compensatory mutations offset fitness defects resulting from CD8+ T lymphocyte (CD8TL)-mediated escape, but their impact on viral evolution following transmission to naïve hosts remains unclear. Here, we investigated the reversion kinetics of Gag181-189CM9 CD8TL escape-associated compensatory mutations in SIV-infected macaques. Pre-existing compensatory mutations did not result in acute-phase escape and instead required a tertiary mutation for stabilization in the absence of Gag181-189CM9 escape mutations. Therefore, transmitted compensatory mutations do not necessarily predict rapid CD8TL escape.
    Journal of Virology 12/2013; DOI:10.1128/JVI.03304-13 · 4.65 Impact Factor
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    ABSTRACT: Deep sequencing has revolutionized major histocompatibility complex (MHC) class I analysis of nonhuman primates by enabling high-throughput, economical, and comprehensive genotyping. Full-length MHC class I cDNA sequences, which are required to generate reagents such as MHC-peptide tetramers, cannot be directly obtained by short read deep sequencing. We combined data from two next-generation sequencing platforms to discover novel full-length MHC class I mRNA/cDNA transcripts in Chinese rhesus macaques. We first genotyped macaques by Roche/454 pyrosequencing using a 530-bp amplicon spanning the densely polymorphic exons 2 through 4 of the MHC class I loci that encode the peptide-binding region. We then mapped short paired-end 250 bp Illumina sequence reads spanning the full-length transcript to each 530-bp amplicon at high stringency and used paired-end information to reconstruct full-length allele sequences. We characterized 65 full-length sequences from six Chinese rhesus macaques. Overall, approximately 70 % of the alleles distinguished in these six animals contained new sequence information, including 29 novel transcripts. The flexibility of this approach should make full-length MHC class I allele genotyping accessible for any nonhuman primate population of interest. We are currently optimizing this method for full-length characterization of other highly polymorphic, duplicated loci such as the MHC class II DRB and killer immunoglobulin-like receptors. We anticipate that this method will facilitate rapid expansion and near completion of sequence libraries of polymorphic loci, such as MHC class I, within a few years.
    Immunogenetics 11/2013; 66(1). DOI:10.1007/s00251-013-0744-3 · 2.49 Impact Factor
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    ABSTRACT: The emergence of human-transmissible H5N1 avian influenza viruses poses a major pandemic threat. H5N1 viruses are thought to be highly genetically diverse both among and within hosts; however, the effects of this diversity on viral replication and transmission are poorly understood. Here we use deep sequencing to investigate the impact of within-host viral variation on adaptation and transmission of H5N1 viruses in ferrets. We show that, although within-host genetic diversity in haemagglutinin (HA) increases during replication in inoculated ferrets, HA diversity is dramatically reduced upon respiratory droplet transmission, in which infection is established by only 1-2 distinct HA segments from a diverse source virus population in transmitting animals. Moreover, minor HA variants present in as little as 5.9% of viruses within the source animal become dominant in ferrets infected via respiratory droplets. These findings demonstrate that selective pressures acting during influenza virus transmission among mammals impose a significant bottleneck.
    Nature Communications 10/2013; 4:2636. DOI:10.1038/ncomms3636 · 10.74 Impact Factor
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    ABSTRACT: Epstein-Barr virus (EBV) is a vaccine/immunotherapy target due to its association with several human malignancies. EBNA-1 is an EBV protein consistently expressed in all EBV-associated cancers. Herein, EBNA-1-specific T cell epitopes were evaluated after AdC-rhEBNA-1 immunizations in chronically lymphocryptovirus-infected rhesus macaques, an EBV infection model. Pre-existing rhEBNA-1-specific responses were augmented in 4/12 animals and new epitopes were recognized in 5/12 animals after vaccinations. This study demonstrated that EBNA-1-specific T cells can be expanded by vaccination.
    Journal of Virology 10/2013; DOI:10.1128/JVI.01947-13 · 4.65 Impact Factor
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    ABSTRACT: Human pegivirus (HPgV), formerly GB virus C or hepatitis G virus, is a positive-strand flavivirus that has garnered significant attention due to its anti-HIV properties, including slowing disease progression and prolonged survival in HIV infected patients. Currently, there are six proposed HPgV genotypes whose distribution roughly corresponds to geographic origin. Genotypes 2 and 3 are the most comprehensively characterized, whereas those genotypes occurring on the African continent, where HPgV prevalence is highest, are more poorly resolved. Using deep-sequencing methods, we identified four new complete coding sequences in patients in rural Uganda, East Africa. One of these sequences corresponds to genotype 1, and is the first complete genome from East Africa for this genotype. The remaining three sequences correspond to genotype 5, a genotype that was previously considered exclusively South African. All four samples were collected within a geographic area of less than 25 km2, suggesting that the genetic diversity within this region is high, and that multiple genotypes overlap spatially. Analysis of intra-host viral genetic diversity revealed that total single-nucleotide polymorphism abundance was approximately ten-fold lower in HPgV than in hepatitis C virus. Finally, one patient was co-infected with HPgV and HIV, which, in combination with the high prevalence of HIV in this area, implies that rural East Africa would be a useful locale to study the interactions and co-evolution of these viruses.
    Journal of General Virology 09/2013; DOI:10.1099/vir.0.055509-0 · 3.53 Impact Factor
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    ABSTRACT: High genetic diversity at both inter- and intra-host level are hallmarks of RNA viruses due to the error-prone nature of their genome replication. Several groups have evaluated the extent of viral variability using different RNA virus deep sequencing methods. Although much of this effort has been dedicated to pathogens that cause chronic infections in humans, few studies investigated arthropod-borne, acute viral infections. We deep sequenced the complete genome of ten DENV2 isolates from representative classical and severe cases sampled in a large outbreak in Brazil using two different approaches. Analysis of the consensus genomes confirmed the larger extent of the 2010 epidemic in comparison to a previous epidemic caused by the same viruses in another city two years before (genetic distance = 0.002 and 0.0008 respectively). Analysis of viral populations within the host revealed a high level of conservation. After excluding homopolymer regions of 454/Roche generated sequences, we found 10 to 44 variable sites per genome population at a frequency of >1%, resulting in very low intra-host genetic diversity. While up to 60% of all variable sites at intra-host level were non-synonymous changes, only 10% of inter-host variability resulted from non-synonymous mutations, indicative of purifying selection at the population level. Despite the error-prone nature of RNA-dependent RNA-polymerase, dengue viruses maintain low levels of intra-host variability.
    PLoS ONE 08/2013; 8(8):e70318. DOI:10.1371/journal.pone.0070318 · 3.53 Impact Factor
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    ABSTRACT: GB virus B (GBV-B; family Flaviviridae, genus Hepacivirus) has been studied in New World primates as a model for human hepatitis C virus infection, but the distribution of GBV-B and its relatives in nature has remained obscure. Here, we report the discovery of a novel and highly divergent GBV-B-like virus in an Old World monkey, the black-and-white colobus (Colobus guereza) in Uganda. The new virus, guereza hepacivirus (GHV), clusters phylogenetically with GBV-B and recently described hepaciviruses infecting African bats and North American rodents, and it shows evidence of ancient recombination with these other hepaciviruses. Direct sequencing of reverse-transcribed RNA from blood plasma from three of nine colobus yielded near-complete GHV genomes, comprising two distinct viral variants. The viruses contain an exceptionally long nonstructural 5A (NS5A) gene, approximately half of which codes for a protein with no discernible homology to known proteins. Computational structure-based analyses indicate that the amino terminus of the GHV NS5A protein may serve a zinc-binding function, similar to the NS5A of other viruses within the family Flaviviridae. However, the 521 amino acid carboxy terminus is intrinsically disordered, reflecting an unusual degree of structural plasticity and polyfunctionality. These findings shed new light on the natural history and evolution of the hepaciviruses and on the extent of structural variation within the Flaviviridae.
    Journal of Virology 06/2013; DOI:10.1128/JVI.00888-13 · 4.65 Impact Factor
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    ABSTRACT: The use of Chinese-origin rhesus macaques (Macaca mulatta) for infectious disease immunity research is increasing, despite the relative lack of major histocompatibility complex (MHC) class I immunogenetics information available for this population. We determined transcript-based MHC class I haplotypes for 385 Chinese rhesus macaques from five different experimental cohorts, providing a concise representation of the full complement of MHC class I major alleles expressed by each animal. In total, 123 Mamu-A and Mamu-B haplotypes were defined in the full Chinese rhesus macaque cohort. We then performed an analysis of haplotype frequencies across the experimental cohorts of Chinese rhesus macaques, as well as a comparison against a group of 96 Indian rhesus macaques. Notably, 35 of the 51 Mamu-A and Mamu-B haplotypes observed in Indian rhesus macaques were also detected in the Chinese population, with 85% of the 385 Chinese-origin rhesus macaques expressing at least one of these class I haplotypes. This unexpected conservation of Indian rhesus macaque MHC class I haplotypes in the Chinese rhesus macaque population suggests that immunologic insights originally gleaned from studies utilizing Indian rhesus macaques may be more applicable to Chinese rhesus macaques than previously appreciated and may provide an opportunity for studies of CD8+ T cell responses between populations. It may also be possible to extend these studies across multiple species of macaques, as we found evidence of shared ancestral haplotypes between Chinese rhesus and Mauritian cynomolgus macaques.
    G3-Genes Genomes Genetics 05/2013; DOI:10.1534/g3.113.006254 · 2.51 Impact Factor

Publication Stats

6k Citations
779.38 Total Impact Points

Institutions

  • 2002–2014
    • University of Wisconsin–Madison
      • • Department of Pathology and Laboratory Medicine
      • • Department of Plant Pathology
      Madison, Wisconsin, United States
    • Oregon Health and Science University
      Portland, Oregon, United States
  • 1999–2014
    • Wisconsin National Primate Research Center
      Madison, Wisconsin, United States
  • 2013
    • McGill University
      • Department of Biology
      Montréal, Quebec, Canada
  • 2001–2010
    • University of South Carolina
      • Department of Biological Sciences
      Columbia, SC, United States
  • 2008
    • National Institutes of Health
      • Branch of Vaccine
      Bethesda, MD, United States
  • 2003
    • University of Alabama at Birmingham
      Birmingham, Alabama, United States