Virology Commons^™

Cellular Immunity In Mouse Models Of Viral Encephalitis, Christina Dawn Steel

Theses and Dissertations in Biomedical Sciences

Evidence is presented herein that intranasal application of vesicular stomatitis virus (VSV) caused acute infection of the murine central nervous system (CNS) with associated morbidity and significant mortality in mice. However, VSV encephalitis was not invariably fatal, suggesting that the CNS contained a professional antigen-presenting cell (APC) capable of inducing or propagating a protective antiviral immune response. To examine this possibility, we administered VSV via the intranasal route and then characterized the cellular elements that infiltrate the brain as well as the activation status of resident microglia, cells widely believed to represent the major APC population in the CNS. To …

Coronavirus Replicase Proteins: Multifunctional Mediators Of Replication And Innate Immunity Evasion, Mark Anthony Clementz

Dissertations

Coronaviruses are positive-sense, single-stranded RNA viruses. The majority of the RNA encodes non-structural proteins (nsps) that are translated as a large polyprotein, which is cleaved by the papain-like (PLP) and picornavirus 3C-like (3CLpro) proteases. The nsps modify host membranes to produce double membrane vesicles (DMVs) upon which the replicase-transcriptase assembles and synthesizes viral RNA. nsp3, nsp4, and nsp6 are integral membrane proteins believed to be involved in DMV formation. Work presented here demonstrates that nsp4 is subjected to N-linked glycosylation and mutation of N258 to threonine in nsp4 confers a temperature sensitive phenotype to MHV-A59 infectious clone virus. This virus …

Subtype-Associated Differences In Hiv-1 Reverse Transcription Affect The Viral Replication, Sergey Iordanskiy, Mackenzie Waltke, Yanjun Feng, Charles Wood

Nebraska Center for Virology: Faculty Publications

Background: The impact of the products of the pol gene, specifically, reverse transcriptase (RT) on HIV-1 replication, evolution, and acquisition of drug resistance has been thoroughly characterized for subtype B. For subtype C, which accounts of almost 60% of HIV cases worldwide, much less is known. It has been reported that subtype C HIV-1 isolates have a lower replication capacity than B; however, the basis of these differences remains unclear.

Results: We analyzed the impact of the pol gene products from HIV-1 B and C subtypes on the maturation of HIV virions, accumulation of reverse transcription products, integration of …

Chronology And Evolution Of The Hiv-1 Subtype C Epidemic In Ethiopia, Damien C. Tully, Charles Wood

Nebraska Center for Virology: Faculty Publications

Objective—To reconstruct the onset date and evolutionary history of the HIV-1 subtype C epidemic in Ethiopia - one of the earliest recorded subtype C epidemics in the world.

Design—HIV-1 C env sequences with a known sampling year isolated from HIV-1 positive patients from Ethiopia between 1984 and 2003.

Methods—Evolutionary parameters including origin and demographic growth patterns were estimated using a Bayesian coalescent-based approach under either strict or relaxed molecular clock models.

Results—Bayesian evolutionary analysis indicated a most recent common ancestor date of 1965 with three distinct epidemic growth phases. Regression analysis of root-to-tip distances revealed a highly similar estimate for …

Topological Layers In The Hiv-1 Gp120 Inner Domain Regulate Gp41 Interaction And Cd4-Triggered Conformational Transitions, Andrés Finzi, Shi-Hua Xiang, Beatriz Pacheco, Dana-Farber Cancer Institute Wang, Jessica Haight, Aemro Kassa, Brenda Danek, Marie Pancera, Peter D. Kwong, Joseph Sodroski

Nebraska Center for Virology: Faculty Publications

The entry of human immunodeficiency virus (HIV-1) into cells is initiated by binding of the gp120 exterior envelope glycoprotein to the receptor, CD4. How does CD4 binding trigger conformational changes in gp120 that allow the gp41 transmembrane envelope glycoprotein to mediate viral-cell membrane fusion? The transition from the unliganded to the CD4-bound state is regulated by two potentially flexible topological layers (layers 1 and 2) in the gp120 inner domain. Both layers apparently contribute to the noncovalent association of unliganded gp120 with gp41. After CD4 makes initial contact with the gp120 outer domain, layer 1-layer 2 interactions strengthen gp120-CD4 binding …

Phocine Distemper Virus Induced Demyelination In The Spinal Cord Of Infected Harbor Seals (Phoca Vitulina), Thomas Siemens

All Theses And Dissertations

Phocine Distemper Virus (PDV) is a Morbillivirus that has been responsible for the death of approximately 40,000 phocid seals in the last three decades. The most commonly reported pathology is virally induced demyelination of the cerebrum and brainstem which leaves axons bare and limits their conductivity of action potentials. While these conditions have been studied at length, there is little mention of spinal cord involvement. This study aims to determine whether demyelination found in the brainstem continues into the cervical spinal cord. The results indicate that demyelination in the cervical spinal cord does not occur alongside the brainstem. It is …

Effect Of Dipterinyl Calcium Pentahydrate On Hepatitis B Virus Replication In Transgenic Mice, P Moheno, John D. Morrey, D Fuchs

John D. Morrey

Dipterinyl calcium pentahydrate (DCP) has previously been shown to inhibit MDA-MB-231 human breast cancer xenographs in nude mice in a manner correlated with increases in plasma IL-12 and IL-4 concentrations, and decreases in plasma IL-6 levels. DCP also inhibits indoleamine 2,3-dioxygenase (IDO), an immuno-inhibitory enzyme, in human PBMCs (Peripheral Blood Mononuclear Cells).

Assessing Changes In Vascular Permeability In A Hamster Model Of Viral Hemorrhagic Fever, B B. Gowen, J G. Julander, N R. London, M H. Wong, D Larson, John D. Morrey, D Y. Li, M Bray

John D. Morrey

A number of RNA viruses cause viral hemorrhagic fever (VHF), in which proinflammatory mediators released from infected cells induce increased permeability of the endothelial lining of blood vessels, leading to loss of plasma volume, hypotension, multi-organ failure, shock and death. The optimal treatment of VHF should therefore include both the use of antiviral drugs to inhibit viral replication and measures to prevent or correct changes in vascular function. Although rodent models have been used to evaluate treatments for increased vascular permeability (VP) in bacterial sepsis, such studies have not been performed for VHF.

Development Of A New Tacaribe Arenavirus Infection Model And Its Use To Explore Antiviral Activity Of A Novel Aristeromycin Analog, B B. Gowen, M H. Wong, D Larson, W Ye, K H. Jung, E J. Sefing, R Skirpstunas, D F. Smee, John D. Morrey, S W. Schneller

John D. Morrey

A growing number of arenaviruses can cause a devastating viral hemorrhagic fever (VHF) syndrome. They pose a public health threat as emerging viruses and because of their potential use as bioterror agents. All of the highly pathogenic New World arenaviruses (NWA) phylogenetically segregate into clade B and require maximum biosafety containment facilities for their study. Tacaribe virus (TCRV) is a nonpathogenic member of clade B that is closely related to the VHF arenaviruses at the amino acid level. Despite this relatedness, TCRV lacks the ability to antagonize the host interferon (IFN) response, which likely contributes to its inability to cause …

Effects Of The Combination Of Favipiravir (T-705) And Oseltamivir On Influenza A Virus Infections In Mice, D F. Smee, B L. Hurst, M H. Wong, K W. Bailey, E B. Tarbet, John D. Morrey, Y Furuta

John D. Morrey

Favipiravir (T-705 [6-fluoro-3-hydroxy-2-pyrazinecarboxamide]) and oseltamivir were combined to treat influenza virus A/NWS/33 (H1N1), A/Victoria/3/75 (H3N2), and A/Duck/MN/1525/81 (H5N1) infections. T-705 alone inhibited viruses in cell culture at 1.4 to 4.3 µM. Oseltamivir inhibited these three viruses in cells at 3.7, 0.02, and 0.16 µM and in neuraminidase assays at 0.94, 0.46, and 2.31 nM, respectively. Oral treatments were given twice daily to mice for 5 to 7 days starting, generally, 24 h after infection. Survival resulting from 5 days of oseltamivir treatment (0.1 and 0.3 mg/kg/day) was significantly better in combination with 20 mg/kg of body weight/day of T-705 against …

Interactions Of The Cellular Sumoylation System With Influenza A Virus And Its Non-Structural Protein Ns1a (Ns1a), Sangita Pal

Open Access Theses & Dissertations

The most important current anti-influenza weapons, vaccination and antiviral drugs, can be rapidly rendered fully ineffective thanks to the virus's high mutational rate, which produces viruses exhibiting new antigenic properties and structural proteins insensitive to the drug's mechanism of action. One attractive alternative is to develop drugs that modulate the activity of cellular systems either required for viral growth or able to neutralize viral growth. Here we demonstrate that the cellular SUMOylation system, a post-translational modification involving the conjugation of the Small Ubiquitin-like MOdifier (SUMO) to specific protein targets using a Ubiquitin-like enzymatic cascade, interacts closely with influenza virus during …

The Role Of Sumoylation Of Ledgf/P75 In Hiv-1 Infection, Murilo Tadeu Domingues Bueno

Open Access Theses & Dissertations

The lens epithelium-derived growth factor (LEDGF) proteins p75 and p52 are transcriptional co-activators that protect cells from stresses through modulation of stress and heat shock-related genes. Besides regulating such genes, LEDGF/p75 is also important in the process of HOX gene expression and leukemia transformation driven by the MLL histone methyl transferase complex. By exploiting a similar mechanism of interaction between LEDGF/p75 and MLL, the HIV-1 viral protein Integrase (IN) associates with LEDGF/p75 in order to execute efficient viral DNA integration. This present work has identified that LEDGF proteins are posttranslationally modified by SUMO-1 and -3. SUMOylation was found to target …

Functional Properties Of The Hiv-1 Subtype C Envelope Glycoprotein Associated With Mother-To-Child Transmission, Hong Zhang, Marzena Rola, John T. West, Damien C. Tully, Piotr Kubis, Jun He, Chipepo Kankasa, Charles Wood

Nebraska Center for Virology: Faculty Publications

Understanding the properties of viruses capable of establishing infection during perinatal transmission of HIV-1 is critical for designing effective means of limiting transmission. We previously demonstrated that the newly transmitted viruses (in infant) were more fit in growth, as imparted by their envelope glycoproteins, than those in their corresponding mothers. Here, we further characterized the viral envelope glycoproteins from six mother-infant transmission pairs and determined whether any specific envelope functions correlate with HIV-1 subtype C perinatal transmission. We found that most newly transmitted viruses were less susceptible to neutralization by their maternal plasma compared to contemporaneous maternal viruses. However, the …

Enhancement Of Autophagy During Lytic Replication By The Kaposi’S Sarcoma-Associated Herpesvirus Replication And Transcription Activator, Hui-Ju Wen, Zhilong Yang, You Zhou, Charles Wood

Nebraska Center for Virology: Faculty Publications

Autophagy is one of two major degradation systems in eukaryotic cells. The degradation mechanism of autophagy is required to maintain the balance between the biosynthetic and catabolic processes and also contributes to defense against invading pathogens. Recent studies suggest that a number of viruses can evade or subvert the host cell autophagic pathway to enhance their own replication. Here, we investigated the effect of autophagy on the KSHV (Kaposi’s sarcoma-associated herpesvirus) life cycle. We found that the inhibition of autophagy reduces KSHV lytic reactivation from latency, and an enhancement of autophagy can be detected during KSHV lytic replication. In addition, …

Chlorella Viruses Encode Most, If Not All, Of The Machinery To Glycosylate Their Glycoproteins Independent Of The Endoplasmic Reticulum And Golgi, James L. Van Etten, James Gurnon, Giane M. Yanai-Balser, David Dunigan, Michael V. Graves

Nebraska Center for Virology: Faculty Publications

In contrast to all other viruses that use the host machinery located in the endoplasmic reticulum and Golgi to glycosylate their glycoproteins, the large dsDNA-containing chlorella viruses encode most, if not all, of the components to glycosylate their major capsid proteins. Furthermore, all experimental results indicate that glycosylation occurs independent of the endoplasmic reticulum and Golgi. (Review article)

Primary Gamma-Herpesviral Infection In Zambian Children, Veenu Minhas, Brad P, Brayfield, Kay L. Crabtree, Chipepo Kankasa, Charles D. Mitchell, Charles Wood

Nebraska Center for Virology: Faculty Publications

Background: HHV-8 is closely related to Epstein-Barr virus (EBV), but the clinical presentations of these two infections in early childhood are not well understood. Also, it is not known whether infection by one virus correlates with another. Here, we compare the natural history of infection by these two viruses along with the clinical manifestations and risk factors that are associated with early childhood infection in Zambia, which is an endemic area for HHV-8.

Methods: This study was conducted in a cohort of 12 month old Zambian children (N = 677). Data on socio-economic status and a wide range …

Short Communication: Antiretroviral Therapy Resistance Mutations Present In The Hiv Type 1 Subtype C Pol And Env Regions From Therapy-Naive Patients In Zambia, Sandra Gonzalez, Clement Gondwe, Damien C. Tully, Veenu Minhas, Danielle Shea, Chipepo Kankasa, Tendai M'Soka, Charles Wood

Nebraska Center for Virology: Faculty Publications

The prevalence of antiretroviral therapy (ART) resistance mutations present in HIV-1 subtype C pol and env regions of the proviral DNA was analyzed and compared from therapy-naive individuals before (Cohort A) and after (Cohort B) the availability of free ART in Zambia. Mutations present in sequences published in a previous study from Zambian ART-naive individuals infected with subtype C were analyzed using current parameters for the classification of ART drug resistance and compared with Cohorts A and B. No statistically significant differences were observed when comparing mutations present in the pol and env of these cohorts. However, an increase in …

Primary Gamma-Herpesviral Infection In Zambian Children, Veenu Minhas, Brad P. Brayfield, Kay L. Crabtree, Chipepo Kankasa, Charles D. Mitchell, Charles Wood

Nebraska Center for Virology: Faculty Publications

Background: HHV-8 is closely related to Epstein-Barr virus (EBV), but the clinical presentations of these two infections in early childhood are not well understood. Also, it is not known whether infection by one virus correlates with another. Here, we compare the natural history of infection by these two viruses along with the clinical manifestations and risk factors that are associated with early childhood infection in Zambia, which is an endemic area for HHV-8.

Methods: This study was conducted in a cohort of 12 month old Zambian children (N = 677). Data on socio-economic status and a wide range …

Restricted Genetic Diversity Of Hiv-1 Subtype C Envelope Glycoprotein From Perinatally Infected Zambian Infants, Hong Zhang, Damien C. Tully, Federico G. Hoffmann, Jun He, Chipepo Kankasa, Charles Wood

Nebraska Center for Virology: Faculty Publications

Background: Mother-to-child transmission of HIV-1 remains a significant problem in the resource-constrained settings where anti-retroviral therapy is still not widely available. Understanding the earliest events during HIV-1 transmission and characterizing the newly transmitted or founder virus is central to intervention efforts. In this study, we analyzed the viral env quasispecies of six mother-infant transmission pairs (MIPs) and characterized the genetic features of envelope glycoprotein that could influence HIV-1 subtype C perinatal transmission.

Methodology and Findings: The V1-V5 region of env was amplified from 6 MIPs baseline samples and 334 DNA sequences in total were analyzed. A comparison of …

Subtype-Associated Differences In Hiv-1 Reverse Transcription Affect The Viral Replication, Sergey Iordanskiy, Mackenzie Waltke, Yanjun Feng, Charles Wood

Nebraska Center for Virology: Faculty Publications

Background: The impact of the products of the pol gene, specifically, reverse transcriptase (RT) on HIV-1 replication, evolution, and acquisition of drug resistance has been thoroughly characterized for subtype B. For subtype C, which accounts of almost 60% of HIV cases worldwide, much less is known. It has been reported that subtype C HIV-1 isolates have a lower replication capacity than B; however, the basis of these differences remains unclear.

Results: We analyzed the impact of the pol gene products from HIV-1 B and C subtypes on the maturation of HIV virions, accumulation of reverse transcription products, integration …