bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detection and Typing of Human Herpesvirus 6 by Molecular Methods in Specimens from Patients Diagnosed with Encephalitis or Meningitis
Authors: Tavakoli Norma P. , Nattanmai Seela , Hull Rene , Fusco Heather , Dzigua Lela , Wang Heng , Dupuis Michelle 
Published: October 2007

ABSTRACT

Human herpesvirus 6 (HHV-6) was detected in specimens from patients hospitalized with symptoms of encephalitis or meningitis. A real-time PCR assay was developed which has a linear dynamic range of 5 to 5 × 10
6
copies of HHV-6 and a sensitivity of five gene copies per reaction. While the assay detects both subtypes, HHV-6A and HHV-6B, it is specific and does not cross-react with a selected specificity panel. A total of 1,482 patient specimens, which were collected between 2003 and 2007, were tested; 26 specimens from 24 patients were found to be positive for HHV-6 by real-time PCR. The HHV-6 detection rate in this population was therefore 1.75%. The majority of the specimens tested (>95%) were cerebrospinal fluid (CSF) specimens. We were able to type 20 of the 26 positive specimens by conventional PCR and sequence analysis; all were HHV-6B. Forty-two percent of the patients were 3 years of age or younger, which may indicate a primary infection in these patients. Given the ages of the remaining patients (from 4 to 81 years), their infections were most probably due to virus reactivations. Where information was available, symptoms of patients included fever (71%), altered mental status (67%), and abnormal CSF profile (75%). Fifty percent of patients of 3 years of age or younger suffered from seizures. The detection of HHV-6 in specimens from patients diagnosed with encephalitis or meningitis, in the absence of a positive PCR result for other agents, strongly suggests a role for HHV-6 in the pathogenesis of these central nervous system diseases.
Emergence of a New Norovirus Variant in Scotland in 2006
Authors: Adamson W. E. , Gunson R. N. , Maclean A. , Carman W. F. 
Published: October 2007

ABSTRACT
For each month between January 2005 and August 2006, a representative number of outbreaks was examined using nucleic acid sequence analysis. Using this method, we showed that an increase in norovirus activity coincided with the emergence of a new GII genotype 4 variant, which by March 2006 was detected in the majority of health boards in Scotland.
Human Immunodeficiency Virus Type 1 gp41 Antibodies That Mask Membrane Proximal Region Epitopes: Antibody Binding Kinetics, Induction, and Potential for Regulation in Acute Infection
Authors: Alam S. Munir , Scearce Richard M. , Parks Robert J. , Plonk Kelly , Plonk Steven G. , Sutherland Laura L. , Gorny Miroslaw K. , Zolla-Pazner Susan , VanLeeuwen Stacie , Moody M. Anthony , Xia Shi-Mao , Montefiori David C. , Tomaras Georgia D. , Weinhold Kent J. , Karim Salim Abdool , Hicks Charles B. , Liao Hua-Xin , Robinson James , Shaw George M. , Haynes Barton F. 
Published: October 2007

ABSTRACTTwo human monoclonal antibodies (MAbs) (2F5 and 4E10) against the human immunodeficiency virus type 1 (HIV-1) envelope g41 cluster II membrane proximal external region (MPER) broadly neutralize HIV-1 primary isolates. However, these antibody specificities are rare, are not induced by Env immunization or HIV-1 infection, and are polyspecific and also react with lipids such as cardiolipin or phosphatidylserine. To probe MPER anti-gp41 antibodies that are produced in HIV-1 infection, we have made two novel murine MAbs, 5A9 and 13H11, against HIV-1 gp41 envelope that partially cross-blocked 2F5 MAb binding to Env but did not neutralize HIV-1 primary isolates or bind host lipids. Competitive inhibition assays using labeled 13H11 MAb and HIV-1-positive patient plasma samples demonstrated that cluster II 13H11-blocking plasma antibodies were made in 83% of chronically HIV-1 infected patients and were acquired between 5 to 10 weeks after acute HIV-1 infection. Both the mouse 13H11 MAb and the three prototypic cluster II human MAbs (98-6, 126-6, and 167-D) blocked 2F5 binding to gp41 epitopes to variable degrees; the combination of 98-6 and 13H11 completely blocked 2F5 binding. These data provide support for the hypothesis that in some patients, B cells make nonneutralizing cluster II antibodies that may mask or otherwise down-modulate B-cell responses to immunogenic regions of gp41 that could be recognized by B cells capable of producing antibodies like 2F5.
WFDC1/ps20 Is a Novel Innate Immunomodulatory Signature Protein of Human Immunodeficiency Virus (HIV)-Permissive CD4+CD45RO+Memory T Cells That Promotes Infection by Upregulating CD54 Integrin Expression and Is Elevated in HIV Type 1 Infection
Authors: Alvarez R. , Reading J. , King D. F. L. , Hayes M. , Easterbrook P. , Farzaneh F. , Ressler S. , Yang F. , Rowley D. , Vyakarnam A. 
Published: October 2007

ABSTRACTUnderstanding why human immunodeficiency virus (HIV) preferentially infects some CD4+CD45RO+memory T cells has implications for antiviral immunity and pathogenesis. We report that differential expression of a novel secreted factor, ps20, previously implicated in tissue remodeling, may underlie why some CD4 T cells are preferentially targeted. We show that (i) there is a significant positive correlation between endogenous ps20 mRNA in diverse CD4 T-cell populations and in vitro infection, (ii) a ps20+permissive cell can be made less permissive by antibody blockade- or small-interference RNA-mediated knockdown of endogenous ps20, and (iii) conversely, a ps20lowcell can be more permissive by adding ps20 exogenously or engineering stable ps20 expression by retroviral transduction. ps20 expression is normally detectable in CD4 T cells after in vitro activation and interleukin-2 expansion, and such oligoclonal populations comprise ps20positiveand ps20low/negativeisogenic clones at an early differentiation stage (CD45RO+/CD25+/CD28+/CD57−). This pattern is altered in chronic HIV infection, where ex vivo CD4+CD45RO+T cells express elevated ps20. ps20 promoted HIV entry via fusion and augmented CD54 integrin expression; both of these effects were reversed by anti-ps20 antibody. We therefore propose ps20 to be a novel signature of HIV-permissive CD4 T cells that promotes infection in an autocrine and paracrine manner and that HIV has coopted a fundamental role of ps20 in promoting cell adhesion for its benefit. Disrupting the ps20 pathway may therefore provide a novel anti-HIV strategy.
A Naturally Occurring Deletion in Its NS Gene Contributes to the Attenuation of an H5N1 Swine Influenza Virus in Chickens
Authors: Zhu Qiyun , Yang Huanliang , Chen Weiye , Cao Wenyan , Zhong Gongxun , Jiao Peirong , Deng Guohua , Yu Kangzhen , Yang Chinglai , Bu Zhigao , Kawaoka Yoshihiro , Chen Hualan 
Published: October 2007

ABSTRACT
In 2001 and 2003, we isolated two H5N1 viruses, A/swine/Fujian/1/01 (SW/FJ/01) and A/swine/Fujian/1/03 (SW/FJ/03), from pigs in Fujian Province, southern China. Genetically, these two viruses are similar, although the NS gene of the SW/FJ/03 virus has a 15-nucleotide deletion at coding positions 612 to 626. The SW/FJ/01 virus is highly lethal for chickens, whereas the SW/FJ/03 virus is nonpathogenic for chickens when administrated intravenously or intranasally. To understand the molecular basis for the difference in virulence, we used reverse genetics to create a series of single-gene recombinants of both viruses. We found that a recombinant virus containing the mutated NS gene from the SW/FJ/03 virus in the SW/FJ/01 virus background was completely attenuated in chickens. We also found that viruses expressing the mutant NS1 protein of SW/FJ/03 did not antagonize the induction of interferon (IFN) protein. Conversely, only the recombinant virus containing the wild-type SW/FJ/01 NS gene in the SW/FJ/03 background was lethal in chickens and antagonized IFN protein levels. Further, we proved that the NS1 genes of the two viruses differ in their stabilities in the host cells and in their abilities to interact with the chicken cleavage and polyadenylation specificity factor. These results indicate that the deletion of amino acids 191 to 195 of the NS1 protein is critical for the attenuation of the SW/FJ/03 virus in chickens and that this deletion affects the ability of the virus to antagonize IFN induction in host cells.
Antigen-Specific B-Cell Responses to Porcine Reproductive and Respiratory Syndrome Virus Infection
Authors: Mulupuri Prasad , Zimmerman Jeffrey J. , Hermann Joseph , Johnson Craig R. , Cano Jean Paul , Yu Wanqin , Dee Scott A. , Murtaugh Michael P. 
Published: October 2007

ABSTRACTPorcine reproductive and respiratory syndrome virus (PRRSV) causes an acute, viremic infection of 4 to 6 weeks, followed by a persistent infection lasting for several months. We characterized antibody and B-cell responses to viral proteins in acute and persistent infection to better understand the immunological basis of the prolonged infection. The humoral immune response to PRRSV was robust overall and varied among individual viral proteins, with the important exception of a delayed and relatively weak response to envelope glycoprotein 5 (GP5). Memory B cells were in secondary lymphoid organs, not in bone marrow or Peyer's patches, in contrast to the case for many mammalian species. Potent anti-PRRSV memory responses were elicited to recall antigen in vitro, even though a second infection did not increase the B-cell response in vivo, suggesting that productive reinfection does not occur in vivo. Antibody titers to several viral proteins decline over time, even though abundant antigen is known to be present in lymphoid tissues, possibly indicating ineffective antigen presentation. The appearance of antibodies to GP5 is delayed relative to the resolution of viremia, suggesting that anti-GP5 antibodies are not crucial for resolving viremia. Lastly, viral infection had no immunosuppressive effect on the humoral response to a second, unrelated antigen. Taking these data together, the active effector and memory B-cell responses to PRRSV are robust, and over time the humoral immune response to PRRSV is effective. However, the delayed response against GP5 early in infection may contribute to the prolonged acute infection and the establishment of persistence.
Basal Expression Levels of IFNAR and Jak-STAT Components Are Determinants of Cell-Type-Specific Differences in Cardiac Antiviral Responses
Authors: Zurney Jennifer , Howard Kristina E. , Sherry Barbara 
Published: October 2007

ABSTRACTViral myocarditis is an important human disease, and reovirus-induced murine myocarditis provides an excellent model system for study. Cardiac myocytes, like neurons in the central nervous system, are not replenished, yet there is no cardiac protective equivalent to the blood-brain barrier. Thus, cardiac myocytes may have evolved a unique antiviral response relative to readily replenished cell types, such as cardiac fibroblasts. Our previous comparisons of these two cell types revealed a conundrum: reovirus T3D induces more beta-interferon (IFN-β) mRNA in cardiac myocytes, yet there is a greater induction of IFN-stimulated genes (ISGs) in cardiac fibroblasts. Here, we investigated possible underlying molecular determinants. We found that greater basal expression of IFN-β in cardiac myocytes results in greater basal activated nuclear STAT1 and STAT2 and greater basal ISG mRNA expression and provides greater basal antiviral protection relative to cardiac fibroblasts. Conversely, cardiac fibroblasts express greater basal IFN-α/β receptor 1 (IFNAR1) and greater basal cytoplasmic Jak1, Tyk2, STAT2, and IRF9, leading to a greater increase in reovirus T3D- or IFN-induced nuclear activated STAT1 and STAT2 and greater induction of ISGs for a greater IFN-induced antiviral protection relative to cardiac myocytes. Our results suggest that high basal IFN-β expression in cardiac myocytes prearms this vulnerable, nonreplenishable cell type, while high basal expression of IFNAR1 and latent Jak-STAT components in adjacent cardiac fibroblasts renders these cells more responsive to IFN and prevents them from inadvertently serving as a reservoir for viral replication and spread to cardiac myocytes. These studies provide the first indication of an integrated network of cell-type-specific innate immune components for organ protection.
Direct Interaction between the N- and C-Terminal Portions of the Herpes Simplex Virus Type 1 Origin Binding Protein UL9 Implies the Formation of a Head-to-Tail Dimer
Authors: Chattopadhyay Soma , Weller Sandra K. 
Published: October 2007

ABSTRACT
UL9, a superfamily II helicase, is a multifunctional protein required for herpes simplex virus type 1 replication in vivo. Although the C-terminal 317-amino-acid DNA binding domain of UL9 exists as a monomer, the full-length protein behaves as a dimer in solution. Thus, it has been assumed that the N-terminal 534 residues contain a region necessary for efficient dimerization and that UL9 dimers are in a head-to-head configuration. We recently showed, however, that residues in the N terminus could modulate the inhibitory properties of UL9 by decreasing the DNA binding ability of the C terminus (S. Chattopadhyay and S. K. Weller, J. Virol. 80:4491-4500, 2006). We suggested that a direct interaction between the N- and C-terminal portions of UL9 might exist and serve to modulate the DNA binding activities of the C terminus. In this study, we used a coimmunoprecipitation assay to show that the N-terminal portion of UL9 can indeed directly interact with the C terminus. A series of truncation mutant proteins were used to show that a region in the N terminus between residues 293 and 321 is necessary for efficient interaction. Similarly, a region in the C terminus between residues 600 and 800 is required for this interaction. The simplest model to explain these data is that UL9 dimers are oriented in a head-to-tail arrangement in which the N terminus is in contact with the C terminus.
A Highly Divergent Picornavirus in a Marine Mammal
Authors: Kapoor A. , Victoria J. , Simmonds P. , Wang C. , Shafer R. W. , Nims R. , Nielsen O. , Delwart E. 
Published: October 2007

ABSTRACT

Nucleic acids from an unidentified virus from ringed seals (
Phoca hispida
) were amplified using sequence-independent PCR, subcloned, and then sequenced. The full genome of a novel RNA virus was derived, identifying the first sequence-confirmed picornavirus in a marine mammal. The phylogenetic position of the tentatively named seal picornavirus 1 (SePV-1) as an outlier to the grouping of parechoviruses was found consistently in alignable regions of the genome. A mean protein sequence identity of only 19.3 to 30.0% was found between the 3D polymerase gene sequence of SePV-1 and those of other picornaviruses. The predicted secondary structure of the short 506-base 5′-untranslated region showed some attributes of a type IVB internal ribosome entry site, and the polyprotein lacked an apparent L peptide, both properties associated with the
Parechovirus
genus. The presence of two SePV-1 2A genes and of the canonical sequence required for cotranslational cleavage resembled the genetic organization of Ljungan virus. Minor genetic variants were detected in culture supernatants derived from 8 of 108 (7.4%) seals collected in 2000 to 2002, indicating a high prevalence of SePV-1 in this hunted seal population. The high level of genetic divergence of SePV-1 compared to other picornaviruses and its mix of characteristics relative to its closest relatives support the provisional classification of SePV-1 as the prototype for a new genus in the family
Picornaviridae
.
Inhibition of Methyltransferases Results in Induction of G
2
/M Checkpoint and Programmed Cell Death in Human T-Lymphotropic Virus Type 1-Transformed Cells
Authors: Dasgupta Arindam , Jung Kyung-Jin , Jeong Soo-Jin , Brady John N. 
Published: October 2007

ABSTRACT

Human T-lymphotropic virus type 1 (HTLV-1) is the etiologic agent for adult T-cell leukemia. The HTLV-1-encoded protein Tax transactivates the viral long terminal repeat and plays a critical role in virus replication and transformation. Previous work from our laboratory demonstrated that coactivator-associated arginine methytransferase 1, a protein arginine methytransferase, was important for Tax-mediated transactivation. To further investigate the role of methyltransferases in viral transcription, we utilized adenosine-2,3-dialdehyde (AdOx), an adenosine analog and
S
-adenosylmethionine-dependent methyltransferase inhibitor. The addition of AdOx decreased Tax transactivation in C81, Hut102, and MT-2 cells. Unexpectedly, we found that AdOx potently inhibited the growth of HTLV-1-transformed cells. Further investigation revealed that AdOx inhibited the Tax-activated NF-κB pathway, resulting in reactivation of p53 and induction of p53 target genes. Analysis of the NF-κB pathway demonstrated that AdOx treatment resulted in degradation of the IκB kinase complex and inhibition of NF-κB through stabilization of the NF-κB inhibitor IκBα. Our data further demonstrated that AdOx induced G
2
/M cell cycle arrest and cell death in HTLV-1-transformed but not control lymphocytes. These studies demonstrate that protein methylation plays an important role in NF-κB activation and survival of HTLV-1-transformed cells.
Attenuation of Recombinant Vesicular Stomatitis Virus-Human Immunodeficiency Virus Type 1 Vaccine Vectors by Gene Translocations and G Gene Truncation Reduces Neurovirulence and Enhances Immunogenicity in Mice
Authors: Cooper David , Wright Kevin J. , Calderon Priscilla C. , Guo Min , Nasar Farooq , Johnson J. Erik , Coleman John W. , Lee Margaret , Kotash Cheryl , Yurgelonis Irene , Natuk Robert J. , Hendry R. Michael , Udem Stephen A. , Clarke David K. 
Published: October 2007

ABSTRACT

Recombinant vesicular stomatitis virus (rVSV) has shown great potential as a new viral vector for vaccination. However, the prototypic rVSV vector described previously was found to be insufficiently attenuated for clinical evaluation when assessed for neurovirulence in nonhuman primates. Here, we describe the attenuation, neurovirulence, and immunogenicity of rVSV vectors expressing human immunodeficiency virus type 1 Gag. These rVSV vectors were attenuated by combinations of the following manipulations: N gene translocations (N4), G gene truncations (CT1 or CT9), noncytopathic M gene mutations (Mncp), and positioning of the
gag
gene into the first position of the viral genome (gag1). The resulting N4CT1-gag1, N4CT9-gag1, and MncpCT1-gag1 vectors demonstrated dramatically reduced neurovirulence in mice following direct intracranial inoculation. Surprisingly, in spite of a very high level of attenuation, the N4CT1-gag1 and N4CT9-gag1 vectors generated robust Gag-specific immune responses following intramuscular immunization that were equivalent to or greater than immune responses generated by the more virulent prototypic vectors. MncpCT1-gag1 also induced Gag-specific immune responses following intramuscular immunization that were equivalent to immune responses generated by the prototypic rVSV vector. Placement of the
gag
gene in the first position of the VSV genome was associated with increased in vitro expression of Gag protein, in vivo expression of Gag mRNA, and enhanced immunogenicity of the vector. These findings demonstrate that through directed manipulation of the rVSV genome, vectors that have reduced neurovirulence and enhanced immunogenicity can be made.
Kaposi's Sarcoma-Associated Herpesvirus K-Cyclin Interacts with Cdk9 and Stimulates Cdk9-Mediated Phosphorylation of p53 Tumor Suppressor
Authors: Chang Pei-Ching , Li Mengtao 
Published: October 2007

ABSTRACT

K-cyclin, encoded by Kaposi's sarcoma-associated herpesvirus, has previously been demonstrated to activate cyclin-dependent kinase 6 (Cdk6) to induce the phosphorylation of various cell cycle regulators. In this study, we identified Cdk9 as a new K-cyclin-associated Cdk and showed that K-cyclin interacted with Cdk9 through its basic domain. We hypothesized that K-cyclin served as a regulatory subunit for the activity of Cdk9. Recent reports show that Cdk9 phosphorylates tumor suppressor p53, and we found that the K-cyclin/Cdk9 interaction greatly enhanced the kinase activity of Cdk9 toward p53. The phosphorylation site(s) of K-cyclin/Cdk9 kinase complexes was mapped in the transactivation domain of p53. We showed that the ectopic expression of K-cyclin led to a sustained increase of p53 phosphorylation on Ser
33
in vivo, and the phosphorylation could be inhibited by a dominant negative Cdk9 mutant, dn-Cdk9. Using p53-positive U2OS and p53-null SaOS2 cells, we demonstrated that K-cyclin-induced growth arrest was associated with the presence of p53. In addition, K-cyclin-induced p53-dependent growth arrest was rescued by the dn-Cdk9- or Cdk9-specific short hairpin RNA in SaOS2 cells. Together, our findings for the first time demonstrated the interaction of K-cyclin and Cdk9 and revealed a new molecular link between K-cyclin and p53.
Inhibition of the Cyclin-Dependent Kinases at the Beginning of Human Cytomegalovirus Infection Specifically Alters the Levels and Localization of the RNA Polymerase II Carboxyl-Terminal Domain Kinases cdk9 and cdk7 at the Viral Transcriptosome
Authors: Kapasi Anokhi J. , Spector Deborah H. 
Published: October 2007

ABSTRACT
We previously reported that defined components of the host transcription machinery are recruited to human cytomegalovirus immediate-early (IE) transcription sites, including cdk9 and cdk7 (S. Tamrakar, A. J. Kapasi, and D. H. Spector, J. Virol. 79:15477-15493, 2005). In this report, we further document the complexity of this site, referred to as the transcriptosome, through identification of additional resident proteins, including viral UL69 and cellular cyclin T1, Brd4, histone deacetylase 1 (HDAC1), and HDAC2. To examine the role of cyclin-dependent kinases (cdks) in the establishment of this site, we used roscovitine, a specific inhibitor of cdk1, cdk2, cdk7, and cdk9, that alters processing of viral IE transcripts and inhibits expression of viral early genes. In the presence of roscovitine, IE2, cyclin T1, Brd4, HDAC1, and HDAC2 accumulate at the transcriptosome. However, accumulation of cdk9 and cdk7 was specifically inhibited. Roscovitine treatment also resulted in decreased levels of cdk9 and cdk7 RNA. There was a corresponding reduction in cdk9 protein but only a modest decrease in cdk7 protein. However, overexpression of cdk9 does not compensate for the effects of roscovitine on cdk9 localization or viral gene expression. Delaying the addition of roscovitine until 8 h postinfection prevented all of the observed effects of the cdk inhibitor. These data suggest that IE2 and multiple cellular factors needed for viral RNA synthesis accumulate within the first 8 h at the viral transcriptosome and that functional cdk activity is required for the specific recruitment of cdk7 and cdk9 during this time interval.