bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antibodies Specific for the Hia Adhesion Proteins of NontypeableHaemophilus influenzaeMediate Opsonophagocytic Activity
Authors: Winter Linda E. , Barenkamp Stephen J. 
Published: May 2009

ABSTRACTThe Hia autotransporter proteins are highly immunogenic surface adhesins expressed by nontypeableHaemophilus influenzae(NTHI). The objective of our study was to assess the opsonophagocytic activity of anti-Hia antibodies against homologous and heterologous NTHI. A segment of thehiagene that encodes a surface-exposed portion of theH. influenzaestrain 11 Hia protein was cloned into a pGEMEX-2 expression vector.Escherichia coliJM101 was transformed with the resulting pGEMEX-Hia BstEII del recombinant plasmid, and recombinant fusion protein was recovered. An immune serum against recombinant GEMEX-Hia (rGEMEX-Hia)-mediated killing of the homologous NTHI strain 11 at a 1:160 titer and five heterologous Hia-expressing strains at titers of ≥1:40. Immune serum did not mediate killing of two Hia-knockout strains whosehiagenes were inactivated but did mediate killing of one knockout strain at a high titer after the strain was transformed with a plasmid containing thehiagene. Immune serum did not mediate killing of HMW1/HMW2-expressing NTHI strains, which do not express the Hia adhesin. However, when two representative HMW1/HMW2-expressing strains were transformed with the plasmid containing thehiagene, they expressed abundant Hia and were susceptible to killing by the immune serum. Immune serum did not mediate killing of HMW1/HMW2-expressing strains transformed with the plasmid without thehiagene. Our results demonstrate that the Hia proteins of NTHI are targets of opsonophagocytic antibodies and that shared epitopes recognized by such antibodies are present on the Hia proteins of unrelated NTHI strains. These data argue for the continued investigation of the Hia proteins as vaccine candidates for the prevention of NTHI disease.
Early Detection of Human Immunodeficiency Virus Type 1-Specific B-Lymphocyte-Derived Antibodies in a High-Risk Population
Authors: Odinsen Odd , Parker David , Radebe Frans , Guness Mikey , Lewis David A 
Published: May 2009

ABSTRACT
Diagnosis of acute human immunodeficiency virus (HIV) infection, a key driver of the HIV epidemic, remains a public health challenge. The PlasmAcute technology offers an opportunity to detect early anti-HIV antibody responses. B lymphocytes (B cells) were isolated from the blood of seronegative miners in South Africa by using the PlasmAcute method. B-cell lysates and paired sera were tested for anti-HIV-1 antibodies by two different enzyme-linked immunosorbent assays; immunoreactivity was confirmed by Western blotting. All volunteers were tested for HIV type 1 (HIV-1) viral load, p24 antigen, and CD4 count. Sera from HIV-seronegative men who had positive viral loads and were positive for p24 antigen were retested for anti-HIV antibodies after immune complex dissociation. Anti-HIV antibodies were detected in lysates from 16/259 subjects without immunoreactivity in paired sera. Four subjects, one of whom had a positive viral load initially, subsequently seroconverted. Six subjects showed transient anti-HIV-1 antibodies in the lysates and tested negative for all markers at the follow-up. Five subjects without follow-up data initially had lysate-positive/serum-negative samples, and these cases were classified as inconclusive. One subject had lysate antibodies and a detectable viral load but was seronegative at follow-up. In conclusion, lysate-derived anti-HIV-1 B-cell antibodies can be detected prior to seroconversion and earlier than or contemporary with HIV-1 RNA detection.
Ultra-High-Throughput, Automated Nucleic Acid Detection of Human Immunodeficiency Virus (HIV) for Infant Infection Diagnosis Using the Gen-Probe Aptima HIV-1 Screening Assay
Authors: Stevens Wendy S. , Noble Lara , Berrie Leigh , Sarang Somaya , Scott Lesley E. 
Published: May 2009

ABSTRACT
The early diagnosis of human immunodeficiency virus (HIV) infection in infants is critical to ensure the initiation of treatment before significant immunological compromise. Each year an estimated 300,000 HIV-exposed infants in South Africa require access to tests for the diagnosis of HIV infection. Currently, testing is performed at several facilities by using PCR amplification of HIV DNA at 6 weeks of age by the use of dried blood spots (DBSs) and whole blood (WB). The Gen-Probe Aptima HIV type 1 (HIV-1) screening assay (the Aptima assay) is a qualitative nucleic acid test based on transcription-mediated amplification (TMA), a technology routinely used in blood banks in South Africa. The performance characteristics of Gen-Probe's TMA technology compared well to those of the Roche Amplicor HIV-1 DNA (version 1.5) assay. The sensitivity of the assay with WB and DBS samples was 100%, and the specificities were 99.4% and 99.5% for DBSs and WB, respectively. The detection of HIV by the Aptima assay at greater levels of dilution in samples negative by the comparator assay indicates an improvement in sensitivity by the use of the TMA technology. The ability to process 1,900 samples in a 24-h period on the Tigris instrument makes the Aptima assay an attractive option for high-volume, centralized laboratories.
Mupirocin Resistance among Methicillin-ResistantStaphylococcus aureus-Colonized Patients at Admission to a Tertiary Care Medical Center
Authors: Babu Tara , Rekasius Violeta , Parada Jorge P. , Schreckenberger Paul , Challapalli Malliswari 
Published: May 2009

ABSTRACTAll patients admitted to our tertiary care hospital from 1 December 2007 to 10 June 2008 were screened for methicillin (meticillin)-resistantStaphylococcus aureus(MRSA) nasal colonization, and the isolates were tested for mupirocin susceptibility by using Etest. Mupirocin resistance (MR) was noted to occur in 3.4% of MRSA carriers, and high-level MR was noted to occur in 0.62% of carriers.
Lack of Adaptation of Chimeric GB Virus B/Hepatitis C Virus in the Marmoset Model: Possible Effects of Bottleneck
Authors: Weatherford Trudie , Chavez Deborah , Brasky Kathleen M. , Lemon Stanley M. , Martin Annette , Lanford Robert E. 
Published: May 2009

ABSTRACT

Approximately 3% of the world population is chronically infected with hepatitis C virus (HCV). GB virus B (GBV-B), a surrogate model for HCV, causes hepatitis in tamarins and is the virus phylogenetically most closely related to HCV. Previously we described a chimeric GBV-B containing an HCV insert from the 5′ noncoding region (NCR) that was adapted for efficient replication in tamarins (
Saguinus
species). We have also demonstrated that wild-type (WT) GBV-B rapidly adapts for efficient replication in a closely related species, the common marmoset (
Callithrix jacchus
). Here, we demonstrate that the chimeric virus failed to adapt during serial passage in marmosets. The chimeric virus was passaged four times through 24 marmosets. During passage, two marmoset phenotypes were observed: susceptible and partially resistant. Although appearing to adapt in a resistant animal during a prolonged and gradual increase in viremia, the chimeric GBV-B failed to replicate efficiently upon passage to a naïve marmoset. The resistance was specific to the chimeric virus, as the chimeric virus-resistant animals were susceptible to marmoset-adapted WT virus during rechallenge studies. Three isolates of the chimeric virus were sequenced, and 20 nucleotide changes were observed, including eight amino acid changes. Three unique changes were observed in the 5′ NCR chimeric insert, an area that is highly conserved in HCV. We speculate that the failure of the chimeric virus to adapt in marmosets might be due to a bottleneck that occurs at the time of infection of resistant animals, which may lead to a loss of fitness upon serial passage.
Mutations That Increase DNA Binding by the Processivity Factor of Herpes Simplex Virus Affect Virus Production and DNA Replication Fidelity
Authors: Jiang Changying , Komazin-Meredith Gloria , Tian Wang , Coen Donald M. , Hwang Charles B. C. 
Published: May 2009

ABSTRACT

The interactions of the herpes simplex virus processivity factor UL42 with the catalytic subunit of the viral polymerase (Pol) and DNA are critical for viral DNA replication. Previous studies, including one showing that substitution of glutamine residue 282 with arginine (Q282R) results in an increase of DNA binding in vitro, have indicated that the positively charged back surface of UL42 interacts with DNA. To investigate the biological consequences of increased DNA binding by
UL42
mutations, we constructed two additional UL42 mutants, including one with a double substitution of alanine for aspartic acid residues (D270A/D271A) and a triple mutant with the D270A/D271A and Q282R substitutions. These UL42 mutants exhibited increased and prolonged DNA binding without an effect on binding to a peptide corresponding to the C terminus of Pol. Plasmids expressing any of the three UL42 mutants with an increased positive charge on the back surface of UL42 were qualitatively competent for complementation of growth and DNA replication of a
UL42
null mutant on Vero cells. We then engineered viruses expressing these mutant proteins. The UL42 mutants were more resistant to detergent extraction than wild-type UL42, suggesting that they are more tightly associated with DNA in infected cells. All three UL42 mutants formed smaller plaques on Vero cells and replicated to reduced yields compared with results for a control virus expressing wild-type UL42. Moreover, mutants with double and triple mutations, which contain D270A/D271A mutations, exhibited increased mutation frequencies, and mutants containing the Q282R mutation exhibited elevated ratios of virion DNA copies per PFU. These results suggest that herpes simplex virus has evolved so that UL42 neither binds DNA too tightly nor too weakly to optimize virus production and replication fidelity.
Deficiency of Niemann-Pick Type C-1 Protein Impairs Release of Human Immunodeficiency Virus Type 1 and Results in Gag Accumulation in Late Endosomal/Lysosomal Compartments
Authors: Tang Yuyang , Leao Ihid Carneiro , Coleman Ebony M. , Broughton Robin Shepard , Hildreth James E. K. 
Published: May 2009

ABSTRACTHuman immunodeficiency virus type 1 (HIV-1) relies on cholesterol-laden lipid raft membrane microdomains for entry into and egress out of susceptible cells. In the present study, we examine the need for intracellular cholesterol trafficking pathways with respect to HIV-1 biogenesis using Niemann-Pick type C-1 (NPC1)-deficient (NPCD) cells, wherein these pathways are severely compromised, causing massive accumulation of cholesterol in late endosomal/lysosomal (LE/L) compartments. We have found that induction of an NPC disease-like phenotype through treatment of various cell types with the commonly used hydrophobic amine drug U18666A resulted in profound suppression of HIV-1 release. Further, NPCD Epstein-Barr virus-transformed B lymphocytes and fibroblasts from patients with NPC disease infected with a CD4-independent strain of HIV-1 or transfected with an HIV-1 proviral clone, respectively, replicated HIV-1 poorly compared to normal cells. Infection of the NPCD fibroblasts with a vesicular stomatitis virus G-pseudotyped strain of HIV-1 produced similar results, suggesting a postentry block to HIV-1 replication in these cells. Examination of these cells using confocal microscopy showed an accumulation and stabilization of Gag in LE/L compartments. Additionally, normal HIV-1 production could be restored in NPCD cells upon expression of a functional NPC1 protein, and overexpression of NPC1 increased HIV-1 release. Taken together, our findings demonstrate that intact intracellular cholesterol trafficking pathways mediated by NPC1 are needed for efficient HIV-1 production.
Mutagenesis of Varicella-Zoster Virus Glycoprotein B: Putative Fusion Loop Residues Are Essential for Viral Replication, and the Furin Cleavage Motif Contributes to Pathogenesis in Skin Tissue In Vivo
Authors: Oliver Stefan L. , Sommer Marvin , Zerboni Leigh , Rajamani Jaya , Grose Charles , Arvin Ann M. 
Published: May 2009

ABSTRACT

Glycoprotein B (gB), the most conserved protein in the family
Herpesviridae
, is essential for the fusion of viral and cellular membranes. Information about varicella-zoster virus (VZV) gB is limited, but homology modeling showed that the structure of VZV gB was similar to that of herpes simplex virus (HSV) gB, including the putative fusion loops. In contrast to HSV gB, VZV gB had a furin recognition motif ([R]-X-[KR]-R-|-X, where | indicates the position at which the polypeptide is cleaved) at residues 491 to 494, thought to be required for gB cleavage into two polypeptides. To investigate their contribution, the putative primary fusion loop or the furin recognition motif was mutated in expression constructs and in the context of the VZV genome. Substitutions in the primary loop, W180G and Y185G, plus the deletion mutation Δ
491
RSRR
494
and point mutation
491
GSGG
494
in the furin recognition motif did not affect gB expression or cellular localization in transfected cells. Infectious VZV was recovered from parental Oka (pOka)-bacterial artificial chromosomes that had either the Δ
491
RSRR
494
or
491
GSGG
494
mutation but not the point mutations W180G and Y185G, demonstrating that residues in the primary loop of gB were essential but gB cleavage was not required for VZV replication in vitro. Virion morphology, protein localization, plaque size, and replication were unaffected for the pOka-gBΔ
491
RSRR
494
or pOka-gB
491
GSGG
494
virus compared to pOka in vitro. However, deletion of the furin recognition motif caused attenuation of VZV replication in human skin xenografts in vivo. This is the first evidence that cleavage of a herpesvirus fusion protein contributes to viral pathogenesis in vivo, as seen for fusion proteins in other virus families.
Mitochondrial Antiviral Signaling Protein Plays a Major Role in Induction of the Fish Innate Immune Response against RNA and DNA Viruses
Authors: Biacchesi Stéphane , LeBerre Monique , Lamoureux Annie , Louise Yoann , Lauret Emilie , Boudinot Pierre , Brémont Michel 
Published: May 2009

ABSTRACT
Viral infection triggers host innate immune responses through cellular sensor molecules which activate multiple signaling cascades that induce the production of interferons (IFN) and other cytokines. The recent identification of mammalian cytoplasmic viral RNA sensors, such as retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs) and their mitochondrial adaptor, the mitochondrial antiviral signaling protein (MAVS), also called IPS-1, VISA, and Cardif, highlights the significance of these molecules in the induction of IFN. Teleost fish also possess a strong IFN system, but nothing is known concerning the RLRs and their downstream adaptor. In this study, we cloned MAVS cDNAs from several fish species (including salmon and zebrafish) and showed that they were orthologs of mammalian MAVS. We demonstrated that overexpression of these mitochondrial proteins in fish cells led to a constitutive induction of IFN and IFN-stimulated genes (ISGs). MAVS-overexpressing cells were almost fully protected against RNA virus infection, with a strong inhibition of both DNA and RNA virus replication (1,000- and 10,000-fold decreases, respectively). Analyses of MAVS deletion mutants showed that both the N-terminal CARD-like and C-terminal transmembrane domains, but not the central proline-rich region, were indispensable for MAVS signaling function. In addition, we cloned the cDNAs encoding a RIG-I-like molecule from salmonid and cyprinid cell lines. Like the case with MAVS, overexpression of RIG-I CARDs in fish cells led to a strong induction of both IFN and ISGs, conferring on fish cells full protection against RNA virus infection. This report provides the first demonstration that teleost fish possess a functional RLR pathway in which MAVS may play a central role in the induction of the innate immune response.
Loss of MicroRNA Targets in the 3′ Untranslated Region as a Mechanism of Retroviral Insertional Activation of Growth Factor Independence 1
Authors: Dabrowska Magdalena Julia , Dybkaer Karen , Johnsen Hans Erik , Wang Bruce , Wabl Matthias , Pedersen Finn Skou 
Published: May 2009

ABSTRACT

The non-oncogene-bearing retrovirus SL3-3 murine leukemia virus induces strictly T-cell lymphomas with a mean latency of 2 to 4 months in mice of the NMRI-inbred (NMRI-i) strain. By high-throughput sequencing of retroviral tags, we have identified the genomic region carrying the transcriptional repressor and oncogene growth factor independence 1 (
Gfi1
) as a frequent target for SL3-3 in the NMRI-i mouse genome. Twenty-four SL3-3 insertions were identified within a 1-kb window of the 3′ untranslated region (3′UTR) of the
Gfi1
gene, a clustering pattern unique for this lymphoma model. Expression analysis determined that the
Gfi1
gene was transcriptionally activated by SL3-3 insertions, and an upregulation of Gfi1 protein expression was detected for tumors harboring insertions in the
Gfi1
3′UTR. Here we provide data in support of a mechanism by which retroviral insertions in the
Gfi1
3′UTR decouple microRNA-mediated posttranscriptional regulation.
Complete Virion Assembly with Scaffolding Proteins Altered in the Ability To Perform a Critical Conformational Switch
Authors: Cherwa James E. , Fane Bentley A. 
Published: May 2009

ABSTRACT
In the φX174 procapsid, 240 external scaffolding proteins form a nonquasiequivalent lattice. To achieve this arrangement, the four structurally unique subunits must undergo position-dependent conformational switches. One switch is mediated by glycine residue 61, which allows a 30° kink to form in α-helix 3 in two subunits, whereas the helix is straight in the other two subunits. No other amino acid should be able to produce a bend of this magnitude. Accordingly, all substitutions for G61 are nonviable but mutant proteins differ vis-à-vis recessive and dominant phenotypes. As previously reported, amino acid substitutions with side chains larger than valine confer dominant lethal phenotypes. Alone, these mutant proteins appear to have little or no biological activity but rather require the wild-type protein to interact with other structural proteins. Proteins with conservative substitutions for G61, serine and alanine, have now been characterized. Unlike the dominant lethal proteins, these proteins do not require wild-type subunits to interact with other viral proteins and cause assembly defects reminiscent of those conferred by the lethal dominant proteins in concert with wild-type subunits. Although atomic structures suggest that only a glycine residue can provide the proper torsion angle for assembly, mutants that can productively utilize the altered external scaffolding proteins were isolated, and the mutations were mapped to the coat and internal scaffolding proteins. Thus, the ability to isolate strains that could utilize the single mutant D protein species would not have been predicted from past structural analyses.
Human Bocavirus Can Be Cultured in Differentiated Human Airway Epithelial Cells
Authors: Dijkman Ronald , Koekkoek Sylvie M. , Molenkamp Richard , Schildgen Oliver , van der Hoek Lia 
Published: May 2009

ABSTRACT

In 2005, a human bocavirus was discovered in children with respiratory tract illnesses. Attempts to culture this virus on conventional cell lines has failed thus far. We investigated whether the virus can replicate on pseudostratified human airway epithelium. This cell culture system mimics the human airway environment and facilitates culturing of various respiratory agents. The cells were inoculated with human bocavirus-positive nasopharyngeal washes from children, and virus replication was monitored by measuring apical release of the virus via real-time PCR. Furthermore, we identified different viral mRNAs in the infected cells. All mRNAs were transcribed from a single promoter but varied due to alternative splicing and alternative polyadenylation, similar to what has been described for bovine parvovirus and minute virus of canines, the other two members of the
Bocavirus
genus. Thus, transcription of human bocavirus displays strong homology to the transcription of the other bocaviruses. In conclusion, we report here for the first time that human bocavirus can be propagated in an in vitro culture system and present a detailed map of the set of mRNAs that are produced by the virus.
The Lipidomes of Vesicular Stomatitis Virus, Semliki Forest Virus, and the Host Plasma Membrane Analyzed by Quantitative Shotgun Mass Spectrometry
Authors: Kalvodova Lucie , Sampaio Julio L. , Cordo Sandra , Ejsing Christer S. , Shevchenko Andrej , Simons Kai 
Published: May 2009

ABSTRACT

Although enveloped virus assembly in the host cell is a crucial step in the virus life cycle, it remains poorly understood. One issue is how viruses include lipids in their membranes during budding from infected host cells. To analyze this issue, we took advantage of the fact that baby hamster kidney cells can be infected by two different viruses, namely, vesicular stomatitis virus and Semliki Forest virus, from the
Rhabdoviridae
and
Togaviridae
families, respectively. We purified the host plasma membrane and the two different viruses after exit from the host cells and analyzed the lipid compositions of the membranes by quantitative shotgun mass spectrometry. We observed that the lipid compositions of these otherwise structurally different viruses are virtually indistinguishable, and only slight differences were detected between the viral lipid composition and that of the plasma membrane. Taken together, the facts that the lipid compositions of the two viruses are so similar and that they strongly resemble the composition of the plasma membrane suggest that these viruses exert little selection in including lipids in their envelopes.
John N. Brady (1952-2009): a Generous Spirit
Authors: Enquist Lynn W. 
Published: May 2009

ABSTRACT

John N. Brady, Chief of the Virus Tumor Biology Section of the Laboratory of Cellular Oncology, National Institutes of Health, died of cancer on 27 April 2009. John was a stellar member of the virology community. He was a longtime
Journal of Virology
reviewer and a member of the editorial board. He will be missed. Fatah Kashanchi of the George Washington University Medical Center has written John's memorial. Fatah worked with John at the NIH and published more than 30 papers with him. Fatah thanks all the people who contributed to John's obituary, including Kuan-Teh Jeang, Lou Laimins, Mary Loeken, Renaud Mehieux, Paul Lambert, Graziella Piras, Scott Gitlin, Paul Lindholm, Nadia Rosenthal, Sergi Nekhai, Brian Wigdahl, David Price, Susan J. Marriott, Cynthia Masison, Jurgen Dittmer, Eric Verdin, Bassel E. Sawaya, and John's longtime assistants Janet Duvall Grimm and Michael Radonovich, who gave immense support to all the individuals who went through John's lab.