bluuebunny/crossref_metadata_2025_split huggingface dataset:
Potent Neutralization of Hendra and Nipah Viruses by Human Monoclonal Antibodies
Authors: Zhu Zhongyu , Dimitrov Antony S. , Bossart Katharine N. , Crameri Gary , Bishop Kimberly A. , Choudhry Vidita , Mungall Bruce A. , Feng Yan-Ru , Choudhary Anil , Zhang Mei-Yun , Feng Yang , Wang Lin-Fa , Xiao Xiaodong , Eaton Bryan T. , Broder Christopher C. , Dimitrov Dimiter S. 
Published: December 2005

ABSTRACT

Hendra virus
(HeV) and
Nipah virus
(NiV) are closely related emerging viruses comprising the
Henipavirus
genus of the
Paramyxovirinae
. Each has a broad species tropism and can cause disease with high mortality in both animal and human hosts. These viruses infect cells by a pH-independent membrane fusion event mediated by their attachment (G) and fusion (F) envelope glycoproteins (Envs). Seven Fabs, m101 to -7, were selected for their significant binding to a soluble form of Hendra G (sG) which was used as the antigen for panning of a large naïve human antibody library. The selected Fabs inhibited, to various degrees, cell fusion mediated by the HeV or NiV Envs and virus infection. The conversion of the most potent neutralizer of infectious HeV, Fab m101, to immunoglobulin G1 (IgG1) significantly increased its cell fusion inhibitory activity: the 50% inhibitory concentration was decreased more than 10-fold to approximately 1 μg/ml. The IgG1 m101 was also exceptionally potent in neutralizing infectious HeV; complete (100%) neutralization was achieved with 12.5 μg/ml, and 98% neutralization required only 1.6 μg/ml. The inhibition of fusion and infection correlated with binding of the Fabs to full-length G as measured by immunoprecipitation and less with binding to sG as measured by enzyme-linked immunosorbent assay and Biacore. m101 and m102 competed with the ephrin-B2, which we recently identified as a functional receptor for both HeV and NiV, indicating a possible mechanism of neutralization by these antibodies. The m101, m102, and m103 antibodies competed with each other, suggesting that they bind to overlapping epitopes which are distinct from the epitopes of m106 and m107. In an initial attempt to localize the epitopes of m101 and m102, we measured their binding to a panel of 11 G alanine-scanning mutants and identified two mutants, P185A and Q191 K192A, which significantly decreased binding to m101 and one, G183, which decreased binding of m102 to G. These results suggest that m101 to -7 are specific for HeV or NiV or both and exhibit various neutralizing activities; they are the first human monoclonal antibodies identified against these viruses and could be used for treatment, prophylaxis, and diagnosis and as research reagents and could aid in the development of vaccines.
The Amino-Terminal Domain of Bovine Viral Diarrhea Virus NproProtein Is Necessary for Alpha/Beta Interferon Antagonism
Authors: Gil Laura H. V. G. , Ansari Israrul H. , Vassilev Ventzislav , Liang Delin , Lai Vicky C. H. , Zhong Weidong , Hong Zhi , Dubovi Edward J. , Donis Ruben O. 
Published: December 2005

ABSTRACTThe alpha/beta interferon (IFN-α/β) system is the first line of defense against viral infection and a critical link between the innate and adaptive immune responses. IFN-α/β secretion is the hallmark of cellular responses to acute RNA virus infections. As part of their survival strategy, many viruses have evolved mechanisms to counteract the host IFN-α/β response.Bovine viral diarrhea virus(BVDV) (genusPestivirus) was reported to trigger interferon production in infected cultured cells under certain circumstances or to suppress it under others. Our studies with various cultured fibroblasts and epithelial bovine cells indicated that cytopathic (cp) BVDV induces IFN-α/β very inefficiently. Using a set of engineered cp BVDVs expressing mutant Nproand appropriate controls, we found that the IFN-α/β response to infection was dependent on Nproexpression and independent of viral replication efficiency. In order to investigate whether the protease activity of Nprois required for IFN-α/β antagonism, we engineered Npromutants lacking protease activity by replacement of amino acid E22, H49, or C69. We found that E22and H49substitutions abolished the ability of Nproto suppress IFN, whereas C69had no effect, suggesting that the structural integrity of the N terminus of Nprowas more important than its catalytic activity for IFN-α/β suppression. A catalytically active mutant with a change at a conserved Nproregion near the N terminus (L8P) in both BVDV biotypes did not antagonize IFN-α/β production, confirming its involvement in this process. Taken together, these results not only provide direct evidence for the role of Nproin blocking IFN-α/β induction, but also implicate the amino-terminal domain of the protein in this function.
Immune Response to Individual Maedi-Visna VirusgagAntigens
Authors: Singh Inderpal , McConnell Ian , Blacklaws Barbara 
Published: December 2005

ABSTRACTThe lesions caused by maedi-visna virus (MVV) are known to be immune mediated with a presumed contribution by the response to viral antigens. However, very little is known about the T-cell response to individual viral proteins. We have therefore expressed the three individualgagantigens of MVV strain EV1 (p16, p25, and p14) in a bacterial expression system and used the purified recombinant proteins to analyze the antibody and CD4+T-cell response to MVV. Plasma samples were taken from sheep after 1 year of infection with MVV. The titers for antibodies in these samples were determined by indirect enzyme-linked immunosorbent assays and were as follows: anti-p25 antibody, 1:400 to >1:3,200; anti-p16 antibody, 1:400 to 1:3,200; and anti-p14 antibody, 1:<100 to 1:3,200. When the induction of antibodies was followed over time postinfection (p.i.), samples positive for anti-p25 were seen by day 24 p.i., followed by anti-p16 by day 45 p.i., and lastly anti-p14 by day 100 p.i. T-cell proliferative responses to all threegagantigens were detected in persistently infected sheep peripheral blood lymphocytes. The antigens were therefore used to raise T-cell lines from persistently infected sheep. These T-cell lines were shown to be specific for the recombinantgagantigens and for viral antigen expressed on infected macrophages. The proliferative response was restricted to major histocompatibility complex class II HLA-DR and so was due to CD4+T lymphocytes. All threegagantigens may therefore play a role in immune-mediated lesion formation in MVV disease by presentation on infected macrophages in lesions.
Human Cytomegalovirus Immediate-Early 2 Protein IE86 Blocks Virus-Induced Chemokine Expression
Authors: Taylor R. Travis , Bresnahan Wade A. 
Published: December 2005

ABSTRACTThe effect of human cytomegalovirus (HCMV) gene expression on cytokine (beta interferon) and chemokine (RANTES, MIG, MCP-2, MIP-1α, and interleukin-8) expression was examined. We demonstrate that HCMV gene expression is required to suppress the transcriptional induction of these cytokines and that the HCMV immediate-early 2 gene product IE86 can effectively block the expression of cytokines and proinflammatory chemokines during HCMV and Sendai virus infection. Additionally, we present data on viral mutants and ectopic protein expression which demonstrate that pp65, another identified HCMV cytokine antagonist, is not involved in regulating these proinflammatory cytokines. This is the first report to demonstrate that IE86 can act to suppress virus-induced proinflammatory cytokine transcript expression, extending the antiviral properties of this multifunctional viral protein.
Functional Analysis of the Triplex Proteins (VP19C and VP23) of Herpes Simplex Virus Type 1
Authors: Okoye Mercy E. , Sexton Gerry L. , Huang Eugene , McCaffery J. Michael , Desai Prashant 
Published: December 2005

ABSTRACT

The triplex of herpesvirus capsids is a unique structural element. In herpes simplex virus type 1 (HSV-1), one molecule of VP19C and two of VP23 form a three-pronged structure that acts to stabilize the capsid shell through interactions with adjacent VP5 molecules. The interaction between VP19C and VP23 was inferred by yeast cryoelectron microscopy studies and subsequently confirmed by the two-hybrid assay. In order to define the functional domains of VP19C and VP23, a Tn
7
-based transposon was used to randomly insert 15 bp into the coding regions of these two proteins. The mutants were initially screened for interaction in the yeast two-hybrid assay to identify the domains important for triplex formation. Using genetic complementation assays in HSV-1-infected cells, the domains of each protein required for virus replication were similarly uncovered. The same mutations that abolish interaction between these two proteins in the yeast two-hybrid assay similarly failed to complement the growth of the VP23- and VP19C-null mutant viruses in the genetic complementation assay. Some of these mutants were transferred into recombinant baculoviruses to analyze the effect of the mutations on herpesvirus capsid assembly in insect cells. The mutations that abolished the interaction in the yeast two-hybrid assay also abolished capsid assembly in insect cells. The outcome of these experiments showed that insertions in at least four regions and especially the amino terminus of VP23 abolished function, whereas the amino terminus of VP19C can tolerate transposon insertions. A novel finding of these studies was the ability to assemble herpesvirus capsids in insect cells using VP5 and VP19C that contained a histidine handle at their amino terminus.
Monoclonal Antibodies Targeting the HR2 Domain and the Region Immediately Upstream of the HR2 of the S Protein Neutralize In Vitro Infection of Severe Acute Respiratory Syndrome Coronavirus
Authors: Lip Kuo-Ming , Shen Shuo , Yang Xiaoming , Keng Choong-Tat , Zhang Aihua , Oh Hsueh-Ling Janice , Li Zhi-Hong , Hwang Le-Ann , Chou Chih-Fong , Fielding Burtram C. , Tan Timothy H. P. , Mayrhofer Josef , Falkner Falko G. , Fu Jianlin , Lim Seng Gee , Hong Wanjin , Tan Yee-Joo 
Published: December 2005

ABSTRACT

We have previously shown that an
Escherichia coli
-expressed, denatured spike (S) protein fragment of the severe acute respiratory coronavirus, containing residues 1029 to 1192 which include the heptad repeat 2 (HR2) domain, was able to induce neutralizing polyclonal antibodies (C. T. Keng, A. Zhang, S. Shen, K. M. Lip, B. C. Fielding, T. H. Tan, C. F. Chou, C. B. Loh, S. Wang, J. Fu, X. Yang, S. G. Lim, W. Hong, and Y. J. Tan, J. Virol. 79:3289-3296, 2005). In this study, monoclonal antibodies (MAbs) were raised against this fragment to identify the linear neutralizing epitopes in the functional domain and to investigate the mechanisms involved in neutralization. Eighteen hybridomas secreting the S protein-specific MAbs were obtained. Binding sites of these MAbs were mapped to four linear epitopes. Two of them were located within the HR2 region and two immediately upstream of the HR2 domain. MAbs targeting these epitopes showed in vitro neutralizing activities and were able to inhibit cell-cell membrane fusion. These results provide evidence of novel neutralizing epitopes that are located in the HR2 domain and the spacer region immediately upstream of the HR2 of the S protein.
Human Cytomegalovirus Protein pp71 Disrupts Major Histocompatibility Complex Class I Cell Surface Expression
Authors: Trgovcich Joanne , Cebulla Colleen , Zimmerman Pete , Sedmak Daniel D. 
Published: December 2005

ABSTRACTThe human cytomegalovirus tegument protein pp71 is the product of the UL82 gene. Roles for pp71 in stimulating gene transcription, increasing infectivity of viral DNA, and the degradation of retinoblastoma family proteins have been described. Here we report a novel function for pp71 in limiting accumulation of cell surface major histocompatibility complex (MHC) class I complexes. MHC molecules were analyzed in glioblastoma cells exposed to a replication-defective adenovirus expressing UL82 (Adpp71) or after transient transfection of the UL82 gene. Accumulation of cell surface MHC class I levels diminished in a specific and dose-dependent manner after exposure to Adpp71 but not after exposure to an adenovirus expressing β-galactosidase (Adβgal). UL82 expression did not interfere with accumulation of either MHC class I heavy-chain transcript or protein, nor did UL82 expression correlate with markers of apoptosis. Rather, UL82 expression correlated with an increased proportion of MHC class I molecules exhibiting sensitivity to endoglycosidase H treatment. Finally, we show that, in cells infected with recombinant virus strain missing all of the unique short region MHC class I evasion genes, disruption of UL82 expression by short, interfering RNAs led to increased accumulation of cell surface MHC class I complexes. These findings support a novel role for HCMV pp71 in disruption of the MHC class I antigen presentation pathway.
Adenovirus E1B 55-Kilodalton Protein Is Required for both Regulation of mRNA Export and Efficient Entry into the Late Phase of Infection in Normal Human Fibroblasts
Authors: Gonzalez Ramon , Huang Wenying , Finnen Renee , Bragg Courtney , Flint S. J. 
Published: December 2005

ABSTRACT

The human adenovirus type 5 (Ad5) E1B 55-kDa protein is required for selective nuclear export of viral late mRNAs from the nucleus and concomitant inhibition of export of cellular mRNAs in HeLa cells and some other human cell lines, but its contributions(s) to replication in normal human cells is not well understood. We have therefore examined the phenotypes exhibited by viruses carrying mutations in the E1B 55-kDa protein coding sequence in normal human fibroblast (HFFs). Ad5 replicated significantly more slowly in HFFs than it does in tumor cells, a difference that is the result of delayed entry into the late phase of infection. The A143 mutation, which specifically impaired export of viral late mRNAs from the nucleus in infected HeLa cells (R. A. Gonzalez and S. J. Flint, J. Virol.
76:
4507-4519, 2002), induced a more severe defect in viral mRNA export in HFFs. This observation indicates that the E1B 55-kDa protein regulates mRNA export during the late phase of infection of normal human cells. Other mutants exhibited phenotypes not observed in HeLa cells. In HFFs infected by the null mutant Hr6, synthesis of viral late mRNAs and proteins was severely impaired. Such defects in late gene expression were the result of inefficient progression into the late phase of infection, for viral DNA synthesis was 10-fold less efficient in Hr6-infected HFFs than in cells infected by Ad5. Similar, but less severe, defects in viral DNA synthesis were induced by the insertion mutation H224, which has been reported to inhibit binding of the E1B 55-kDa protein to p53 (C. C. Kao, P. R. Yew, and A. J. Berk, Virology
179:
806-814, 1990).
Natural History of Human Respiratory Syncytial Virus Inferred from Phylogenetic Analysis of the Attachment (G) Glycoprotein with a 60-Nucleotide Duplication
Authors: Trento Alfonsina , Viegas Mariana , Galiano Mónica , Videla Cristina , Carballal Guadalupe , Mistchenko Alicia S. , Melero José A. 
Published: December 2005

ABSTRACT
A total of 47 clinical samples were identified during an active surveillance program of respiratory infections in Buenos Aires (BA) (1999 to 2004) that contained sequences of human respiratory syncytial virus (HRSV) with a 60-nucleotide duplication in the attachment (G) protein gene. This duplication was analogous to that previously described for other three viruses also isolated in Buenos Aires in 1999 (A. Trento et al., J. Gen. Virol. 84:3115-3120, 2003). Phylogenetic analysis indicated that BA sequences with that duplication shared a common ancestor (dated about 1998) with other HRSV G sequences reported worldwide after 1999. The duplicated nucleotide sequence was an exact copy of the preceding 60 nucleotides in early viruses, but both copies of the duplicated segment accumulated nucleotide substitutions in more recent viruses at a rate apparently higher than in other regions of the G protein gene. The evolution of the viruses with the duplicated G segment apparently followed the overall evolutionary pattern previously described for HRSV, and this genotype has replaced other prevailing antigenic group B genotypes in Buenos Aires and other places. Thus, the duplicated segment represents a natural tag that can be used to track the dissemination and evolution of HRSV in an unprecedented setting. We have taken advantage of this situation to reexamine the molecular epidemiology of HRSV and to explore the natural history of this important human pathogen.
Host Response to the Attenuated Poxvirus Vector NYVAC: Upregulation of Apoptotic Genes and NF-κB-Responsive Genes in Infected HeLa Cells
Authors: Guerra Susana , López-Fernández Luis A. , Pascual-Montano Alberto , Nájera José Luis , Zaballos Angel , Esteban Mariano 
Published: December 2005

ABSTRACT
NYVAC has been engineered as a safe, attenuated vaccinia virus (VV) vector for use in vaccination against a broad spectrum of pathogens and tumors. Due to the interest in NYVAC-based vectors as vaccines and current phase I/II clinical trials with this vector, there is a need to analyze the human host response to NYVAC infection. Using high-density cDNA microarrays, we found 368 differentially regulated genes after NYVAC infection of HeLa cells. Clustering of the regulated genes identified six discrete gene clusters with altered expression patterns. Clusters 1 to 3 represented 47.5% of the regulated genes, with three patterns of gene activation kinetics, whereas clusters 4 to 6 showed distinct repression kinetics. Quantitative real-time reverse transcription-PCR analysis of selected genes validated the array data. Upregulated transcripts correlated with genes implicated in immune responses, including those encoding interleukin-1 receptor 2 (IL-1R2), IL-6, ISG-15, CD-80, and TNFSF7. NYVAC upregulated several intermediates of apoptotic cascades, including caspase-9, correlating with its ability to induce apoptosis. NYVAC infection also stimulated the expression of NF-κB1 and NF-κB2 as well as that of NF-κB target genes. Expression of the VV host range K1L gene during NYVAC infection prevented NF-κB activation, but not the induction of apoptosis. This study is the first overall analysis of the transcriptional response of human cells to NYVAC infection and provides a framework for future functional studies to evaluate this vector and its derivatives as human vaccines.
Consistent Patterns of Change during the Divergence of Human Immunodeficiency Virus Type 1 Envelope from That of the Inoculated Virus in Simian/Human Immunodeficiency Virus-Infected Macaques
Authors: Blay W.M. , Gnanakaran S. , Foley B. , Doria-Rose N. A. , Korber B. T. , Haigwood N. L. 
Published: December 2005

ABSTRACTWe have analyzed changes to proviral Env gp120 sequences and the development of neutralizing antibodies (NAbs) during 1 year of simian/human immunodeficiency virus SHIV-89.6P infection in 11Macaca nemestrinamacaques. Seven macaques had significantenvdivergence from that of the inoculum, and macaques with greater divergence had higher titers of homologous NAbs. Substitutions in sequons encoding potential N-linked glycosylation sites (PNGs) were among the first to be established, although overall the total number of sequons did not increase significantly. The majority (19 of 23) of PNGs present in the inoculum were conserved in the sequences from all macaques. Statistically significant variations in PNGs occurred in multiple macaques within constrained regions we term “hot spots,” resulting in the selection of sequences more similar to the B consensus. These included additions on V1, the N-terminal side of V4, and the outer region of C2. Complex mutational patterns resulted in convergent PNG shifts in V2 and V5. Charge changes in Env V1V2, resulting in a net acidic charge, and a proline addition in V5 occurred in several macaques. Molecular modeling of the 89.6P sequence showed that the conserved glycans lie on the silent face of Env and that many are proximal to disulfide bonds, while PNG additions and shifts are proximal to the CD4 binding site. Nonsynonymous-to-synonymous substitution ratios suggest that these changes result from selective pressure. This longitudinal and cross-sectional study of mutations in human immunodeficiency virus (HIV)envin the SHIV background provides evidence that there are more constraints on the configuration of the glycan shield than were previously appreciated.
Bone Morphogenetic Protein-2–Induced Transformation Involves the Activation of Mammalian Target of Rapamycin
Authors: Langenfeld Elaine M. , Kong Yingxin , Langenfeld John 
Published: December 2005

AbstractBone morphogenetic protein-2 (BMP-2) is an evolutionary conserved protein that is essential for embryonic development. BMP-2 is highly expressed in ∼98% of human lung carcinomas with little expression in normal lung tissues. BMP-2 has been shown to enhance mobility, invasiveness, and metastasis of cancer cell lines. During development, BMP-2 induces the proto-oncogene phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) signaling pathway to regulate stem cell differentiation. We show that BMP-2 induces the phosphorylation of mTOR in A549 and H1299 lung cancer cell lines, which is attenuated by the PI3K antagonists LY-294002 and wortmannin. p70S6 kinase, which is a direct downstream target of mTOR, is also regulated by BMP-2 in lung cancer cell lines. We find that BMP-2 induces cyclin E in A549 and H1299 cells, which is mediated by the PI3K/mTOR signaling pathway. The regulation of cyclin E by BMP-2 occurs through a Smad 1/5–independent mechanism. Forced expression of BMP-2 in A549 cells (A549/BMP-2) induces transformation as shown by an increase in foci formation. The mTOR antagonist, rapamycin, prevented foci formation of the A549/BMP-2 cells. This study provides evidence that BMP-2-mediated transformation of lung cancer cells involves the activation of the PI3K/mTOR signaling pathway. (Mol Cancer Res 2005;3(12):679–84)
Buddy Bots: How Turing's Fast Friends Are Undermining Consumer Privacy
Authors: Kerr Ian R. , Bornfreund Marcus 
Published: December 2005

Intelligent agents are currently being deployed in virtual environments to enable interaction with consumers in furtherance of various corporate strategies involving marketing, sales, and customer service. Some online businesses have recently begun to adopt automation technologies that are capable of altering both their own, and consumers', legal rights and obligations. In a rapidly evolving field known as affective computing, the creators of some automation technologies are utilizing various principles of cognitive science and artificial intelligence to generate avatars capable of garnering consumer trust. Unfortunately, this trust has been exploited by some to undertake extensive, clandestine consumer profiling under the guise of friendly conversation. Buddy bots and other such applications have been used by businesses to collect valuable personal information and private communications without lawful consent. This article critically examines such practices and provides basic consumer protection principles, an adherence to which promises to generate a more socially responsible vision of the application of artificial intelligence in automated electronic commerce. I care so much for you—didn't think that I could, I can't tell my heart that you're no good. Bob Dylan, Honest With Me