bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of a Mouse Cytomegalovirus Gene Selectively Targeting CD86 Expression on Antigen-Presenting Cells
Authors: Loewendorf Andrea , Krüger Corinna , Borst Eva Maria , Wagner Markus , Just Ursula , Messerle Martin 
Published: November 2004

ABSTRACT

We and others have shown that infection of dendritic cells with murine cytomegalovirus (MCMV) leads to severe functional impairment of these antigen-presenting cells (D. M. Andrews, C. E. Andoniou, F. Granucci, P. Ricciardi-Castagnoli, and M. A. Degli-Esposti, Nat. Immunol.
2:
1077-1084, 2001; S. Mathys, T. Schroeder, J. Ellwart, U. H. Koszinowski, M. Messerle, and U. Just, J. Infect. Dis.
187:
988-999, 2003). Phenotypically, reduced surface expression of costimulatory molecules and major histocompatibility complex molecules was detected. In order to identify the molecular basis for the observed effects, we generated MCMV mutants with large deletions of nonessential genes. The study was facilitated by the finding that a monocyte-macrophage cell line displayed similar phenotypic alterations after MCMV infection. By analyzing the expression of cell surface molecules on infected cells, we identified a mutant virus which is no longer able to downmodulate the expression of the costimulatory molecule CD86. Additional mutants with smaller deletions allowed us to pin down the responsible gene to a certain genomic region. RNA analysis led to the identification of the spliced gene m147.5, encoding a protein with 145 amino acids. Experiments with an m147.5 mutant revealed that the protein affects CD86 expression only, suggesting that additional MCMV genes are responsible for downmodulation of the other surface molecules. Identification of viral gene products interfering with functionally important proteins of antigen-presenting cells will provide the basis to dissect the complex interaction of CMV with these important cells and to evaluate the biological importance of these viral genes in vivo.
Bracoviruses Contain a Large Multigene Family Coding for Protein Tyrosine Phosphatases
Authors: Provost Bertille , Varricchio Paola , Arana Eloisa , Espagne Eric , Falabella Patrizia , Huguet Elisabeth , La Scaleia Raffaella , Cattolico Laurence , Poirié Marylène , Malva Carla , Olszewski Julie A. , Pennacchio Francesco , Drezen Jean-Michel 
Published: November 2004

ABSTRACT

The relationship between parasitic wasps and bracoviruses constitutes one of the few known mutualisms between viruses and eukaryotes. The virions produced in the wasp ovaries are injected into host lepidopteran larvae, where virus genes are expressed, allowing successful development of the parasite by inducing host immune suppression and developmental arrest. Bracovirus-bearing wasps have a common phylogenetic origin, and contemporary bracoviruses are hypothesized to have been inherited by chromosomal transmission from a virus that originally integrated into the genome of the common ancestor wasp living 73.7 ± 10 million years ago. However, so far no conserved genes have been described among different braconid wasp subfamilies. Here we show that a gene family is present in bracoviruses of different braconid wasp subfamilies (
Cotesia congregata
, Microgastrinae, and
Toxoneuron nigriceps
, Cardiochilinae) which likely corresponds to an ancient component of the bracovirus genome that might have been present in the ancestral virus. The genes encode proteins belonging to the protein tyrosine phosphatase family, known to play a key role in the control of signal transduction pathways. Bracovirus protein tyrosine phosphatase genes were shown to be expressed in different tissues of parasitized hosts, and two protein tyrosine phosphatases were produced with recombinant baculoviruses and tested for their biochemical activity. One protein tyrosine phosphatase is a functional phosphatase. These results strengthen the hypothesis that protein tyrosine phosphatases are involved in virally induced alterations of host physiology during parasitism.
Separate Sequences in a Murine Retroviral Envelope Protein Mediate Neuropathogenesis by Complementary Mechanisms with Differing Requirements for Tumor Necrosis Factor Alpha
Authors: Peterson Karin E. , Hughes Scott , Dimcheff Derek E. , Wehrly Kathy , Chesebro Bruce 
Published: November 2004

ABSTRACT

The innate immune response, through the induction of proinflammatory cytokines and antiviral factors, plays an important role in protecting the host from pathogens. Several components of the innate response, including tumor necrosis factor alpha (TNF-α), monocyte chemoattractant protein 1, interferon-inducible protein 10, and RANTES, are upregulated in the brain following neurovirulent retrovirus infection in humans and in animal models. However, it remains unclear whether this immune response is protective, pathogenic, or both. In the present study, by using TNF-α
−/−
mice we analyzed the contribution of TNF-α to neurological disease induced by four neurovirulent murine retroviruses, with three of these viruses encoding portions of the same neurovirulent envelope protein. Surprisingly, only one retrovirus (EC) required TNF-α for disease induction, and this virus induced less TNF-α expression in the brain than did the other retroviruses. Analysis of glial fibrillary acidic protein and F4/80 in EC-infected TNF-α
−/−
mice showed normal activation of astrocytes but not of microglia. Thus, TNF-α-mediated microglial activation may be important in the pathogenic process initiated by EC infection. In contrast, TNF-α was not required for pathogenesis of the closely related BE virus and the BE virus induced disease in TNF-α
−/−
mice by a different mechanism that did not require microglial activation. These results provide new insights into the multifactorial mechanisms involved in retrovirus-induced neurodegeneration and may also have analogies to other types of neurodegeneration.
Inhibition of Tumor Necrosis Factor (TNF) Signal Transduction by the Adenovirus Group C RID Complex Involves Downregulation of Surface Levels of TNF Receptor 1
Authors: Fessler Shawn P. , Chin Y. Rebecca , Horwitz Marshall S. 
Published: November 2004

ABSTRACTAdenoviruses employ multiple genes to inhibit the host antiviral responses. There is increasing evidence that these immunoregulatory genes may function either during lytic or latent infection. Adenovirus early transcription region 3 (E3) encodes at least seven proteins, five of which block the acquired or innate immune response. Previous findings from this laboratory demonstrated that the E3 proteins 10.4K and 14.5K, which form a complex in the plasma membrane, inhibit tumor necrosis factor (TNF)-induced activation of NF-κB and the synthesis of chemokines. To determine the mechanism of inhibition of these pathways by the adenovirus E3 10.4K/14.5K proteins, we have examined the effects of this viral complex on the inhibition of AP-1 and NF-κB activation by TNF and found a reduction in assembly of the TNF receptor 1 (TNFR1) signaling complex at the plasma membrane accompanied by downregulation of surface levels of TNFR1.
Gender Differences in Human Immunodeficiency Virus Type 1-Specific CD8 Responses in the Reproductive Tract and Colon following Nasal Peptide Priming and Modified Vaccinia Virus Ankara Boosting
Authors: Peacock James W. , Nordone Sushila K. , Jackson Shawn S. , Liao Hua-Xin , Letvin Norman L. , Yafal Alicia Gomez , Gritz Linda , Mazzara Gail P. , Haynes Barton F. , Staats Herman F. 
Published: November 2004

ABSTRACTInduction of mucosal anti-human immunodeficiency virus type 1 (HIV-1) T-cell responses in males and females will be important for the development of a successful HIV-1 vaccine. An HIV-1 envelope peptide, DNA plasmid, and recombinant modified vaccinia virus Ankara (rMVA) expressing the H-2Dd-restricted cytotoxic T lymphocyte P18 epitope were used as immunogens to test for their ability to prime and boost anti-HIV-1 T-cell responses at mucosal and systemic sites in BALB/c mice. We found of all prime-boost combinations tested, an HIV-1 Env peptide subunit mucosal prime followed by systemic (intradermal) boosting with rMVA yielded the maximal induction of gamma interferon (IFN-γ) spot-forming cells in the female genital tract and colon. However, this mucosal prime-systemic rMVA boost regimen was minimally immunogenic for the induction of genital, colon, or lung anti-HIV-1 T-cell responses in male mice. We determined that a mucosal Env subunit immunization could optimally prime an rMVA boost in female but not male mice, as determined by the magnitude of antigen-specific IFN-γ responses in the reproductive tracts, colon, and lung. Defective mucosal priming in male mice could not be overcome by multiple mucosal immunizations. However, rMVA priming followed by an rMVA boost was the optimal prime-boost strategy for male mice as determined by the magnitude of antigen-specific IFN-γ responses in the reproductive tract and lung. Thus, prime-boost immunization strategies able to induce mucosal antigen-specific IFN-γ responses were identified for male and female mice. Understanding the cellular and molecular basis of gender-determined immune responses will be important for optimizing induction of anti-HIV-1 mucosal immune responses in both males and females.
Human Cytomegalovirus-Specific CD4
+
-T-Cell Cytokine Response Induces Fractalkine in Endothelial Cells
Authors: Bolovan-Fritts Cynthia A. , Trout Rodney N. , Spector Stephen A. 
Published: November 2004

ABSTRACT

Cytomegalovirus (CMV) infection has been linked to inflammation-related disease processes in the human host, including vascular diseases and chronic transplant rejection. The mechanisms through which CMV affects the pathogenesis of these diseases are for the most part unknown. To study the contributing role of the host immune response to CMV in these chronic inflammatory processes, we examined endothelial cell interactions with peripheral blood mononuclear cells (PBMC). Endothelial cultures were monitored for levels of fractalkine induction as a marker for initiating the host inflammatory response. Our results demonstrate that in the presence of CMV antigen PBMC from normal healthy CMV-seropositive donors produce soluble factors that induce fractalkine in endothelial cells. This was not observed in parallel assays with PBMC from seronegative donors. Examination of subset populations within the PBMC further revealed that CMV antigen-stimulated CD4
+
T cells were the source of the factors, gamma interferon and tumor necrosis factor alpha, driving fractalkine induction. Direct contact between CD4
+
cells and the endothelial monolayers is required for this fractalkine induction, where the endothelial cells appear to provide antigen presentation functions. These findings indicate that CMV may represent one member of a class of persistent pathogens where the antigen-specific T-cell response can result in the induction of fractalkine, leading to chronic inflammation and endothelial cell injury.
Comprehensive Cross-Clade Neutralization Analysis of a Panel of Anti-Human Immunodeficiency Virus Type 1 Monoclonal Antibodies
Authors: Binley James M. , Wrin Terri , Korber Bette , Zwick Michael B. , Wang Meng , Chappey Colombe , Stiegler Gabriela , Kunert Renate , Zolla-Pazner Susan , Katinger Hermann , Petropoulos Christos J. , Burton Dennis R. 
Published: November 2004

ABSTRACTBroadly neutralizing monoclonal antibodies (MAbs) are potentially important tools in human immunodeficiency virus type 1 (HIV-1) vaccine design. A few rare MAbs have been intensively studied, but we still have a limited appreciation of their neutralization breadth. Using a pseudovirus assay, we evaluated MAbs from clade B-infected donors and a clade B HIV+plasma against 93 viruses from diverse backgrounds. Anti-gp120 MAbs exhibited greater activity against clade B than non-B viruses, whereas anti-gp41 MAbs exhibited broad interclade activity. Unexpectedly, MAb 4E10 (directed against the C terminus of the gp41 ectodomain) neutralized all 90 viruses with moderate potency. MAb 2F5 (directed against an epitope adjacent to that of 4E10) neutralized 67% of isolates, but none from clade C. Anti-gp120 MAb b12 (directed against an epitope overlapping the CD4 binding site) neutralized 50% of viruses, including some from almost every clade. 2G12 (directed against a high-mannose epitope on gp120) neutralized 41% of the viruses, but none from clades C or E. MAbs to the gp120 V3 loop, including 447-52D, neutralized a subset of clade B viruses (up to 45%) but infrequently neutralized other clades (≤7%). MAbs b6 (directed against the CD4 binding site) and X5 (directed against a CD4-induced epitope of gp120) neutralized only sensitive primary clade B viruses. The HIV+plasma neutralized 70% of the viruses, including some from all major clades. Further analysis revealed five neutralizing immunotypes that were somewhat associated with clades. As well as the significance for vaccine design, our data have implications for passive-immunization studies in countries where clade C viruses are common, given that only MAbs b12 and 4E10 were effective against viruses from this clade.
Biological Significance of the Second Receptor Binding Site of Newcastle Disease Virus Hemagglutinin-Neuraminidase Protein
Authors: Bousse Tatiana L. , Taylor Garry , Krishnamurthy Sateesh , Portner Allen , Samal Siba K. , Takimoto Toru 
Published: November 2004

ABSTRACT

The paramyxovirus hemagglutinin-neuraminidase (HN) is a multifunctional protein responsible for attachment to receptors containing sialic acid, neuraminidase (NA) activity, and the promotion of membrane fusion, which is induced by the fusion protein. Analysis of the three-dimensional structure of Newcastle disease virus (NDV) HN protein revealed the presence of a large pocket, which mediates both receptor binding and NA activities. Recently, a second sialic acid binding site on HN was revealed by cocrystallization of the HN with a thiosialoside Neu5Ac-2-
S
-α(2,6)Gal1OMe, suggesting that NDV HN contains an additional sialic acid binding site. To evaluate the role of the second binding site on the life cycle of NDV, we rescued mutant viruses whose HNs were mutated at Arg516, a key residue that is involved in the second binding site. Loss of the second binding site on mutant HNs was confirmed by the hemagglutination inhibition test, which uses an inhibitor designed to block the NA active site. Characterization of the biological activities of HN showed that the mutation at Arg516 had no effect on NA activity. However, the fusion promotion activity of HN was substantially reduced by the mutation. Furthermore, the mutations at Arg516 slowed the growth rate of virus in tissue culture cells. These results suggest that the second binding site facilitates virus infection and growth by enhancing the fusion promotion activity of the HN.
Reevaluation of the Virulence of Prototypic Strain 15 of Pneumonia Virus of Mice
Authors: Krempl Christine D. , Collins Peter L. 
Published: November 2004

ABSTRACT
Prototypic strain 15 of pneumonia virus of mice (PVM) has been described as being nonpathogenic in mice, in contrast to the mouse-passaged, highly virulent strain J3666. Previous sequence analysis also indicated that strain 15 encodes an attachment G protein that is truncated at the amino terminus, which for the amino terminally anchored protein deletes the cytoplasmic tail. However, we found that PVM strain 15 obtained from the American Type Culture Collection was highly virulent in mice and was essentially indistinguishable on that basis from strain J3666. Sequence analysis showed that this preparation of virus encodes a G protein with an intact cytoplasmic tail: the truncated predicted protein in the previous sequence appeared to be due to a single nucleotide insertion that disrupted the upstream end of the open reading frame and shifted the translational start site to the next downstream AUG. Taken together, the two studies indicate that strain 15 is an inherently virulent strain but that a nonpathogenic variant that was generated during passage in vitro and encodes a truncated G protein exists. Interestingly, the majority sequence of strain J3666 was found to encode a G protein with an extended cytoplasmic tail, suggesting that there is the potential for considerable plasticity in the cytoplasmic tail of the G protein of PVM.
Raf-Induced Vascular Endothelial Growth Factor Augments Kaposi's Sarcoma-Associated Herpesvirus Infection
Authors: Hamden Khalief E. , Ford Patrick W. , Whitman Audy G. , Dyson Ossie F. , Cheng Shi-Yuan , McCubrey James A. , Akula Shaw M. 
Published: November 2004

ABSTRACT

Recombinant green fluorescent protein encoding Kaposi's sarcoma-associated herpesvirus (rKSHV.152) infection of β-estradiol stimulated human foreskin fibroblasts (HFF) or HFF/ΔB-Raf
[FF]
:ER (expressing a weaker form of B-Raf) could be enhanced to levels comparable to that of HFF/ΔB-Raf
[DD]
:ER cells by pretreating cells with soluble vascular endothelial growth factor (VEGF). Conversely, VEGF expression and infection efficiency typically observed in β-estradiol stimulated HFF/ΔB-Raf
[DD]
:ER cells could be lowered significantly by treating with VEGF small interfering RNA. In addition, we observed enhancement of the KSHV infection in HFF cells transfected with human VEGF
121
. These results confirm the ability of Raf-induced VEGF to augment KSHV infection of cells.
RNA Degradation Induced by the Herpes Simplex Virus vhs Protein Proceeds 5′ to 3′ In Vitro
Authors: Perez-Parada Jorge , Saffran Holly A. , Smiley James R. 
Published: November 2004

ABSTRACT
The herpes simplex virus virion host shutoff protein (vhs) is an mRNA-specific RNase that contributes to shutoff of host protein synthesis. We show here that vhs-induced mRNA decay proceeds 5′ to 3′ in an in vitro assay system derived from rabbit reticulocyte lysate.
A MULTILEVEL FUSION APPROACH TO OBJECT IDENTIFICATION IN OUTDOOR ROAD SCENES
Authors: MURINO VITTORIO , REGAZZONI CARLO S. , FORESTI GIAN LUCA , VERNAZZA GIANNI 
Published: November 2004

The task of object identification is fundamental to the operations of an autonomous vehicle. It can be accomplished by using techniques based on a Multisensor Fusion framework, which allows the integration of data coming from different sensors. In this paper, an approach to the synergic interpretation of data provided by thermal and visual sensors is proposed. Such integration is justified by the necessity for solving the ambiguities that may arise from separate data interpretations. The architecture of a distributed Knowledge-Based system is described. It performs an Intelligent Data Fusion process by integrating, in an opportunistic way, data acquired with a thermal and a video (b/w) camera. Data integration is performed at various architecture levels in order to increase the robustness of the whole recognition process. A priori models allow the system to obtain interesting data from both sensors; to transform such data into intermediate symbolic objects; and, finally, to recognize environmental situations on which to perform further processing. Some results are reported for different environmental conditions (i.e. a road scene by day and by night, with and without the presence of obstacles).
A NEW STRUCTURAL TECHNIQUE FOR RECOGNIZING PRINTED ARABIC TEXT
Authors: AL-SADOUN HUMOUD B. , AMIN ADNAN 
Published: November 2004

This paper proposes a new structural technique for Arabic text recognition. The technique can be divided into five major steps: (1) preprocessing and binarization; (2) thinning; (3) binary tree construction; (4) segmentation; and (5) recognition. The advantage of this technique is that its execution does not depend on either the font or size of character. Thus, this same technique might be utilized for the recognition of machine or hand printed text. The relevant algorithm is implemented on a microcomputer. Experiments were conducted to verify the accuracy and the speed of this algorithm using about 20,000 subwords each with an average length of 3 characters. The subwords used were written using different fonts. The recognition rate obtained in the experiments indicated an accuracy of 93.38 % with a speed of 2.7 characters per second.
COOPERATING SYSTEMS OF THREE-WAY, TWO-DIMENSIONAL FINITE AUTOMATA
Authors: WANG YUE , INOUE KATSUSHI , TAKANAMI ITSUO 
Published: November 2004

This paper introduces a cooperating system of three-way, two-dimensional finite automata (CS-TR2-FA) which is a restricted version of a cooperating system of four- way, two-dimensional finite automata (CS-2-FA), and mainly investigates several fundamental properties of this system as a two-dimensional language acceptor whose input tapes are restricted to square ones. We show that (1) CS-TR2-FA’s are equivalent in accepting power to three-way, two-dimensional simple multihead finite automata, (2) CS-2-FA’s are more powerful than CS-TR2-FA’s, (3) £[CS-TR2-DFA(k)S] ⊊ £[CS-TR2-NFA(k)S], (4) ⋃1≤k<∞ £[CS-TR2-DFA(k)S] ⊊ ⋃1≤k<∞ £[CS-TR2-NFA(k)S], and (5) £[CS-TR2-DFA(k)S] (£[CS-TR2-NFA(k)S]) ⊊ £[CS-TR2-DFA(k+1)S] (£[CS-TR2-NFA(k+1)S]), where £[CS-TR2-DFA(k)S] (£[CS-TR2-NFA(k)S]) denotes the class of sets of square input tapes accepted by CS-TR2-FA’s which consist of k deterministic (non-deterministic) finite automata.
HIDDEN MARKOV MODELS IN TEXT RECOGNITION
Authors: ANIGBOGU J.C. , BELAÏD A. 
Published: November 2004

A multi-level multifont character recognition is presented. The system proceeds by first delimiting the context of the characters. As a way of enhancing system performance, typographical information is extracted and used for font identification before actual character recognition is performed. This has the advantage of sure character identification as well as text reproduction in its original form. The font identification is based on decision trees where the characters are automatically arranged differently in confusion classes according to the physical characteristics of fonts. The character recognizers are built around the first and second order hidden Markov models (HMM) as well as Euclidean distance measures. The HMMs use the Viterbi and the Extended Viterbi algorithms to which enhancements were made. Also present is a majority-vote system that polls the other systems for “advice” before deciding on the identity of a character. Among other things, this last system is shown to give better results than each of the other systems applied individually. The system finally uses combinations of stochastic and dictionary verification methods for word recognition and error-correction.
SPECIFIC SAFETY ASPECTS OF ELECTRIC ROAD VEHICLE TRACTION SYSTEMS
Authors: VAN DEN BOSSCHE P. 
Published: November 2004

Due to their beneficial effect on environment in urban traffic, electric vehicles are an important factor for the improvement of traffic and more particularly for a healthier living environment. Electric vehicles however represent a completely different technology compared with internal combustion engines. This means that new safety hazards, mainly related to the characteristics of high-power electric equipment, may be present. The electric vehicle system will be designed to operate safely in all conditions; a number of specific problems will be treated, concentrating on aspects of vehicle behaviour which are typical for electric vehicles. At this moment the standards and official regulations concerning electric road vehicles are not very clearly defined. The existing documents and standards are far from harmonised, and they cover a vehicle in full technological evolution. Another aspect is the psychological awareness of these "new" risks: the presence of high voltages or of battery chemicals may be used as an argument against electric vehicles; the fact that internal-combustion-engined vehicles present large risks too is often overlooked, since people get accustomed to the danger.