bluuebunny/crossref_metadata_2025_split huggingface dataset:
Induction of Human Immunodeficiency Virus (HIV)-Specific CD8 T-Cell Responses byListeria monocytogenesand a HyperattenuatedListeriaStrain Engineered To Express HIV Antigens
Authors: Friedman Rachel S. , Frankel Fred R. , Xu Zhan , Lieberman Judy 
Published: July 2002

ABSTRACTInduction of cell-mediated immunity may be essential for an effective AIDS vaccine.Listeria monocytogenesis an attractive bacterial vector to elicit T-cell immunity to human immunodeficiency virus (HIV) because it specifically infects monocytes, key antigen-presenting cells, and because natural infection originates at the mucosa. Immunization with recombinantL. monocytogeneshas been shown to protect mice from lymphocytic choriomeningitis virus, influenza virus, and tumor inoculation.L. monocytogenesexpressing HIVgagelicits sustained high levels of Gag-specific cytotoxic T lymphocytes (CTLs) in mice. We have examined the ability ofListeriato infect human monocytes and present HIV antigens to CD8 T lymphocytes of HIV-infected donors to induce a secondary T-cell immune response. Using this in vitro vaccination protocol, we show thatL. monocytogenesexpressing the HIV-1gaggene efficiently provides a strong stimulus for Gag-specific CTLs in HIV-infected donor peripheral blood mononuclear cells.Listeriaexpressing Nef also elicits a secondary in vitro anti-Nef CTL response. SinceL. monocytogenesis a pathogen, before it can be seriously considered as a human vaccine vector, safety concerns must be addressed. We therefore have produced a highly attenuated strain ofL. monocytogenesthat requiresd-alanine for viability. The recombinant bacteria are attenuated at least 105-fold. We show that when these hyperattenuated bacteria are engineered to express HIV-1 Gag, they are at least as efficient at stimulating Gag-specific human CTLs in vitro as wild-type recombinants. These results suggest that attenuatedListeriais an attractive candidate vaccine vector to induce T-cell immunity to HIV in humans.
The Vaccinia Virus Soluble Alpha/Beta Interferon (IFN) Receptor Binds to the Cell Surface and Protects Cells from the Antiviral Effects of IFN
Authors: Alcamı́ Antonio , Symons Julian A. , Smith Geoffrey L. 
Published: July 2002

ABSTRACT
Poxviruses encode a broad range of proteins that interfere with host immune functions, such as soluble versions of receptors for the cytokines tumor necrosis factor, interleukin-1β, gamma interferon (IFN-γ), IFN-α/β, and chemokines. These virus-encoded cytokine receptors have a profound effect on virus pathogenesis and enable the study of the role of cytokines in virus infections. The vaccinia virus (VV) Western Reserve gene B18R encodes a secreted protein with 3 immunoglobulin domains that functions as a soluble receptor for IFN-α/β. We have found that after secretion B18R binds to both uninfected and infected cells. The B18R protein present at the cell surface maintains the properties of the soluble receptor, binding IFN-α/β with high affinity and with broad species specificity, and protects cells from the antiviral state induced by IFN-α/β. VV strain Wyeth expressed a truncated B18R protein lacking the C-terminal immunoglobulin domain. This protein binds IFN with lower affinity and retains its ability to bind to cells, indicating that the C-terminal region of B18R contributes to IFN binding. The replication of a VV B18R deletion mutant in tissue culture was restricted in the presence of IFN-α, whereas the wild-type virus replicated normally. Binding of soluble recombinant B18R to cells protected the cultures from IFN and allowed VV replication. This represents a novel strategy of virus immune evasion in which secreted IFN-α/β receptors not only bind the soluble cytokine but also bind to uninfected cells and protect them from the antiviral effects of IFN-α/β, maintaining the cells' susceptibility to virus infections. The adaptation of this soluble receptor to block IFN-α/β activity locally will help VV to replicate in the host and spread in tissues. This emphasizes the importance of local effects of IFN-α/β against virus infections.
Expression and Characterization of a Single-Chain Polypeptide Analogue of the Human Immunodeficiency Virus Type 1 gp120-CD4 Receptor Complex
Authors: Fouts Timothy R. , Tuskan Robert , Godfrey Karla , Reitz Marvin , Hone David , Lewis George K. , DeVico Anthony L. 
Published: July 2002

ABSTRACT

The infection of CD4
+
host cells by human immunodeficiency virus type 1 (HIV-1) is initiated by a temporal progression of interactions between specific cell surface receptors and the viral envelope protein, gp120. These interactions produce a number of intermediate structures with distinct conformational, functional, and antigenic features that may provide important targets for therapeutic and vaccination strategies against HIV infection. One such intermediate, the gp120-CD4 complex, arises from the interaction of gp120 with the CD4 receptor and enables interactions with specific coreceptors needed for viral entry. gp120-CD4 complexes are thus promising targets for anti-HIV vaccines and therapies. The development of such strategies would be greatly facilitated by a means to produce the gp120-CD4 complexes in a wide variety of contexts. Accordingly, we have developed single-chain polypeptide analogues that accurately replicate structural, functional, and antigenic features of the gp120-CD4 complex. One analogue (FLSC) consists of full-length HIV-1BaL gp120 and the D1D2 domains of CD4 joined by a 20-amino-acid linker. The second analogue (TcSC) contains a truncated form of the gp120 lacking portions of the C1, C5, V1, and V2 domains. Both molecules exhibited increased exposure of epitopes in the gp120 coreceptor-binding site but did not present epitopes of either gp120 or CD4 responsible for complex formation. Further, the FLSC and TcSC analogues bound specifically to CCR5 (R5) and blocked R5 virus infection. Thus, these single-chain chimeric molecules represent the first generation of soluble recombinant proteins that mimic the gp120-CD4 complex intermediate that arises during HIV replication.
The Membrane-Proximal Stem Region of Vesicular Stomatitis Virus G Protein Confers Efficient Virus Assembly
Authors: Robison Clinton S. , Whitt Michael A. 
Published: July 2002

ABSTRACT
In this report, we show that the glycoprotein of vesicular stomatitis virus (VSV G) contains within its extracellular membrane-proximal stem (GS) a domain that is required for efficient VSV budding. To determine a minimal sequence in GS that provides for high-level virus assembly, we have generated a series of recombinant ΔG-VSVs which express chimeric glycoproteins having truncated stem sequences. The recombinant viruses having chimeras with 12 or more membrane-proximal residues of the G stem, and including the G protein transmembrane-cytoplasmic tail domains, produced near-wild-type levels of particles. In contrast, viruses encoding chimeras with shorter or no G-stem sequences produced ∼10- to 20-fold less. This budding domain when present in chimeric glycoproteins also promoted their incorporation into the VSV envelope. We suggest that the G-stem budding domain promotes virus release by inducing membrane curvature at sites where virus budding occurs or by recruiting condensed nucleocapsids to sites on the plasma membrane which are competent for efficient virus budding.
Disulfide Bonds and Membrane Topology of the Vaccinia Virus A17L Envelope Protein
Authors: Betakova Tatiana , Moss Bernard 
Published: July 2002

ABSTRACT
The envelope protein encoded by the vaccinia virus A17L open reading frame is essential for virion assembly. Our mutagenesis studies indicated that cysteines 101 and 121 form an intramolecular disulfide bond and that cysteine 178 forms an intermolecular disulfide linking two A17L molecules. This arrangement of disulfide bonds has important implications for the topology of the A17L protein and supports a two-transmembrane model in which cysteines 101 and 121 are intraluminal and cysteine 178 is cytoplasmic. The structure of the A17L protein, however, was not dependent on these disulfide bonds, as a recombinant vaccinia virus with all three cysteine codons mutated to serines retained infectivity.
Human T-Cell Leukemia Virus Type 2 Tax Mutants That Selectively Abrogate NFκB or CREB/ATF Activation Fail To Transform Primary Human T Cells
Authors: Ross Ted M. , Narayan Murli , Fang Zhi-Yu , Minella Alex C. , Green Patrick L. 
Published: July 2002

ABSTRACT

Human T-cell leukemia virus (HTLV) Tax protein has been implicated in the HTLV oncogenic process, primarily due to its pleiotropic effects on cellular genes involved in growth regulation and cell cycle control. To date, several approaches attempting to correlate Tax activation of the CREB/activating transcription factor (ATF) or NFκB/Rel transcriptional activation pathway to cellular transformation have yielded conflicting results. In this study, we use a unique HTLV-2 provirus (HTLV
c-enh
) that replicates by a Tax-independent mechanism to directly assess the role of Tax transactivation in HTLV-mediated T-lymphocyte transformation. A panel of well-characterized
tax-2
mutations is utilized to correlate the respective roles of the CREB/ATF or NFκB/Rel signaling pathway. Our results demonstrate that viruses expressing
tax-2
mutations that selectively abrogate NFκB/Rel or CREB/ATF activation display distinct phenotypes but ultimately fail to transform primary human T lymphocytes. One conclusion consistent with our results is that the activation of NFκB/Rel provides a critical proliferative signal early in the cellular transformation process, whereas CREB/ATF activation is required to promote the fully transformed state. However, complete understanding will require correlation of Tax domains important in cellular transformation to those Tax domains important in the modulation of gene transcription, cell cycle control, induction of DNA damage, and other undefined activities.
Recombinant Modified Vaccinia Virus Ankara Expressing the Surface gp120 of Simian Immunodeficiency Virus (SIV) Primes for a Rapid Neutralizing Antibody Response to SIV Infection in Macaques
Authors: Ourmanov Ilnour , Bilska Miroslawa , Hirsch Vanessa M. , Montefiori David C. 
Published: July 2002

ABSTRACTNeutralizing antibodies were assessed before and after intravenous challenge with pathogenic SIVsmE660 in rhesus macaques that had been immunized with recombinant modified vaccinia virus Ankara expressing one or more simian immunodeficiency virus gene products (MVA-SIV). Animals received either MVA-gag-pol, MVA-env, MVA-gag-pol-env, or nonrecombinant MVA. Although no animals were completely protected from infection with SIV, animals immunized with recombinant MVA-SIV vaccines had lower virus loads and prolonged survival relative to control animals that received nonrecombinant MVA (I. Ourmanov et al., J. Virol. 74:2740–2751, 2000). Titers of neutralizing antibodies measured with the vaccine strain SIVsmH-4 were low in the MVA-envand MVA-gag-pol-envgroups of animals and were undetectable in the MVA-gag-poland nonrecombinant MVA groups of animals on the day of challenge (4 weeks after final immunization). Titers of SIVsmH-4-neutralizing antibodies remained unchanged 1 week later but increased approximately 100-fold 2 weeks postchallenge in the MVA-envand MVA-gag-pol-envgroups while the titers remained low or undetectable in the MVA-gag-poland nonrecombinant MVA groups. This anamnestic neutralizing antibody response was also detected with T-cell-line-adapted stocks of SIVmac251 and SIV/DeltaB670 but not with SIVmac239, as this latter virus resisted neutralization. Most animals in each group had high titers of SIVsmH-4-neutralizing antibodies 8 weeks postchallenge. Titers of neutralizing antibodies were low or undetectable until about 12 weeks of infection in all groups of animals and showed little or no evidence of an anamnestic response when measured with SIVsmE660. The results indicate that recombinant MVA is a promising vector to use to prime for an anamnestic neutralizing antibody response following infection with primate lentiviruses that cause AIDS. However, the Env component of the present vaccine needs improvement in order to target a broad spectrum of viral variants, including those that resemble primary isolates.
Nonrandom Transduction of Recombinant Adeno-Associated Virus Vectors in Mouse Hepatocytes In Vivo: Cell Cycling Does Not Influence Hepatocyte Transduction
Authors: Miao Carol H. , Nakai Hiroyuki , Thompson Arthur R. , Storm Theresa A. , Chiu Winnie , Snyder Richard O. , Kay Mark A. 
Published: July 2002

ABSTRACT
Recombinant adeno-associated virus vectors (rAAV) show promise in preclinical trials for the treatment of genetic diseases including hemophilia. Liver-directed gene transfer results in a slow rise in transgene expression, reaching steady-state levels over a period of 5 weeks concomitant with the conversion of the single-stranded rAAV molecules into high-molecular-weight concatemers in about 5% of hepatocytes. Immunohistochemistry and RNA in situ hybridization show that the transgene product is made in about ∼5% of hepatocytes, suggesting that most rAAV-mediated gene expression occurs in hepatocytes containing the double-stranded concatemers. In this study, the mechanism(s) involved in stable transduction in vivo was evaluated. While only ∼5% of hepatocytes are stably transduced, in situ hybridization experiments demonstrated that the vast majority of the hepatocytes take up AAV-DNA genomes after portal vein infusion of the vector. Two different vectors were infused together or staggered by 1, 3, or 5 weeks, and two-color fluorescent in situ hybridization and molecular analyses were performed 5 weeks after the infusion of the second vector. These experiments revealed that a small but changing subpopulation of hepatocytes were permissive to stable transduction. Furthermore, in animals that received a single infusion of two vectors, about one-third of the transduced cells contained heteroconcatemers, suggesting that dimer formation was a critical event in the process of concatemer formation. To determine if the progression through the cell cycle was important for rAAV transduction, animals were continuously infused with 5′-bromo-2′-deoxyuridine (BrdU), starting at the time of administration of a rAAV vector that expressed cytoplasmic β-galactosidase. Colabeling for β-galactosidase and BrdU revealed that there was no preference for transduction of cycling cells. This was further confirmed by demonstrating no increase in rAAV transduction efficiencies in animals whose livers were induced to cycle at the time of or after vector administration. Taken together, our studies suggest that while virtually all hepatocytes take up vector, unknown cellular factors are required for stable transduction, and that dimer formation is a critical event in the transduction pathway. These studies have important implications for understanding the mechanism of integration and may be useful for improving liver gene transfer in vivo.
Mus cervicolor
Murine Leukemia Virus Isolate M813 Belongs to a Unique Receptor Interference Group
Authors: Prassolov Vladimir , Hein Sibyll , Ziegler Marion , Ivanov Dmitry , Münk Carsten , Löhler Jürgen , Stocking Carol 
Published: July 2002

ABSTRACT

Murine leukemia virus (MuLV) M813 was originally isolated from the Southeast Asian rodent
Mus cervicolor
. As with the ecotropic MuLVs derived from
Mus musculus
, its host range is limited to rodent cells. Earlier studies have mapped its receptor to chromosome 2, but it has not been established whether M813 shares a common receptor with any other MuLVs. In this study, we have performed interference assays with M813 and viruses from four interference groups of MuLV. The infection efficiency of M813 was not compromised in cells expressing any one of the other MuLVs, demonstrating that M813 must use a distinct receptor for cell entry. The entire M813
env
coding region was molecularly cloned. Sequence analysis revealed high similarity with other MuLVs but with a unique receptor-binding domain. Substitution of M813
env
sequences in Moloney MuLV resulted in a replication-competent virus with a host range and interference profile similar to those of the biological clone M813. M813 thus defines a novel receptor interference group of type C MuLVs.
MEK-Specific Inhibitor U0126 Blocks Spread of Borna Disease Virus in Cultured Cells
Authors: Planz Oliver , Pleschka Stephan , Ludwig Stephan 
Published: July 2002

ABSTRACTBorna disease virus (BDV) is a highly neurotropic virus that causes Borna disease, a virus-induced immune-mediated encephalomyelitis, in a variety of warm-blooded animals. Recent studies reported that BDV can be detected in patients with psychiatric disorders. BDV is noncytopathic, replicates in the nucleus of infected cells, and spreads intraaxonally in vivo. Upon infection of susceptible cultured cells, virus can be detected in foci. Little is known about the cellular components required for BDV replication. Here, we show that the cellular Raf/MEK/ERK signaling cascade is activated upon infection with BDV. In the presence of the MEK-specific inhibitor U0126, cells get infected with BDV; however, there is a block in virus spread to neighboring cells. The effect of the inhibitor on virus spread was still observed when the compound was added 2 h postinfection but not if treatment was initiated as late as 4 h after infection. Our results provide new insights into the BDV-host cell interaction and show that virus infection can be controlled with drugs interfering with a cellular signaling pathway. Since concentrations of the MEK inhibitor required to block BDV focus formation are not toxic for the host cells, our finding may be important with respect to antiviral drug development.
Patient-Specific Cytotoxic T-Lymphocyte Cross-Recognition of Naturally Occurring Variants of a Human Immunodeficiency Virus Type 1 (HIV-1) p24gagEpitope by HIV-1-Infected Children
Authors: Buseyne F. , Chaix M.-L. , Rouzioux C. , Blanche S. , Rivière Y. 
Published: July 2002

ABSTRACTWe tested seven human immunodeficiency virus-infected children for their cytotoxic T-lymphocyte (CTL) activities towards the p24gagQASQEVKNW epitope and its nine variant sequences. Our data confirm that most, but not all, CTL responses are broadly cross-specific. For the first time, we show the high interpatient variability in cross-recognition of mutant CTL epitopes. These interindividual variations in the CTL response to the same epitope should be taken into account in the design and the evaluation of vaccines.
Virological Properties and Nucleotide Sequences of Cas-E-Type Endogenous Ecotropic Murine Leukemia Viruses in South Asian Wild Mice,
Mus musculus castaneus
Authors: Ikeda Hidetoshi , Kato Kanako , Kitani Hiroshi , Suzuki Takako , Yoshida Takamasa , Inaguma Yutaka , Yamamoto Naoyuki , Suh Jun-Gyo , Hyun Byung-Hwa , Yamagata Takahiro , Namikawa Takao , Tomita Takeshi 
Published: July 2002

ABSTRACT

Two types of endogenous ecotropic murine leukemia viruses (MuLVs), termed AKV- and Cas-E-type MuLVs, differ in nucleotide sequence and distribution in wild mouse subspecies. In contrast to AKV-type MuLV, Cas-E-type MuLV is not carried by common laboratory mice. Wild mice of
Mus musculus (M. m.) castaneus
carry multiple copies of Cas-E-type endogenous MuLV, including the

Fv-4
r

gene that is a truncated form of integrated MuLV and functions as a host's resistance gene against ecotropic MuLV infection. Our genetic cross experiments showed that only the

Fv-4
r

gene was associated with resistance to ecotropic F-MuLV infection. Because the spontaneous expression of infectious virus was not detected in
M. m. castaneus
, we generated mice that did not carry the

Fv-4
r

gene but did carry a single or a few endogenous MuLV loci. In mice not carrying the

Fv-4
r

gene, infectious MuLVs were isolated in association with three of six Cas-E-type endogenous MuLV loci. The isolated viruses showed a weak syncytium-forming activity for XC cells, an interfering property of ecotropic MuLV, and a slight antigenic variation. Two genomic DNAs containing endogenous Cas-E-type MuLV were cloned and partially sequenced. All of the Cas-E-type endogenous MuLVs were closely related, hybrid-type viruses with an ecotropic
env
gene and a xenotropic long terminal repeat. Duplications and a deletion were found in a restricted region of the hypervariable proline-rich region of Env glycoprotein.
Marek's Disease Virus (MDV) Encodes an Interleukin-8 Homolog (vIL-8): Characterization of the vIL-8 Protein and a vIL-8 Deletion Mutant MDV
Authors: Parcells Mark S. , Lin Su-Fang , Dienglewicz Robert L. , Majerciak Vladimir , Robinson Dan R. , Chen Hua-Chien , Wu Zining , Dubyak George R. , Brunovskis Peter , Hunt Henry D. , Lee Lucy F. , Kung Hsing-Jien 
Published: July 2002

ABSTRACTChemokines induce chemotaxis, cell migration, and inflammatory responses. We report the identification of an interleukin-8 (IL-8) homolog, termed vIL-8, encoded within the genome of Marek's disease virus (MDV). The 134-amino-acid vIL-8 shares closest homology to mammalian and avian IL-8, molecules representing the prototype CXC chemokine. The gene for vIL-8 consists of three exons which map to theBamHI-L fragment within the repeats flanking the unique long region of the MDV genome. A 0.7-kb transcript encoding vIL-8 was detected in ann-butyrate-treated, MDV-transformed T-lymphoblastoid cell line, MSB-1. This induction is essentially abolished by cycloheximide and herpesvirus DNA polymerase inhibitor phosphonoacetate, indicating that vIL-8 is expressed with true late (γ2) kinetics. Baculovirus-expressed vIL-8 was found to be secreted into the medium and shown to be functional as a chemoattractant for chicken peripheral blood mononuclear cells but not for heterophils. To characterize the function of vIL-8 with respect to MDV infection in vivo, a recombinant MDV was constructed with a deletion of all three exons and a soluble-modified green fluorescent protein (smGFP) expression cassette inserted at the site of deletion. In two in vivo experiments, the vIL-8 deletion mutant (RB1BvIL-8ΔsmGFP) showed a decreased level of lytic infection in comparison to its parent virus, an equal-passage-level parent virus, and to another recombinant MDV containing the insertion of a GFP expression cassette at the nonessential US2 gene. RB1BvIL-8ΔsmGFP retained oncogenicity, albeit at a greatly reduced level. Nonetheless, we have been able to establish a lymphoblastoid cell line from an RB1BvIL-8ΔsmGFP-induced ovarian lymphoma (MDCC-UA20) and verify the presence of a latent MDV genome lacking vIL-8. Taken together, these data describe the identification and characterization of a chemokine homolog encoded within the MDV genome that is dispensable for transformation but may affect the level of MDV in vivo lytic infection.