bluuebunny/crossref_metadata_2025 huggingface dataset:
Mapping of Genetic Determinants of Rubella Virus Associated with Growth in Joint Tissue
Authors: Lund Karen D. , Chantler Janet K.
Published: July 2002

Rubella virus (RV) strains vary in their abilities to replicate and persist in cell cultures derived from human joint tissue (synovial cells [SC]), and this arthrotropism appears to be linked to their association with joint symptoms in vivo. In order to map the genetic determinants of arthrotropism, an infectious clone of the Cendehill vaccine strain of RV was constructed, as well as two chimeric clones containing cDNAs from both Cendehill and Therien (wild-type) strains. Replacement of the entire structural gene region of Therien in the infectious clone pROBO302 with the corresponding region of Cendehill did not affect growth in SC. A further observation that Cendehill bound equally well to SC and the permissive Vero cell line indicated that restriction was not at the level of receptor binding, a function of the envelope proteins. Mutations that affected growth in joint cells were mapped to two locations in the nonstructural gene region. The first of these (nucleotides 2803 and 6416) resulted in a 10-fold decrease in yield of progeny virus from SC. This region contained five mutations, at nucleotides 2829, 3060, 3164, and 3528 (near the carboxy terminus of P150 where the protease domain is located) and at nucleotide 4350 in p90. Further substitution of the sequence representing nucleotides 1 to 2803 to give a complete Cendehill infectious clone restricted growth in SC by a further 100-fold to less than 10 PFU/ml. This region contains three mutations, at nucleotides 34, 37, and 55, within the 5′ stem-loop structure. In conclusion, the Cendehill-specific mutations believed to be determinants of joint cell growth are located in two regions, the 5′ nontranslated region and in a sequence that encodes the carboxy-terminal region of p150 extending into the helicase domain of p90.
CD21-Mediated Entry and Stable Infection by Epstein-Barr Virus in Canine and Rat Cells
Authors: Yang Lixin , Maruo Seiji , Takada Kenzo
Published: July 2002

We developed an adenovirus vector for transduction of the human CD21 gene (Adv-CD21), the Epstein-Barr virus (EBV)-specific receptor on human B lymphocytes, to overcome the initial barrier of EBV infection in nonprimate mammalian cells. Inoculation of Adv-CD21 followed by exposure to recombinant EBV carrying a selectable marker resulted in the successful entry of EBV into three of seven nonprimate mammalian cell lines as evidenced by expression of EBV-determined nuclear antigen (EBNA). The EBV-susceptible cell lines included rat glioma-derived 9L, rat mammary carcinoma-derived c-SST-2, and canine kidney-derived MDCK. Subsequent selection culture with G418 yielded drug-resistant cell clones. In these cell clones, EBV existed as an episomal form, as evidenced through the Gardella gel technique. Among the known EBV latency-associated gene products, EBV-encoded small RNAs, EBNA1 and transcripts from the
Bam
HI-A rightward reading frame (BARF0), and latent membrane protein 2A were expressed in all EBV-infected cell clones. The viral lytic events could be induced in these cell clones by simultaneous treatment with 12-
O
-tetradecanoylphorbol-13-acetate and
n
-butyric acid, but they were abortive, and infectious virus was not produced. These results indicate that once the initial barrier for attachment is overcome artificially, EBV can establish a stable infection in some nonprimate mammalian cells, and they raise the possibility that transgenic animals with the human CD21 gene could provide an animal model for EBV infection.
The Level of CD4 Expression Limits Infection of Primary Rhesus Monkey Macrophages by a T-Tropic Simian Immunodeficiency Virus and Macrophagetropic Human Immunodeficiency Viruses
Authors: Bannert Norbert , Schenten Dominik , Craig Stewart , Sodroski Joseph
Published: July 2002

The entry of primate immunodeficiency viruses into cells is dependent on the interaction of the viral envelope glycoproteins with receptors, CD4, and specific members of the chemokine receptor family. Although in many cases the tropism of these viruses is explained by the qualitative pattern of coreceptor expression, several instances have been observed where the expression of a coreceptor on the cell surface is not sufficient to allow infection by a virus that successfully utilizes the coreceptor in a different context. For example, both the T-tropic simian immunodeficiency virus (SIV) SIVmac239 and the macrophagetropic (M-tropic) SIVmac316 can utilize CD4 and CCR5 as coreceptors, and both viruses can infect primary T lymphocytes, yet only SIVmac316 can efficiently infect CCR5-expressing primary macrophages from rhesus monkeys. Likewise, M-tropic strains of human immunodeficiency virus type 1 (HIV-1) do not infect primary rhesus monkey macrophages efficiently. Here we show that the basis of this restriction is the low level of CD4 on the surface of these cells. Overexpression of human or rhesus monkey CD4 in primary rhesus monkey macrophages allowed infection by both T-tropic and M-tropic SIV and by primary M-tropic HIV-1. By contrast, CCR5 overexpression did not specifically compensate for the inefficient infection of primary monkey macrophages by T-tropic SIV or M-tropic HIV-1. Apparently, the limited ability of these viruses to utilize a low density of CD4 for target cell entry accounts for the restriction of these viruses in primary rhesus monkey macrophages.
Varicella-Zoster Virus Proteins in Skin Lesions: Implications for a Novel Role of ORF29p in Chickenpox
Authors: Annunziato Paula W. , Lungu Octavian , Panagiotidis Christos , Zhang Jing H. , Silvers David N. , Gershon Anne A. , Silverstein Saul J.
Published: July 2002

Skin biopsy samples from varicella-zoster virus (VZV)-infected patients examined by immunohistochemistry demonstrated VZV replication in nonepithelial cell types. ORF29p, a nonstructural nuclear protein, was found in nerves of two of six patients with chickenpox. In tissue culture, ORF29p was secreted by VZV-infected fibroblasts. Extracellular ORF29p can be taken up through endocytosis by human neurons, implying a novel role for this protein in pathogenesis.
Herpes Simplex Virus Type 1-Specific Cytotoxic T-Lymphocyte Arming Occurs within Lymph Nodes Draining the Site of Cutaneous Infection
Authors: Jones Claerwen M. , Cose Stephen C. , Coles Richard M. , Winterhalter Adam C. , Brooks Andrew G. , Heath William R. , Carbone Francis R.
Published: July 2002

Various studies have shown that major histocompatibility complex class I-restricted cytotoxic T lymphocytes (CTL) can be isolated from lymph nodes draining sites of cutaneous infection with herpes simplex virus type 1 (HSV-1). Invariably, detection of this cytolytic activity appeared to require some level of in vitro culture of the isolated lymph node cells, usually for 3 days, in the absence of exogenous viral antigen. This in vitro “resting” period was thought to represent the phase during which committed CD8+T cells become “armed” killers after leaving the lymph nodes and prior to their entry into infected tissue as effector CTL. In this study we reexamined the issue of CTL appearance in the HSV-1 immune response and found that cytolytic activity can be isolated directly from draining lymph nodes, although at levels considerably below those found after in vitro culture. By using T-cell receptor elements that represent effective markers for class I-restricted T cells specific for an immunodominant glycoprotein B (gB) determinant from HSV-1, we show that the increase in cytotoxicity apparent after in vitro culture closely mirrors the expansion of gB-specific CTL during the same period. Taken together, our results suggest that HSV-1-specific CTL priming does not appear to require any level of cytolytic machinery arming outside the lymph node compartment despite the absence of any detectable infection within that site.
Hepadnavirus Infection in Captive Gibbons
Authors: Lanford Robert E. , Chavez Deborah , Rico-Hesse Rebeca , Mootnick Alan
Published: July 2002

The recent isolation of a nonhuman primate hepadnavirus from woolly monkeys prompted an examination of other primates for potentially new hepadnaviruses. A serological analysis of 30 captive gibbons revealed that 47% were positive for at least one marker of ongoing or previous infection with a hepatitis B virus (HBV). The amino acid sequences of the core and surface genes of human and gibbon virus isolates were very similar. Phylogenetic analysis indicated that the gibbon isolates lie within the human HBV family, indicating that these HBV isolates most likely stem from infection of gibbons from a human source.
Detection and Characterization of Porcine Endogenous Retrovirus in Porcine Plasma and Porcine Factor VIII
Authors: Takefman Daniel M. , Wong Susan , Maudru Thomas , Peden Keith , Wilson Carolyn A.
Published: July 2002

The pig genome contains porcine endogenous retroviruses (PERVs) capable of infecting human cells. Detection of infectious retrovirus in porcine peripheral blood mononuclear cells and endothelial cells suggested to us that pig plasma is likely to contain PERV. Both PERV
env
sequences and viral reverse transcriptase (RT) activity were detected in all plasma samples isolated from four NIH minipigs. To detect infectious virus from plasma, we performed a culture assay using three cell lines of feline, swine, and human origin that had previously been shown to be permissive for PERV. Infectious virus was successfully cultured from all four NIH minipig plasmas on the swine cell line ST-IOWA. Using RT-PCR with
env
-specific primers, we could detect expression of PERV class C envelope in the supernatant of ST-IOWA cells that had been exposed to each pig plasma. We next examined a pig plasma derivative, Hyate:C (porcine factor VIII), and found evidence of PERV particles, since all six lots examined were positive for PERV RNA and RT activity. However, infectious virus could not be detected in clinical lots of Hyate:C, suggesting that the manufacturing process might reduce the load of infectious virus to levels below detectable limits of the assay. Detection of infectious virus in porcine plasma confirms and extends the previous findings that certain porcine cells express PERV when manipulated in vitro and clearly demonstrates that there are porcine cells that express infectious PERV constitutively in vivo.
B2 but Not B1 Cells Can Contribute to CD4+T-Cell-Mediated Clearance of Rotavirus in SCID Mice
Authors: Kushnir Natasha , Bos Nicolaas A. , Zuercher Adrian W. , Coffin Susan E. , Moser Charlotte A. , Offit Paul A. , Cebra John J.
Published: July 2002

Studies utilizing various immunodeficient mouse models of rotavirus (RV) infection demonstrated significant roles of RV-specific secretory immunoglobulin A (IgA), CD4+T cells, and CD8+T cells in the clearance of RV and protection from secondary infection. Secretion of small but detectable amounts of IgA in RV-infected αβ T-cell receptor knockout mice (11) and distinctive anatomical localization and physiology of B1 cells suggested that B1 cells might be capable of producing RV-specific intestinal IgA in a T-cell-independent fashion and, therefore, be responsible for ablation of RV shedding. We investigated the role of B1 cells in the resolution of primary RV infection using a SCID mouse model. We found that the adoptive transfer of unseparated peritoneal exudate cells ablates RV shedding and leads to the production of high levels of RV-specific intestinal IgA. In contrast, purified B1 cells do not ablate RV shedding and do not induce a T-cell-independent or T-cell-dependent, RV-specific IgA response but do secrete large amounts of polyclonal (total) intestinal IgA. Cotransfer of mixtures of purified B1 cells and B1-cell-depleted peritoneal exudate cells differing in IgA allotypic markers also demonstrated that B2 cells (B1-cell-depleted peritoneal exudate cells) and not B1 cells produced RV-specific IgA. To our knowledge, this is the first observation that B1 cells are unable to cooperate with CD4+T cells and produce virus-specific intestinal IgA antibody. We also observed that transferred CD4+T cells alone are capable of resolving RV shedding, although no IgA is secreted. These data suggest that RV-specific IgA may not be obligatory for RV clearance but may protect from reinfection and that effector CD4+T cells alone can mediate the resolution of primary RV infection. Reconstitution of RV-infected SCID mice with B1 cells results in the outgrowth of contaminating, donor CD4+T cells that are unable to clear RV, possibly because their oligoclonal specificities may be ineffective against RV antigens.
Novel, Soluble Isoform of the Herpes Simplex Virus (HSV) Receptor Nectin1 (or PRR1-HIgR-HveC) Modulates Positively and Negatively Susceptibility to HSV Infection
Authors: Lopez Marc , Cocchi Francesca , Avitabile Elisa , Leclerc Annouck , Adelaide Jose , Campadelli-Fiume Gabriella , Dubreuil Patrice
Published: July 2002

A novel member of the nectin family, nectin1γ, was molecularly cloned. The cDNA has the same ectodomain as nectin1α and nectin1β, the two known transmembrane isoforms that serve as receptors for herpes simplex virus (HSV) entry into human cell lines (nectin1α and nectin1β, also called PRR1-HveC and HIgR, respectively). The 1.4-kb transcript, which originated by alternative splicing, is expressed in human cell lines, and appears to have a narrow distribution in human tissues. The sequence does not have a hydrophobic anchoring region, and the protein is secreted in the culture medium of cells transfected with the cDNA. Nectin1γ, purified from culture medium, can compete with membrane-bound nectin1β and reduce HSV infectivity. The expression of nectin1γ cDNA in cells resistant to HSV infection and lacking HSV receptors enables HSV to enter the cell, which implies that it is present at the cell surface. Thus, nectin1γ has the potential both to mediate and to reduce HSV entry into cells.
Immunoreceptor Tyrosine-Based Activation Motif-Dependent Signaling by Kaposi's Sarcoma-Associated Herpesvirus K1 Protein: Effects on Lytic Viral Replication
Authors: Lagunoff Michael , Lukac David M. , Ganem Don
Published: July 2002

The Kaposi's sarcoma-associated herpesvirus (KSHV) K1 gene encodes a polypeptide bearing an immunoreceptor tyrosine-based activation motif (ITAM) that is constitutively active for ITAM-based signal transduction. Although ectopic overexpression of K1 in cultured fibroblasts can lead to growth transformation, in vivo this gene is primarily expressed in lymphoid cells undergoing lytic infection. Here we have examined function of K1 in the setting of lytic replication, through the study of K1 mutants lacking functional ITAMs. Expression of such mutants in BJAB cells cotransfected with wild-type K1 results in dramatic inhibition of K1 signal transduction, as judged by impaired activation of Syk kinase and phospholipase C-γ2 as well as by diminished expression of a luciferase reporter gene dependent upon K1-induced calcium and Ras signaling. Thus, the mutants behave as dominantly acting inhibitors of K1 function. To assess the role of K1 in lytic replication, we introduced these K1 mutants into BCBL-1 cells, a B-cell lymphoma line latently infected with KSHV, and induced lytic replication by ectopic expression of the KSHV ORF50 transactivator. Expression of lytic cycle genes was diminished up to 80% in the presence of a K1 dominant negative mutant. These inhibitory effects could be overridden by tetradecanoyl phorbol acetate treatment, indicating that inhibition was not due to irreversible cell injury and suggesting that other signaling events could bypass the block. We conclude that ITAM-dependent signaling by K1 is not absolutely required for lytic reactivation but functions to modestly augment lytic replication in B cells, the natural reservoir of KSHV.
Plasmacytoid Dendritic Cells Are Highly Susceptible to Human Immunodeficiency Virus Type 1 Infection and Release Infectious Virus
Authors: Patterson Steven , Rae Aaron , Hockey Nicola , Gilmour Jill , Gotch Frances
Published: July 2002

Plasmacytoid dendritic cells (pcDC) and myeloid dendritic cells (myDC) are shown to express CD4 and low levels of CCR5 and CXCR4, but only myDC express DC SIGN, a C-type lectin that binds human immunodeficiency virus but does not mediate virus entry. Both DC types were more susceptible to infection with a macrophage than a lymphotropic strain of human immunodeficiency virus type 1, but pcDC were more readily infected than myDC.
RING Finger Z Protein of Lymphocytic Choriomeningitis Virus (LCMV) Inhibits Transcription and RNA Replication of an LCMV S-Segment Minigenome
Authors: Cornu Tatjana I. , de la Torre Juan Carlos
Published: July 2002

Arenaviruses have a bisegmented negative-strand RNA genome whose proteomic capability is limited to only four polypeptides, namely, nucleoprotein (NP), surface glycoprotein (GP) that is proteolytically processed into GP1+GP2, polymerase (L), and a small (11-kDa) RING finger protein (Z). The role of Z during the
Lymphocytic choriomeningitis virus
(LCMV) life cycle is poorly understood. We investigated the function of Z in virus transcription and replication by using a reverse genetic system for the prototypic arenavirus LCMV. This system involves an LCMV minigenome and the minimal viral
trans
-acting factors (NP and L), expressed from separated cotransfected plasmids. Cotransfection of the Z cDNA strongly inhibited LCMV minigenome expression. The effect required synthesis of Z protein; its magnitude was dose dependent and occurred with levels of Z protein substantially lower than those observed in LCMV-infected cells. Coexpression of Z did not prevent the encapsidation of plasmid supplied minigenome, but it affected both transcription and RNA replication similarly. Mutations in Z that unfolded its RING finger domain eliminated its inhibitory activity, but RING proteins not related to Z did not affect LCMV minigenome expression. Consistent with the minigenome results, cells transiently expressing Z exhibited decreased susceptibility to infection with LCMV.
Nonmyeloablative Immunosuppressive Regimen Prolongs In Vivo Persistence of Gene-Modified Autologous T Cells in a Nonhuman Primate Model
Authors: Berger Carolina , Huang Meei-Li , Gough Michael , Greenberg Philip D. , Riddell Stanley R. , Kiem Hans-Peter
Published: July 2002

The in vivo persistence of gene-modified cells can be limited by host immune responses to transgene-encoded proteins. In this study we evaluated in a nonhuman primate model whether the administration of a nonmyeloablative regimen consisting of low-dose total-body irradiation with 200 cGy followed by immunosuppression with mycophenolate mofetil and cyclosporin A for 28 and 35 days, respectively, could be used to facilitate persistence of autologous gene-modified T cells when a transgene-specific immune response had already been established or to induce long-lasting tolerance in unprimed recipients. Two macaques (Macaca nemestrina) received infusions of T cells transduced to express either the enhanced green fluorescent protein and neomycin phosphotransferase genes or the hygromycin phosphotransferase and herpes simplex virus thymidine kinase genes. In the absence of immunosuppression, both macaques developed potent class I major histocompatibility complex-restricted CD8+cytotoxic T-lymphocyte (CTL) responses that rapidly eliminated the gene-modified T cells and that persisted long term as memory CTL. Treatment with the nonmyeloablative regimen failed to abrogate preexisting memory CTL responses but interfered with the induction of transgene-specific CTL and facilitated in vivo persistence of gene-modified cells in an unprimed host. However, sustained tolerance to gene-modified T cells was not achieved with this regimen, indicating that further modifications will be required to permit sustained persistence of gene-modified T cells.
Herpes Simplex Virus with Highly Reduced gD Levels Can Efficiently Enter and Spread between Human Keratinocytes
Authors: Huber Mary T. , Wisner Todd W. , Hegde Nagendra R. , Goldsmith Kimberley A. , Rauch Daniel A. , Roller Richard J. , Krummenacher Claude , Eisenberg Roselyn J. , Cohen Gary H. , Johnson David C.
Published: July 2002

The rapid spread of herpes simplex virus type 1 (HSV-1) in mucosal epithelia and neuronal tissue depends primarily on the ability of the virus to navigate within polarized cells and the tissues they constitute. To understand HSV entry and the spread of virus across cell junctions, we have previously characterized a human keratinocyte cell line, HaCaT. These cells appear to reflect cells infected in vivo more accurately than many of the cultured cells used to propagate HSV. HSV mutants lacking gE/gI are highly compromised in spread within epithelial and neuronal tissues and also show defects in cell-to-cell spread in HaCaT cells, but not in other, nonpolarized cells. HSV gD is normally considered absolutely essential for entry and cell-to-cell spread, both in cultured cells and in vivo. Here, an HSV-1 gD mutant virus, F-US6kan, was found to efficiently enter HaCaT cells and normal human keratinocytes and could spread from cell to cell without gD provided by complementing cells. By contrast, entry and spread into other cells, especially highly transformed cells commonly used to propagate HSV, were extremely inefficient. Further analyses of F-US6kan indicated that this mutant expressed extraordinarily low (1/500 wild-type) levels of gD. Neutralizing anti-gD monoclonal antibodies inhibited entry of F-US6kan, suggesting F-US6kan utilized this small amount of gD to enter cells. HaCaT cells expressed high levels of an HSV gD receptor, HveC, and entry of F-US6kan into HaCaT cells could also be inhibited with antibodies specific for HveC. Interestingly, anti-HveC antibodies were not fully able to inhibit entry of wild-type HSV-1 into HaCaT cells. These results help to uncover important properties of HSV and human keratinocytes. HSV, with exceedingly low levels of a crucial receptor-binding glycoprotein, can enter cells expressing high levels of receptor. In this case, surplus gD may be useful to avoid neutralization by anti-gD antibodies.
The Absence of Glycoprotein gL, but Not gC or gK, Severely Impairs Pseudorabies Virus Neuroinvasiveness
Authors: Flamand Anne , Bennardo Thérèse , Babic Nathalie , Klupp Barbara G. , Mettenleiter Thomas C.
Published: July 2002

Penetration and propagation of herpesviruses in the nervous system require the action of several glycoproteins. To assay for a function of glycoproteins gC, gK, and gL in the neuroinvasiveness of pseudorabies virus (PrV), deletion mutants lacking one of these glycoproteins and corresponding rescuants were inoculated in the nasal cavity of adult mice. We demonstrate that the lack of gL almost prevented the virus from penetrating and propagating in trigeminal, sympathetic, and parasympathetic tracks innervating the nasal cavity, while the lack of gC and gK only slowed the invasion of the nervous system. The conclusion of this and previous studies is that only gB, gD, gH, and gL are indispensable for penetration into neurons, while gB, gH, and gL (and, in some categories of neurons, also gE and gI) are necessary for transneuronal transfer in the mouse model. The deletion of other glycoprotein genes has little effect on PrV neuroinvasiveness although it may affect the dissemination of the virus.
Value of Immunological Markers in Predicting Responsiveness to Influenza Vaccination in Elderly Individuals
Authors: Goronzy Jörg J. , Fulbright James W. , Crowson Cynthia S. , Poland Gregory A. , O'Fallon William M. , Weyand Cornelia M.
Published: July 2002

Elderly individuals are at high risk for morbidity and mortality when infected with influenza virus. Vaccinations with inactivated virus are less effective in the elderly due to the declining competency of the aging immune system. We have explored whether immunological parameters predict poor anti-influenza virus vaccine responses and can be used as biological markers of immunosenescence. One hundred fifty-three residents of community-based retirement facilities aged 65 to 98 years received a trivalent influenza vaccine. Vaccine-induced antibody responses were determined by comparing hemagglutination inhibition titers before and 28 days after immunization. The composition of the T-cell compartment was analyzed by flow cytometry and the sizes of three T-cell subsets, CD4+CD45RO+cells, CD4+CD28nullcells, and CD8+CD28nullcells, were determined. Only 17% of the vaccine recipients were able to generate an increase in titers of antibody to all three vaccine components, and 46% of the immunized individuals failed to respond to any of the three hemagglutinins. The likelihood of successful vaccination declined with age and was independently correlated with the expansion of a particular T-cell subset, CD8+CD28nullT cells. The sizes of the CD4+CD45RO+memory T-cell and CD4+CD28nullT-cell subsets had no effect on the ability to mount anti-influenza virus antibody responses. Frequencies of CD8+CD28nullT cells are useful biological markers of compromised immunocompetence, identifying individuals at risk for insufficient antibody responses.
Human Parainfluenza Virus Type 3 Inhibits Gamma Interferon-Induced Major Histocompatibility Complex Class II Expression Directly and by Inducing Alpha/Beta Interferon
Authors: Gao Jing , De Bishnu P. , Han Yulong , Choudhary Suresh , Ransohoff Richard , Banerjee Amiya K.
Published: July 2002

Human parainfluenza virus type 3 (HPIV3) is one of the major causes of bronchiolitis, pneumonia, and croup in newborns and infants. Cellular immunity involving major histocompatibility complex (MHC) class I and class II molecules plays an important role in controlling virus infection. Several viruses have been shown to down-regulate gamma interferon (IFN-γ)-mediated MHC class II expression. In this communication, we show that HPIV3 strongly inhibits the IFN-γ-induced MHC class II expression in HT1080 human fibrosarcoma cells. The culture supernatant of HPIV3-infected cells also inhibited IFN-γ-induced MHC class II expression, a phenomenon that was found to be due, in large part, to alpha/beta interferon (IFN-α/β). Expression of MHC class I and intercellular adhesion molecule 1 occurred efficiently in cells simultaneously infected with HPIV3 and treated with IFN-γ, indicating that the inhibitory effect of HPIV3 was specific to MHC class II. STAT1 activation was not affected by HPIV3 at early postinfection times but was partially inhibited at later times. These data suggested that the potent inhibition of MHC class II expression was, in major part, due to a defect downstream of STAT1 activation in the IFN-γ-induced MHC class II expression pathway. Class II transactivator (CIITA) is the unique mediator of IFN-γ-induced transcription from the MHC class II promoter. By RNase protection analysis, CIITA expression was found to be strongly inhibited in HPIV3-infected cells. The culture supernatant containing IFN-α/β, on the other hand, inhibited MHC class II expression without affecting STAT1 and CIITA expression. These data indicate that HPIV3 inhibits IFN-γ-induced MHC class II expression primarily by the viral gene products targeting CIITA and additionally by inducing IFN-α/β to target one or more steps further downstream.
Genetic Evidence for an Interferon-Antagonistic Function of Rift Valley Fever Virus Nonstructural Protein NSs
Authors: Bouloy Michèle , Janzen Christian , Vialat Pierre , Khun Huot , Pavlovic Jovan , Huerre Michel , Haller Otto
Published: July 2002

Rift Valley fever virus
(RVFV), a phlebovirus of the family
Bunyaviridae
, is a major public health threat in Egypt and sub-Saharan Africa. The viral and host cellular factors that contribute to RVFV virulence and pathogenicity are still poorly understood. All pathogenic RVFV strains direct the synthesis of a nonstructural phosphoprotein (NSs) that is encoded by the smallest (S) segment of the tripartite genome and has an undefined accessory function. In this report, we show that MP12 and clone 13, two attenuated RVFV strains with mutations in the NSs gene, were highly virulent in IFNAR
−/−
mice lacking the alpha/beta interferon (IFN-α/β) receptor but remained attenuated in IFN-γ receptor-deficient mice. Both attenuated strains proved to be excellent inducers of early IFN-α/β production. In contrast, the virulent strain ZH548 failed to induce detectable amounts of IFN-α/β and replicated extensively in both IFN-competent and IFN-deficient mice. Clone 13 has a defective NSs gene with a large in-frame deletion. This defect in the NSs gene results in expression of a truncated protein which is rapidly degraded. To investigate whether the presence of the wild-type NSs gene correlated with inhibition of IFN-α/β production, we infected susceptible IFNAR
−/−
mice with S gene reassortant viruses. When the S segment of ZH548 was replaced by that of clone 13, the resulting reassortants became strong IFN inducers. When the defective S segment of clone 13 was exchanged with the wild-type S segment of ZH548, the reassortant virus lost the capacity to stimulate IFN-α/β production. These results demonstrate that the ability of RVFV to inhibit IFN-α/β production correlates with viral virulence and suggest that the accessory protein NSs is an IFN antagonist.
Targeting Avian Leukosis Virus Subgroup A Vectors by Using a TVA-VEGF Bridge Protein
Authors: Snitkovsky Sophie , Niederman Thomas M. J. , Mulligan Richard C. , Young John A. T.
Published: July 2002

Previously, we have demonstrated that bridge proteins comprised of avian leukosis virus (ALV) receptors fused to epidermal growth factor (EGF) can be used to selectively target retroviral vectors with ALV envelope proteins to cells expressing EGF receptors. To determine whether another type of ligand incorporated into an ALV receptor-containing bridge protein can also function to target retroviral infection, the TVA-VEGF110 bridge protein was generated. TVA-VEGF110 consists of the extracellular domain of the TVA receptor for ALV subgroup A (ALV-A), fused via a proline-rich linker peptide to a 110-amino-acid form of vascular endothelial growth factor (VEGF). This bridge protein bound specifically to its cell surface receptor, VEGFR-2, and efficiently mediated the entry of an ALV-A vector into cells. These studies indicate that ALV receptor-ligand bridge proteins may be generally useful tools for retroviral targeting approaches.
Kaposi's Sarcoma-Associated Herpesvirus vCyclin Open Reading Frame Contains an Internal Ribosome Entry Site
Authors: Bieleski Lara , Talbot Simon J.
Published: July 2002

We have previously examined the transcription and splicing of open reading frames (ORFS) 71 (K13), 72, and 73 of Kaposi's sarcoma-associated herpesvirus (KSHV) in the primary effusion lymphoma cell line BCP-1 (latently infected with KSHV) (45). The three genes encoded by these ORFs (for vFLIP, vCyclin, and latency-associated nuclear antigen [LANA]) are transcribed from a common transcription start site in BCP-1 cells during both latency and the lytic cycles. The resulting transcript is spliced to yield a 5.32-kb message encoding LANA, vCyclin, and vFLIP and a 1.7-kb bicistronic message encoding vCyclin and vFLIP. To investigate whether the vFLIP protein could be expressed from this vCyclin/vFLIP message, we utilized a bicistronic luciferase reporter system. The genes for
Renilla
and firefly luciferases (which utilize different substrates) were cloned in tandem downstream from a T7 RNA polymerase promoter. Fragments of DNA immediately upstream from the initiating codon of vFLIP were cloned between the two luciferase genes. The relative expression of the two luciferases, one directed by the putative internal ribosome entry site (IRES) sequences and the other by cap-dependent ribosome scanning, was used to compare the activities of the different DNA fragments. A minimum fragment of 233 bp within the coding region of vCyclin was found to direct efficient expression of the downstream cistron (firefly luciferase). The activity of this IRES was orientation dependent and unaffected by methods used to inhibit cap-dependent translation. This is the first demonstration of an IRES element encoded by a DNA virus and may represent a novel mechanism through which KSHV controls protein expression.
Rubella Virus E2 Signal Peptide Is Required for Perinuclear Localization of Capsid Protein and Virus Assembly
Authors: Law Lok Man J. , Duncan Robert , Esmaili Ali , Nakhasi Hira L. , Hobman Tom C.
Published: July 2002

The rubella virus (RV) structural proteins capsid, E2, and E1 are synthesized as a polyprotein precursor. The signal peptide that initiates translocation of E2 into the lumen of the endoplasmic reticulum remains attached to the carboxy terminus of the capsid protein after cleavage by signal peptidase. Among togaviruses, this feature is unique to RV. The E2 signal peptide has previously been shown to function as a membrane anchor for the capsid protein. In the present study, we demonstrate that this domain is required for RV glycoprotein-dependent localization of the capsid protein to the juxtanuclear region and subsequent virus assembly at the Golgi complex.
Characterization of CHAT and Cox Type 1 Live-Attenuated Poliovirus Vaccine Strains
Authors: Martín Javier , Minor Philip D.
Published: July 2002

CHAT and Cox type 1 live-attenuated poliovirus strains were developed in the 1950s to be used as vaccines for humans. This paper describes their characterization with respect to virulence, sensitivity for growth at high temperatures, and complete nucleotide and amino acid sequences. The results are compared to those for their common parental wild virus, the Mahoney strain, and to those for two other poliovirus strains derived from Mahoney, the Sabin 1 vaccine strain and the mouse-adapted LS-a virus. Analysis of four isolates from cases of vaccine-associated paralytic poliomyelitis related to the CHAT vaccine revealed genetic and phenotypic properties of the CHAT strain following replication in the human gut. CHAT-VAPP strain 134 contained a genome highly evolved from that of CHAT (1.1% nucleotide differences), suggesting long-term circulation of a vaccine-derived strain in the human population. The molecular mechanisms of attenuation and evolution of poliovirus in humans are discussed in the context of the global polio eradication initiative.
Characterizing and Mapping Porcine Endogenous Retroviruses in Westran Pigs
Authors: Lee Jun-Heon , Webb Graham C. , Allen Richard D. M. , Moran Chris
Published: July 2002

Since porcine endogenous retroviruses (PERVs) can infect cultured human cells, they are a potential hazard to xenotransplantation. For this reason, endogenous retroviruses from the Westran (Westmead Hospital transplantation) inbred line of pigs were analyzed by using consensus primers for the type A and type B viruses to amplify 1.8-kb envelope gene fragments. After preliminary analysis with restriction enzymesKpnI andMboI, 31 clones were sequenced. Between types A and B, five recombinant clones were identified. Fifty-five percent of clones (17 of 31) had premature stop codons within the envelope protein-encoding region. Endogenous retroviruses in Westran pigs were physically mapped by fluorescence in situ hybridization (FISH) using PERV-A and PERV-B envelope clones as probes to identify at least 32 integration sites (19 PERV-A sites and 13 PERV-B sites). The chromosomal sites of integration in the Westran strain are quite different from those in the European Large White pig. The recombinant clones suggest that defective PERVs could become infective through recombination and further that PERVs might recombine with human endogenous retroviruses in xenotransplants.
High-Frequency Intermolecular Homologous Recombination during Herpes Simplex Virus-Mediated Plasmid DNA Replication
Authors: Fu Xinping , Wang Hua , Zhang Xiaoliu
Published: July 2002

Homologous recombination is a prominent feature of herpes simplex virus (HSV) type 1 DNA replication. This has been demonstrated and traditionally studied in experimental settings where repeated sequences are present or are being introduced into a single molecule for subsequent genome isomerization. In the present study, we have designed a pair of unique HSV amplicon plasmids to examine in detail intermolecular homologous recombination (IM-HR) between these amplicon plasmids during HSV-mediated DNA replication. Our data show that IM-HR occurred at a very high frequency: up to 60% of the amplicon concatemers retrieved from virion particles underwent intermolecular homologous recombination. Such a high frequency of IM-HR required that both plasmids be replicated by HSV-mediated replication, as IM-HR events were not detected when either one or both plasmids were replicated by simian virus 40-mediated DNA replication, even with the presence of HSV infection. In addition, the majority of the homologous recombination events resulted in sequence replacement or targeted gene repair, while the minority resulted in sequence insertion. These findings imply that frequent intermolecular homologous recombination may contribute directly to HSV genome isomerization. In addition, HSV-mediated amplicon replication may be an attractive model for studying intermolecular homologous recombination mechanisms in general in a mammalian system. In this regard, the knowledge obtained from such a study may facilitate the development of better strategies for targeted gene correction for gene therapy purposes.
Effects of Antiretroviral Drugs on Human Immunodeficiency Virus Type 1-Induced CD4+T-Cell Death
Authors: Estaquier Jérôme , Lelièvre Jean-Daniel , Petit Frédéric , Brunner Thomas , Moutouh-de Parseval Laure , Richman Douglas D. , Ameisen Jean Claude , Corbeil Jacques
Published: July 2002

Apoptosis of peripheral blood T cells plays an important role in the pathogenesis of human immunodeficiency virus (HIV) infection. In this study, we found that HIV type 1 (HIV-1) primes CD4+T cells from healthy donors for apoptosis, which occurs after CD95 ligation or CD3-T-cell receptor (TCR) stimulation. CD95-mediated death did not depend on CD4 T-cell infection, since it occurred in the presence of the reverse transcriptase inhibitor didanosine (ddI). In contrast, apoptosis induced by productive infection (CD3-TCR stimulation) is prevented by both CD95 decoy receptor and ddI. Our data suggest that HIV-1 triggers at least two distinct death pathways: a CD95-dependent pathway that does not require viral replication and a viral replication-mediated cell death independent of the CD95 pathway. Further experiments indicated that saquinavir, a protease inhibitor, at a 0.2 μM concentration, decreased HIV-mediated CD95 expression and thus cell death, which is independent of its role in inhibiting viral replication. However, treatment of peripheral blood mononuclear cells from healthy donors with a higher concentration (10 μM) of an HIV protease inhibitor, saquinavir or indinavir, induced both a loss in mitochondrial membrane potential (ΔΨm) and cell death. Thus, protease inhibitors have the potential for both beneficial and detrimental effects on CD4+T cells independent of their antiretroviral effects.
Erratum to: Resonance Enhancement of the Faraday Effect in a Magnetoplasmonic Composite
Authors: Tomilin S. V. , Karavaynikov A. V. , Lyashko S. D. , Milyukova E. T. , Tomilina O. A. , Berzhansky V. N.
Published: February 2025

An Erratum to this paper has been published: https://doi.org/10.1134/S0031918X24120056
Free Energies of Adsorption of Dipeptides and 2,5-Piperazinediones on Silica from Neutral Aqueous Solutions as Estimated from High-Performance Liquid-Chromatographic Retention Data
Authors: Basiuk Vladimir A. , Gromovoy Taras Yu.
Published: July 2002

The equilibrium constants (K) and free energies (-∆G) of adsorption of dipeptides and their cyclic derivatives, 2,5-piperazinediones, on silica from neutral aqueous solutions were calculated from their HPLC retention data on a silica gel column. For the majority of the dipeptides -∆G values were negative, ranging from -1 170 to 430 J mol-1, and K < 1, thus indicating a very weak adsorption. The 2,5-piperazinediones under study exhibited higher adsorbabilities (-∆G -1 070 + 3 030 J mol-1, K > 1) as compared to the respective dipeptides. The effect of the α-substituent structure on the adsorbability is analyzed. A linear dependence of -∆G on the number of aliphatic carbon atoms in a sorbate molecule was observed for the series of dipeptides and 2,5-piperazinediones derived from bifunctional aliphatic amino acids.
Preparation of 1-Hydroxyxanthen-9(9H)-ones and 1-Hydroxyacridin-9(10H)-ones via Corresponding 3,4-Dihydro-1,9(2H)-diones
Authors: Rádl Stanislav
Published: July 2002

Target 10-cyclopropyl-7-fluoro-1-hydroxy-6-(4-methyl-1-piperazinyl)acridin-9(10H)-one (IVc) and 7-fluoro-1-hydroxy-6-(4-methyl-1-piperazinyl)-9H-xanthen-9-one (IVd) were obtained from corresponding difluoro derivatives IVa and IVb, respectively. These intermediates were synthesized via respective 3,4-dihydro-1,9(2H)-diones Va and Vb. Acridine derivative (10-cyclopropyl-6,7-difluoro-3,4-dihydro-1H-acridine-1,9(2H,10H)-dione, Va) was synthesized from 1-cyclopropyl-6,7-difluoroisatoic anhydride (XI) and xanthene derivative (6,7-difluoro-3,4-dihydro-1H-xanthen-1,9(2H)-dione, Vb) from cyclohexenone derivative VIb. Several unsuccessful attempts to prepare hydroxyacridone IVc and/or some useful intermediates of its synthesis are also described.
Reactions of Substituted 5-Nitro-3-furoylthioureas
Authors: Štetinová Jarmila , Lojkásková Martina , Dandárová Miloslava , Leško Ján , Kada Rudolf
Published: July 2002

Some cyclization and cyclocondensation reactions of 1-(5-nitro-3-furoyl)-3-(4-R-phenyl)thioureas 1a-1e (R = H, CH3, N(C2H5)2, Br, CN) were conducted. 6-R-2-(5-Nitro-3-furoylamino)benzothiazoles 2a-2c (R = H, CH3, Br) were obtained by bromine-induced cyclization of the corresponding thioureas. Reacted with bromoacetone and ω-bromoacetophenone, respectively, the derivatives 1a-1e gave 2-(4-R-phenylimino)-3-(5-nitro-3-furoyl)-4-R1-4-thiazolines 3a-3e (R = H, CH3, N(C2H5)2, Br, CN; R1 = CH3) and 3f-3j (R = H, CH3, N(C2H5)2, Br, CN; R1 = C6H5), respectively. The structure of the compounds synthesized was confirmed by IR, UV, 1H NMR and MS data.
Symmetrical Tris(4,6-diamino-5-methylene-2-pyrimidones): New Building Blocks for Self-Assembly of Hollow Spherical Supramolecules Locked by Hydrogen Bonds
Authors: Alexander Daniel , Holý Petr , Fiedler Pavel , Havlas Zdeněk , Závada Jiří
Published: July 2002

Concise synthesis of the tris(pyrimidones) 1a,b is described. Molecular modeling study demonstrated that both the prepared models 1a,b are capable of self-assembling under formation of spherical dimers locked by 18 hydrogen bonds. Extreme insolubility in all common solvents precluded investigation of the self-assembly in solution. Circumstantial evidence in favor of the self-assembly has been provided in the solid and gas phase.
"Abbreviated" NAD+ Analogues Containinga Phosphonate Function
Authors: Hocková Dana , Masojídková Milena , Holý Antonín
Published: July 2002

"Abbreviated" NAD+ analogues with anionic phosphonate function as a part of the link between the adenine and nicotinamide moieties, 9-(2-phosphonomethoxyethyl)adenine 2-(3-carbamoylpyridinium)ethyl ester (1a), (R)- and (S)-9-(2-phosphonomethoxypropyl)adenine 2-(3-carbamoylpyridinium)ethyl ester (1b and 1c), (RS)-9-(3-hydroxy-2-phosphonomethoxypropyl)adenine 2-(3-carbamoylpyridinium)ethyl ester (1d), and (S)- and (R)-1-[3-(adenin-9-yl)-2-phosphonatomethoxypropyl]-3-carbamoylpyridinium (2a and 2b), were prepared by multistep syntheses using the Zincke reaction in the last step.
99 Semesters of Chemistry - A Personal Retrospective on the Molecular State Approach by Preparative Chemists
Authors: Bock Hans
Published: July 2002

Molecular states are the real building blocks of the chemist, because the structure of a molecule can change considerably as its energy and thus its electron distribution varies within the time-domain of dynamic relaxation. The ever increasing use of measuring methods from the armory of physics to characterize molecules by their molecular state fingerprints and, above all, of computers to rationalize both their properties and their microscopic reaction pathways, provides a wealth of information for the development of chemistry. To deal with the complexity of molecular states, a qualitative model based on the topology and symmetry of their structures as well as of their energies resulting from the electron distribution over the respective effective nuclear potentials is presented and is illustrated by examples of our own efforts to elucidate molecular state properties including time-dependent dynamics, microscopic reaction pathways both in the gas phase and in solution, and the self-assembly of molecules on crystallization. In conclusion, a personal retrospective is summarized and some prospects for the future are outlined.
Polynuclear Cadmium Compounds Containing cis-[Co(en)2(OH)2]+ Ligands
Authors: Müller Susanne , Thewalt Ulf
Published: July 2002

Polynuclear heterometallic compounds containing cobalt and cadmium were prepared by the reaction of CdCl2 with salts of the cis-[Co(en)2(H2O)2]3+ cation. X-Ray analyses of the tetranuclear Co2Cd2 complex [Cd2(mi-Cl)Cl4{(OH)2Co(en)2}2]ClO4 (1) and the polymeric compound [[Cd(mi-Cl)-(H2O)2{(OH)2Co(en)2}]Cl2]n (2) confirm that the [Co(en)2(OH)2]+ groups act as chelating ligands toward the Cd atoms. The Cd coordination octahedra are connected by a face in 1 and by corners in 2.
Reaction of Pyrylium Salts with Nucleophiles. Part 24.New Mono- and Bispyridinium Salts with a Central 2,5-Diaryloxazole Group
Authors: Schiketanz Iosif , Istrati Daniela , Deleanu Calin , Draghici Constantin , Balaban Alexandru T.
Published: July 2002

Reduction of nitro substituted 2,5-diaryloxazoles with hydrazine hydrate and Raney nickel affords in good yield 2,5-diaryloxazoles having amino group(s) on the aryl ring(s) . The reaction of 2,4,6-trisubstituted pyrylium perchlorates with mono- and diamino-2,5-diaryloxazoles yields new mono- and bispyridinium perchlorates with a central 2,5-diaryloxazole group. Their electronic, 13C NMR and 1H NMR spectra are presented and discussed.
Synthetic Studies Connected with the Preparation of 4-Cyclopropyl-7-fluoro-6-(4-methylpiperazin-1-yl)-1,2,4,9-tetrahydrothiazolo[5,4-b]quinoline-2,9-dione
Authors: Rádl Stanislav
Published: July 2002

Target 4-cyclopropyl-7-fluoro-6-(4-methylpiperazin-1-yl)-1,2,4,9-tetrahydrothiazolo[5,4-b]quinoline-2,9-dione (5a) was obtained from 3-amino-1-cyclopropyl-6-fluoro-7-(4-methylpiperazin-1-yl)-2-mercaptoquinolin-4(1H)-one (9b). This intermediate was obtained from 3-amino-1-cyclopropyl- 6,7-difluoro-2-(methylsulfinyl)quinolin-4(1H)-one (9f) via 3-amino-1-cyclopropyl-6-fluoro-7-(4-methylpiperazin-1-yl)-2-(methylsulfinyl)quinolin-4(1H)-one (9c). Compound 9f was prepared from 2,4,5-trifluoroacetophenone (6a) in several steps. 4-Cyclopropyl-6,7-difluoro-2,3,4,9-tetrahydrothiazolo[5,4-b]quinoline-3,4-dione (5b) was prepared similarly as the target compound. Treatment of 5b with N-methylpiperazine did not afford 5a but 1-cyclopropyl-6,7-difluoro-2-mercapto-3-[(4-methylpiperazin-1-yl)carbonylamino]quinolin-4(1H)-one (11). Several unsuccessful attempts to prepare compound 5a and/or some useful intermediates of its synthesis are also described.
Synthesis and Biological Activity of New 16,17-Secoestrone Derivatives
Authors: Jovanović-Šanta Suzana , Andrić Silvana , Kovačević Radmila , Pejanović Vjera
Published: July 2002

Starting from estrone 3-benzyloxy-17β-hydroxyestra-1,3,5(10)-trien-16-one oxime (3b) was synthesized, which underwent Beckmann fragmentation giving the 3-benzyloxy-17-oxo- 16,17-secoestra-1,3,5(10)-triene-16-nitrile (4b). Sodium borohydride reduction of this compound afforded 3-benzyloxy-17-hydroxy-16,17-secoestra-1,3,5(10)-triene-16-nitrile (5b). The deprotection of the 3-hydroxy group was achieved by action of hydrogen upon derivatives4band5bin presence of Pd/C as a catalyst, yielding 3-hydroxy-17-oxo-16,17-secoestra- 1,3,5(10)-triene-16-nitrile (4a) and 3,17-dihydroxy-16,17-secoestra-1,3,5(10)-triene-16-nitrile (5a). In biological tests on experimental animals, compounds4a,4b,5aand5bshowed virtually a complete loss of estrogenic activity, whereas compounds4a,5aand5bexhibited moderate antiestrogenic effect.