bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunochromatographic Strip Test for Rapid Detection of Diphtheria Toxin: Description and Multicenter Evaluation in Areas of Low and High Prevalence of Diphtheria
Authors: Engler K. H. , Efstratiou A. , Norn D. , Kozlov R. S. , Selga I. , Glushkevich T. G. , Tam M. , Melnikov V. G. , Mazurova I. K. , Kim V. E. , Tseneva G. Y. , Titov L. P. , George R. C. 
Published: July 2002

ABSTRACT

An immunochromatographic strip (ICS) test was developed for the detection of diphtheria toxin by using an equine polyclonal antibody as the capture antibody and colloidal gold-labeled monoclonal antibodies specific for fragment A of the diphtheria toxin molecule as the detection antibody. The ICS test has been fully optimized for the detection of toxin from bacterial cultures; the limit of detection was approximately 0.5 ng of diphtheria toxin per ml within 10 min. In a comparative study with 915 pure clinical isolates of
Corynebacterium
spp., the results of the ICS test were in complete agreement with those of the conventional Elek test. The ICS test was also evaluated for its ability to detect toxigenicity from clinical specimens (throat swabs) in two field studies conducted within areas of the former USSR where diphtheria is epidemic. Eight hundred fifty throat swabs were examined by conventional culture and by use of directly inoculated broth cultures for the ICS test. The results showed 99% concordance (848 of 850 specimens), and the sensitivity and specificity of the ICS test were 98% (95% confidence interval, 91 to 99%) and 99% (95% confidence interval, 99 to 100%), respectively.
Comparative Evaluation of the BD Phoenix and VITEK 2 Automated Instruments for Identification of Isolates of the
Burkholderia cepacia
Complex
Authors: Brisse Sylvain , Stefani Stefania , Verhoef Jan , Van Belkum Alex , Vandamme Peter , Goessens Wil 
Published: July 2002

ABSTRACT

We evaluated two new automated identification systems, the BD Phoenix (Becton Dickinson) and the VITEK 2 (bioMérieux), for identification of isolates of the
Burkholderia cepacia
complex (BCC). The test sample included 42 isolates of the highly virulent and epidemic genomovar III, 45 isolates of
B. multivorans
, and 47 isolates of other members of the BCC. Rates of correct identification by the BD Phoenix and VITEK 2 were similar when all BCC isolates were considered (50 and 53%, respectively) but differed markedly for genomovar III (71 and 38%;
P
< 0.01) and for
B. multivorans
(58 and 89%;
P
< 0.001). For the BD Phoenix as well as the VITEK 2, taking all 134 isolates of the BCC together, rates of correct identification of clinical isolates (56 and 55%, respectively;
n
= 85) were higher than those of environmental isolates (21 and 39%, respectively;
n
= 28). Clinical isolates of genomovar III (
n
= 27) showed correct identification rates of 81% (BD Phoenix) and 48% (VITEK 2) (
P
< 0.01). Rates of misidentification for BD Phoenix and VITEK 2 were 9 and 17% for genomovar III, 22 and 7% for
B. multivorans
, and 36 and 13% for the other BCC members (
P
< 0.01), respectively. More than half of the isolates misidentified by each instrument were identified as
Ralstonia pickettii
,
Ralstonia paucula
(CDC IV C-2 group),
Alcaligenes faecalis
,
Achromobacter
spp., or, for the VITEK 2, “various nonfermenters.” This study reemphasizes that confirmatory identification of BCC, preferably by molecular methods, is highly recommended.
Evaluation of the Subtype Specificity of Monoclonal Antibodies Raised against H1 and H3 Subtypes of Human Influenza A Virus Hemagglutinins
Authors: Varečková Eva , Cox Nancy , Klimov Alexander 
Published: July 2002

ABSTRACT
Three previously described monoclonal antibodies (MAbs) specific for influenza A(H1) hemagglutinins (HA) revealed high sensitivity (98.2 to 99.1%) and specificity (100%) when tested against 245 strains of different subtypes. One of them was included in the World Health Organization's influenza reagent kit for 2001 to 2002. In contrast, two MAbs raised against human influenza A(H3) HA revealed cross-reactivity with viruses of other subtypes.
Differences between C57BL/6 and BALB/cBy Mice in Mortality and Virus Replication after Intranasal Infection with Neuroadapted Sindbis Virus
Authors: Thach Dzung C. , Kimura Takashi , Griffin Diane E. 
Published: July 2002

ABSTRACTNeuroadapted Sindbis virus (NSV), given intranasally, caused fatal encephalitis in 100% of adult C57BL/6 mice and 0% of BALB/cBy mice. Most C57BL/6 mice developed severe kyphoscoliosis followed by hind-limb paralysis, while BALB/cBy mice did not. In situ hybridization for detecting NSV RNA and immunohistochemistry for detecting NSV antigen indicated that virus delivered by this route infected neurons of the olfactory region and spread caudally without infection of ependymal cells. Virus antigen was more abundant and infectious virus increased more rapidly and reached higher levels in C57BL/6 mice than in BALB/cBy mice. Surprisingly, infectious virus was cleared faster in C57BL/6 mice, and this was associated with more rapid production of neutralizing antibody. However, viral RNA was cleared more slowly in C57BL/6 mice. In both mouse strains, more infectious virus was present in the lumbar spinal cord than in the cervical spinal cord. These data suggest that genetic susceptibility to fatal NSV encephalomyelitis is determined at least in part by the efficiency of viral replication and spread in the central nervous system. The differences identified in this study provide possible phenotypes for mapping genetic loci involved in susceptibility.
CDP Is a Repressor of Mouse Mammary Tumor Virus Expression in the Mammary Gland
Authors: Zhu Quan , Gregg Keqin , Lozano Mary , Liu Jinqi , Dudley Jaquelin P. 
Published: July 2002

ABSTRACT
Mouse mammary tumor virus (MMTV) transcription is highest in the lactating mammary gland but is detectable in a variety of other tissues. Previous results have shown that MMTV expression is suppressed in lymphoid and other tissues through the binding of the homeodomain-containing repressor special AT-rich binding protein 1 to a negative regulatory element (NRE) in the MMTV long terminal repeat (LTR). Another homeoprotein repressor, CCAAT displacement protein (CDP), also binds to the MMTV NRE, but a role for CDP in MMTV transcriptional suppression has not yet been demonstrated. In this paper, we show that the level of CDP decreases during development of the mammary gland and that this decline in CDP level correlates with the known increase in MMTV expression observed during mammary gland differentiation. Moreover, CDP overexpression was able to suppress MMTV LTR-reporter gene activity up to 20-fold in transient-transfection assays of mouse mammary cells. To determine if this effect was due to direct binding of CDP to the promoter-proximal NRE, we performed DNase I protection assays to map two CDP-binding sites from +835 to +845 and +920 to +931 relative to the first base of the LTR. Mutations engineered into each of these sites decreased CDP binding to the proximal NRE, whereas a combination of these mutations further reduced binding. Subsequently, each of these mutations was introduced into the full-length MMTV LTR upstream of the luciferase reporter gene. Analysis of stable transfectants of LTR constructs showed that CDP binding site mutations in the proximal NRE elevated reporter gene expression two- to sixfold compared to wild-type LTR constructs. Thus, MMTV expression increases during mammary gland development, in part due to decreased CDP levels and CDP binding to the LTR. Together, these experiments provide the first evidence that CDP acts as a repressor of MMTV transcription in the mammary gland.
Gamma Interferon Impedes the Establishment of Herpes Simplex Virus Type 1 Latent Infection but Has No Impact on Its Maintenance or Reactivation in Mice
Authors: Lekstrom-Himes Julie A. , LeBlanc Rona A. , Pesnicak Lesley , Godleski Matthew , Straus Stephen E. 
Published: July 2002

ABSTRACTMurine models of gamma interferon (IFN-γ) deficiency demonstrate the role of this cytokine in attenuating acute herpes simplex virus (HSV) disease; however, the effect of IFN-γ on the establishment and maintenance of neuronal latency and viral reactivation is not known. Using the IFN-γ knockout (GKO) model of IFN-γ deficiency and sensitive quantitative PCR methods, we show that IFN-γ significantly reduces the ganglion content of latent HSV-1 in BALB/c mice, which in turn delays viral time to reactivation following UV irradiation. Similar effects were not seen in the C57BL/6 strain. These results indicate that IFN-γ significantly attenuates latent HSV infection in the mouse model of ocular infection but has no impact on the maintenance of latency or virus reactivation.
Potential Dengue Virus-Triggered Apoptotic Pathway in Human Neuroblastoma Cells: Arachidonic Acid, Superoxide Anion, and NF-κB Are Sequentially Involved
Authors: Jan Jia-Tsrong , Chen Bor-Horng , Ma Shiou-Hwa , Liu Chiu-I , Tsai Hui-Ping , Wu Han-Chung , Jiang Shian-Yuan , Yang Kuen-Der , Shaio Men-Fang 
Published: July 2002

ABSTRACTDirect in vivo evidence for the susceptibility of human neuronal cells to dengue virus has not been reported. In this study, we demonstrated that type 2 dengue (DEN-2) virus infection induced extensive apoptosis in the human neuroblastoma cell line SK-N-SH. Phospholipase A2(PLA2) was activated by DEN-2 infection, which led to the generation of arachidonic acid (AA). Inhibition of PLA2activity by the PLA2inhibitors, AACOCF3and ONO-RS-082, diminished DEN-2 virus-induced apoptosis. In contrast, the cyclooxygenase inhibitors aspirin and indomethacin, thought to increase AA accumulation by blocking AA catabolism, enhanced apoptosis. Exogenous AA induced apoptosis in a dose-dependent manner. Superoxide anion, which is thought to be generated through the AA-activated NADPH oxidase, was increased after infection. Pretreatment with superoxide dismutase (SOD) protected cells against DEN-2 virus-induced apoptosis. Furthermore, generation of superoxide anion was blocked by AACOCF3. In addition, the transcription factors, NF-κB and c-Jun, were found to be activated after DEN-2 virus infection. However, pretreatment of cells with oligodeoxynucleotides containing NF-κB, but not c-Jun, binding sites (transcription factor decoy) strongly prevented dengue virus-induced apoptosis. The finding that AACOCF3and SOD significantly block activation of NF-κB suggests that this activation is derived from the AA-superoxide anion pathway. Our results indicate that DEN-2 virus infection of human neuroblastoma cells triggers an apoptotic pathway through PLA2activation to superoxide anion generation and subsequently to NF-κB activation. This apoptotic effect can be either directly derived from the action of AA and superoxide anion on mitochondria or indirectly derived from the products of apoptosis-related genes activated by NF-κB.
A Human Milk Factor Susceptible to Cathepsin D Inhibitors Enhances Human Immunodeficiency Virus Type 1 Infectivity and Allows Virus Entry into a Mammary Epithelial Cell Line
Authors: El Messaoudi Kamal , Thiry Lise F. , Liesnard Corinne , Van Tieghem Nicole , Bollen Alex , Moguilevsky Nicole 
Published: July 2002

ABSTRACT
Human immunodeficiency virus type 1 (HIV-1) growth in lymphocyte cultures was increased when the virus inoculum was incubated in breast milk. The enhancing effect of milk was abolished by anti-cathepsin D antibody or by pepstatin A, a cathepsin D inhibitor. The cathepsin D-producing CD4-negative MCF7 mammary cells supported the growth of some HIV-1 isolates. An MCF7 line chronically producing HIV-1 IIIb was obtained. Cathepsin D may induce conformational modification of viral gp120, allowing direct interaction with a coreceptor. We demonstrated the presence of CXCR4 mRNA in MCF7 cells.
The Murine Double-Stranded RNA-Dependent Protein Kinase PKR Is Required for Resistance to Vesicular Stomatitis Virus
Authors: Stojdl David F. , Abraham Ninan , Knowles Shane , Marius Ricardo , Brasey Ann , Lichty Brian D. , Brown Earl G. , Sonenberg Nahum , Bell John C. 
Published: July 2002

ABSTRACTInterferon (IFN)-induced antiviral responses are mediated through a variety of proteins, including the double-stranded RNA-dependent protein kinase PKR. Here we show that fibroblasts derived from PKR−/−mice are more permissive for vesicular stomatitis virus (VSV) infection than are wild-type fibroblasts and demonstrate a deficiency in alpha/beta-IFN-mediated protection. We further show that mice lacking PKR are extremely susceptible to intranasal VSV infection, succumbing within days after instillation with as few as 50 infectious viral particles. Again, alpha/beta-IFN was unable to rescue PKR−/−mice from VSV infection. Surprisingly, intranasally infected PKR−/−mice died not from pathology of the central nervous system but rather from acute infection of the respiratory tract, demonstrating high virus titers in the lungs compared to similarly infected wild-type animals. These results confirm the role of PKR as the major component of IFN-mediated resistance to VSV infection. Since previous reports have shown PKR to be nonessential for survival in animals challenged with encephalomyocarditis virus, influenza virus, and vaccinia virus (N. Abraham et al., J. Biol. Chem. 274:5953–5962, 1999; Y. Yang et al., EMBO J. 14:6095–6106, 1995), our findings serve to highlight the premise that host dependence on the various mediators of IFN-induced antiviral defenses is pathogen specific.
Persistent Infection of Human Pancreatic Islets by Coxsackievirus B Is Associated with Alpha Interferon Synthesis in β Cells
Authors: Chehadeh Wassim , Kerr-Conte Julie , Pattou François , Alm Gunar , Lefebvre Jean , Wattré Pierre , Hober Didier 
Published: July 2002

ABSTRACTThe interactions of coxsackievirus B3 (CVB3), CVB4E2 (diabetogenic), and CVB4JBV (nondiabetogenic) strains with human pancreatic islets from eight adult brain-dead donors were investigated. Persistent replication of viruses in human islets was proved by detection of viral RNA by in situ hybridization, VP1 capsid protein by immunofluorescence (IF) staining, negative-strand viral RNA by reverse transcription-PCR in extracted RNA from islets, and release of infectious particles up to 30 days after infection without obvious cytolysis. By double IF staining, glucagon-containing α cells and insulin-containing β cells were shown to be susceptible to CVB. The persistence of CVB3 and CVB4 in islet cells was associated with the chronic synthesis of alpha interferon (IFN-α), as evidenced by the detection of IFN-α mRNA and immunoreactive IFN-α with antiviral activity. By double IF staining, IFN-α was detected in insulin-producing β cells only. Experiments with neutralizing anti-coxsackievirus and adenovirus receptor (CAR) antibodies provided evidence that CAR was expressed by α and β cells and that it played a role in the infection of these cells with CVB and the consecutive IFN-α expression in β cells. The viral replication and the expression of IFN-α in islets were not restricted to the CVB4E2 diabetogenic strain and did not depend on the genetic background of the host. The neutralization of endogenous IFN-α significantly enhanced the CVB replication in islet cells and resulted in rapid destruction of islets. Thus, human β cells can harbor a persistent CVB infection, and CVB-induced IFN-α plays a role in the initiation and/or maintenance of chronic CVB infection in human islets.
Impaired Gamma Interferon Responses against Parvovirus B19 by Recently Infected Children
Authors: Corcoran Amanda , Doyle Sean , Waldron David , Nicholson Alfred , Mahon Bernard P. 
Published: July 2002

ABSTRACTParvovirus B19 is the causative agent of “fifth disease” of childhood. It has been implicated in a variety of conditions, including unsuccessful pregnancy and rheumatoid arthritis, and is a potential contaminant of blood products. There has been little study of immunity to parvovirus B19, and the exact nature of the protective humoral and cell-mediated immune response is unclear. Immune responses to purified virus capsid proteins, VP1 and VP2, were examined from a cohort of recently infected children and compared with responses from long-term convalescent volunteers. The results demonstrate that antibody reactivity is primarily maintained against conformational epitopes in VP1 and VP2. The unique region of VP1 appears to be a major target for cell-mediated immune responses, particularly in recently infected individuals. We confirm that antibody reactivity against linear epitopes of VP2 is lost shortly after infection but find no evidence of the proposed phenotypic switch in either the subclass of parvovirus B19-specific antibody or the pattern of cytokine production by antigen-specific T cells. The dominant subclass of specific antibody detected from both children and adults was immunoglobulin G1. No evidence was found for interleukin 4 (IL-4) or IL-5 production by isolated lymphocytes from children or adults. In contrast, lymphocytes from convalescent adults produced a typical type 1 response associated with high levels of IL-2 and gamma interferon (IFN-γ). However, we observed a significant (P< 0.001) deficit in the production of IFN-γ in response to VP1 or VP2 from lymphocytes isolated from children. Taken together, these results imply that future parvovirus B19 vaccines designed for children will require the use of conformationally preserved capsid proteins incorporating Th1 driving adjuvants. Furthermore, these data suggest novel mechanisms whereby parvovirus B19 infection may contribute to rheumatoid arthritis and unsuccessful pregnancy.
Identification of a Membrane Targeting and Degradation Signal in the p42 Protein of Influenza C Virus
Authors: Pekosz Andrew , Lamb Robert A. 
Published: July 2002

ABSTRACTTwo mRNA species are derived from the influenza C virus RNA segment six, (i) a colinear transcript containing a 374-amino-acid residue open reading frame (referred to herein as the seg 6 ORF) which is translated to yield the p42 protein, and (ii) a spliced mRNA which encodes the influenza C virus matrix (CM1) protein consisting of the first 242 amino acids of p42. The p42 protein undergoes proteolytic cleavage at a consensus signal peptidase cleavage site after residue 259, yielding the p31 and CM2 proteins. Translocation of p42 into the endoplasmic reticulum membrane occurs cotranslationally and requires the hydrophobic internal signal peptide (residues 239 to 259), as well as the predicted transmembrane domain of CM2 (residues 285 to 308). The p31 protein was found to undergo rapid degradation after cleavage from p42. Addition of the 26S proteasome inhibitor lactacystin to influenza C virus-infected or seg 6 ORF cDNA-transfected cells drastically reduced p31 degradation. Transfer of the 17-residue C-terminal region of p31 to heterologous proteins resulted in their rapid turnover. The hydrophobic nature, but not the specific amino acid sequence of the 17-amino-acid C terminus of p31 appears to act as the signal for targeting the protein to membranes and for degradation.
Two Distinct Gamma-2 Herpesviruses in African Green Monkeys: a Second Gamma-2 Herpesvirus Lineage among Old World Primates?
Authors: Greensill Julie , Sheldon Julie A. , Renwick Neil M. , Beer Brigitte E. , Norley Steve , Goudsmit Jaap , Schulz Thomas F. 
Published: July 2002

ABSTRACT

Primate gamma-2 herpesviruses (rhadinoviruses) have so far been found in humans (Kaposi's sarcoma-associated herpesvirus [KSHV], also called human herpesvirus 8), macaques (
Macaca
spp.) (rhesus rhadinovirus [RRV] and retroperitoneal fibromatosis herpesvirus [RFHV]), squirrel monkeys (
Saimiri sciureus
) (herpesvirus saimiri), and spider monkeys (
Ateles
spp.) (herpesvirus ateles). Using serological screening and degenerate consensus primer PCR for the viral DNA polymerase gene, we have detected sequences from two distinct gamma-2 herpesviruses, termed
Chlorocebus
rhadinovirus 1 (ChRV1) and ChRV2, in African green monkeys. ChRV1 is more closely related to KSHV and RFHV, whereas ChRV2 is closest to RRV. Our findings suggest the existence of two distinct rhadinovirus lineages, represented by the KSHV/RFHV/ChRV1 group and the RRV/ChRV2 group, respectively, in at least two Old World monkey species. Antibodies to members of the RRV/ChRV2 lineage may cross-react in an immunofluorescence assay for early and late KSHV antigens.
Virus-Induced Abrogation of Transplantation Tolerance Induced by Donor-Specific Transfusion and Anti-CD154 Antibody
Authors: Welsh Raymond M. , Markees Thomas G. , Woda Bruce A. , Daniels Keith A. , Brehm Michael A. , Mordes John P. , Greiner Dale L. , Rossini Aldo A. 
Published: July 2002

ABSTRACTTreatment with a 2-week course of anti-CD154 antibody and a single transfusion of donor leukocytes (a donor-specific transfusion or DST) permits skin allografts to survive for >100 days in thymectomized mice. As clinical trials of this methodology in humans are contemplated, concern has been expressed that viral infection of graft recipients may disrupt tolerance to the allograft. We report that acute infection with lymphocytic choriomeningitis virus (LCMV) induced allograft rejection in mice treated with DST and anti-CD154 antibody if inoculated shortly after transplantation. Isografts resisted LCMV-induced rejection, and the interferon-inducing agent polyinosinic:polycytidylic acid did not induce allograft rejection, suggesting that the effect of LCMV is not simply a consequence of nonspecific inflammation. Administration of anti-CD8 antibody to engrafted mice delayed LCMV-induced allograft rejection. Pichinde virus also induced acute allograft rejection, but murine cytomegalovirus and vaccinia virus (VV) did not. Injection of LCMV ∼50 days after tolerance induction and transplantation had minimal effect on subsequent allograft survival. Treatment with DST and anti-CD154 antibody did not interfere with clearance of LCMV, but a normally nonlethal high dose of VV during tolerance induction and transplantation killed graft recipients. We conclude that DST and anti-CD154 antibody induce a tolerant state that can be broken shortly after transplantation by certain viral infections. Clinical application of transplantation tolerance protocols may require patient isolation to facilitate the procedure and to protect recipients.
A Novel Mechanism of Resistance to Mouse Mammary Tumor Virus Infection
Authors: Golovkina Tatyana V. 
Published: July 2002

ABSTRACTExogenous mouse mammary tumor virus (MMTV) is carried from the gut of suckling pups to the mammary glands by lymphocytes and induces mammary gland tumors. MMTV-induced tumor incidence in inbred mice of different strains ranges from 0 to as high as 100%. For example, mice of the C3H/HeN strain are highly susceptible, whereas mice of the I/LnJ strain are highly resistant. Of the different factors that together determine the susceptibility of mice to development of MMTV-induced mammary tumors, genetic elements play a major role, although very few genes that determine a susceptibility-resistance phenotype have been identified so far. Our data indicate that MMTV fails to infect mammary glands in I/LnJ mice foster nursed on viremic C3H/HeN females, even though the I/LnJ mammary tissue is not refractory to MMTV infection. Lymphocytes from fostered I/LnJ mice contained integrated MMTV proviruses and shed virus but failed to establish infection in the mammary glands of susceptible syngeneic (I × C3H.JK)F1females. Based on the susceptible-resistant phenotype distribution in N2females, both MMTV mammary gland infection and mammary gland tumor development in I/LnJ mice are controlled by a single locus.