bluuebunny/crossref_metadata_2025_split huggingface dataset:
Serum Immunoglobulin G Immune Response to
Helicobacter pylori
Antigens in Mongolian Gerbils
Authors: Kumagai Toshiko , Yan Jing , Graham David Y. , Tozuka Minoru , Okimura Yukie , Ikeno Tatsuo , Sugiyama Atsushi , Katsuyama Tsutomu , Ota Hiroyoshi 
Published: July 2002

ABSTRACT

The Mongolian gerbil model for
Helicobacter pylori
infection is an animal model that mimics human disease. We examined the serum immune response to
H. pylori
infection in gerbils by enzyme-linked immunosorbent assay (ELISA) and Western blotting, both with whole-cell (
H. pylori
) extracts. A total of 66 7-week-old specific-pathogen-free male gerbils were inoculated orogastrically with
H. pylori
strain ATCC 43504. Sera were collected 1, 2, 4, 8, 12, 26, 38, and 52 weeks after
H. pylori
inoculation. Sixty-nine noninfected gerbils and their sera were used as controls. The specificity of the ELISA was 95.7%. The frequency of seropositivity increased over time: 2 of 10 (20%), 7 of 10 (70%), and 7 of 7 (100%) samples of sera from inoculated gerbils were positive for
H. pylori
at 2, 4, and 8 weeks postinoculation, respectively. Western blot assays showed that the primary immunoglobulin G (IgG) response against low-molecular-mass (25-, 30-, and 20-kDa) proteins appeared after a lag period of 2 to 8 weeks after inoculation. Antibodies against 160-, 150-, 110-, 120-, 80-, 66-, and 63-kDa proteins were observed 12 weeks after inoculation. The early reactive 30-kDa protein was identified as a urease α subunit by N-terminal amino acid sequencing. After 26 weeks, two groups of animals could be distinguished: one group developed ulcers (
n
= 5), and the other developed hyperplastic polyps without ulcers (
n
= 19). Gerbils in the gastric ulcer group showed significantly higher serum anti-
H. pylori
IgG levels than did gerbils in the hyperplastic group (
P
= 0.001) as measured by ELISA. Furthermore, a higher proportion of animals developed antibodies to
H. pylori
proteins of 26, 25, and 20 kDa in the ulcer group than those animals with hyperplastic polyps (75 to 100% versus 17 to 50%) in Western blot assays. These results highlight the importance of the immune response of the host in the development of
H. pylori
-related gastric lesions.
Prevalence of Human Immunodeficiency Virus Type 1 (HIV-1) Non-B Subtypes in Foreigners Living in Madrid, Spain, and Comparison of the Performances of the AMPLICOR HIV-1 MONITOR Version 1.0 and the New Automated Version 1.5
Authors: Holguı́n Africa , Aracil Belén , Álvarez Amparo , Barros Carlos , Soriano Vincent 
Published: July 2002

ABSTRACT

Plasma specimens collected in 1999 from 32 human immunodeficiency virus type 1 (HIV-1)-infected foreigners living in Madrid, Spain, were examined for the presence of non-B subtypes. Furthermore, plasma viremia was quantified using two different AMPLICOR HIV-1 MONITOR tests, version 1.0 and the new upgraded and automated version 1.5 (COBAS). Most patients came from Africa, where they most likely had acquired HIV-1 infection through sexual contact. HIV-1 genetic subtyping was based on the phylogenetic analysis of the
protease
gene. Twenty-two subtype B, six subtype G, two subtype C, one subtype A, and one D subtype infection were found. Overall, non-B subtypes represented 31.25% of the study population. Irrespective of the HIV-1 variant, viral load values above the detection limit (200 HIV RNA copies/ml) increased from 56.2 to 71.9% for results obtained using MONITOR version 1.0 and COBAS, respectively. Moreover, significant differences in viral load values (>0.5 logs) were recognized in up to 37.5% of samples. In summary, COBAS seemed to be more reliable for testing plasma viral load in HIV-infected immigrants living in Spain, one third of whom carried non-B subtypes.
Identification of Strains of
Alcaligenes
and
Agrobacterium
by a Polyphasic Approach
Authors: Clermont Dominique , Harmant Christine , Bizet Chantal 
Published: July 2002

ABSTRACT

The number of stable discriminant biochemical characters is limited in the genera
Alcaligenes
and
Agrobacterium
, whose species are consequently difficult to distinguish from one another by conventional tests. Moreover, genomic studies have recently drastically modified the nomenclature of these genera; for example,
Alcaligenes xylosoxidans
was transferred to the genus
Achromobacter
in 1998. Twenty-five strains of
Achromobacter xylosoxidans
, three strains of an
Agrobacterium
sp., five strains of an
Alcaligenes
sp., and four unnamed strains belonging to the Centers for Disease Control and Prevention group IVc-2 were examined. These strains were characterized by conventional tests, including biochemical tests. The assimilation of 99 carbohydrates, organic acids, and amino acids was studied by using Biotype-100 strips, and rRNA gene restriction patterns were obtained with the automated Riboprinter microbial characterization system after cleavage of total DNA with
Eco
RI or
Pst
I restriction endonuclease. This polyphasic approach allowed the two subspecies of
A. xylosoxidans
to be clearly separated. Relationships between five strains and the
Ralstonia paucula
type strain were demonstrated. Likewise, three strains were found to be related to the
Ochrobactrum anthropi
type strain. We showed that substrate assimilation tests and automated ribotyping provide a simple, rapid, and reliable means of identifying
A. xylosoxidans
subspecies and that these two methods can be used as alternative methods to characterize unidentified strains rapidly when discriminant biochemical characters are missing.
PCR M Typing: a New Method for Rapid Typing of Group A Streptococci
Authors: Vitali Luca A. , Zampaloni Claudia , Prenna Manuela , Ripa Sandro 
Published: July 2002

ABSTRACTA new approach for the M-typing ofStreptococcus pyogenesis reported. Oligonucleotide primers were used in a PCR to amplify the N-terminal region of theemmgene. The presence of the PCR amplification product is associated with the corresponding M serotype. This technique offers potential advantages over other molecular typing methods.
Rapid Typing of
Bordetella pertussis
Pertussis Toxin Gene Variants by LightCycler Real-Time PCR and Fluorescence Resonance Energy Transfer Hybridization Probe Melting Curve Analysis
Authors: Mäkinen Johanna , Mertsola Jussi , Viljanen Matti K. , Arvilommi Heikki , He Qiushui 
Published: July 2002

ABSTRACT

A LightCycler real-time PCR hybridization probe assay was developed for rapid typing of gene variants of the
Bordetella pertussis
virulence factor pertussis toxin. The assay correctly identified the
ptxS1
alleles of all strains tested, comprising 57 Finnish clinical isolates and 2 vaccine strains. The method is simple, reliable, and suitable for large-scale screening of
B. pertussis
strains.
Comparative Study of Two Methods for RNA Extraction Prior to Detection of Resistance to Human Immunodeficiency Virus Type 1 with the Line Probe Assay
Authors: Eiros Jose María , Labayru Cristina , Hernández Beatriz , Ortiz de Lejarazu Raúl , Rodríguez Torres Antonio 
Published: July 2002

ABSTRACTWe evaluated two methods from Roche and Promega for RNA extraction prior to the genotypic detection of human immunodeficiency virus type 1 resistance by line probe assay (LiPA). Fifty plasma RNA extracts were processed in parallel by LiPA. Results obtained by the Roche method were superior in the proportion of amplified samples, the percentage of mutated samples, and band intensity.
Quantitative Analysis of the Antiviral Activity of CD8+T Cells from Human Immunodeficiency Virus-Positive Asymptomatic Patients with Different Rates of CD4+T-Cell Decrease
Authors: Salerno-Gonçalves Rosângela , Lu Wei , Andrieu Jean-Marie 
Published: July 2002

ABSTRACTWe have measured in 22 asymptomatic human immunodeficiency virus type 1-infected patients (10 rapid progressors and 12 slow progressors) the proviral load of CD4+T cells homogeneously superinfected by the same dose of a non-syncytium-inducing virus in the presence or in the absence of autologous CD8+T cells. We demonstrated that the antiviral activity of CD8+T cells was highly predictive of the rate of peripheral CD4+T-cell decline.
Analysis of Gene Expression in a Human Cell Line Stably Transduced with Herpesvirus Saimiri
Authors: Hall Kersten T. , Giles Mathew S. , Goodwin Delyth J. , Calderwood Michael A. , Carr Ian M. , Stevenson Alex J. , Markham Alex F. , Whitehouse Adrian 
Published: July 2002

ABSTRACTHerpesvirus saimiri (HVS) is the prototype gamma-2 herpesvirus; it has significant homology to the human gammaherpesviruses Kaposi's sarcoma-associated virus and Epstein-Barr virus and the murine gammaherpesvirus murine herpesvirus 68. HVS causes a persistent asymptomatic infection in its natural host, the squirrel monkey. Both subgroups A and C possess the ability to immortalize common marmoset T lymphocytes to interleukin-2-independent proliferation. However, only subgroup C is capable of transforming human, rabbit, and rhesus monkey lymphocytes in vitro. In addition, HVS can stably transduce a variety of human cell lines where the virus persists as a nonintegrating circular episome. In this study, we have developed a system in which the HVS DNA is stably maintained as a nonintegrated circular episome in the human lung carcinoma cell line A549. Virus production can be reactivated using chemical inducing agents, including tetradecanoyl phorbol acetate andn-butyrate, suggesting that the infection in human A549 cells is latent. To analyze virus gene expression in these stably transduced cells, Northern blot analysis was performed using a series of probes produced from restriction fragments spanning the entire coding region of the HVS genome. This demonstrated that an adjacent set of genes containing open reading frames (ORFs) 71 to 73 are expressed in this stably transduced cell line. Moreover, these genes are transcribed as a polycistronic mRNA species produced from a common promoter upstream of ORF 73. This model may serve as a useful tool in the further analysis of the role of ORFs 71 to 73 in gamma-2 herpesvirus latency.
Determination of the Frequency of Retroviral Recombination between Two Identical Sequences within a Provirus
Authors: Li Ting , Zhang Jiayou 
Published: July 2002

ABSTRACT

Retroviruses use RNA as their genetic material within viral particles and DNA (provirus) as their genetic material within cells. The rate of recombination during reverse transcription between two identical sequences within the same RNA molecule is very high. In this study, we have developed a sensitive system to study recombination occurring within the proviral sequence. This system includes a murine Moloney leukemia virus vector which contains a neomycin resistance gene (
neo
) and two mutated green fluorescent protein genes (
gfp
) in tandem positions. The 3′ end of the first
gfp
and the 5′ end of the second
gfp
gene are both mutated, so that neither of these two
gfp
genes is functional. However, if recombination occurs between the two
gfp
genes it will create a functional
gfp
protein. Cells containing such a functional recombinant
gfp
appear green under fluorescence microscopy. The rate of recombination between the two
gfp
sequences during a single round of replication is as high as 51%. Green cells appear during proliferation of a clonal clear-cell population and allow a small portion of these recombinations between sequences of proviral DNA to be detected. The frequency of recombination at the proviral DNA level is about 10
−5
events/cell division, which is very low compared with the frequency of recombination (51%) caused by reverse transcriptase and/or RNA polymerase II.
Moloney Murine Leukemia Virus-Induced Tumors Show Altered Levels of Proapoptotic and Antiapoptotic Proteins
Authors: Bonzon Christine , Fan Hung 
Published: July 2002

ABSTRACTMoloney murine leukemia virus (M-MuLV) is a replication-competent, simple retrovirus that induces T-cell lymphomas when inoculated into neonatal mice. The tumor cells are typically derived from immature T cells. During preleukemic times, a marked decrease in thymic size is apparent in M-MuLV-inoculated mice. We previously demonstrated that this thymic regression is correlated with enhanced levels of thymocyte apoptosis (C. Bonzon and H. Fan, J. Virol. 73:2434-2441, 1999). In this study, we investigated the apoptotic state of M-MuLV-induced tumors. M-MuLV-induced tumors were screened for expression of the apoptotic proteins Fas and Bcl-2 by three-color flow cytometric analysis. Single-positive (SP; CD4+CD8−and CD4−CD8+) tumor cells generally displayed lower cell surface expression of Fas than SP thymocytes from uninoculated control mice. Double-positive (DP; CD4+CD8+) M-MuLV-induced tumor cells fell into two categories: those with normal high levels of Fas and those with low levels of Fas. Additionally, the vast majority of DP tumors showed elevated Bcl-2 levels. The DP tumor cells retaining normal/high Fas expression were capable of transducing an apoptotic signal upon anti-Fas engagement. In addition, DP and CD4+SP tumor populations displayed higher levels of Fas ligand than normal thymocytes with the same phenotypes. In contrast, CD8+SP and CD4−CD8−tumors did not show elevated Fas ligand expression. There was no significant correlation between Fas and Fas ligand expression in the DP tumors, suggesting that Fas Ligand expression was not the driving force behind Fas down-regulation. These results suggest that both the Fas death receptor and mitochondrial pathways of apoptotic death are active in M-MuLV-induced tumors and that they must be modulated to permit cell survival and tumor outgrowth.
Anti-Feline Immunodeficiency Virus (FIV) Soluble Factor(s) Produced from Antigen-Stimulated Feline CD8+T Lymphocytes Suppresses FIV Replication
Authors: Choi In-Soo , Hokanson Regina , Collisson Ellen W. 
Published: July 2002

ABSTRACTFeline immunodeficiency virus (FIV) causes AIDS-like symptoms in infected cats. Concanavalin A (ConA)-stimulated peripheral blood mononuclear cells (PBMC) from chronically FIV strain PPR-infected cats readily expressed FIV. In contrast, when PBMC from these animals were stimulated with irradiated, autologous antigen-presenting cells (APC), at least a 10-fold drop in viral production was observed. In addition to FIV-specific cytotoxic T lymphocytes, anti-FIV activity was demonstrated in the cell-free supernatants of effector T lymphocytes stimulated with APC. The FIV-suppressive activity was induced from APC-stimulated PBMC of either FIV-infected or uninfected cats but not from ConA-stimulated PBMC. Suppression of FIV strain PPR replication was observed for both autologous and heterologous feline PBMC, was dose dependent, and demonstrated cross-reactivity and cell specificity. It was also demonstrated that the anti-FIV activity originated from CD8+T lymphocytes and was mediated by a noncytolytic mechanism.
Measles Virus-Induced Disruption of the Glial-Fibrillary-Acidic Protein Cytoskeleton in an Astrocytoma Cell Line (U-251)
Authors: Duprex W. Paul , McQuaid Stephen , Rima Bert K. 
Published: July 2002

ABSTRACT
A recombinant measles virus which expresses enhanced green fluorescent protein (MVeGFP) has been used to infect two astrocytoma cell lines (GCCM and U-251) to study the effect of virus infection on the cytoskeleton. Indirect immunocytochemistry was used to demonstrate the cellular localization of the cytoskeletal components. Enhanced green fluorescent protein autofluorescence was used to identify measles virus-infected cells. No alteration of the actin, tubulin, or vimentin components of the cytoskeleton was observed in either cell type, whereas a disruption of the glial-fibrillary-acidic protein filament (GFAP) network was noted in MVeGFP-infected U-251 cells. The relative amounts of GFAP present in infected and uninfected U-251 cells were quantified by image analysis of data sets obtained by confocal microscopy by using vimentin, another intermediate filament on which MVeGFP has no effect, as a control.
The Vaccinia Virus A14.5L Gene Encodes a Hydrophobic 53-Amino-Acid Virion Membrane Protein That Enhances Virulence in Mice and Is Conserved among Vertebrate Poxviruses
Authors: Betakova Tatiana , Wolffe Elizabeth J. , Moss Bernard 
Published: July 2002

ABSTRACTA short sequence, located between the A14L and A15L open reading frames (ORFs) of vaccinia virus, was predicted to encode a hydrophobic protein of 53 amino acids that is conserved in orthopoxviruses, leporipoxviruses, yatapoxiruses, and molluscipoxviruses. We constructed a recombinant vaccinia virus with a 10-codon epitope tag appended to the C terminus of the A14.5L ORF. Synthesis of the tagged protein occurred at late times and was blocked by an inhibitor of DNA replication, consistent with regulation by a predicted late promoter just upstream of the A14.5L ORF. Hydrophobicity of the protein was demonstrated by extraction into the detergent phase of Triton X-114. The protein was associated with purified vaccinia virus particles and with membranes of immature and mature virions that were visualized by electron microscopy of infected cells. Efficient release of the protein from purified virions occurred after treatment with a nonionic detergent and reducing agent. A mutant virus, in which the A14.5L ORF was largely deleted, produced normal-size plaques in several cell lines, and the yields of infectious intra- and extracellular viruses were similar to those of the parent. In contrast, with a mouse model, mutant viruses with the A14.5L ORF largely deleted were attenuated relative to that of the parental virus or a mutant virus with a restored A14.5L gene.
An Epstein-Barr Virus Protein Interacts with Notch
Authors: Kusano Shuichi , Raab-Traub Nancy 
Published: July 2002

ABSTRACT

The Epstein-Barr virus (EBV)
Bam
HI A mRNAs were originally identified in cDNA libraries from nasopharyngeal carcinoma, where they are expressed at high levels. The RNAs are differentially spliced to form several open reading frames and also contain the BARF0 open reading frame at the 3′ end. One cDNA, RK-BARF0, included a potential endoplasmic reticulum-targeting signal peptide sequence. The RK-BARF0 protein is shown here to interact with the Notch4 ligand binding domain, using yeast two-hybrid screening, coimmunoprecipitation, and confocal microscopy. This interaction induces translocation of a portion of the full-length unprocessed Notch4 to the nucleus by using the Notch nuclear localization signal. These effects of RK-BARF0 on Notch intracellular location indicate that EBV possibly modulates Notch signaling. Unprocessed Notch4 was also detected in immunoprecipitated complexes from EBV-infected cells by using a rabbit antiserum raised against a BARF0-specific peptide. This finding provides additional evidence for expression of RK-BARF0 and its interaction with Notch during EBV infection. In EBV-infected, EBNA2-negative cells, RK-BARF0 induced the expression of EBV latent membrane protein 1 (LMP1), and this induction was dependent on the RK-BARF0/Notch interaction domain. The activation of LMP1 expression by RK-BARF0 may be responsible for expression of LMP1 in EBV latent infections in the absence of EBNA2.
Nonspecific Down-Regulation of CD8+T-Cell Responses in Mice Expressing Human Papillomavirus Type 16 E7 Oncoprotein from the Keratin-14 Promoter
Authors: Tindle Robert W. , Herd Karen , Doan Tracy , Bryson Greg , Leggatt Graham R. , Lambert Paul , Frazer Ian H. , Street Michael 
Published: July 2002

ABSTRACTThe E7 oncoprotein of human papillomavirus 16 (HPV16) transforms basal and suprabasal cervical epithelial cells and is a tumor-specific antigen in cervical carcinoma, to which immunotherapeutic strategies aimed at cytotoxic T-lymphocyte (CTL) induction are currently directed. By quantifying major histocompatibility complex class I tetramer-binding T cells and CTL in mice expressing an HPV16 E7 transgene from the keratin-14 (K14) promoter in basal and suprabasal keratinocytes and in thymic cortical epithelium, we show that antigen responsiveness of both E7- and non-E7-specific CD8+cells is down-regulated compared to non-E7 transgenic control mice. We show that the effect is specific for E7, and not another transgene, expressed from the K14 promoter. Down-regulation did not involve deletion of CD8+T cells of high affinity or high avidity, and T-cell receptor (TCR) Vβ-chain usage and TCR receptor density were similar in antigen-responsive cells from E7 transgenic and non-E7 transgenic mice. These data indicate that E7 expressed chronically from the K14 promoter nonspecifically down-regulates CD8+T-cell responses. The in vitro data correlated with the failure of immunized E7 transgenic mice to control the growth of an E7-expressing tumor challenge. We have previously shown that E7-directed CTL down-regulation correlates with E7 expression in peripheral but not thymic epithelium (T. Doan et al., J. Virol. 73:6166–6170, 1999). The findings have implications for the immunological consequences of E7-expressing tumor development and E7-directed immunization strategies. Generically, the findings illustrate a T-cell immunomodulatory function for a virally encoded human oncoprotein.
Heparin Inhibits Retrovirus Binding to Fibronectin as Well as Retrovirus Gene Transfer on Fibronectin Fragments
Authors: Carstanjen D. , Dutt P. , Moritz T. 
Published: July 2002

ABSTRACT
Fibronectin fragments have been shown to improve retrovirus gene transfer efficiency by binding retrovirus and target cells. Using a novel virus adhesion assay, we confirmed binding of type C oncoretrovirus vectors to the heparin II domain of fibronectin and demonstrated inhibition of viral binding and gene transfer by heparin.
Identification and Characterization of a Spliced C-Type Lectin-Like Gene Encoded by Rat Cytomegalovirus
Authors: Voigt Sebastian , Sandford Gordon R. , Ding Lijun , Burns William H. 
Published: July 2002

ABSTRACTThe English isolate of rat cytomegalovirus (RCMV) encodes a 20-kDa protein with a C-type lectin-like domain that is expressed in the delayed-early and late phases of the viral replication cycle. Genomic sequence analysis of the restriction fragmentKpnR of RCMV revealed significant homology to several C-type lectin-containing molecules implicated in natural killer (NK) and T-cell interactions, as well as genes from four poxviruses and African swine fever virus. The gene is spliced into five exons and shows a splicing pattern with exon boundaries similar to those observed in the human differentiation antigen CD69. The cap site of the gene was mapped by RNase protection, 5′ rapid amplification of cDNA ends, and primer extension experiments. This analysis demonstrated that the core promoter of the RCMV lectin-like gene contains a GATA rather than a TATA box. Splicing patterns were confirmed with isolates from an infected-cell cDNA library. A unique aspect of the protein is that its translation is not initiated by the canonical methionine but rather by alanine. To study its role in virus replication and pathogenesis, a recombinant virus was constructed in which the gene is interrupted. Replication in tissue culture was similar to that of wild-type virus.