bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Single Amino Acid Change in Rabies Virus Glycoprotein Increases Virus Spread and Enhances Virus Pathogenicity
Authors: Faber Milosz , Faber Marie-Luise , Papaneri Amy , Bette Michael , Weihe Eberhard , Dietzschold Bernhard , Schnell Matthias J. 
Published: October 2005

ABSTRACT

Several rabies virus (RV) vaccine strains containing an aspartic acid (Asp) or glutamic acid (Glu) instead of an arginine (Arg) at position 333 of the RV glycoprotein (G) are apathogenic for immunocompetent mice even after intracranial inoculation. However, we previously showed that the nonpathogenic phenotype of the highly attenuated RV strain SPBNGA, which contains a Glu at position 333 of G, is unstable when this virus is passaged in newborn mice. While the Glu
333
remained unchanged after five mouse passages, an Asn
194
→Lys
194
mutation occurred in RV G. This mutation was associated with increased pathogenicity for adult mice. Using site-directed mutagenesis to exchange Asn
194
with Lys
194
in the G protein of SPBNGA, resulting in SPBNGA-K, we show here that this mutation is solely responsible for the increase in pathogenicity and that the Asn
194
→Lys
194
mutation does not arise when Asn
194
is exchanged with Ser
194
(SPBNGA-S). Our data presented indicate that the increased pathogenicity of SPBNGA-K is due to increased viral spread in vivo and in vitro, faster internalization of the pathogenic virus into cells, and a shift in the pH threshold for membrane fusion. These results are consistent with the notion that the RV G protein is a major contributor to RV pathogenesis and that the more pathogenic RVs escape the host responses by a faster spread than that of less pathogenic RVs.
Immunogenicity of Recombinant Fiber-Chimeric Adenovirus Serotype 35 Vector-Based Vaccines in Mice and Rhesus Monkeys
Authors: Nanda Anjali , Lynch Diana M. , Goudsmit Jaap , Lemckert Angelique A. C. , Ewald Bonnie A. , Sumida Shawn M. , Truitt Diana M. , Abbink Peter , Kishko Michael G. , Gorgone Darci A. , Lifton Michelle A. , Shen Ling , Carville Angela , Mansfield Keith G. , Havenga Menzo J. E. , Barouch Dan H. 
Published: October 2005

ABSTRACT
Preexisting immunity to adenovirus serotype 5 (Ad5) has been shown to suppress the immunogenicity of recombinant Ad5 (rAd5) vector-based vaccines for human immunodeficiency virus type 1 (HIV-1) in both preclinical studies and clinical trials. A potential solution to this problem is to utilize rAd vectors derived from rare Ad serotypes, such as Ad35. However, rAd35 vectors have appeared less immunogenic than rAd5 vectors in preclinical studies to date. In this study, we explore the hypothesis that the differences in immunogenicity between rAd5 and rAd35 vectors may be due in part to differences between the fiber proteins of these viruses. We constructed capsid chimeric rAd35 vectors containing the Ad5 fiber knob (rAd35k5) and compared the immunogenicities of rAd5, rAd35k5, and rAd35 vectors expressing simian immunodeficiency virus Gag and HIV-1 Env in mice and rhesus monkeys. In vitro studies demonstrated that rAd35k5 vectors utilized the Ad5 receptor CAR rather than the Ad35 receptor CD46. In vivo studies showed that rAd35k5 vectors were more immunogenic than rAd35 vectors in both mice and rhesus monkeys. These data suggest that the Ad5 fiber knob contributes substantially to the immunogenicity of rAd vectors. Moreover, these studies demonstrate that capsid chimeric rAd vectors can be constructed to combine beneficial immunologic and serologic properties of different Ad serotypes.
Phenotypic, Functional, and Kinetic Parameters Associated with Apparent T-Cell Control of Human Immunodeficiency Virus Replication in Individuals with and without Antiretroviral Treatment
Authors: Emu Brinda , Sinclair Elizabeth , Favre David , Moretto Walter J. , Hsue Priscilla , Hoh Rebecca , Martin Jeffrey N. , Nixon Douglas F. , McCune Joseph M. , Deeks Steven G. 
Published: October 2005

ABSTRACT

The human immunodeficiency virus (HIV)-mediated immune response may be beneficial or harmful, depending on the balance between expansion of HIV-specific T cells and the level of generalized immune activation. The current study utilizes multicolor cytokine flow cytometry to study HIV-specific T cells and T-cell activation in 179 chronically infected individuals at various stages of HIV disease, including those with low-level viremia in the absence of therapy (“controllers”), low-level drug-resistant viremia in the presence of therapy (partial controllers on antiretroviral therapy [PCAT]), and high-level viremia (“noncontrollers”). Compared to noncontrollers, controllers exhibited higher frequencies of HIV-specific interleukin-2-positive gamma interferon-positive (IL-2
+
IFN-γ
+
) CD4
+
T cells. The presence of HIV-specific CD4
+
IL-2
+
T cells was associated with low levels of proliferating T cells within the less-differentiated T-cell subpopulations (defined by CD45RA, CCR7, CD27, and CD28). Despite prior history of progressive disease, PCAT patients exhibited many immunologic characteristics seen in controllers, including high frequencies of IL-2
+
IFN-γ
+
CD4
+
T cells. Measures of immune activation were lower in all CD8
+
T-cell subsets in controllers and PCAT compared to noncontrollers. Thus, control of HIV replication is associated with high levels of HIV-specific IL-2
+
and IFN-γ
+
CD4
+
T cells and low levels of T-cell activation. This immunologic state is one where the host responds to HIV by expanding but not exhausting HIV-specific T cells while maintaining a relatively quiescent immune system. Despite a history of advanced HIV disease, a subset of individuals with multidrug-resistant HIV exhibit an immunologic profile comparable to that of controllers, suggesting that functional immunity can be reconstituted with partially suppressive highly active antiretroviral therapy.
Human Immunodeficiency Virus Type 1 Can Establish Latent Infection in Resting CD4+T Cells in the Absence of Activating Stimuli
Authors: Swiggard William J. , Baytop Clifford , Yu Jianqing J. , Dai Jihong , Li Chuanzhao , Schretzenmair Richard , Theodosopoulos Ted , O'Doherty Una 
Published: October 2005

ABSTRACTResting CD4+T cells are the best-defined reservoir of latent human immunodeficiency virus type 1 (HIV-1) infection, but how the reservoir is formed is unclear. Understanding how the reservoir of latently infected cells forms is critical because it is a major barrier to curing HIV infection. The system described here may provide an in vitro model of latent HIV-1 infection in resting CD4+T cells. We demonstrated that HIV-1 integrates into the genomes of in vitro-inoculated resting CD4+T cells that have not received activating stimuli and have not entered cell cycle stage G1b. A percentage of the resting CD4+T cells that contain integrated DNA produce virus upon stimulation, i.e., are latently infected. Our results show that latent HIV-1 infection occurs in unstimulated resting CD4+T cells and suggest a new route for HIV-1 reservoir formation.
Protective Cytotoxic T-Cell Responses Induced by Venezuelan Equine Encephalitis Virus Replicons Expressing Ebola Virus Proteins
Authors: Olinger Gene G. , Bailey Michael A. , Dye John M. , Bakken Russell , Kuehne Ana , Kondig John , Wilson Julie , Hogan Robert J. , Hart Mary Kate 
Published: October 2005

ABSTRACT

Infection with Ebola virus causes a severe disease accompanied by high mortality rates, and there are no licensed vaccines or therapies available for human use. Filovirus vaccine research efforts still need to determine the roles of humoral and cell-mediated immune responses in protection from Ebola virus infection. Previous studies indicated that exposure to Ebola virus proteins expressed from packaged Venezuelan equine encephalitis virus replicons elicited protective immunity in mice and that antibody-mediated protection could only be demonstrated after vaccination against the glycoprotein. In this study, the murine CD8
+
T-cell responses to six Ebola virus proteins were examined. CD8
+
T cells specific for Ebola virus glycoprotein, nucleoprotein, and viral proteins (VP24, VP30, VP35, and VP40) were identified by intracellular cytokine assays using splenocytes from vaccinated mice. The cells were expanded by restimulation with peptides and demonstrated cytolytic activity. Adoptive transfer of the CD8
+
cytotoxic T cells protected filovirus naïve mice from challenge with Ebola virus. These data support a role for CD8
+
cytotoxic T cells as part of a protective mechanism induced by vaccination against six Ebola virus proteins and provide additional evidence that cytotoxic T-cell responses can contribute to protection from filovirus infections.
Characterization of Parvovirus B19 Genotype 2 in KU812Ep6 Cells
Authors: Blümel Johannes , Eis-Hübinger Anna Maria , Stühler Albert , Bönsch Claudia , Gessner Matthias , Löwer Johannes 
Published: October 2005

ABSTRACT
An infectious parvovirus B19 (B19V) genotype 2 variant was identified as a high-titer contaminant in a human plasma donation. Genome analysis revealed a 138-bp insertion within the p6 promoter. The inserted sequence was represented by an additional 30 bp from the end of the inverted terminal repeat adjacent to a 108-bp element found also, in inverted orientation, at the extreme right end of the unique sequence of the genome. However, despite the profound variations in the promoter region, the pattern of gene expression and DNA replication did not differ between genotype 1 and genotype 2 in permissive erythroid KU812Ep6 cells. Capsid proteins of both genotypes differ in their amino acid sequences. However, equivalent kinetics of virus inactivation at 56°C or pH 4 indicated a comparable physicochemical stability of virus capsids. Sera from six individuals infected by B19V genotype 1 were investigated on cross-neutralization of B19V genotype 2 in vitro. Similar neutralization of both B19V genotypes was observed in sera from three individuals, while the sera from three other individuals showed weaker cross-neutralization for genotype 2. In conclusion, the in vitro replication characteristics and physical stability of B19V capsids are very similar between human parvovirus B19 genotypes 1 and 2, and cross-neutralization indicates a close antigenic relation of genotypes 1 and 2.
Interaction between Brome Mosaic Virus Proteins and RNAs: Effects on RNA Replication, Protein Expression, and RNA Stability
Authors: Gopinath K. , Dragnea B. , Kao C. 
Published: October 2005

ABSTRACT

Brome mosaic virus (BMV) RNA replication has been examined in a number of systems, including
Saccharomyces cerevisiae
. We developed an efficient T-DNA-based gene delivery system using
Agrobacterium tumefaciens
to transiently express BMV RNAs in
Nicotiana benthamiana
. The expressed RNAs can systemically infect plants and provide material to extract BMV replicase that can perform template-dependent RNA-dependent RNA synthesis in vitro. We also expressed the four BMV-encoded proteins from nonreplicating RNAs and analyzed their effects on BMV RNA accumulation. The capsid protein that coinfiltrated with constructs expressing RNA1 and RNA2 suppressed minus-strand levels but increased plus-strand RNA accumulation. The replication proteins 1a and 2a could function in
trans
to replicate and transcribe the BMV RNAs. None of the BMV proteins or RNA could efficiently suppress posttranscriptional silencing. However, 1a expressed in
trans
will suppress the production of a recombinant green fluorescent protein expressed from the nontranslated portions of BMV RNA1 and RNA2, suggesting that 1a may regulate translation from BMV RNAs. BMV replicase proteins 1a did not affect the accumulation of the BMV RNAs in the absence of RNA replication, unlike the situation reported for
S. cerevisiae
. This work demonstrates that the
Agrobacterium
-mediated gene delivery system can be used to study the
cis
- and
trans
-acting requirements for BMV RNA replication in plants and that significant differences can exist for BMV RNA replication in different hosts.
Mutation of a Single Conserved Nucleotide between the Cloverleaf and Internal Ribosome Entry Site Attenuates Poliovirus Neurovirulence
Authors: DeJesus Nidia , Franco David , Paul Aniko , Wimmer Eckard , Cello Jeronimo 
Published: October 2005

ABSTRACT

The chemical synthesis of poliovirus (PV) cDNA combined with the cell-free synthesis of infectious particles yielded virus whose mouse neurovirulence was highly attenuated (J. Cello, A. V. Paul, and E. Wimmer, Science 297:1016-1018, 2002). Compared to the wild-type PV1 (Mahoney) [PV1(M)] sequence, the synthetic virus genome harbored 27 nucleotide (nt) changes deliberately introduced as genetic markers. Of the 27 nucleotide substitutions, the UA-to-GG exchanges at nucleotides 102/103, mapping to a region between the cloverleaf and the internal ribosome entry site (IRES) in the 5′-nontranslated region, were found to be involved in the observed attenuation phenotype in mice. The UA/GG mutation at nt 102/103 in the synthetic PV1(M) [sPV1(M)] background conferred also a ts phenotype of replication to the virus in human neuroblastoma cells. Conversely, the exchange of GG to wild-type (wt) UA at 102/103 in an sPV1(M) background restored wt neurovirulence in
CD155
transgenic (tg) mice and suppressed the ts phenotype in SK-N-MC cells. All poliovirus variants replicated well in HeLa cells at the two temperatures, regardless of the sequence at the 102/103 locus. Analyses of variants isolated from sPV(M)-infected
CD155
tg mice revealed that the G
102
G
103
-to-G
102
A
103
reversion alone reestablished the neurovirulent phenotype. This suggests that a single mutation is responsible for the observed change of the neurovirulence phenotype. sPV1(M) RNA is translated in cell extracts of SK-N-MC cells with significantly lower efficiency than PV1(M) RNA or sPV1(M) RNA with a G
102
-to-A
102
reversion. These studies suggest a function for the conserved nucleotide (A
103
) located between the cloverleaf and the IRES which is important for replication of PV in the central nervous system of
CD155
tg mice and in human cells of neuronal origin.
Effect of Alternating Passage on Adaptation of Sindbis Virus to Vertebrate and Invertebrate Cells
Authors: Greene Ivorlyne P. , Wang Eryu , Deardorff Eleanor R. , Milleron Rania , Domingo Esteban , Weaver Scott C. 
Published: October 2005

ABSTRACT
Mosquito-borne alphaviruses, which replicate alternately and obligately in mosquitoes and vertebrates, appear to experience lower rates of evolution than do many RNA viruses that replicate solely in vertebrates. This genetic stability is hypothesized to result from the alternating host cycle, which constrains evolution by imposing compromise fitness solutions in each host. To test this hypothesis, Sindbis virus was passaged serially, either in one cell type to eliminate host alteration or alternately between vertebrate (BHK) and mosquito (C6/36) cells. Following 20 to 50 serial passages, mutations were identified and changes in fitness were assessed using competition assays against genetically marked, surrogate parent viruses. Specialized viruses passaged in a single cell exhibited more mutations and amino acid changes per passage than those passaged alternately. Single host-adapted viruses exhibited fitness gains in the cells in which they specialized but fitness losses in the bypassed cell type. Most but not all viruses passaged alternately experienced lesser fitness gains than specialized viruses, with fewer mutations per passage. Clonal populations derived from alternately passaged viruses also exhibited adaptation to both cell lines, indicating that polymorphic populations are not required for simultaneous fitness gains in vertebrate and mosquito cells. Nearly all passaged viruses acquired Arg or Lys substitutions in the E2 envelope glycoprotein, but enhanced binding was only detected for BHK cells. These results support the hypothesis that arbovirus evolution may be constrained by alternating host transmission cycles, but they indicate a surprising ability for simultaneous adaptation to highly divergent cell types by combinations of mutations in single genomes.
Posttranslational Modification of α-Dystroglycan, the Cellular Receptor for Arenaviruses, by the Glycosyltransferase LARGE Is Critical for Virus Binding
Authors: Kunz Stefan , Rojek Jillian M. , Kanagawa Motoi , Spiropoulou Christina F. , Barresi Rita , Campbell Kevin P. , Oldstone Michael B. A. 
Published: October 2005

ABSTRACTThe receptor for lymphocytic choriomeningitis virus (LCMV), the human pathogenic Lassa fever virus (LFV), and clade C New World arenaviruses is α-dystroglycan (α-DG), a cell surface receptor for proteins of the extracellular matrix (ECM). Specific posttranslational modification of α-DG by the glycosyltransferase LARGE is critical for its function as an ECM receptor. In the present study, we show that LARGE-dependent modification is also crucial for α-DG's function as a cellular receptor for arenaviruses. Virus binding involves the mucin-type domain of α-DG and depends on modification by LARGE. A crucial role of the LARGE-dependent glycosylation of α-DG for virus binding is found for several isolates of LCMV, LFV, and the arenaviruses Mobala and Oliveros. Since the posttranslational modification by LARGE is crucial for α-DG recognition by both arenaviruses and the host-derived ligand laminin, it also influences competition between virus and laminin for α-DG. Hence, LARGE-dependent glycosylation of α-DG has important implications for the virus-host cell interaction and the pathogenesis of LFV in humans.
PrP
TSE
Distribution in a Primate Model of Variant, Sporadic, and Iatrogenic Creutzfeldt-Jakob Disease
Authors: Herzog Christian , Rivière Julie , Lescoutra-Etchegaray Nathalie , Charbonnier Aurore , Leblanc Virginie , Salès Nicole , Deslys Jean-Philippe , Lasmézas Corinne Ida 
Published: October 2005

ABSTRACT

Human prion diseases, such as Creutzfeldt-Jakob disease (CJD), are neurodegenerative and fatal. Sporadic CJD (sCJD) can be transmitted between humans through medical procedures involving highly infected organs, such as the central nervous system. However, in variant CJD (vCJD), which is due to human contamination with the bovine spongiform encephalopathy (BSE) agent, lymphoreticular tissue also harbors the transmissible spongiform encephalopathy-associated prion protein (PrP
TSE
), which poses a particularly acute risk for iatrogenic transmission. Two blood transfusion-related cases are already documented. In addition, the recent observation of PrP
TSE
in spleen and muscle in sCJD raised the possibility that peripheral PrP
TSE
is not limited to vCJD cases. We aimed to clarify the peripheral pathogenesis of human TSEs by using a nonhuman primate model which mimics human diseases. A highly sensitive enzyme-linked immunosorbent assay was adapted to the detection of extraneural PrP
TSE
. We show that affected organs can be divided into two groups. The first is peripheral organs accumulating large amounts of PrP
TSE
, which represent a high risk of iatrogenic transmission. This category comprises only lymphoreticular organs in the vCJD/BSE model. The second is organs with small amounts of PrP
TSE
associated with nervous structures. These are the muscles, adrenal glands, and enteric nervous system in the sporadic, iatrogenic, and variant CJD models. In contrast to the first set of organs, this low level of tissue contamination is not strain restricted and seems to be linked to secondary centrifugal spread of the agent through nerves. It might represent a risk for iatrogenic transmission, formerly underestimated despite previous reports of low rates of transmission from peripheral organs of humans to nonhuman primates (5, 10). This study provides an additional experimental basis for the classification of human organs into different risk categories and a rational re-evaluation of current risk management measures.
Establishment and Maintenance of Kaposi's Sarcoma-Associated Herpesvirus Latency in B Cells
Authors: Chen Lei , Lagunoff Michael 
Published: October 2005

ABSTRACT
Kaposi's sarcoma (KS)-associated herpesvirus (KSHV) is the infectious cause of Kaposi's sarcoma and is also associated with two B-cell lymphoproliferative diseases, primary effusion lymphoma and the plasmablastic form of multicentric Castleman's disease. KSHV is also found in the B-cell fraction of peripheral blood mononucleocytes of some KS patients. Despite in vivo infection of B cells and the ability of KSHV to infect many cell types in culture, to date B cells in culture have been resistant to KSHV infection. However, as shown here, the lack of infection is not due to the inability of B cells to support latent KSHV infection. When KSHV DNA is introduced into B cells, the virus is maintained as an episome and can establish and maintain latency over the course of months. As in all primary effusion lymphoma cell lines, there is a low level of spontaneous lytic replication in latently infected BJAB cells. Importantly, viral gene expression is similar to that of primary effusion lymphoma cell lines. Furthermore, the virus can be reactivated to higher levels with specific stimuli and transmitted to other cells, indicating that this is a productive infection. Thus B cells in culture are capable of establishing, maintaining, and reactivating from latency. These studies provide a controlled system to analyze how KSHV alters B cells during KSHV latency and reactivation.
Genomic Analysis of Anti-Hepatitis B Virus (HBV) Activity by Small Interfering RNA and Lamivudine in Stable HBV-Producing Cells
Authors: Guo Yong , Guo Hongyan , Zhang Liang , Xie Hongying , Zhao Xin , Wang Fangxun , Li Ze , Wang Yahui , Ma Shiliang , Tao Jiaping , Wang Weixing , Zhou Yuxiang , Yang Weiping , Cheng Jing 
Published: October 2005

ABSTRACTHepatitis B virus (HBV) causes acute and chronic hepatitis and hepatocellular carcinoma. Small interfering RNA (siRNA) and lamivudine have been shown to have anti-HBV effects through different mechanisms. However, assessment of the genome-wide effects of siRNA and lamivudine on HBV-producing cell lines has not been reported, which may provide a clue to interrogate the HBV-cell interaction and to evaluate the siRNA's side effect as a potential drug. In the present study, we designed seven siRNAs based on the conserved HBV sequences and tested their effects on the expression of HBV genes following sorting of siRNA-positive cells. Among these seven siRNAs, siRNA-1 and siRNA-7 were found to effectively suppress HBV gene expression. We further addressed the global gene expression changes in stable HBV-producing cells induced by siRNA-1 and siRNA-7 by use of human genome-wide oligonucleotide microarrays. Data from the gene expression profiling indicated that siRNA-1 and siRNA-7 altered the expression of 54 and 499 genes, respectively, in HepG2.2.15 cells, which revealed that different siRNAs had various patterns of gene expression profiles and suggested a complicated influence of siRNAs on host cells. We further observed that 18 of these genes were suppressed by both siRNA-1 and siRNA-7. Interestingly, seven of these genes were originally activated by HBV, which suggested that these seven genes might be involved in the HBV-host cell interaction. Finally, we have compared the effects of siRNA and lamivudine on HBV and host cells, which revealed that siRNA is more effective at inhibiting HBV expression at the mRNA and protein level in vitro, and the gene expression profile of HepG2.2.15 cells treated by lamivudine is totally different from that seen with siRNA.