bluuebunny/crossref_metadata_2025_split huggingface dataset:
T-Cell Responses before and after the Fifth Consecutive Acellular Pertussis Vaccination in 4-Year-Old Dutch Children
Authors: Schure Rose-Minke , Hendrikx Lotte H. , de Rond Lia G. H. , Öztürk Kemal , Sanders Elisabeth A. M. , Berbers Guy A. M. , Buisman Anne-Marie 
Published: September 2012

ABSTRACTImmunization with acellular pertussis vaccine (aP) induces higher specific antibody levels and fewer adverse reactions than does immunization with the whole-cell vaccine (wP). However, antibody levels in infants induced by both types of pertussis vaccines wane already after 1 year. Therefore, long-term T-cell responses upon vaccination might play a role in protection against pertussis. In a cross-sectional study (ISRCTN65428640), we investigated T-helper (Th) cell immune responses in wP- or aP-vaccinated children before and after an aP low-dose or high-dose preschool booster at 4 years of age in The Netherlands. T cells were stimulated with pertussis vaccine antigens. The numbers of gamma interferon-producing cells and Th1, Th2, Th17, and interleukin-10 (IL-10) cytokine concentrations were determined. In addition, pertussis-specific IgE levels were measured in plasma. Children being vaccinated with aP vaccinations at 2, 3, 4, and 11 months of age still showed higher pertussis-specific T-cell responses at 4 years of age than did wP-vaccinated children. These T-cell responses failed to show a typical increase in cytokine production after a fifth aP vaccination but remained high after a low-dose booster and seemed to decline even after a high-dose booster. Importantly, elevated IgE levels were induced after this booster vaccination. In contrast, wP-vaccinated children had only low prebooster T-cell responses, and these children showed a clear postbooster T-cell memory response even after a low-dose booster vaccine. Four high-dose aP vaccinations in infancy induce high T-cell responses still present even 3 years after vaccination and enhanced IgE responses after preschool booster vaccination. Therefore, studies of changes in vaccine dosage, timing of pertussis (booster) vaccinations, and the possible association with local side effects are necessary.
Protective Efficacy of a Toxoplasma gondii Rhoptry Protein 13 Plasmid DNA Vaccine in Mice
Authors: Wang Pei-Yuan , Yuan Zi-Guo , Petersen Eskild , Li Jie , Zhang Xiu-Xiang , Li Xiu-Zhen , Li Hao-Xin , Lv Zhi-Cheng , Cheng Tian , Ren Di , Yang Gui-Lian , Lin Rui-Qing , Zhu Xing-Quan 
Published: September 2012

ABSTRACTToxoplasma gondiiis an obligate intracellular parasite infecting humans and other warm-blooded animals, resulting in serious public health problems and economic losses worldwide. Rhoptries are involved inT. gondiiinvasion and host cell interaction and have been implicated as important virulence factors. In the present study, a DNA vaccine expressing rhoptry protein 13 (ROP13) ofT. gondiiinserted into eukaryotic expression vector pVAX I was constructed, and the immune protection it induced in Kunming mice was evaluated. Kunming mice were immunized intramuscularly with pVAX-ROP13 and/or with interleukin-18 (IL-18). Then, we evaluated the immune response using a lymphoproliferative assay, cytokine and antibody measurements, and the survival times of mice challenged with the virulentT. gondiiRH strain (type I) and the cyst-forming PRU strain (type II). The results showed that pVAX-ROP13 alone or with pVAX/IL-18 induced a high level of specific anti-T. gondiiantibodies and specific lymphocyte proliferative responses. Coinjection of pVAX/IL-18 significantly increased the production of gamma interferon (IFN-γ), IL-2, IL-4, and IL-10. Further, challenge experiments showed that coimmunization of pVAX-ROP13 with pVAX/IL-18 significantly (P< 0.05) increased survival time (32.3 ± 2.7 days) compared with pVAX-ROP13 alone (24.9 ± 2.3 days). Immunized mice challenged withT. gondiicysts (strain PRU) had a significant reduction in the number of brain cysts, suggesting that ROP13 could trigger a strong humoral and cellular response againstT. gondiicyst infection and that it is a potential vaccine candidate against toxoplasmosis, which provided the foundation for further development of effective vaccines againstT. gondii.
Pseudo-Outbreak of Lecanicillium and Acremonium Species in Orthopedic Surgery Patients
Authors: Neal Carolyn O. S. , Deak Eszter , Chang Loretta S. , Gilmartin Heather , Gade Lalitha , Imanishi Maho , Price Connie , Brandt Mary E. , Chiller Tom , Balajee S. Arunmozhi 
Published: September 2012

ABSTRACT

Acremonium
species cause a variety of human infections, while
Lecanicillium
species have not been reported as human pathogens. We describe a pseudo-outbreak involving both organisms, highlighting the role and limitations of molecular methods in the characterization of rare fungal isolates. Repeated isolation of these fungi from patient tissue samples raises concerns about exogenous contamination in the hospital environment.
Identification of and Screening for Human Helicobacter cinaedi Infections and Carriers via Nested PCR
Authors: Oyama Kohta , Khan Shahzada , Okamoto Tatsuya , Fujii Shigemoto , Ono Katsuhiko , Matsunaga Tetsuro , Yoshitake Jun , Sawa Tomohiro , Tomida Junko , Kawamura Yoshiaki , Akaike Takaaki 
Published: September 2012

ABSTRACT

Helicobacter cinaedi
is the most frequently reported enterohepatic
Helicobacter
species isolated from humans. Earlier research suggested that certain patients with
H. cinaedi
infection may remain undiagnosed or incorrectly diagnosed because of difficulties in detecting the bacteria by conventional culture methods. Here, we report a nested PCR assay that rapidly detects the cytolethal distending toxin gene (
cdt
) of
H. cinaedi
with high specificity and sensitivity. Specificity of the assay was validated by using different species of
Helicobacter
and
Campylobacter
, as well as known
H. cinaedi
-positive and -negative samples. The sensitivity of detection for the
cdt
gene in the assay was 10
2
CFU/ml urine or 10
2
CFU/10
5
infected RAW 264.7 cells. In an
H. cinaedi
-infected mouse model, the
cdt
gene of
H. cinaedi
was effectively detected via the assay with urine (6/7), stool (2/3), and blood (2/6) samples. Importantly, it detected
H. cinaedi
in blood, urine, and stool samples from one patient with a suspected
H. cinaedi
infection and three patients with known infections. The assay was further used clinically to follow up two
H. cinaedi
-infected patients after antibiotic treatment. Stool samples from these two patients evaluated by nested PCR after antibiotic therapy showed clearance of bacterial DNA. Finally, analysis of stool specimens from healthy volunteers showed occasional positive reactions (4/30) to
H. cinaedi
DNA, which suggests intestinal colonization by
H. cinaedi
in healthy subjects. In conclusion, this nested PCR assay may be useful for the rapid diagnosis, antimicrobial treatment evaluation, and epidemiological study of
H. cinaedi
infection.
Prospective Multicenter Study of Pneumocystis jirovecii Colonization among Cystic Fibrosis Patients in France
Authors: Hernández-Hernández Francisca , Fréalle Emilie , Caneiro Patrick , Salleron Julia , Durand-Joly Isabelle , Accoceberry Isabelle , Bouchara Jean-Philippe , Wallaert Benoit , Dei-Cas Eduardo , Delhaes Laurence 
Published: September 2012

ABSTRACT

Pneumocystis
carriage was detected in 12.5% of 104 cystic fibrosis (CF) patients during a prospective multicenter French study, with a prevalence of genotype 85C/248C and geographic variations. It was significantly associated with the absence of
Pseudomonas aeruginosa
colonization and a greater forced expiratory volume in 1 s. Results are discussed considering the natural history of CF.
Activating KIR Copy Number Variation Is Associated with Granzyme B Release by NK Cells during Primary Simian Immunodeficiency Virus Infection in Rhesus Monkeys
Authors: Hellmann Ina , Schmitz Jörn E. , Letvin Norman L. 
Published: September 2012

ABSTRACT
Here we show that the number of activating killer cell immunoglobulin-like receptor (KIR) copies in rhesus monkeys is associated with the extent of release of cytotoxic granules by cytolytic NK cells during primary simian immunodeficiency virus SIVmac251 infection. These findings suggest that NK cells expressing high levels of activating KIRs efficiently kill SIVmac251-infected cells, and this efficient killing contributes to the NK cell-mediated control of replication of this virus during early infection.
In Vitro
Assembly of an Empty Picornavirus Capsid follows a Dodecahedral Path
Authors: Li Chenglei , Wang Joseph Che-Yen , Taylor Milton W. , Zlotnick Adam 
Published: September 2012

ABSTRACT

The
Picornaviridae
are a large family of small, spherical RNA viruses that includes numerous pathogens. The picornavirus structural proteins VP0, VP1, and VP3 are believed to first form protomers, which then form 14S particles and subsequently assemble to form empty and RNA-filled particles. 14S particles have long been presumed to be pentamers. However, the structure of the 14S particles, their mechanism of assembly, and the role of empty particles during infection are all unknown. We established an
in vitro
assembly system for bovine enterovirus (BEV) by using purified baculovirus-expressed proteins. By Rayleigh scattering, we determined that 14S particles are 488 kDa, confirming they are pentamers. Image reconstructions based on negative-stain electron microscopy showed that 14S particles have 5-fold symmetry, and their structures correlate extremely well with the corresponding pentamer from crystal structures of mature BEV. Purified 14S particles readily assemble in response to increasing ionic strength or temperature to form 5.8-MDa 12-pentamer particles, indistinguishable from native empty particles. Surprisingly, empty particles were sufficiently stable that, under physiological conditions, dissociation is unlikely to be a biologically relevant reaction. This suggests that empty particles are not a storage form of 14S particles, at least for bovine enterovirus, but are either a dead-end product or direct precursor into which viral RNA is packaged by as-yet-unidentified machinery.
Human Metapneumovirus M2-2 Protein Inhibits Innate Cellular Signaling by Targeting MAVS
Authors: Ren Junping , Wang Qingrong , Kolli Deepthi , Prusak Deborah J. , Tseng Chien-Te K. , Chen Zhijian J. , Li Kui , Wood Thomas G. , Bao Xiaoyong 
Published: September 2012

ABSTRACT
Human metapneumovirus (hMPV) is a leading cause of respiratory infections in pediatric populations globally, with no prophylactic or therapeutic measures. Recently, a recombinant hMPV lacking the M2-2 protein (rhMPV-ΔM2-2) demonstrated reduced replication in the respiratory tract of animal models, making it a promising live vaccine candidate. However, the exact nature of the interaction between the M2-2 protein and host cells that regulates viral infection/propagation is largely unknown. By taking advantage of the available reverse genetics system and ectopic expression system for viral protein, we found that M2-2 not only promotes viral gene transcription and replication but subverts host innate immunity, therefore identifying M2-2 as a novel virulence factor, in addition to the previously described hMPV G protein. Since we have shown that the RIG-I/MAVS pathway plays an important role in hMPV-induced signaling in airway epithelial cells, we investigated whether M2-2 antagonizes the host cellular responses by targeting this pathway. Reporter gene assays and coimmunoprecipitation studies indicated that M2-2 targets MAVS, an inhibitory mechanism different from what we previously reported for hMPV G, which affects RIG-I- but not MAVS-dependent gene transcription. In addition, we found that the domains of M2-2 responsible for the regulation of viral gene transcription and antiviral signaling are different. Our findings collectively demonstrate that M2-2 contributes to hMPV immune evasion through the inhibition of MAVS-dependent cellular responses.
Heparan Sulfate Facilitates Rift Valley Fever Virus Entry into the Cell
Authors: de Boer S. M. , Kortekaas J. , de Haan C. A. M. , Rottier P. J. M. , Moormann R. J. M. , Bosch B. J. 
Published: September 2012

ABSTRACT
Rift Valley fever virus (RVFV), an emerging arthropod-borne pathogen, has a broad host and cell tropism. Here we report that the glycosaminoglycan heparan sulfate, abundantly present on the surface of most animal cells, is required for efficient entry of RVFV. Entry was significantly reduced by preincubating the virus inoculum with highly sulfated heparin, by enzymatic removal of heparan sulfate from cells and in cells genetically deficient in heparan sulfate synthesis.
Influenza Virus Neuraminidases with Reduced Enzymatic Activity That Avidly Bind Sialic Acid Receptors
Authors: Zhu Xueyong , McBride Ryan , Nycholat Corwin M. , Yu Wenli , Paulson James C. , Wilson Ian A. 
Published: September 2012

ABSTRACT

Influenza virus neuraminidase (NA) cleaves off sialic acid from cellular receptors of hemagglutinin (HA) to enable progeny escape from infected cells. However, NA variants (D151G) of recent human H3N2 viruses have also been reported to bind receptors on red blood cells, but the nature of these receptors and the effect of the mutation on NA activity were not established. Here, we compare the functional and structural properties of a human H3N2 NA from A/Tanzania/205/2010 and its D151G mutant, which supports HA-independent receptor binding. While the wild-type NA efficiently cleaves sialic acid from both α2-6- and α2-3-linked glycans, the mutant exhibits much reduced enzymatic activity toward both types of sialosides. Conversely, while wild-type NA shows no detectable binding to sialosides, the D151G NA exhibits avid binding with broad specificity toward α2-3 sialosides. D151G NA binds the 3′ sialyllactosamine (3′-SLN) and 6′-SLN sialosides with equilibrium dissociation constant (

K
D

) values of 30.0 μM and 645 μM, respectively, which correspond to much higher affinities than the corresponding affinities (low mM) of HA to these glycans. Crystal structures of wild-type and mutant NAs reveal the structural basis for glycan binding in the active site by exclusively impairing the glycosidic bond hydrolysis step. The general significance of D151 among influenza virus NAs was further explored by introducing the D151G mutation into three N1 NAs and one N2 NA, which all exhibited reduced enzymatic activity and preferential binding to α2-3 sialosides. Since the enzymatic and binding activities of NAs are not routinely assessed, the potential for NA receptor binding to contribute to influenza virus biology may be underappreciated.
Properties of the Adeno-Associated Virus Assembly-Activating Protein
Authors: Naumer Matthias , Sonntag Florian , Schmidt Kristin , Nieto Karen , Panke Christian , Davey Norman E. , Popa-Wagner Ruth , Kleinschmidt Jürgen A. 
Published: September 2012

ABSTRACT

Adeno-associated virus (AAV) capsid assembly requires expression of the assembly-activating protein (AAP) together with capsid proteins VP1, VP2, and VP3. AAP is encoded by an alternative open reading frame of the
cap
gene. Sequence analysis and site-directed mutagenesis revealed that AAP contains two hydrophobic domains in the N-terminal part of the molecule that are essential for its assembly-promoting activity. Mutation of these sequences reduced the interaction of AAP with the capsid proteins. Deletions and a point mutation in the capsid protein C terminus also abolished capsid assembly and strongly reduced the interaction with AAP. Interpretation of these observations on a structural basis suggests an interaction of AAP with the VP C terminus, which forms the capsid protein interface at the 2-fold symmetry axis. This interpretation is supported by a decrease in the interaction of monoclonal antibody B1 with VP3 under nondenaturing conditions in the presence of AAP, indicative of steric hindrance of B1 binding to its C-terminal epitope by AAP. In addition, AAP forms high-molecular-weight oligomers and changes the conformation of nonassembled VP molecules as detected by conformation-sensitive monoclonal antibodies A20 and C37. Combined, these observations suggest a possible scaffolding activity of AAP in the AAV capsid assembly reaction.
Interferon-Inducible Protein Mx1 Inhibits Influenza Virus by Interfering with Functional Viral Ribonucleoprotein Complex Assembly
Authors: Verhelst Judith , Parthoens Eef , Schepens Bert , Fiers Walter , Saelens Xavier 
Published: September 2012

ABSTRACTMx1 is a GTPase that is part of the antiviral response induced by type I and type III interferons in the infected host. It inhibits influenza virus infection by blocking viral transcription and replication, but the molecular mechanism is not known. Polymerase basic protein 2 (PB2) and nucleoprotein (NP) were suggested to be the possible target of Mx1, but a direct interaction between Mx1 and any of the viral proteins has not been reported. We investigated the interplay between Mx1, NP, and PB2 to identify the mechanism of Mx1's antiviral activity. We found that Mx1 inhibits the PB2-NP interaction, and the strength of this inhibition correlated with a decrease in viral polymerase activity. Inhibition of the PB2-NP interaction is an active process requiring enzymatically active Mx1. We also demonstrate that Mx1 interacts with the viral proteins NP and PB2, which indicates that Mx1 protein has a direct effect on the viral ribonucleoprotein complex. In a minireplicon system, avian-like NP from swine virus isolates was more sensitive to inhibition by murine Mx1 than NP from human influenza A virus isolates. Likewise, murine Mx1 displaced avian NP from the viral ribonucleoprotein complex more easily than human NP. The stronger resistance of the A/H1N1 pandemic 2009 virus against Mx1 also correlated with reduced inhibition of the PB2-NP interaction. Our findings support a model in which Mx1 interacts with the influenza ribonucleoprotein complex and interferes with its assembly by disturbing the PB2-NP interaction.
Genome-Wide Analyses of Zta Binding to the Epstein-Barr Virus Genome Reveals Interactions in both Early and Late Lytic Cycles and an Epigenetic Switch Leading to an Altered Binding Profile
Authors: Ramasubramanyan Sharada , Kanhere Aditi , Osborn Kay , Flower Kirsty , Jenner Richard G. , Sinclair Alison J. 
Published: September 2012

ABSTRACT

The Epstein-Barr virus (EBV) genome sustains substantial epigenetic modification involving chromatin remodelling and DNA methylation during lytic replication. Zta (ZEBRA, BZLF1), a key regulator of the EBV lytic cycle, is a transcription and replication factor, binding to Zta response elements (ZREs) in target promoters and EBV lytic origins of replication.
In vitro
, Zta binding is modulated by DNA methylation; a subset of CpG-containing Zta binding sites (CpG ZREs) is bound only in a DNA methylation-dependent manner. The question of how the dynamic epigenetic environment impacts Zta interaction during the EBV lytic cycle is unknown. To address this, we used chromatin immunoprecipitation coupled with next-generation sequencing (ChIP-Seq) to identify Zta binding sites across the EBV genome before and after viral DNA replication. Replication did not alter the association of Zta across many regions of the EBV genome, but a striking reduction in Zta binding occurred at some loci that contain CpG ZREs. Separating Zta-bound DNA into methylated and nonmethylated fractions, we found that promoters that contain CpG ZREs were enriched in the methylated fraction but that Zta binding to promoters lacking CpG ZREs was not reduced. We hypothesize that the loss of DNA methylation on the EBV genome during the lytic cycle causes the reduced binding to CpG ZREs; this may act as a lytic cycle epigenetic switch. However, the epigenetic changes associated with the replicated EBV genome do not affect the interaction of Zta with many loci that are rich in non-CpG ZREs; this leads to sustained binding at these regions.
Genetic Characterization of Simian Foamy Viruses Infecting Humans
Authors: Rua Réjane , Betsem Edouard , Calattini Sara , Saib Ali , Gessain Antoine 
Published: September 2012

ABSTRACTSimian foamy viruses (SFVs) are retroviruses that are widespread among nonhuman primates (NHPs). SFVs actively replicate in their oral cavity and can be transmitted to humans after NHP bites, giving rise to a persistent infection even decades after primary infection. Very few data on the genetic structure of such SFVs found in humans are available. In the framework of ongoing studies searching for SFV-infected humans in south Cameroon rainforest villages, we studied 38 SFV-infected hunters whose times of infection had presumably been determined. By long-term cocultures of peripheral blood mononuclear cells with BHK-21 cells, we isolated five new SFV strains and obtained complete genomes of SFV strains from chimpanzee (Pan troglodytes troglodytes; strains BAD327 and AG15), monkey (Cercopithecus nictitans; strain AG16), and gorilla (Gorilla gorilla; strains BAK74 and BAD468). These zoonotic strains share a very high degree of similarity with their NHP counterparts and have a high degree of conservation of the genetic elements important for viral replication. Interestingly, analysis of FV DNA sequences obtained before cultivation revealed variants with deletions in both the U3 region andtasthat may correlate within vivochronicity in humans. Genomic changes inbet(a premature stop codon) andgagwere also observed. To determine if such changes were specific to zoonotic strains, we studied local SFV-infected chimpanzees and found the same genomic changes. Our study reveals that natural polymorphism of SFV strains does exist at both the intersubspecies level (gag,bet) and the intrasubspecies (U3,tas) levels but does not seem to reflect a viral adaptation specific to zoonotic SFV strains.
Cytosolic Phospholipase A2 Gamma Is Involved in Hepatitis C Virus Replication and Assembly
Authors: Xu Song , Pei Rongjuan , Guo Min , Han Qingxia , Lai Juan , Wang Yun , Wu Chunchen , Zhou Yuan , Lu Mengji , Chen Xinwen 
Published: September 2012

ABSTRACT
Similar to other positive-sense, single-stranded RNA viruses, hepatitis C virus (HCV) replicates its genome in a remodeled intracellular membranous structure known as the membranous web (MW). To date, the process of MW formation remains unclear. It is generally acknowledged that HCV nonstructural protein 4B (NS4B) can induce MW formation through interaction with the cytosolic endoplasmic reticulum (ER) membrane. Many host proteins, such as phosphatidylinositol 4-kinase IIIα (PI4KIIIα), have been identified as critical factors required for this process. We now report a new factor, the cytosolic phospholipase A2 gamma (PLA2G4C), which contributes to MW formation, HCV replication, and assembly. The PLA2G4C gene was identified as a host gene with upregulated expression upon HCV infection. Knockdown of PLA2G4C in HCV-infected cells or HCV replicon-containing cells by small interfering RNA (siRNA) significantly suppressed HCV replication and assembly. In addition, the chemical inhibitor methyl arachidonyl fluorophosphonate (MAFP), which specifically inhibits PLA2, reduced HCV replication and assembly. Electron microscopy demonstrated that MW structure formation was defective after PLA2G4C knockdown in HCV replicon-containing cells. Further analysis by immunostaining and immunoprecipitation assays indicated that PLA2G4C colocalized with the HCV proteins NS4B and NS5A in cells infected with JFH-1 and interacted with NS4B. In addition, PLA2G4C was able to transport the HCV nonstructural proteins from replication sites to lipid droplets, the site for HCV assembly. These data suggest that PLA2G4C plays an important role in the HCV life cycle and might represent a potential target for anti-HCV therapy.