bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of Indirect Enzyme-Linked Immunosorbent Assays and IgG Avidity Assays Using a Protein A-Peroxidase Conjugate for Serological Distinction between
Brucella abortus
S19-Vaccinated and -Infected Cows
Authors: Pajuaba Ana C. A. M. , Silva Deise A. O. , Mineo José R. 
Published: February 2010

ABSTRACT

This study aimed to evaluate the use of protein A-peroxidase (horseradish peroxidase [HRPO]) in indirect enzyme-linked immunosorbent assays (iELISAs) and IgG avidity assays for serological distinction between
Brucella abortus
S19-vaccinated and -infected cows. Four groups were analyzed: GI, 41 nonvaccinated seropositive cows; GII, 79 S19-vaccinated heifers analyzed at 3 months postvaccination; GIII, 105 S19-vaccinated cows analyzed after 24 months of age; and GIV, 278 nonvaccinated seronegative cows. IgG levels and avidity to
B. abortus
smooth lipopolysaccharide (S-LPS) were determined using anti-bovine IgG-HRPO or protein A-HRPO conjugates. Similar levels of IgG anti-S-LPS were found with GI using both conjugates. Lower IgG levels were detected with GII, GIII, and GIV using protein A-HRPO. Both conjugates showed high performance in discriminating GI from GIII, with high sensitivity (Se; 97.6%) and specificity (Sp; 97.1%). Protein A-HRPO was better in distinguishing GI from GIV (Se, 97.6%; Sp, 94.6%) and GI from GII (Se, 80.5%; Sp, 94.9%). Protein A-HRPO excluded a higher number of positive samples with GII and GIV. IgG avidity showed that protein A-HRPO, but not anti-IgG-HRPO, was able to distinguish nonvaccinated from vaccinated cattle, showing a higher avidity index (AI) with GI than with GII, with 78% of serum samples in GII showing an AI of <50%. Therefore, the iELISA using
B. abortus
S-LPS antigen and protein A-HRPO conjugate for preferential detection of the IgG2 subclass was shown to be suitable for serological distinction between S19-vaccinated and -infected cows. Also, antibodies generated after vaccination showed lower avidity, suggesting a role for the IgG2 subclass as an antibody of higher-affinity maturation after infection, constituting an additional tool for differentiating vaccinated from infected cattle.
Multicenter External Quality Assessment of Molecular Methods for Detection of Human Herpesvirus 6
Authors: de Pagter P. J. , Schuurman R. , de Vos N. M. , Mackay W. , van Loon A. M. 
Published: February 2010

ABSTRACT

The purpose of this study was to evaluate the performance of laboratories for the detection and quantification of human herpesvirus 6 (HHV-6) by an external quality assessment (EQA) evaluation. The HHV-6 EQA panel consisted of eight samples containing various concentrations of HHV-6 type A (strain GS) or type B (strain Z29), two samples containing other herpesviruses (i.e., human cytomegalovirus [HCMV] and Epstein-Barr virus [EBV]), and two HHV-6-negative samples. Panel samples were prepared in human plasma, heat inactivated, and lyophilized. Panel distribution, data management, and analysis were coordinated by Quality Control for Molecular Diagnostics (QCMD), Glasgow, United Kingdom. Fifty-one laboratories participated and submitted 57 data sets. Eleven (19.3%) data sets were generated using conventional in-house assays, 11 (19.3%) data sets using commercial real-time PCR assays, and 35 (61.4%) data sets using in-house real-time PCR assays. The presence of HHV-6 DNA at viral loads exceeding 6,000 copies/ml was detected by all participants, and over 80% of the participants still reported correct qualitative results for the sample containing just over 200 copies/ml. The false-positivity rate was 1.8% for both the negative samples and the samples containing HCMV or EBV DNA. The majority (23/33; 69.7%) of quantitative data sets were generated using in-house real-time PCR assays. The standard deviations of the geometric means of the samples ranged from 0.5 to 0.7 log
10
. The results of this first international EQA demonstrate encouraging analytical sensitivity for the detection of HHV-6-DNA in human plasma, although we observed extensive interlaboratory variation of quantitative HHV-6 DNA results. Standardization needs to be improved to allow further elucidation of the clinical significance of HHV-6 loads.
Prognostic Features of Galactomannan Antigenemia in Galactomannan-Positive Invasive Aspergillosis
Authors: Koo Sophia , Bryar Julie M. , Baden Lindsey R. , Marty Francisco M. 
Published: February 2010

ABSTRACT

Prognostic features of serum galactomannan (GM) remain poorly defined in patients with GM-positive invasive aspergillosis (GPA). We identified 93 patients with proven or probable invasive aspergillosis (IA) and GM values of ≥0.50 from January 2005 to March 2009. We used Cox modeling of time to 6- and 12-week mortality for the GM level at the time of diagnosis (GM
0
), GM decay in the week following diagnosis in 72 patients with ≥2 GM values, other predictors of mortality, and antifungal use during the week following diagnosis. Six-week mortality was 55% in the whole cohort and 43% in patients with ≥2 GM determinations. The hazard ratio (HR) of GM
0
per unit increase and 1-week GM decay per unit decline per week were 1.25 (95% confidence interval [CI], 1.01 to 1.54;
P
= 0.04) and 0.78 (95% CI, 0.63 to 0.96;
P
= 0.02), respectively, adjusting for other predictors of IA mortality; these values remained stable after adjusting for antifungal use and were predictive of all-cause mortality at 12 weeks with similar adjusted HR values. We conclude that the combination of GM
0
and 1-week GM decay is predictive of all-cause mortality in patients with GPA, independent of other traditional risk factors for mortality and antifungal exposure, supporting GM decay as a potential surrogate endpoint for future antifungal therapeutic trials.
Type I Interferon-Sensitive Recombinant Newcastle Disease Virus for Oncolytic Virotherapy
Authors: Elankumaran Subbiah , Chavan Vrushali , Qiao Dan , Shobana Raghunath , Moorkanat Gopakumar , Biswas Moanaro , Samal Siba K. 
Published: February 2010

ABSTRACTNewcastle disease virus (NDV), an avian paramyxovirus, is tumor selective and intrinsically oncolytic because of its potent ability to induce apoptosis. Several studies have demonstrated that NDV is selectively cytotoxic to tumor cells but not normal cells due to defects in the interferon (IFN) antiviral responses of tumor cells. Many naturally occurring strains of NDV have an intact IFN-antagonistic function and can still replicate in normal human cells. To avoid potential toxicity issues with NDV, especially in cancer patients with immunosuppression, safe NDV-oncolytic vectors are needed. We compared the cell killing abilities of (i) a recombinant NDV (rNDV) strain, Beaudette C, containing an IFN-antagonistic, wild-type V protein (rBC), (ii) an isogenic recombinant virus with a mutant V protein (rBC-Edit virus) that induces increased IFN in infected cells and whose replication is restricted in normal human cells, and (iii) a recombinant LaSota virus with a virulent F protein cleavage site that is as interferon sensitive as rBC-Edit virus (LaSota V.F. virus). Our results indicated that the tumor-selective replication of rNDV is determined by the differential regulation of IFN-α and downstream antiviral genes induced by IFN-α, especially through the IRF-7 pathway. In a nude mouse model of human fibrosarcoma, we show that the IFN-sensitive NDV variants are as effective as IFN-resistant rBC virus in clearing the tumor burden. In addition, mice treated with rNDV exhibited no signs of toxicity to the viruses. These findings indicate that augmentation of innate immune responses by NDV results in selective oncolysis and offer a novel and safe virotherapy platform.
Stimulation of HIV-1 Replication in Immature Dendritic Cells in Contact with Primary CD4 T or B Lymphocytes
Authors: Holl Vincent , Xu Ke , Peressin Maryse , Lederle Alexandre , Biedma Marina Elizabeth , Delaporte Maryse , Decoville Thomas , Schmidt Sylvie , Laumond Géraldine , Aubertin Anne-Marie , Moog Christiane 
Published: February 2010

ABSTRACTSexual transmission is the major route of HIV-1 infection worldwide. Dendritic cells (DCs) from the mucosal layers are considered to be the initial targets of HIV-1 and probably play a crucial role in HIV-1 transmission. We investigated the role of cell-to-cell contact between HIV-1-exposed immature DCs and various lymphocyte subsets in the stimulation of HIV-1 replication. We found that HIV-1 replication and production in DCs were substantially enhanced by the coculture of DCs with primary CD4 T or nonpermissive B lymphocytes but not with primary activated CD8 T lymphocytes or human transformed CD4 T lymphocytes. Most of the new virions released by cocultures of HIV-1-exposed immature DCs and primary B lymphocytes expressed the DC-specific marker CD1a and were infectious for both immature DCs and peripheral blood mononuclear cells (PBMCs). Cocultured DCs thus produced large numbers of infectious viral particles under these experimental conditions. The soluble factors present in the supernatants of the cocultures were not sufficient to enhance HIV-1 replication in DCs, for which cell-to-cell contact was required. The neutralizing monoclonal antibody IgG1b12 and polyclonal anti-HIV-1 sera efficiently blocked HIV-1 transfer to CD4 T lymphocytes but did not prevent the increase in viral replication in DCs. Neutralizing antibodies thus proved to be more efficient at blocking HIV-1 transfer than previously thought. Our findings show that HIV-1 exploits DC-lymphocyte cross talk to upregulate replication within the DC reservoir. We provide evidence for a novel mechanism that may facilitate HIV-1 replication and transmission. This mechanism may favor HIV-1 pathogenesis, immune evasion, and persistence.
NKp46 O-Glycan Sequences That Are Involved in the Interaction with Hemagglutinin Type 1 of Influenza Virus
Authors: Mendelson Michal , Tekoah Yoram , Zilka Alon , Gershoni-Yahalom Orly , Gazit Roi , Achdout Hagit , Bovin Nicolai V. , Meningher Tal , Mandelboim Michal , Mandelboim Ofer , David Ayelet , Porgador Angel 
Published: February 2010

ABSTRACT
Natural killer (NK) cells serve as a crucial first-line defense against tumors and virus-infected cells. We previously showed that lysis of influenza virus (IV)-infected cells is mediated by the interaction between the NK receptor, NKp46, and the IV hemagglutinin (HA) type 1 expressed by the infected cells. This interaction requires the presence of sialyl groups on the NKp46-T225 O-glycoforms. In the current study, we analyzed the O-glycan sequences that are imperative for the interaction between recombinant NKp46 (rNKp46) and IV H1N1 strains. We first showed that rNKp46 binding to IV H1N1 is not mediated by a glycoform unique to the Thr225 site. We then characterized the O-glycan sequences that mediate the interaction of rNKp46 and IV H1N1; we employed rNKp46s with dissimilar glycosylation patterns and IV H1N1 strains with different sialic acid α2,3 and α2,6 linkage preferences. The branched α2,3-sialylated O-glycoform Neu5NAcα2,3-Galβ1,4-GlcNAcβ1,6[Neu5NAcα2,3-Galβ1,3]GalNAc competently mediated the interaction of rNKp46 with IV H1N1, manifesting a preference for α2,3 linkage. In contrast, the linear α2,3-sialylated O-glycoform Neu5NAcα2,3-Galβ1,3-GalNAc was not correlated with enhanced interaction between rNKp46 and IV H1N1 or a preference for α2,3 linkage. The branched α2,3- and α2,6-sialylated O-glycoform Neu5NAcα2,3-Galβ1,3[Neu5NAcα2,6]GalNAc competently mediated the interaction of rNKp46 with IV H1N1, manifesting a preference for α2,6 linkage. Previous viral HA-binding-specificity studies were performed with glycopolymer conjugates, free synthetic sialyl oligosaccharides, and sialidase-treated cells. This study shed light on the O-glycan sequences involved in the interaction of glycoprotein and viral hemagglutinins and may help in the design of agents inhibitory to hemagglutinin for influenza treatment.
Polyubiquitination of APOBEC3G Is Essential for Its Degradation by HIV-1 Vif
Authors: Shao Qiujia , Wang Yudi , Hildreth James E. K. , Liu Bindong 
Published: February 2010

ABSTRACT

Proteasomal degradation of APOBEC3G is a critical step for human immunodeficiency virus type 1 (HIV-1) replication. However, the necessity for polyubiquitination of APOBEC3G in this process is still controversial. In this study, we showed that although macaque simian immunodeficiency virus (SIVmac) Vif is more stable than HIV-1 Vif in human cells, SIVmac Vif induces degradation of APBOEC3G as efficiently as HIV-1 Vif. Overexpression of APOBEC3G or lysine-free APOBEC3G stabilized HIV-1 Vif, indicating that APOBEC3G degradation is independent of the degradation of Vif. Furthermore, an
in vivo
polyubiquitination assay showed that lysine-free APOBEC3G was also polyubiquitinated. These data suggest that polyubiquitination of APOBEC3G, not that of HIV-1 Vif, is crucial for APOBEC3G degradation.
Donor and Recipient Envs from Heterosexual Human Immunodeficiency Virus Subtype C Transmission Pairs Require High Receptor Levels for Entry
Authors: Alexander Melissa , Lynch Rebecca , Mulenga Joseph , Allen Susan , Derdeyn Cynthia A. , Hunter Eric 
Published: February 2010

ABSTRACT
Compact, glycan-restricted envelope (Env) glycoproteins are selected during heterosexual transmission of subtype C HIV-1. Donor and recipient glycoproteins (Envs) from six transmission pairs were evaluated for entry into HeLa cells expressing different levels of CD4 and CCR5. Donor and recipient Envs demonstrated efficient entry into cells expressing high levels of CD4 and CCR5, and entry declined as CCR5 levels decreased. Infectivity for all Envs was severely impaired in cells expressing low levels of CD4, even at the highest CCR5 levels. In 5/6 pairs, there was no significant difference in efficiency of receptor utilization between the donor and recipient Envs in these HeLa-derived cell lines. Thus, HIV-1 transmission does not appear to select for viruses that can preferentially utilize low levels of entry receptors.
T Cells Engineered with a Cytomegalovirus-Specific Chimeric Immunoreceptor
Authors: Full Florian , Lehner Manfred , Thonn Veronika , Goetz Gabriel , Scholz Brigitte , Kaufmann Kerstin B. , Mach Michael , Abken Hinrich , Holter Wolfgang , Ensser Armin 
Published: February 2010

ABSTRACT
Cytomegalovirus (CMV) infection in patients receiving hematopoietic stem cell transplants (HSCT) is associated with morbidity and mortality. Adoptive T cell immunotherapy has been used to treat viral reactivation but is hardly feasible in high-risk constellations of CMV-positive HSCT patients and CMV-negative stem cell donors. We endowed human effector T cells with a chimeric immunoreceptor (cIR) directed against CMV glycoprotein B. These cIR-engineered primary T cells mediated antiviral effector functions such as cytokine production and cytolysis. This first description of cIR-redirected CMV-specific T cells opens up a new perspective for HLA-independent immunotherapy of CMV infection in high-risk patients.
The Elk-1 and Serum Response Factor Binding Sites in the Major Immediate-Early Promoter of Human Cytomegalovirus Are Required for Efficient Viral Replication in Quiescent Cells and Compensate for Inactivation of the NF-κB Sites in Proliferating Cells
Authors: Caposio Patrizia , Luganini Anna , Bronzini Matteo , Landolfo Santo , Gribaudo Giorgio 
Published: February 2010

ABSTRACT

The major immediate-early promoter (MIEP) region of human cytomegalovirus (HCMV) plays a critical role in the regulation of lytic and latent infections by integrating multiple signals supplied by the infecting virus, the type and physiological state of the host cell, and its extracellular surroundings. The interaction of cellular transcription factors with their cognate binding sites, which are present at high densities within the enhancer upstream from the MIEP core promoter, regulate the rate of IE gene transcription and thus affect the outcome of HCMV infection. We have shown previously that the NF-κB binding sites within the MIEP enhancer and cellular NF-κB activity induced by HCMV infection are required for efficient MIEP activity and viral replication in quiescent cells (P. Caposio, A. Luganini, G. Hahn, S. Landolfo, and G. Gribaudo, Cell. Microbiol.
9:
2040-2054, 2007). We now show that the inactivation of either the Elk-1 or serum response factor (SRF) binding site within the enhancer also reduces MIEP activation and viral replication of recombinant HCMV viruses in quiescent fibroblasts. In these cells, we show that the expression of either Elk-1 or SRF is required for optimal IE gene expression, and that the HCMV-stimulated activation of the MEK1/2-ERK1/2 signaling axis leads to Elk-1 transcriptional competency. Furthermore, the replication kinetics of recombinant viruses in which NF-κB, Elk-1, and SRF binding sites all are inactivated demonstrate that the higher levels of Elk-1 and SRF binding to MIEP in proliferating cells can compensate even for a lack of HCMV-induced NF-κB-mediated MIEP transactivation. These observations highlight the importance of the combination of different MIEP binding sites to optimize IE gene expression in cells in different physiological states.
Hepatitis B Virus Replication Induces Methylation of both Host and Viral DNA
Authors: Vivekanandan Perumal , Daniel Hubert Darius-J , Kannangai Rajesh , Martinez-Murillo Francisco , Torbenson Michael 
Published: February 2010

ABSTRACTControl of viral replication is a major therapeutic goal to reduce morbidity and mortality from chronic hepatitis B virus (HBV) infection. Recently, methylation has been identified as a novel host defense mechanism, and methylation of viral DNA leads to downregulation of HBV gene expression. To better understand the mechanisms of HBV methylation, cell lines were exposed to HBV using a model system that mimics natural infection and the expression of host DNA methyltransferase genes (DNMTs) was measured. DNMT1, DNMT2, and DNMT3 were all significantly upregulated in response to HBV. DNMT3 was further studied because of its known role in thede novomethylation of DNA. Cotransfection experiments with full-length HBV and DNMT3 led to the downregulation of viral protein and pregenomic RNA production. To investigate whether the upregulation of DNMTs could also have an effect on the methylation of host DNA, cell lines were exposed to HBV in two independent model systems, one that mimics natural infection and a second model with temporary transfection. Host DNA methylation was measured by DNA microarray analysis. Increased methylation of host CpG islands was detected in both experimental systems. Two CpG islands, corresponding to genes SUFU and TIRAP, were selected, and the downregulation of these genes in hepatocellular carcinomas was confirmed. In conclusion, hepatocytes respond to HBV infection by upregulating DNMTs. The DNMTs methylate viral DNA, leading to decreased viral gene expression and decreased viral replication. However, virus-induced overexpression of DNMTs also leads to methylation of host CpG islands.
Viral Dynamics during Primary Simian Immunodeficiency Virus Infection: Effect of Time-Dependent Virus Infectivity
Authors: Vaidya Naveen K. , Ribeiro Ruy M. , Miller Christopher J. , Perelson Alan S. 
Published: February 2010

ABSTRACTA recent experiment involving simian immunodeficiency virus (SIV) infection of macaques revealed that the infectivity of this virus decreased over the first few months of infection. Based on this observation, we introduce a viral dynamic model in which viral infectivity varies over time. The model is fit to viral load data from eight (donor) monkeys infected by intravaginal inoculation of SIVmac251, three monkeys infected by intravenous inoculation of virus isolated from the donors during the ramp-up phase of acute infection, and three monkeys infected by intravenous inoculation of virus isolated at the viral set-point. Although we only analyze data from 14 monkeys, the new model with time-dependent infectivity seems to fit the data significantly better than a widely used model with constant infectivity (P= 2.44 × 10−11). Our results indicate that plasma virus infectivity on average decays ∼8-fold (95% confidence interval [CI] = 5.1 to 10.3) over the course of acute infection, with the decay occurring exponentially with an average rate of 0.28 day−1(95% CI = 0.14 to 0.42 day−1). The decay rate in set point plasma virus recipient animals is ∼16 times slower than in ramp-up plasma virus recipient animals and ∼6 times slower than in donor animals. Throughout acute infection up to the set-point, the infection rate is higher in ramp-up plasma virus recipient animals than in set-point plasma virus recipient animals. These results show that the infectivity depends upon the source of viral infection.
Relocalization of Upstream Binding Factor to Viral Replication Compartments Is UL24 Independent and Follows the Onset of Herpes Simplex Virus 1 DNA Synthesis
Authors: Lymberopoulos Maria H. , Pearson Angela 
Published: February 2010

ABSTRACT
Herpes simplex virus 1 (HSV-1) induces relocalization of several nucleolar proteins. We have found that, as for fibrillarin, the HSV-1-induced redistribution of two RNA polymerase I components, upstream binding factor (UBF) and RPA194, was independent of the viral protein UL24, which affects nucleolin localization. Nevertheless, the kinetics and sites of redistribution for fibrillarin and UBF differed. Interestingly, UBF remained associated with RPA194 during infection. Although UBF is redistributed to viral replication compartments during infection, we did not detect foci of UBF at early sites of viral DNA synthesis, suggesting that it may not be directly involved in this process at early times.
Virus-Specific CD8+T-Cell Responses Better Define HIV Disease Progression than HLA Genotype
Authors: Dinges Warren L. , Richardt Julia , Friedrich David , Jalbert Emilie , Liu Yi , Stevens Claire E. , Maenza Janine , Collier Ann C. , Geraghty Daniel E. , Smith Jeremy , Moodie Zoe , Mullins James I. , McElrath M. Juliana , Horton Helen 
Published: February 2010

ABSTRACTHLA alleles B57/58, B27, and B35 have the strongest genetic associations with HIV-1 disease progression. The mechanisms of these relationships may be host control of HIV-1 infection via CD8+T-cell responses. We examined these immune responses in subjects from the Seattle Primary Infection Cohort with these alleles. CD8+T-cell responses to conserved HIV epitopes within B57/58 alleles (TW10 and KF11) and B27 alleles (KK10 and FY10) delayed declines in CD4+T-cell counts (4 to 8 times longer), while responses to variable epitopes presented by B35 alleles (DL9 and IL9) resulted in more rapid progression. The plasma viral load was higher in B57/58+and B27+subjects lacking the conserved B57/58- and B27-restricted responses. The presence of certain B57/58-, B27-, and B35-restricted HIV-specific CD8+T-cell responses after primary HIV-1 infection better defined disease progression than the HLA genotype alone, suggesting that it is the HIV-specific CD8+T cells and not the presence of a particular HLA allele that determine disease progression. Further, the most effective host CD8+T-cell responses to HIV-1 were prevalent within an HLA allele, represented a high total allele fraction of the host CD8+T-cell response, and targeted conserved regions of HIV-1. These data suggest that vaccine immunogens should contain only conserved regions of HIV-1.