bluuebunny/crossref_metadata_2025_split huggingface dataset:
T-Cell Recognition of
Paracoccidioides brasiliensis
gp43-Derived Peptides in Patients with Paracoccidioidomycosis and Healthy Individuals
Authors: Iwai Leo Kei , Yoshida Márcia , Sadahiro Aya , da Silva Washington Robert , Marin Maria Lucia , Goldberg Anna Carla , Juliano Maria Aparecida , Juliano Luiz , Shikanai-Yasuda Maria Aparecida , Kalil Jorge , Cunha-Neto Edecio , Travassos Luiz R. 
Published: March 2007

ABSTRACT

Vaccines with synthetic peptides induce the immune response to epitopes that bind to several HLA alleles. By using a TEPITOPE algorithm, we selected and analyzed the T-cell responses of peripheral blood mononuclear cells from 29 paracoccidioidomycosis (PCM) patients to peptides of the immunodominant gp43 antigen of
Paracoccidioides brasiliensis
, the causative agent of PCM.
Determination of the Relationship between Group A Streptococcal Genome Content, M Type, and Toxic Shock Syndrome by a Mixed Genome Microarray
Authors: Vlaminckx Bart J. M. , Schuren Frank H. J. , Montijn Roy C. , Caspers Martien P. M. , Fluit Ad C. , Wannet Wim J. B. , Schouls Leo M. , Verhoef Jan , Jansen Wouter T. M. 
Published: February 2007

ABSTRACTGroup A streptococci (GAS), orStreptococcus pyogenes, are associated with a remarkable variety of diseases, ranging from superficial infections to life-threatening diseases such as toxic-shock-like syndrome (TSS). GAS strains belonging to M types M1 and M3 are associated with TSS. This study aims to obtain insight into the gene profiles underlying different M types and disease manifestations. Genomic differences between 76 clinically well characterized GAS strains collected in The Netherlands were examined using a mixed-genome microarray. Inter-M-type genomic differences clearly outweighed intra-M-type genome variation. Phages were major contributors to observed genome diversification. We identified four novel genes, including two genes encoding fibronectin-binding-like proteins, which are highly specific to a subset of M types and thus may contribute to M-type-associated disease manifestations. All M12 strains were characterized by the unique absence of the citrate lyase complex and reduced growth under hypoxic, nutrient-deprived conditions. Furthermore, six virulence factors, including genes encoding a complement-inhibiting protein (sic), an exotoxin (speA), iron(III) binding factor, collagen binding factor (cpa), and fibrinogen binding factor (prt2-like), were unique to M1 and/or M3 strains. These virulence factors may contribute to the potential of these strains to cause TSS. Finally, in contrast to M-type-specific virulence profiles, we did not identify a common virulence profile among strains associated with TSS irrespective of their M type.
Th1 and Th2 Cells Help CD8 T-Cell Responses
Authors: Ekkens Melinda J. , Shedlock Devon J. , Jung EuiHye , Troy Amy , Pearce Erika L. , Shen Hao , Pearce Edward J. 
Published: February 2007

ABSTRACTHelp from CD4 T cells is often important for the establishment of primary and memory CD8 T-cell responses. However, it has yet to be determined whether T helper polarization affects the delivery of help and/or whether responding CD8 T cells helped by Th1 or Th2 cells express distinct effector properties. To address these issues, we compared CD8 T-cell responses in the context of Th1 or Th2 help by injecting dendritic cells copulsed with the major histocompatibility complex class I-restricted OVA peptide plus, respectively, bacterial or helminth antigens. We found that Th2 cells, like Th1 cells, can help primary and long-lived memory CD8 T-cell responses. Experiments in interleukin-12 (IL-12)−/−and IL-4−/−mice, in which polarized Th1 or Th2 responses, respectively, fail to develop, indicate that the underlying basis of CD4 help is independent of attributes acquired as a response to polarization.
A Booster Vaccination with
Mycobacterium bovis
BCG Does Not Increase the Protective Effect of the Vaccine against Experimental
Mycobacterium ulcerans
Infection in Mice
Authors: Tanghe Audrey , Adnet Pierre-Yves , Gartner Tatiana , Huygen Kris 
Published: February 2007

ABSTRACT

Buruli ulcer, caused by
Mycobacterium ulcerans
, is a necrotizing skin disease emerging particularly in West Africa.
M. bovis
BCG vaccine offers only short-term protection against experimental footpad infection of C57BL/6 mice with
M. ulcerans
, and the duration of this protection cannot be prolonged by a booster vaccination.
Surface Expression of Toll-Like Receptor 9 Is Upregulated on Intestinal Epithelial Cells in Response to Pathogenic Bacterial DNA
Authors: Ewaschuk Julia B. , Backer Jody L. , Churchill Thomas A. , Obermeier Florian , Krause Denis O. , Madsen Karen L. 
Published: February 2007

ABSTRACTColonic epithelial cells are constantly exposed to high levels of bacterial DNA in the intestinal lumen and must recognize and respond appropriately to pathogens, while they maintain a tolerance to nonpathogenic commensal bacterial strains. Bacterial DNA is recognized by Toll-like receptor 9 (TLR9). The aim of this study was to investigate TLR9 expression and localization in colonic epithelial cells under basal conditions and in response to bacterial DNA. HT-29 cells were exposed to DNA from various strains of commensal and pathogenic microbes. TLR9 mRNA expression was determined by real-time reverse transcription-PCR, and interleukin-8 (IL-8) secretion was measured by an enzyme-linked immunosorbent assay. Localization of TLR9 was determined by flow cytometry in HT-29 cells and by immunofluorescence in HT-29 cells and mouse colonic tissue. Immunofluorescence and flow cytometric analyses demonstrated that there was intracellular and surface expression of TLR9 in HT-29 cells under basal conditions. Exposure of cells to DNA from pathogenic strains ofSalmonellaandEscherichia coliresulted in a significant increase in TLR9 mRNA expression.Salmonella entericaserovar Dublin DNA increased surface TLR9 protein and IL-8 secretion. There was no change in mRNA levels or localization of TLR9 in response toBifidobacterium breve. Chloroquine did not block IL-8 secretion in response toS. entericaserovar Dublin DNA. TLR9 was expressed on the colonic apical surface in wild-type mice but not in germfree mice. These results demonstrate that intestinal epithelial cells recognize pathogenic bacterial DNA and respond by increasing surface localization and expression of TLR9, suggesting that the epithelial inflammatory response to pathogenic DNA is mediated at least in part by increased TLR9 expression.
Mechanisms of Decreased Susceptibility to β-Defensins byTreponema denticola
Authors: Brissette Catherine A. , Lukehart Sheila A. 
Published: February 2007

ABSTRACTTreponema denticola, a periodontal pathogen, is relatively resistant to human beta-defensins, which are small cationic antimicrobial peptides produced by a number of cells, including the gingival epithelium. Using two independent methods, we previously demonstrated thatT. denticolaproteases are not responsible for decreased vulnerability to defensins. In this study, we confirmed that the major outer membrane protease, dentilisin, is not responsible forT. denticolainsensitivity to defensins and examined several other possible mechanisms, including reduced binding to the bacterial surface and efflux pump activity. It has been suggested that some bacteria mask their surfaces with serum proteins.T. denticolagrown in a serum-free medium did not exhibit increased susceptibility to human beta-defensin 2 and 3 (hβD-2 and hβD-3, respectively), suggesting that cloaking of the outer surface with host proteins is not involved in defensin resistance. Nonetheless, we demonstrated thatT. denticolabinds significantly less hβD-2 and -3 than susceptible organisms bind, suggesting that the unusual outer membrane composition ofT. denticolamay discourage cationic peptide binding. Efflux pumps have been shown to mediate resistance to antibiotics and cationic peptides in other bacteria, and their role inT. denticola's relative resistance to β-defensins was investigated. Three inhibitors of bacterial ATP-binding cassette (ABC) efflux pumps had no effect onT. denticola's susceptibility to hβD-2 or -3. In contrast, a proton motive force inhibitor, carbonyl cyanide 3-chlorophenylhydrazone, increased the susceptibility ofT. denticolato killing by hβD-3, demonstrating a potential role for efflux pumps (other than ABC pumps) in resistance to this peptide. Our data suggest that the combination of decreased defensin binding and efflux of any peptide which enters the cytoplasm may explainT. denticola's relative resistance to human beta-defensins.
Genotyping of
Candida orthopsilosis
Clinical Isolates by Amplification Fragment Length Polymorphism Reveals Genetic Diversity among Independent Isolates and Strain Maintenance within Patients
Authors: Tavanti Arianna , Hensgens Lambert A. M. , Ghelardi Emilia , Campa Mario , Senesi Sonia 
Published: March 2007

ABSTRACT

Candida parapsilosis
former groups II and III have recently been established as independent species named
C. orthopsilosis
and
C. metapsilosis
, respectively. In this report, 400 isolates (290 patients) previously classified as
C. parapsilosis
by conventional laboratory tests were screened by BanI digestion profile analysis of the secondary alcohol dehydrogenase gene fragment and by amplification fragment length polymorphism (AFLP). Thirty-three strains collected from 13 patients were identified as
C. orthopsilosis
, thus giving the first retrospective evidence that
C. orthopsilosis
was responsible for 4.5% of the infections/colonization attributed to
C. parapsilosis
. AFLP was proven to unambiguously identify
C. orthopsilosis
at the species level and efficiently delineate intraspecific genetic relatedness. A high percentage of polymorphic AFLP bands was observed for independent isolates collected from each patient. Statistical analysis of the pairwise genetic distances and bootstrapping revealed that clonal reproduction and recombination both contribute to
C. orthopsilosis
genetic population structure. AFLP patterns of sequential isolates obtained from two patients demonstrated that a successful strain colonization within the same patient occurred, as revealed by strain maintenance in various body sites. No association between AFLP markers and drug resistance was observed, and none of the clinical
C. orthopsilosis
isolates were found to produce biofilm in vitro.
Multiple Genotypes of Influenza B Viruses Cocirculated in Taiwan in 2004 and 2005
Authors: Chen Guang-Wu , Shih Shin-Ru , Hsiao Mei-Ren , Chang Shih-Cheng , Lin Shu-Hung , Sun Chien-Fen , Tsao Kuo-Chien 
Published: March 2007

ABSTRACT
An influenza B outbreak occurred in Taiwan in 2004 and 2005, during which both Victoria (Vic) and Yamagata (Ya) lineages cocirculated. This study examined 36 influenza B viral genomes isolated during the outbreak to reveal their reassortment patterns. According to the isolate groupings in phylogenetic analysis, we were able to categorize those 36 isolates as being of either the Victoria or Yamagata lineage for all eight influenza B virus genomic segments, except for the NS gene, in which clades A and B existed. Based on these groupings, three genome patterns clearly emerged, namely, pattern I (Vic+Vic+Ya+Vic+Ya+Ya+Ya+A, from segments 1 to 8), pattern II (Ya+Ya+Ya+Ya+Ya+Ya+Ya+B), and pattern III (Ya+Ya+Ya+Ya+Ya+Ya+Ya+A). According to the timeline of those isolates under investigation, it appears that pattern I and II viruses could have generated pattern III via reassortment of the NS gene. On the other hand, a genomewide comparison of all six pattern III Taiwanese viruses with 37 international influenza B viral genomes showed that two international strains, B/Oslo/71/04 and B/England/23/04, were consistently clustered with the pattern III viruses isolated in Taiwan in 2004 and 2005, suggesting that Taiwanese pattern III viruses might also have been imported due to their matching genomic composition.
CD81 Expression Is Important for the Permissiveness of Huh7 Cell Clones for Heterogeneous Hepatitis C Virus Infection
Authors: Akazawa Daisuke , Date Tomoko , Morikawa Kenichi , Murayama Asako , Miyamoto Michiko , Kaga Minako , Barth Heidi , Baumert Thomas F. , Dubuisson Jean , Wakita Takaji 
Published: March 2007

ABSTRACT
Huh7 cells constitute a permissive cell line for cell culture of hepatitis C virus (HCV) particles. However, our Huh7 line shows limited permissiveness for HCV. Thus, in this study we set out to determine which host factors are important for conferring permissiveness. To analyze the limited permissiveness of our Huh7 cells, 70 clones were obtained after single-cell cloning of parental Huh7 cells. The cloned Huh7 cells exhibited various levels of HCV pseudoparticles and JFH-1 virus infection efficiency, and some clones were not permissive. A subgenomic replicon was then transfected into the cloned Huh7 cells. While the replication efficiencies differed among the cloned Huh7 cells, these efficiencies did not correlate with infectious permissibility. Flow cytometry showed that CD81, scavenger receptor class B type I, and low-density-lipoprotein receptor expression on the cell surfaces of the Huh7 clones differed among the clones. Interestingly, we found that all of the permissive cell clones expressed CD81 while the nonpermissive cell clones did not. To confirm the importance of CD81 expression for HCV permissiveness, CD81 was then transiently and stably expressed on a nonpermissive Huh7 cell clone, which was consequently restored to HCV infection permissiveness. Furthermore, permissiveness was down-regulated upon transfection of CD81 silencing RNA into a CD81-positive cell clone. In conclusion, CD81 expression is an important determinant of HCV permissiveness of Huh7 cell clones harboring different characteristics.
Independent Evolution of Human Immunodeficiency Virus Type 1
env
V1/V2 and V4/V5 Hypervariable Regions during Chronic Infection
Authors: Harrington Patrick R. , Nelson Julie A. E. , Kitrinos Kathryn M. , Swanstrom Ronald 
Published: March 2007

ABSTRACT

Using DNA heteroduplex tracking assays, we characterized human immunodeficiency virus type 1
env
V4/V5 genetic populations in multiple blood plasma samples collected over an average of 7 months from 24 chronically infected human subjects. We observed complex and dynamic V4/V5 genetic populations in most subjects. Comparisons of V4/V5 and V1/V2 population changes over the course of the study showed that major shifts in genetic populations frequently occurred in one region but not the other, and these observations were independently confirmed in one subject by single-genome sequencing. These results suggest that the V1/V2 and V4/V5 regions of
env
often evolve independently during chronic infection.
Direct Evidence of Lower Viral Replication Rates In Vivo in Human Immunodeficiency Virus Type 2 (HIV-2) Infection than in HIV-1 Infection
Authors: MacNeil Adam , Sarr Abdoulaye Dieng , Sankalé Jean-Louis , Meloni Seema Thakore , Mboup Souleymane , Kanki Phyllis 
Published: March 2007

ABSTRACT

Studies have shown that human immunodeficiency virus type 2 (HIV-2) is less pathogenic than HIV-1, with a lower rate of disease progression. Similarly, plasma viral loads are lower in HIV-2 infection, suggesting that HIV-2 replication is restricted in vivo in comparison to that of HIV-1. However, to date, in vivo studies characterizing replication intermediates in the viral life cycle of HIV-2 have been limited. In order to test the hypothesis that HIV-2 has a lower replication rate in vivo than HIV-1 does, we quantified total viral DNA, integrated proviral DNA, cell-associated viral mRNA, and plasma viral loads in peripheral blood samples from groups of therapy-naïve HIV-1-infected (
n
= 21) and HIV-2-infected (
n
= 18) individuals from Dakar, Senegal, with CD4
+
T-cell counts of >200/μl. Consistent with our previous findings, total viral DNA loads were similar between HIV-1 and HIV-2 and plasma viral loads were higher among HIV-1-infected individuals. Proportions of DNA in the integrated form were also similar between these viruses. In contrast, levels of viral mRNA were lower in HIV-2 infection. Our study indicates that HIV-2 is able to establish a stable, integrated proviral infection in vivo, but that accumulation of viral mRNA is attenuated in HIV-2 infection relative to that in HIV-1 infection. The differences in viral mRNA are consistent with the differences in plasma viral loads between HIV-1 and HIV-2 and suggest that lower plasma viral loads, and possibly the attenuated pathogenesis of HIV-2, can be explained by lower rates of viral replication in vivo.
A Shared Transcription Termination Signal on Negative and Ambisense RNA Genome Segments of Rift Valley Fever, Sandfly Fever Sicilian, and Toscana Viruses
Authors: Albariño César G. , Bird Brian H. , Nichol Stuart T. 
Published: March 2007

ABSTRACT

The
Phlebovirus
genus (family
Bunyaviridae
) is composed of a diverse group of arboviruses that cause disease syndromes ranging from mild febrile illness to hemorrhagic fever with high fatality. Although antigenically similar, these viruses differ by approximately 25% at the genome level, and their ecologies, including geographic ranges, preferred vector species, and hosts, vary considerably. In contrast to other ambisense viruses, where RNA hairpin structures which serve as transcription termination signals are frequently found separating the opposite-sense open reading frames, no evidence of predicted high-energy hairpin structures was found at the ambisense junctions of phlebovirus S RNA segments. However, a conserved sequence motif was identified on both negative and ambisense genome segments that functions as a transcription termination signal for the N, NSs, and GPC mRNAs in three diverse phleboviruses, namely, Rift Valley fever, sandfly Sicilian, and Toscana viruses. The exact termination of nascent virus mRNA molecules was determined by 3′ rapid amplification of cDNA ends. Surprisingly, analysis of the termini of mRNAs from both S and M segments of these three viruses revealed that transcription termination occurred immediately upstream of a conserved sequence motif with the general features 3′-C
1-3
GUCG/A-5′. In contrast, no corresponding sequence motif was found in the L segments, and analysis indicated a “runoff” transcript approach to L mRNA termination. The absolute requirement of the identified transcription termination motif was demonstrated by using a highly efficient Rift Valley fever virus reverse genetics system to generate live recombinant viruses with S segments lacking the termination signal motif for the NP or NSs mRNA and showing that these recombinant viruses generated mRNAs that failed to terminate correctly.
Immunoadhesins Containing Pre-S Domains of Hepatitis B Virus Large Envelope Protein Are Secreted and Inhibit Virus Infection
Authors: Chai Ning , Gudima Severin , Chang Jinhong , Taylor John 
Published: March 2007

ABSTRACT

Hepatitis B virus (HBV) replication produces three envelope proteins (L, M, and S) that have a common C terminus. L, the largest, contains a domain, pre-S1, not present on M. Similarly M contains a domain, pre-S2, not present on S. The pre-S1 region has important functions in the HBV life cycle. Thus, as an approach to studying these roles, the pre-S1 and/or pre-S2 sequences of HBV (serotype
adw
2, genotype A) were expressed as N-terminal fusions to the Fc domain of a rabbit immunoglobulin G chain. Such proteins, known as immunoadhesins (IA), were highly expressed following transfection of cultured cells and, when the pre-S1 region was present, >80% were secreted. The IA were myristoylated at a glycine penultimate to the N terminus, although mutation studies showed that this modification was not needed for secretion. As few as 30 amino acids from the N terminus of pre-S1 were both necessary and sufficient to drive secretion of IA. Even expression of pre-S1 plus pre-S2, in the absence of an immunoglobulin chain, led to efficient secretion. Overall, these studies demonstrate an unexpected ability of the N terminus of pre-S1 to promote protein secretion. In addition, some of these secreted IA, at nanomolar concentrations, inhibited infection of primary human hepatocytes either by hepatitis delta virus (HDV), a subviral agent that uses HBV envelope proteins, or HBV. These IA have potential to be part of antiviral therapies against chronic HDV and HBV, and may help understand the attachment and entry mechanisms used by these important human pathogens.
Short-term effects of a non-dieting lifestyle intervention program on weight management, fitness, metabolic risk, and psychological well-being in obese premenopausal females with the metabolic syndrome
Authors: Carroll Sean , Borkoles Erika , Polman Remco 
Published: March 2007

Lifestyle modification has been widely acknowledged as the primary treatment for the metabolic syndrome (MetS). We examined the short-term effects of a non-dieting lifestyle intervention program, within the theoretical psychological framework of self-determination theory (SDT), on metabolic fitness and psychological well-being among premenopausal, clinically obese women. A secondary analysis of a randomized, controlled, 3 month, intensive, community-based lifestyle intervention study was performed on 31 pre-menopausal obese women with the MetS (56.4% of original study sample). These participants had been randomly allocated to a non-dieting lifestyle intervention group (n = 17) or waiting list control (n = 14). Among participants who completed repeat anthropometric and cardiorespiratory fitness measurements after 3 months intervention, the lifestyle intervention group showed a significant improvement in VO2 (mL·kg–1·min–1) compared with control (test for interaction, p = 0.003). No significant difference was found for body mass. Metabolic improvements were evident for diastolic blood pressure and high-density lipoprotein cholesterol in both groups. The lifestyle intervention group also showed significantly improved general psychological well-being compared with the control group (test for interaction, p = 0.0005). All of the psychological well-being subscales showed significant favourable changes in the intervention group as compared with controls. This short-term, non-dieting lifestyle intervention, consistent with the “Health at Every Size” (HAES) obesity treatment paradigm, significantly improved cardiorespiratory fitness and psychological well-being. Metabolic risk tended to improve after 3 months intervention with no significant difference in the resolution of the MetS between intervention and control participants.