bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of Cytokine Genes during Pneumococcal and NontypeableHaemophilus influenzaeAcute Otitis Media in the Rat
Authors: Melhus Åsa , Ryan Allen F. 
Published: July 2002

ABSTRACTAcute otitis media (AOM) elicits potent inflammatory responses from the cells of the middle ear mucosa as well as from infiltrating leukocytes. To explore host responses during experimental AOM induced byStreptococcus pneumoniaetype 3 and nontypeableHaemophilus influenzae(NTHi), otomicroscopy findings and expression of cytokine genes in the middle ear were monitored up to 1 month postinoculation. The mucosa and infiltrating cells responded rapidly to the bacterial challenge. Otomicroscopically, AOM appeared 1 day after NTHi inoculation and 3 days after pneumococcus inoculation. Pneumococcal AOM was more severe than NTHi otitis, but in general, lower transcript levels were detected in pneumococcus-infected than in NTHi-infected animals. Interleukin-6 (IL-6) mRNA levels peaked at 3 to 6 h for both pneumococcus-infected and NTHi-infected animals. IL-1α, tumor necrosis factor alpha, and IL-10 mRNA levels peaked at 6 h for NTHi otitis and 1 to 3 days for pneumococcal otitis. Comparing otomicroscopy with expression profiles, it would appear that the majority of cytokine mRNAs had passed their peak before the AOM diagnosis could be made clinically. Only transforming growth factor β mRNA followed a slower time course, peaking very late and continuing expression even after the AOM was otomicroscopically resolved. IL-2 and IL-4 mRNAs were not detected in any animal at any time. Most of the investigated cytokines are very early markers for AOM and may be involved in initiation of inflammation, but they would be poor targets for pharmacological manipulation since their levels decline before clinical signs appear.
Requirement of the
Pseudomonas aeruginosa tonB
Gene for High-Affinity Iron Acquisition and Infection
Authors: Takase Hiroyuki , Nitanai Hironobu , Hoshino Kazuki , Otani Tsuyoshi 
Published: July 2002

ABSTRACT

To investigate the contribution of the TonB protein to high-affinity iron acquisition in
Pseudomonas aeruginosa
, we constructed
tonB
-inactivated mutants from strain PAO1 and its derivative deficient in producing the siderophores pyoverdin and pyochelin. The
tonB
mutants could not grow in a free-iron-restricted medium prepared by apotransferrin addition, even though the medium was supplemented with each purified siderophore or with a heme source (hemoglobin or hemin). The
tonB
inactivation was shown to make
P. aeruginosa
unable to acquire iron from the transferrin with either siderophore. Introduction of a plasmid carrying the intact
tonB
gene restored growth of the
tonB
mutant of PAO1 in the free-iron-restricted medium without any supplements and restored growth of the
tonB
mutant of the siderophore-deficient derivative in the medium supplemented with pyoverdin, pyochelin, hemoglobin, or hemin. In addition, animal experiments showed that, in contrast to PAO1, the
tonB
mutant of PAO1 could not grow in vivo, such as in the muscles and lungs of immunosuppressed mice, and could not kill any of the animals. The in vivo growth ability and lethal virulence were also restored by introduction of the
tonB
-carrying plasmid in the
tonB
mutant. These results indicate clearly that the intact
tonB
gene—and, therefore, the TonB protein encoded by it—is essential for iron acquisition mediated by pyoverdin and pyochelin and via heme uptake in
P. aeruginosa
and suggest that the TonB-dependent iron acquisition may be essential for
P. aeruginosa
to infect the animal host.
CD85/LIR-1/ILT2 and CD152 (Cytotoxic T Lymphocyte Antigen 4) Inhibitory Molecules Down-Regulate the Cytolytic Activity of Human CD4+T-Cell Clones Specific forMycobacterium tuberculosis
Authors: Merlo Andrea , Saverino Daniele , Tenca Claudya , Grossi Carlo Enrico , Bruno Silvia , Ciccone Ermanno 
Published: July 2002

ABSTRACTAntigen-specific cytolytic CD4+T lymphocytes controlMycobacterium tuberculosisinfection by secreting cytokines and by killing macrophages that have phagocytosed the pathogen. However, lysis of the latter cells promotes microbial dissemination, and other macrophages engulf the released bacteria. Subsequently, CD4+T-cell-mediated killing of macrophages goes on, and this persistent process may hamper control of infection, unless regulatory mechanisms maintain a subtle balance between lysis of macrophages by cytolytic CD4+cells and activation of cytolytic CD4+cells by infected macrophages. We asked whether inhibitory molecules expressed by CD4+cytolytic T lymphocytes could play a role in such a balance. To this end, human CD4+T-cell clones specific forM. tuberculosiswere produced that displayed an autologous major histocompatibility complex class II-restricted lytic ability against purified protein derivative (PPD)-pulsed antigen-presenting cells. All T-cell clones expressed CD152 (cytotoxic T-lymphocyte antigen 4 [CTLA-4]) and CD85/leukocyte immunoglobulin-like receptor 1 (LIR-1)/immunoglobulin-like transcript 2 (ILT2) inhibitory receptors, but not CD94 and the killer inhibitory receptor (or killer immunoglobulin-like receptor [KIR]) p58.2. CD3-mediated activation of the clones was inhibited in a redirected killing assay in which CD152 and CD85/LIR-1/ILT2 were cross-linked. Specific antigen-mediated proliferation of the clones was also sharply reduced when CD152 and CD85/LIR-1/ILT2 were cross-linked by specific monoclonal antibody (MAb) followed by goat anti-mouse antiserum. In contrast, blockade of the receptors by specific MAb only increased their proliferation. Production of interleukin 2 (IL-2) and gamma interferon (IFN-γ) by the T-cell clones was also strongly reduced when CD152 and CD85/LIR-1/ILT2 were cross-linked. The lytic activity of the T-cell clones against PPD-pulsed autologous monocytes or Epstein-Barr virus-activated B cells was increased by blockade and decreased by cross-linking of the receptors. These results indicate that CD152 and CD85/LIR-1/ILT2 play a role in the regulation of the antigen-specific activity of CD4+cytolytic T lymphocytes against PPD-presenting cells.
T Cells Augment Monocyte and Neutrophil Function in Host Resistance against Oropharyngeal Candidiasis
Authors: Farah C. S. , Elahi S. , Pang G. , Gotjamanos T. , Seymour G. J. , Clancy R. L. , Ashman R. B. 
Published: July 2002

ABSTRACTThe purpose of this study was to identify the cell populations involved in recovery from oral infections withCandida albicans. Monoclonal antibodies specific for CD4+cells, CD8+cells, and polymorphonuclear leukocytes were used to deplete BALB/c and CBA/CaH mice of the relevant cell populations in systemic circulation. Monocytes were inactivated with the cytotoxic chemical carrageenan. Mice were infected with 108C. albicansyeast cells and monitored for 21 days. Systemic depletion of CD4+and CD8+T lymphocytes alone did not increase the severity of oral infection compared to that of controls. Oral colonization persisted in animals treated with head and neck irradiation and depleted of CD4+T cells, whereas infections in animals that received head and neck irradiation alone or irradiation and anti-CD8 antibody cleared the infection in a comparable fashion. The depletion of polymorphonuclear cells and the cytotoxic inactivation of mononuclear phagocytes significantly increased the severity of oral infection in both BALB/c and CBA/CaH mice. High levels of interleukin 12 (IL-12) and gamma interferon (IFN-γ) were produced by lymphocytes from the draining lymph nodes of recovering animals, whereas IL-6, tumor necrosis factor alpha, and IFN-γ were detected in the oral mucosae of both naı̈ve and infected mice. The results indicate that recovery from oropharyngeal candidiasis in this model is dependent on CD4+-T-cell augmentation of monocyte and neutrophil functions exerted by Th1-type cytokines such as IL-12 and IFN-γ.
Mycobacterial Protein HbhA Binds Human Complement Component C3
Authors: Mueller-Ortiz Stacey L. , Wanger Audrey R. , Norris Steven J. 
Published: July 2002

ABSTRACTMycobacterium tuberculosisandMycobacterium aviumare facultative intracellular pathogens that are able to survive and replicate in mononuclear phagocytes. Human complement component C3 has previously been shown to mediate attachment and phagocytosis of these bacteria by mononuclear phagocytes. In this study, a C3 ligand affinity blot protocol was used to identify a 30-kDa C3-binding protein inM. tuberculosisandMycobacterium smegmatisand a 31-kDa C3-binding protein inM. avium. The C3-binding proteins inM. tuberculosisandM. aviumlocalized to the cell membrane fraction and partitioned to the detergent fraction during Triton X-114 phase partitioning. The C3-binding protein fromM. tuberculosiswas partially purified using a cation exchange column and was shown to bind concanavalin A. The N terminus and an internal fragment of the partially purified C3-binding protein were subjected to amino acid sequence analysis. The resulting amino acid sequences matched theM. tuberculosisheparin-binding hemagglutinin (HbhA) protein. Recombinant full-length HbhA and the C terminus of HbhA fused to maltose-binding protein, but not recombinant HbhA lacking the C-terminal region, bound human C3. Recombinant full-length HbhA coated on polystyrene beads, was found to enhance the adherence and/or phagocytosis of the coated beads to J774.A1 cells in both the presence and absence of human serum. The presence of complement-sufficient serum increased the adherence of the HbhA-coated beads to the J774.A1 cells in a C3-dependent manner. If HbhA within the bacterial cell membrane functions similarly to isolated HbhA, this protein may enhance the adherence and phagocytosis ofM. tuberculosisandM. aviumto mononuclear phagocytes through the binding of C3 and interaction with C3 receptors on mononuclear phagocytes.
Detection ofMycobacterium tuberculosisGroup Organisms in Human and Mouse Joint Tissue by Reverse Transcriptase PCR: Prevalence in Diseased Synovial Tissue Suggests Lack of Specific Association with Rheumatoid Arthritis
Authors: Kempsell Karen E. , Cox Charles J. , McColm Andrew A. , Bagshaw Julie A. , Reece Richard , Veale Douglas J. , Emery Paul , Isaacs John D. , Gaston J. S. Hill , Crowe J. Scott 
Published: July 2002

ABSTRACTInfection with mycobacterial species, includingMycobacterium tuberculosis, has long been implicated in the etiopathology of rheumatoid arthritis (RA) on the basis of clinical and pathological similarities between tuberculosis and RA. Despite evidence of immune responses to mycobacterial antigens in RA patient synovial fluid, cross-reactivity between these and host joint antigens, and the presence ofM. tuberculosisprotein antigen in RA synovial fluid, a definite causal association with RA has not been shown. Previous studies from our laboratory using reverse transcriptase PCR (RT-PCR) of bacterial rRNAs have shown RA synovium to be colonized by a diverse range of bacteria, most of commensal origin. However,M. tuberculosisgroup organism (MTG) RNA sequences were found in one RA patient tissue. Since this was considered of sufficient interest to warrant further investigation, we devised aM. tuberculosis-specific nested RT-PCR test which could be used for detection of MTG in a mixed pool of bacterial crDNAs. This test was used to investigate the distribution of MTG in RA synovial tissue and also non-RA arthritis and healthy control tissues and was also used to examine the tissue distribution of MTG in an acute and chronic model ofM. tuberculosisinfection in the BALB/c mouse. MTG sequences were found in a high proportion of RA patient synovial tissues but also in non-RA arthritis control tissues at lower frequency. This likely reflects trafficking of persistentM. bovisBCG to inflamed joint tissue, irrespective of cause. MTG were not found in healthy synovial tissue or the tissue of patients with undifferentiated arthritis. In both the acute and chronic models of infection in BALB/c mice,M. tuberculosiswas also found to have trafficked to joint tissues, however, no signs of inflammation, arthritis, or pathology associated withM. tuberculosisinfection was seen. These combined results would argue against a specific causal role of MTG in RA-like arthritis; however, their role as adjuvant in immune dysfunction in an innately susceptible host cannot be excluded.
Leukotriene B4Augments Neutrophil Phagocytosis ofKlebsiella pneumoniae
Authors: Mancuso Peter , Nana-Sinkam Patrick , Peters-Golden Marc 
Published: July 2002

ABSTRACTNeutrophils play a critical role in the clearance of bacteria from the lung and other organs by their capacity for phagocytosis and killing. Previously, we identified an important role for the leukotrienes in rat alveolar macrophage phagocytosis ofKlebsiella pneumoniae. In this report, we explored the possibility that the leukotrienes play an important role in phagocytosis by neutrophils as well. Inhibition of endogenous leukotriene synthesis by 5-lipoxygenase knockout in mice or by pharmacologic means in human peripheral blood neutrophils attenuated phagocytosis of opsonizedK. pneumoniae. Reduced phagocytosis was also observed in human neutrophils pretreated with a leukotriene B4receptor but not a cysteinyl-leukotriene receptor antagonist. While leukotriene B4reconstituted defective phagocytosis in leukotriene-deficient neutrophils and enhanced phagocytosis in neutrophils capable of leukotriene synthesis, leukotriene C4, leukotriene D4, 5-hydroperoxyeicosatetraenoic acid, and 5-oxo-eicosatetraenoic acid were ineffective. To determine the opsonin dependence of the leukotriene B4augmentation of phagocytosis, we assessed the ability of leukotriene B4to modulate neutrophil phagocytosis and the adherence of sheep erythrocytes opsonized with immunoglobulin G or the complement fragment C3bi. While leukotriene B4augmented both Fc receptor- and complement receptor-mediated phagocytosis, increased adherence to leukotriene B4-treated neutrophils was limited to complement opsonized targets. In conclusion, we have identified a novel role for leukotriene B4in the augmentation of neutrophil phagocytosis mediated by either the Fc or complement receptor.
Influence of Major Histocompatibility Complex on Bacterial Composition of Fecal Flora
Authors: Toivanen Paavo , Vaahtovuo Jussi , Eerola Erkki 
Published: July 2002

ABSTRACT
Very little is known about how the host genome influences the composition of the gastrointestinal flora, largely due to the great number and diversity of bacteria present in the flora and the difficulties of using traditional methods of bacterial isolation and identification. We have approached the problem by studying bacterium-derived cellular fatty acids in the stool samples of six mouse strains congenic for the major histocompatibility complex (MHC). The results obtained indicate that the composition of the fecal flora is genetically regulated. In addition to undefined gene loci, MHC alone has a pronounced effect, since mice with different MHC in the same background have significantly different fecal floras. Demonstration of the genetic influence on the gastrointestinal flora opens a new approach to studying the pathogenesis of bacterially induced diseases.
Disruption ofPlasmodium falciparumChitinase Markedly Impairs Parasite Invasion of Mosquito Midgut
Authors: Tsai Yao-Lung , Hayward Rhian E. , Langer Rebecca C. , Fidock David A. , Vinetz Joseph M. 
Published: July 2002

ABSTRACTTo initiate invasion of the mosquito midgut,Plasmodiumookinetes secrete chitinolytic activity to penetrate the peritrophic matrix surrounding the blood meal. While ookinetes of the avian malaria parasitePlasmodium gallinaceumappear to secrete products of two chitinase genes, to date only one chitinase gene,PfCHT1, has been identified in the nearly completedPlasmodium falciparumstrain 3D7 genome database. To test the hypothesis that the single identified chitinase ofP. falciparumis necessary for ookinete invasion, thePfCHT1gene was disrupted 39 bp upstream of the stop codon.PfCHT1-disrupted parasites had normal gametocytogenesis, exflagellation, and ookinete formation but were markedly impaired in their ability to form oocysts inAnopheles freebornimidguts. Confocal microscopy demonstrated that the truncated PfCHT1 protein was present in mutant ookinetes but that the concentration of mutant PfCHT1 within the apical end of the ookinetes was substantially reduced. These data suggest that full-length PfCHT1 is essential for intracellular trafficking and secretion and that thePfCHT1gene product is necessary for ookinetes to invade the mosquito midgut.
Adherence Properties of
Staphylococcus aureus
under Static and Flow Conditions: Roles of
agr
and
sar
Loci, Platelets, and Plasma Ligands
Authors: Shenkman Boris , Rubinstein Ethan , Cheung Ambrose L. , Brill Grigory E. , Dardik Rima , Tamarin Ilya , Savion Naphtali , Varon David 
Published: July 2002

ABSTRACT

Global regulatory genes in
Staphylococcus aureus
, including
agr
and
sar
, are known to regulate the expression of multiple virulence factors, including cell wall adhesins. In the present study, the adherence of
S. aureus
RN6390 (wild type), RN6911 (
agr
), ALC136 (
sar
), and ALC135 (
agr sar
) to immobilized fibrinogen, fibronectin, von Willebrand factor (vWF), extracellular matrix (ECM), and human endothelial cells (EC) EAhy.926 was studied. Bacteria grown to postexponential phase were subjected to light oscillation (static condition) or to shear stress at 200 s
−1
(flow condition) on tissue culture polystyrene plates coated with either protein ligands, ECM, or EC. Adherence of nonlabeled bacteria to immobilized ligands was measured by an image analysis system, while adherence of [
3
H]thymidine-labeled
S. aureus
to ECM and EC was measured by a β-scintillation counter. The results showed increased adherence of
agr
and
agr sar
mutants to immobilized fibrinogen and higher potential of these mutants to induce platelet aggregation in suspension, decreased adherence of
sar
and
agr sar
mutants to immobilized fibronectin and vWF as well as to ECM and EC, increased adherence of both
S. aureus
wild type and
sar
mutant to EC treated with platelet-rich plasma (PRP) compared to platelet-poor plasma (PPP) and to EC treated with PPP compared to the control, and increased adherence of
S. aureus
wild type to EC coated with PRP in which platelets were activated with phorbol 12-myristate 13-acetate compared to intact PRP. This finding paralleled the increased adherence to EC of activated compared to intact platelets. It is suggested that platelet-mediated
S. aureus
adherence to EC depends on platelet activation and the number of adherent platelets and available receptors on the platelet membrane. In conclusion, the
agr
locus downregulates
S. aureus
adherence to fibrinogen, while the
sar
locus upregulates
S. aureus
adherence to fibronectin, vWF, ECM, and EC. The effect of both
agr
and
sar
on
S. aureus
adherence properties develops primarily under flow conditions, which suggests different adhesion mechanisms in static and flow conditions.
Protection against Anthrax Lethal Toxin Challenge by Genetic Immunization with a Plasmid Encoding the Lethal Factor Protein
Authors: Price Brian M. , Liner Adriane L. , Park Sukjoon , Leppla Stephen H. , Mateczun Alfred , Galloway Darrell R. 
Published: July 2002

ABSTRACTThe ability of genetic vaccination to protect against a lethal challenge of anthrax toxin was evaluated. BALB/c mice were immunized via gene gun inoculation with eucaryotic expression vector plasmids encoding either a fragment of the protective antigen (PA) or a fragment of lethal factor (LF). Plasmid pCLF4 contains the N-terminal region (amino acids [aa] 10 to 254) ofBacillus anthracisLF cloned into the pCI expression plasmid. Plasmid pCPA contains a biologically active portion (aa 175 to 764) ofB. anthracisPA cloned into the pCI expression vector. One-micrometer-diameter gold particles were coated with plasmid pCLF4 or pCPA or a 1:1 mixture of both and injected into mice via gene gun (1 μg of plasmid DNA/injection) three times at 2-week intervals. Sera were collected and analyzed for antibody titer as well as antibody isotype. Significantly, titers of antibody to both PA and LF from mice immunized with the combination of pCPA and pCLF4 were four to five times greater than titers from mice immunized with either gene alone. Two weeks following the third and final plasmid DNA boost, all mice were challenged with 5 50% lethal doses of lethal toxin (PA plus LF) injected intravenously into the tail vein. All mice immunized with pCLF4, pCPA, or the combination of both survived the challenge, whereas all unimmunized mice did not survive. These results demonstrate that DNA-based immunization alone can provide protection against a lethal toxin challenge and that DNA immunization against the LF antigen alone provides complete protection.
Proteomics Reveals Open Reading Frames in
Mycobacterium tuberculosis
H37Rv Not Predicted by Genomics
Authors: Jungblut Peter R. , Müller Eva-Christina , Mattow Jens , Kaufmann Stefan H. E. 
Published: July 2002

ABSTRACT

Genomics revealed the sequence of 3924 genes of the H37Rv strain of
Mycobacterium tuberculosis
. Proteomics complements genomics in showing which genes are really expressed, and here we show the expression of six genes not predicted by genomics, as proved by two-dimensional electrophoresis and matrix-assisted laser desorption ionization and nano-electrospray mass spectrometry.
Induction of Gamma Interferon and Nitric Oxide by Truncated Pneumolysin That Lacks Pore-Forming Activity
Authors: Baba Hisashi , Kawamura Ikuo , Kohda Chikara , Nomura Takamasa , Ito Yutaka , Kimoto Terumi , Watanabe Isao , Ichiyama Satoshi , Mitsuyama Masao 
Published: July 2002

ABSTRACTPneumolysin (PLY), an important virulence factor ofStreptococcus pneumoniae, is known to exert various effects on the host immune cells, including cytokine induction, in addition to its known cytolytic activity as a member of the thiol-activated cytolysins. It is of interest to determine whether cytolytic activity is involved in triggering the cytokine production. In this study, we constructed full-length recombinant PLY and noncytolytic truncated PLYs with C-terminal deletions to examine the response of spleen cells to these PLY preparations. When cytolytic activity was blocked by treatment with cholesterol, full-length PLY was capable of inducing gamma interferon (IFN-γ) production. Truncated PLYs that originally exhibited no cytolytic activity were also active in IFN-γ induction. Therefore, the IFN-γ-inducing ability of PLY appeared to be independent of the cytolytic activity. Furthermore, IFN-γ-inducing preparations were also capable of inducing nitric oxide synthase expression and nitric oxide (NO) production, and the addition of neutralizing antibody to IFN-γ abolished the NO production. These results clearly demonstrated that PLY is capable of inducing IFN-γ production in spleen cells by a mechanism different from pore formation and that the induced IFN-γ stimulates NO production. These findings were discussed with reference to the contribution of PLY to the virulence ofS. pneumoniaein vivo.
Type III Secretion of
Salmonella enterica
Serovar Typhimurium Translocated Effectors and SseFG
Authors: Hansen-Wester Imke , Stecher Bärbel , Hensel Michael 
Published: July 2002

ABSTRACT

The type III secretion system (TTSS) encoded by
Salmonella
enterica
serovar Typhimurium pathogenicity island 2 (SPI2) is employed by
Salmonella enterica
for interaction with host cells during the intracellular phase of pathogenesis. This TTSS secretes a set of SPI2-encoded proteins in vitro and translocates
Salmonella
serovar Typhimurium translocated effectors (STE) that are encoded by genes outside of SPI2 into host cells. Using an epitope-tagging approach, we analyzed secretion of proteins by the TTSS of SPI2 and identified SseF and SseG as further secreted substrate proteins. Three members of the STE family, SifA, SifB, and SseJ, were secreted under conditions that also induce secretion of SPI2-encoded substrate proteins.