bluuebunny/crossref_metadata_2025 huggingface dataset:
Myd88-Dependent In Vivo Maturation of Splenic Dendritic Cells Induced byLeishmania donovaniand Other Leishmania Species
Authors: De Trez Carl , Brait Maryse , Leo Oberdan , Aebischer Tony , Torrentera Fabiola Aguilar , Carlier Yves , Muraille Eric
Published: January 2004

The usual agent of visceral leishmaniasis in the Old World isLeishmania donovani, which typically produces systemic diseases in humans and mice.L. donovanihas developed efficient strategies to infect and persist in macrophages from spleen and liver. Dendritic cells (DC) are sentinels of the immune system. Following recognition of evolutionary conserved microbial products, DC undergo a maturation process and activate antigen-specific naïve T cells. In the present report we provide new insights into how DC detectLeishmaniain vivo. We demonstrate that in both C57BL/6 and BALB/c mice, systemic injection ofL. donovaniinduced the migration of splenic DC from marginal zones to T-cell areas. During migration, DC upregulated the expression of major histocompatibility complex II and costimulatory receptors (such as CD40, CD80, and CD86).Leishmania-induced maturation requires live parasites and is not restricted toL. donovani, asL. braziliensis,L. major, andL. mexicanainduced a similar process. Using a green fluorescent protein-expressing parasite, we demonstrate that DC undergoing maturation in vivo display no parasite internalization. We also show thatL. donovani-induced DC maturation was partially abolished in MyD88-deficient mice. Taken together, our data suggest thatLeishmania-induced DC maturation results from direct recognition ofLeishmaniaby DC, and not from DC infection, and that MyD88-dependent receptors are implicated in this process.
Candida albicansYeast and Germ Tube Forms Interfere Differently with Human Monocyte Differentiation into Dendritic Cells: a Novel Dimorphism-Dependent Mechanism To Escape the Host's Immune Response
Authors: Torosantucci Antonella , Romagnoli Giulia , Chiani Paola , Stringaro Annarita , Crateri Pasqualina , Mariotti Sabrina , Teloni Raffaela , Arancia Giuseppe , Cassone Antonio , Nisini Roberto
Published: January 2004

The ability ofCandida albicansto convert from the yeast (Y) form to mycelial forms through germ tube (GT) formation is considered a key feature of the transition of the organism from commensalism to virulence. We show here that human monocytes cultured with granulocyte-macrophage colony-stimulating factor and interleukin-4 (IL-4) after phagocytosis of Y forms did not differentiate into dendritic cells (DCs); they retained CD14, did not acquire CD1a, and were unable to express the maturation markers CD83 and CCR7. Moreover, they did not produce IL-12p70 but secreted IL-10. In addition, they spontaneously expressed high levels of tumor necrosis factor alpha (TNF-α), IL-6, and IL-8 mRNA transcripts and were able to induce proliferation of alloreactive memory but not naïve T lymphocytes. Conversely, monocytes that had phagocytosed GT forms differentiated into mature CD83+and CCR7+DCs; however, there was no up-regulation of CD40, CD80, and major histocompatibility complex class II, irrespective of lipopolysaccharide (LPS) treatment. In addition, these cells were unable to produce IL-12 even after LPS stimulation, but they were not functionally exhausted, as shown by their capacity to express TNF-α and IL-8 mRNA transcripts. These cells were able to prime naïve T cells but not to induce their functional polarization into effector cells. These data indicate that phagocytosis of Y and GT forms has profound and distinct effects on the differentiation pathway of monocytes. Thus, the differentiation of human monocytes into DCs appears to be tunable and exploitable byC. albicansto elude immune surveillance.
Identification and Cloning of Immunodominant Antigens ofCoxiella burnetii
Authors: Zhang Guoquan , Kiss Katalin , Seshadri Rekha , Hendrix Laura R. , Samuel James E.
Published: January 2004

A sublethal-challenge model was established in BALB/c mice by using protection from the development of severe splenomegaly as an indicator of vaccinogenic activity for evaluation of the protective efficacies of vaccine candidates. To determine the immunodominant antigens as defined by reaction to an infection-derived antibody, mouse sera from different stages of experimental infection with various doses ofCoxiella burnetiiwere tested by immunoblotting. Proteins with molecular masses of 14, 16, 21, 28, 32, 45 to 50, 57, and 60 kDa were recognized as immunodominant antigens. Antibody responses in whole-cell antigen (WCA)-vaccinated mice were compared with those in unvaccinated mice by immunoblotting using two-dimensional gel-separatedC. burnetiiantigens. The results indicated that there were significantly different antibody responses during different stages of vaccination and challenge, suggesting that several specific immunogenic antigens may play critical roles in the protection of mice against challenge. To clone these immunogenic antigens, a genomic DNA library of Nine Mile phase I was screened with convalescent-phase antisera from mice. Eighteen novel immunoreactive proteins with molecular masses ranging from ∼14 to 67 kDa were cloned and identified. Interestingly, several recombinant proteins reacted with sera from both early-stage infected and WCA-vaccinated prechallenged mice. These results suggest that these proteins may play critical roles in the development of protective immunity and that they are logical candidates for vaccine and serodiagnostic reagents.
Necrotic Death ofRhodococcus equi-Infected Macrophages Is Regulated by Virulence-Associated Plasmids
Authors: Lührmann Anja , Mauder Norman , Sydor Tobias , Fernandez-Mora Eugenia , Schulze-Luehrmann Jan , Takai Shinji , Haas Albert
Published: January 2004

Rhodococcus equiis a gram-positive intracellular pathogen that can cause severe bronchopneumonia in foals and AIDS patients. It has been reported that advanced infection of foals is characterized by tissue necrosis, coinciding with the presence of degenerate bacteria-laden macrophages. Here, we report that the possession of the VapA-expressing plasmid, which has been previously correlated with a high level of virulence for foals and mice, strongly increases cytotoxicity ofR. equifor murine macrophage-like (J774E) cells. Isolates containing different, VapB-expressing plasmids are less virulent and also have a lower cytotoxic potential. Isogenic strains lacking either plasmid are avirulent and have a very low cytotoxic potential. We show, using fluorescence-activated cell sorter analysis (annexin V/7-amino-actinomycin D and sub-G1-analysis), Western blotting [poly(ADP-ribose) polymerase processing analysis], and electron microscopy (macrophage and nucleus morphologies) that the deaths of murine macrophages are the result of necrotic rather than apoptotic events. We demonstrate that the bacteria must be alive in order to act cytotoxic. Therefore, one effect of the virulence-associated plasmids during infection withR. equiis the promotion of necrotic damage to the host.
Caspase-2 and Caspase-7 Are Involved in Cytolethal Distending Toxin-Induced Apoptosis in Jurkat and MOLT-4 T-Cell Lines
Authors: Ohara Masaru , Hayashi Tomonori , Kusunoki Yoichiro , Miyauchi Mutsumi , Takata Takashi , Sugai Motoyuki
Published: January 2004

Cytolethal distending toxin (CDT) fromActinobacillus actinomycetemcomitansis a G2/M cell-cycle-specific growth-inhibitory toxin that leads to target cell distension followed by cell death. To determine the mechanisms by whichA. actinomycetemcomitansCDT acts as an immunosuppressive factor, we examined the effects of highly purified CDT holotoxin on human T lymphocytes. Purified CDT was cytolethal toward normal peripheral T lymphocytes that were activated by in vitro stimulation with phytohemagglutinin. In addition, purified CDT showed cytolethal activity against Jurkat and MOLT-4 cells, which are known to be sensitive and resistant, respectively, to Fas-mediated apoptosis. Death in these cell lines was accompanied by the biochemical features of apoptosis, including membrane conformational changes, intranucleosomal DNA cleavage, and an increase in caspase activity in the cells. Pretreatment of Jurkat cells with the general caspase inhibitor z-VAD-fmk mostly suppressed CDT-induced apoptosis. Furthermore, specific inhibitors of caspase-2 and -7 showed significant inhibitory effects on CDT-induced apoptosis in Jurkat cells, and these inhibitory effects were fully associated with reduced activity of caspase-2 or -7 in the CDT-treated Jurkat cells. These results strongly suggest that CDT possesses the ability to induce human T-cell apoptosis through activation of caspase-2 and -7.
Evaluation of the Association of NineHelicobacter pyloriVirulence Factors with Strains Involved in Low-Grade Gastric Mucosa-Associated Lymphoid Tissue Lymphoma
Authors: Lehours Philippe , Ménard Armelle , Dupouy Sandrine , Bergey Bernard , Richy Fréderique , Zerbib Frank , Ruskoné-Fourmestraux Agnès , Delchier Jean Charles , Mégraud Francis
Published: January 2004

Helicobacter pylorihas been associated with the development of two malignant diseases: gastric adenocarcinoma and gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Although thecagpathogenicity island, especially thecagAgene, has been linked with adenocarcinoma, few data concerningH. pyloripathogenic factors involved in low-grade gastric MALT lymphoma are available. The goal of this study was to analyze the prevalence of and correlation between genes coding for sevenH. pylorivirulence factors (cagA,cagE,vacA,iceA,babA,hopQ, andoipA) and two novel adhesins (sabAandhopZ) by comparing a collection of 43H. pyloristrains isolated from patients with low-grade gastric MALT lymphoma to 39 strains isolated from age-matched patients with gastritis only. Our results show that taken individually, none of the nine genes tested can be considered associated with MALT strains and allow us to conclude that MALT pathogenesis is not linked with more proinflammatoryH. pyloristrains. We demonstrated that in patients infected with strains harboring theiceA1allele,sabAfunctional status, andhopZ“off” status, the odds of developing a MALT lymphoma were 10 times higher. However, the low prevalence of such strains (10 of 43 MALT strains) renders this triple association a low-sensitivity marker for MALT strains. Our data confirmed thatH. pylorivirulence factors are correlated with one another. If the involvement ofH. pyloriin MALT lymphoma is well established, the pathomechanism by which gastric lymphoma occurs remains to be identified.
Production of Secretory Immunoglobulin A against Shiga Toxin-Binding Subunits in Mice by Mucosal Immunization
Authors: Imai Yasuyuki , Nagai Rio , Ono Yousuke , Ishikawa Tomoyuki , Nakagami Hiroki , Tanikawa Takashi , Kurohane Kohta
Published: January 2004

The toxicity of Shiga toxins (Stx) depends on the binding of their B subunits to carbohydrate ligands on host cells. The production of antibodies against B subunits, especially immunoglobulin A (IgA) secreted on the mucosal surface, should contribute to host defense. One of the major problems in attempts to produce IgA against Stx was the poor immunogenicity of B subunits. We were able to produce serum IgA as well as IgG against Stx1B in mice of theH-2dhaplotype by means of intranasal immunization with recombinant B subunits of Stx (Stx1B) together with cholera toxin as a mucosal adjuvant. Secretory IgA (S-IgA) was detected in nasal washes but not in feces. We prepared chemically cross-linked Stx1B for use as an immunogen, and the formation of stable oligomers was revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and mass spectrometry. When the cross-linked Stx1B was used together with cholera toxin for the intranasal immunization of BALB/c mice, strong enhancement of the immune response was observed. The S-IgA titers in nasal washes were 16- to more than 64-fold higher than those in mice immunized with native Stx1B plus cholera toxin. Furthermore, fecal IgA was detectable when the cross-linked Stx1B was used. The use of cholera toxin was necessary for the induction of high titers of S-IgA in the nasal washes. However, the effect of cross-linking was dependent on the major histocompatibility complex haplotype; that is, no enhancement of IgA production was observed in C57BL/6 mice. The present results provide a practical means of producing IgA against Stx1B in BALB/c mice.
RhuR, an Extracytoplasmic Function Sigma Factor Activator, Is Essential for Heme-Dependent Expression of the Outer Membrane Heme and Hemoprotein Receptor of
Bordetella avium
Authors: Kirby Amy E. , King Natalie D. , Connell Terry D.
Published: January 2004

Genes involved in iron (Fe) acquisition often are regulated in response to the local availability of Fe. In many bacteria, Fe-dependent responsiveness is mediated by Fur, a global Fe-dependent transcriptional repressor. Tighter regulatory control of Fur-responsive genes is afforded by incorporating additional regulators into Fur-dependent regulatory cascades. RhuI, a Fur-dependent extracytoplasmic function sigma factor of
Bordetella avium
, in response to the dual stimulation of Fe starvation and the presence of heme (or hemoproteins), regulates P

bhuR

, a heme-responsive promoter which directs expression of the
bhuRSTUV
heme utilization operon. While BhuR, the outer membrane heme receptor, and RhuI have been shown to be indispensable for heme-dependent activation of P

bhuR

, collateral components of the regulatory cascade have not been described. In this investigation, RhuR, an integral cytoplasmic membrane protein with homology to anti-sigma factors, is shown to be an essential activator of P

bhuR

expression. The functional domain of RhuR required for heme-dependent activation of P

bhuR

expression was mapped to the N-terminal 97 amino acids of the protein by use of a chimeric RhuR-BlaM fusion. Expression of the chimera in a
rhuR
mutant rendered P

bhuR

constitutive, thereby decoupling the promoter from heme dependency. Growth studies confirmed that
B. avium
requires RhuR for optimal utilization of hemoglobin, but not hemin, as a sole source of nutrient Fe. These data imply that
B. avium
expresses, in addition to the BhuR heme/hemoprotein utilization system, an alternative RhuR-independent heme utilization mechanism. A model is proposed in which RhuR is the functional bridge between BhuR and RhuI in a heme-dependent regulatory cascade.
Generation ofYersinia pestisAttenuated Strains by Signature-Tagged Mutagenesis in Search of Novel Vaccine Candidates
Authors: Flashner Yehuda , Mamroud Emanuelle , Tidhar Avital , Ber Raphael , Aftalion Moshe , Gur David , Lazar Shirley , Zvi Anat , Bino Tamar , Ariel Naomi , Velan Baruch , Shafferman Avigdor , Cohen Sara
Published: January 2004

In a search for novel attenuated vaccine candidates for use againstYersinia pestis, the causative agent of plague, a signature-tagged mutagenesis strategy was used and optimized for a subcutaneously infected mouse model. A library of tagged mutants of the virulentY. pestisKimberley53 strain was generated. Screening of 300 mutants through two consecutive cycles resulted in selection of 16 mutant strains that were undetectable in spleens 48 h postinfection. Each of these mutants was evaluated in vivo by assays for competition against the wild-type strain and for virulence following inoculation of 100 CFU (equivalent to 100 50% lethal doses [LD50] of the wild type). A wide spectrum of attenuation was obtained, ranging from avirulent mutants exhibiting competition indices of 10−5to 10−7to virulent mutants exhibiting a delay in the mean time to death or mutants indistinguishable from the wild type in the two assays. Characterization of the phenotypes and genotypes of the selected mutants led to identification of virulence-associated genes coding for factors involved in global bacterial physiology (e.g.,purH,purK,dnaE, andgreA) or for hypothetical polypeptides, as well as for the virulence regulator genelcrF. One of the avirulent mutant strains (LD50, >107CFU) was found to be disrupted in thepcmlocus, which is presumably involved in the bacterial response to environmental stress. This Kimberley53pcmmutant was superior to the EV76 live vaccine strain because it induced 10- to 100-fold-higher antibody titers to the protective V and F1 antigens and because it conferred efficacious protective immunity.
In Vivo Phase Variation and Serologic Response to Lipooligosaccharide ofCampylobacter jejuniin Experimental Human Infection
Authors: Prendergast Martina M. , Tribble David R. , Baqar Shahida , Scott Daniel A. , Ferris John A. , Walker Richard I. , Moran Anthony P.
Published: January 2004

SomeCampylobacter jejunistrains which exhibit mimicry of gangliosides in their lipooligosaccharides (LOSs) are associated with development of Guillain-Barré syndrome, which complicates the selection of a suitableC. jejunistrain in a live-attenuated vaccine.C. jejuni81-176 is the most well characterized strain available, but structurally, LOS ofC. jejuni81-176 exhibits mimicry of predominantly GM2and GM3gangliosides. We compared the antiganglioside human serologic responses of 22 volunteers post-oral vaccination (two-dose series, 14 days apart) with a killed whole-cellC. jejunivaccine, those of volunteers (22 following initial challenge and 5 upon rechallenge) experimentally infected with the homologousC. jejunivaccine strain 81-176, and those of 12 volunteers used as controls (placebo recipients). All volunteers were evaluated using thin-layer chromatography immuno-overlay and a panel of nine gangliosides at days 0, 21, and 28 either postvaccination or postinoculation. Antiganglioside antibodies were identified at baseline in 6 of the 61 volunteers (9.8%). There were no antiganglioside antibodies observed following vaccination or experimental infection rechallenge. Evidence of seroconversion was observed in 2 of 22 (9.1%) in the initial infection challenge group, comparable to 1 of 12 (8.3%) in the placebo recipients. Additional testing of seven selected volunteers in the initial challenge group at days 0, 3, 7, 10, 21, 28, and 60 showed that when antiganglioside antibodies occurred (mostly anti-GM1and -GM2), responses were weak and transient. Furthermore, evidence from serologic probing of LOSs of isolates recovered from stools of six volunteers indicated that the isolates had undergone antigenic phase variation in ganglioside mimicry during passage in vivo. Collectively, with the exception of one volunteer with anti-GM2antibodies at day 60, the results show an absence of persistent antiganglioside antibodies after experimental infection withC. jejunior following administration of a killedC. jejuniwhole-cell oral vaccine, although LOS phase variation occurred.
Two Studies Evaluating the Safety and Immunogenicity of a Live, Attenuated
Shigella flexneri
2a Vaccine (SC602) and Excretion of Vaccine Organisms in North American Volunteers
Authors: Katz David E. , Coster Trinka S. , Wolf Marcia K. , Trespalacios Fernando C. , Cohen Dani , Robins Guy , Hartman Antoinette B. , Venkatesan Malabi M. , Taylor David N. , Hale Thomas L.
Published: January 2004

We report the first community-based evaluation of
Shigella flexneri
2a strain SC602, a live, oral vaccine strain attenuated by deletion of the
icsA
(
virG
) plasmid virulence gene, given at 10
4
CFU. The primary objectives of this trial were to determine the safety and immunogenicity of the vaccine and to determine the duration of colonization. Four of 34 volunteers experienced transient fevers, and three reported diarrhea during the first 3 days of the study. Half of the volunteers mounted a positive serum immunoglobulin A (IgA) response to
S. flexneri
lipopolysaccharide. All but one of the volunteers excreted the vaccine in their stools for 1 to 33 days, and this excretion was often intermittent. Data from the community-based study were supplemented with an inpatient trial in which three volunteers received 10
3
and nine received 10
4
CFU. All volunteers who received 10
3
CFU excreted SC602 and had an IgA antibody-secreting cell response. Two of these had a serum IgA response. Six of the nine volunteers who received 10
4
CFU excreted SC602. One vaccinee had a transient fever and two met the definition of diarrhea. Six volunteers that received 10
4
CFU had an antibody-secreting cell response, and four had a serum IgA response. SC602 has now been tested at 10
4
CFU in a total of 58 volunteers. The cumulative results of these clinical trials, reported here and previously (Coster et al., Infect. Immun.
67:
3437-3443, 1999), have demonstrated that SC602 is a substantially attenuated candidate vaccine that can evoke protection against the most severe symptoms of shigellosis in a stringent human challenge model of disease.
Heat Shock Protein 60 Acts as a Receptor for theListeriaAdhesion Protein in Caco-2 Cells
Authors: Wampler Jennifer L. , Kim Kwang-Pyo , Jaradat Ziad , Bhunia Arun K.
Published: January 2004

The 104-kDaListeriaadhesion protein (LAP) inListeria monocytogenesis involved in binding to various mammalian cell lines. However, the receptor that interacts with LAP in eukaryotic cells is unknown. In this study, scanning immunoelectron microscopy qualitatively demonstrated greater binding capacity of wild-type (WT)L. monocytogenesstrain (F4244) than a LAP-deficient mutant strain (KB208) to Caco-2 cells. The goal of this study was identification of the host cell receptor for LAP. Using a Western blot ligand overlay assay, we identified a protein of 58 kDa to be the putative receptor for LAP from Caco-2 cells. N-terminal sequencing and subsequent database search identified this protein as heat shock protein 60 (Hsp60). Modified immunoseparation with protein A-Sepharose beads bound to the LAP-specific monoclonal antibody H7 (MAb-H7) and a sequential incubation with LAP preparation and Caco-2 lysate confirmed the receptor to be the same 58-kDa protein. Western blot analysis with anti-Hsp60 MAb of whole-cell adhesion between Caco-2 and WT also revealed the receptor protein to be a 58-kDa protein, thus corroborating the identification of Hsp60 as a host cell receptor for LAP. Furthermore, the anti-Hsp60 antibody also caused approximately 74% reduction in binding ofL. monocytogenesWT to Caco-2 cells, whereas a control antibody, C11E9, had no effect on binding. The adhesion mechanism ofL. monocytogenesto eukaryotic cells is a complex process, and identification of Hsp60 as a receptor for LAP adds to the list of previously discovered ligand-receptor modules that are essential to achieve successful adhesion.
Mycobacterium bovisBCG Cell Wall-Specific Differentially Expressed Genes Identified by Differential Display and cDNA Subtraction in Human Macrophages
Authors: Begum Nasim A. , Ishii Kazuo , Kurita-Taniguchi Mitsue , Tanabe Masako , Kobayashi Mika , Moriwaki Yasuhiro , Matsumoto Misako , Fukumori Yasuo , Azuma Ichiro , Toyoshima Kumao , Seya Tsukasa
Published: January 2004

We have analyzed the gene expression profile of monocytes in response to a highly purified cell wall fraction ofMycobacterium bovisBCG, a clinically approved adjuvant known as BCG cell wall skeleton (BCG-CWS). It is composed of mycolic acid, arabinogalactan, and peptidoglycan and confers Toll-like receptor 2 (TLR2)- and TLR4-dependent signaling that induces monocytes to differentiate into antigen-presenting cells (APCs). Here we report differential gene expression analysis with BCG-CWS-stimulated versus nonstimulated monocytes. BCG-CWS exerted massive induction of genes regulated by TLR signaling. Marked gene regulatory characteristics in BCG-CWS-stimulated cells compared to lipopolysaccharide (LPS)-stimulated cells follow. (i) Spliced mRNAs encoding soluble forms of TREM-1 and TREM-2 (recently discovered inflammatory-signal-amplifying receptors) were regulated by BCG-CWS, resulting in their differential expression. (ii) The genes for zinc-iron transporter protein (ZIP)-like family proteins HKE-1 and LIV-1 were induced exclusively by BCG-CWS. (iii) Interleukin-23 (IL-23), rather than IL-12p70, was induced by BCG-CWS, while interferon-inducible genes were induced only by LPS. By Northern and reverse transcription-PCR analyses, we confirmed the differential expression of more than 30 BCG-CWS regulatory genes, and their expression was compared with that of LPS and other known TLR ligands. A battery of genes responded rapidly and for a short time to LPS but for a long time to BCG-CWS. Structural analysis of the identified novel or hypothetical proteins revealed that some are potential candidates as signaling mediators or transcriptional regulators. Hence, BCG-CWS may profoundly modulate APC responses in a way distinct from that of LPS, leading to possible advantages for its adjuvant-active therapeutic potential.
Mechanisms of Immunity toEhrlichia muris: a Model of Monocytotropic Ehrlichiosis
Authors: Feng Hui-Min , Walker David H.
Published: January 2004

Ehrlichiaspecies can cause life-threatening infections or chronic persistent infections. Mechanisms of protective immunity were examined in anEhrlichia murismouse model of monocytotropic ehrlichiosis. C57BL/6 mice possessed strong genetic resistance toE. murisof an undetermined mechanism. CD8 T lymphocytes were particularly important, as revealed by 81% fatalities forE. muris-infected, major histocompatibility complex class I gene knockout mice compared with no deaths for wild-type C3H mice. Moreover, 80% of C3H mice depleted of CD8 and CD4 cells died ofE. murisinfection compared with only 44% of CD4 cell-depleted mice. CD8 T lymphocytes were demonstrated for the first time in anEhrlichiainfection to exhibit cytotoxic T-lymphocyte activity againstEhrlichia-infected target cells. Both gamma interferon and tumor necrosis factor were shown to play synergistic roles in protective immunity in vivo for the first time, as demonstrated by 75% fatalities when both cytokines were neutralized compared with minimal mortality when they were depleted separately. Passive transfer of antibodies, but not Fab fragments, toE. murisprotected C3H/SCID mice against lethal infection. The mechanism of increased susceptibility (22% lethality) of C57BL/6 major histocompatibility complex class II gene knockout mice and CD4 cell-depleted C3H mice (i.e., through a gamma interferon or antibody mechanism), as well as the more important role of CD8 T lymphocytes (in the form of cytotoxic T-lymphocyte activity and/or gamma interferon production), remains to be elucidated. Protective immunity against monocytotropicE. murisis mediated by a combination of CD8 and CD4 T lymphocytes, gamma interferon, tumor necrosis factor alpha, and antibodies.
The Staphylococcal Ferritins Are Differentially Regulated in Response to Iron and Manganese and via PerR and Fur
Authors: Morrissey Julie A. , Cockayne Alan , Brummell Kirsty , Williams Paul
Published: January 2004

Staphylococcus aureus
and
Staphylococcus epidermidis
ferritin (FtnA and SefA, respectively) homologues are antigenic and highly conserved. A previous study showed that
ftnA
is a component of the
S. aureus
PerR regulon with its transcription induced by elevated iron and repressed by PerR, which functions as a manganese-dependent transcriptional repressor. We have further investigated the role of iron and Fur in the regulation of PerR regulon genes
ftnA
(ferritin),
ahpC
(alkyl-hydroperoxidase), and
mrgA
(Dps homologue) and shown that iron has a major role in the regulation of the PerR regulon and hence the oxidative stress response, since in the presence of both iron and manganese, transcription of PerR regulon genes is induced above the repressed levels observed with manganese alone. Furthermore the PerR regulon genes are differentially regulated by metal availability and Fur. First, there is an additional level of PerR-independent regulation of
ftnA
under low-iron conditions which is not observed with
ahpC
and
mrgA.
Second, there is a differential response of these genes to Fur as
ftnA
expression is constitutive in a
fur
mutant, while
ahpC
expression is constitutive under low-Fe/Mn conditions but some repression of
ahpC
still occurs in the presence of manganese, whereas
mrgA
expression is still repressed in the
fur
mutant as in wild-type
S. aureus
, although there is a decrease in the overall level of
mrgA
transcription. These studies have also shown that FtnA expression is regulated by growth phase, but maximal transcription of
ftnA
differs dependent on the growth medium. Moreover, there are significant regulatory differences between the
S. aureus
and
S. epidermidis
ferritins, as
sefA
expression in contrast to that of
ftnA
is derepressed under low-Fe/Mn ion conditions.
The
Cryptosporidium
Oocyst Wall Protein Is a Member of a Multigene Family and Has a Homolog in
Toxoplasma
Authors: Templeton Thomas J. , Lancto Cheryl A. , Vigdorovich Vladimir , Liu Chang , London Nicole R. , Hadsall Kelly Z. , Abrahamsen Mitchell S.
Published: January 2004

Coccidian parasites are transmitted via a fecal oocyst stage that is exceptionally resistant to environmental stress and harsh chemical treatments, which allows parasites to stably persist outside a host. Because of its oocyst durability
Cryptosporidium parvum
is a significant water- and food-borne pathogen of humans, as well as animals of agricultural importance. To date, only one apicomplexan oocyst membrane protein has been identified,
Cryptosporidium
oocyst wall protein 1 (COWP1). COWP1 has a highly cysteine-rich periodicity due to arrays of two apicomplexan-specific motifs, designated the type I and type II domains. In this study, exhaustive BLAST screening of a complete
C. parvum
genome sequence database resulted in identification of eight additional genes encoding similar arrays of cysteine-rich type I and/or type II domains. Transcript expression analysis revealed that all COWP genes are abundantly expressed at a time when developing oocysts are observed, roughly 48 to 72 h after inoculation of in vitro cultures. A monoclonal antibody recognizing COWP8 specifically localized to the
C. parvum
oocyst wall, supporting the hypothesis that multiple COWPs play a role in the oocyst wall structure. BLAST screening of the
Toxoplasma gondii
genome sequence database resulted in identification of a gene encoding at least one COWP homolog (
Tg
OWP1), and this multiexon sequence information was used to isolate a full-length cDNA. Exhaustive screening of
Plasmodium
sp. genome sequence databases by using COWP genes as BLAST queries failed to detect similar proteins in
Plasmodium
. We therefore propose that the COWP family of proteins have a structural role in apicomplexan species that produce durable shed cysts capable of surviving environmental stress.
Enhanced Replication ofLeishmania amazonensisAmastigotes in Gamma Interferon-Stimulated Murine Macrophages: Implications for the Pathogenesis of Cutaneous Leishmaniasis
Authors: Qi Hai , Ji Jiaxiang , Wanasen Nanchaya , Soong Lynn
Published: January 2004

DuringLeishmania majorinfection in mice, gamma interferon (IFN-γ) plays an essential role in controlling parasite growth and disease progression. In studies designed to ascertain the role of IFN-γ inLeishmania amazonensisinfection, we were surprised to find that IFN-γ could promoteL. amazonensisamastigote replication in macrophages (MΦs), although it activated MΦs to kill promastigotes. The replication-promoting effect of IFN-γ on amastigotes was independent of the source and genetic background of MΦs, was apparently not affected by surface opsonization of amastigotes, was not mediated by interleukin-10 or transforming growth factor β, and was observed at different temperatures. Consistent with the different fates of promastigotes and amastigotes in IFN-γ-stimulated MΦs,L. amazonensis-specific Th1 transfer helped recipient mice controlL. amazonensisinfection established by promastigotes but notL. amazonensisinfection established by amastigotes. On the other hand, IFN-γ could stimulate MΦs to limit amastigote replication when it was coupled with lipopolysaccharides but not when it was coupled with tumor necrosis factor alpha. Thus, IFN-γ may play a bidirectional role at the level of parasite-MΦ interactions; when it is optimally coupled with other factors, it has a protective effect against infection, and in the absence of such synergy it promotes amastigote growth. These results reveal a quite unexpected aspect of theL. amazonensisparasite and have important implications for understanding the pathogenesis of the disease and for developing vaccines and immunotherapies.
Salmonella entericaSerovar Typhimurium RamA, Intracellular Oxidative Stress Response, and Bacterial Virulence
Authors: van der Straaten Tahar , Zulianello Laurence , van Diepen Angela , Granger Donald L. , Janssen Riny , van Dissel Jaap T.
Published: January 2004

Escherichia coliandSalmonella entericaserovar Typhimurium have evolved genetic systems, such as thesoxR/SandmarAregulons, to detoxify reactive oxygen species, like superoxide, which are formed as by-products of metabolism. Superoxide also serves as a microbicidal effector mechanism of the host's phagocytes. Here, we investigate whether regulatory genes other thansoxR/SandmarAare active in response to oxidative stress inSalmonellaand may function as virulence determinants. We identified a bacterial gene, which was designatedramA(342 bp) and mapped at 13.1 min on theSalmonellachromosome, that, when overexpressed on a plasmid inE. coliorSalmonella, confers a pleiotropic phenotype characterized by increased resistance to the redox-cycling agent menadione and to multiple unrelated antibiotics. TheramAgene is present inSalmonellaserovars but is absent inE. coli.The gene product displays 37 to 52% homology to the transcriptional activatorssoxR/SandmarAand 80 to 100% identity to a multidrug resistance gene inKlebsiella pneumoniaeandSalmonella entericaserovar Paratyphi A. Although aramA soxR/Sdouble null mutant is highly susceptible to intracellular superoxide generated by menadione and displays decreased Mn-superoxide dismutase activity, intracellular survival of this mutant within macrophage-like RAW 264.7 cells and in vivo replication in the spleens in Ityrmice are not affected. We concluded that despite its role in the protective response of the bacteria to oxidative stress in vitro, the newly identifiedramAgene, together withsoxR/S, does not play a role in initial replication ofSalmonellain the organs of mice.
EVALUATION OF THE PSEUDOGAP IN THE TWO-DIMENSIONAL PAIRING MODEL
Authors: MACOCIAN EUGEN-VICTOR
Published: January 2004

In this article, we perform a self-consistent calculation for the self-energy, based on the pairing mechanism for the two-dimensional phenomenological model below half filling. The non-Fermi versus Fermi liquid behavior is analyzed and the self-energies are compared. We also investigate the doping dependence of the pseudogap in the underdoped regime of the phase diagram of cuprates superconductors. Comparing the obtained results with experimental data, it is found that Δpg scales with characteristic temperature T*.
SUBGAP INDUCED BY BILAYER EFFECTS OF CuO2 PLANES IN HIGH Tc SUPERCONDUCTORS
Authors: KOO JE HUAN , CHO GUANGSUP
Published: January 2004

The bilayer effects of CuO 2 planes in high-T c superconductors are investigated. The interaction between a CuO 2 bilayer is found to induce a subgap far below the superconducting transition temperature T c . It is also shown that zero-bias-conductance-peaks (ZBCP) above T c are due to a Kondo-type effect as for low-T c superconductors, but ZBCP far below T c originating from this bilayer effects are different from traditional explanations.
Twinning in Tufted Capuchins (Cebus apella) : Rate, Survivorship, and Weight Gain
Authors: Leighty Katherine A. , Byrne Gayle , Fragaszy Dorothy M. , Visalberghi Elisabetta , Welker Christian , Lussier Isabelle
Published: January 2004

We calculated the rate of twinning across four captive collections of tufted capuchins (Cebus apella) to be 2.4%. This rate contrast with previous reports that twinning in tufted capuchins is rare. Additionally, we present data on the survival and weight gain of twins in this species as compared to singletons. Twins face their greatest risk of mortality on or before the first day of life, when 45% will die compared to 16% of singletons. After the first day of life, twins and singletons demonstrate comparable survival rates. This, in conjunction with the finding that at no time during the first year of life do twins and singletons differ significantly in their weights, suggests that twinning is a viable reproductive form for these animals, especially in the captive setting where nutritional demands are met.
Evolution of Endotoxin-Induced Lung Injury in the Rat beyond the Acute Phase
Authors: Domenici L. , Pieri L. , Gallè M.B. , Romagnoli P. , Adembri C.
Published: January 2004

Objectives: Intratracheal endotoxin in rats causes acute lung injury. Here we have addressed the cellular physiopathology of lung recovery from that injury. Methods: The lungs of 5 untreated rats and rats treated with intratracheal endotoxin from 2, 3, 5, 8 (5 rats each) and 15 days (2 rats) were studied by light and electron microscopy and immunohistochemistry. Results: In the acute phase there was a reduction in the aerated spaces (p < 0.01); diffuse infiltration of granulocytes and macrophages; hyperplasia of type-II pneumocytes, and hypertrophy of interstitial cells. Aerated spaces improved during recovery. In the early recovery phase (3–8 days) the compartmentalization of infiltrating cells varied significantly (p < 0.01): macrophages remained widespread while neutrophils were inside blood vessels. Many pneumocytes were intermediate between type-I and type-II cells. In the late recovery phase (15 days) the infiltrate disappeared; myofibroblasts were significantly more than previously (p < 0.01) and extracellular matrix was abundant; type-II pneumocytes contained non-lamellated lipid inclusions. Conclusions: Macrophages play a pivotal role in the damage-repair processes of the lung following endotoxin injury, leading to an increase in extracellular matrix, differentiation of myofibroblasts and altered secretion of surfactant by newly differentiated type-II pneumocytes.
Digital Chemospectrophotographic Identification of Intracellular Hyperlipidemia in Diabetic Endometrial Epithelial Cells: Structural and Metabolic Basis of Organoatrophy
Authors: Garris Bryan L. , Garris David R.
Published: January 2004

Objective: Digital chemospectrophotographic (DCSP) microscopic analysis and evaluation methodology applicable for enhanced cytopathological analysis of diabetes-induced, cytohyperlipidemia-associated cellular involution in endometrial epithelial and stromal tissues that promotes reproductive dysfunction and organoatrophy. Methods: Combined light microscopy (LM), transmission electron microscopy (TEM) and described DCSP evaluation of endometrial samples collected from control (+/?) and genetically diabetic (db/db) C57BL/KsJ, hyperglycemic-hyperinsulinemic (type II) mice, designed to enhance the intracellular localization of chemically specified triglyceride and free fatty acid depositions, on progressive reproductive tract atrophy and cellular involution indices. Results: Compared to both the LM and TEM analysis of cytopathological changes associated with diabetes-induced endometrial involution and reproductive dysfunction, the application of DCSP provided enhanced pathovisual analysis of chemical-specific metabolic alterations and cytoplasmic structural changes which accompany cytohyperlipidemia-induced endometrial epithelial cell apoptosis and reproductive tract atrophy. Conclusions: DCSP analysis provides an enhanced analytical method for the evaluation of cytoplasmic changes associated with the expression of genomic-, endocrine- or metabolic-based disease states by providing intercytoplasmic specific chemical or metabolic substrate alterations to be identified from conventional pathocellular preparations without requiring the use of exogenous ligand binding or fluorescent methodologies, allowing for a more complete metabolic and cellular evaluation of cytoplasmic indices associated with organoatrophy.
Expression of Cyclooxygenase-1 and Cyclooxygenase-2 in Human Esophageal Mucosa, Dysplasia and Carcinoma
Authors: Kase Satoru , Osaki Mitsuhiko , Honjo Soichiro , Hashimoto Kiyoshi , Adachi Hironobu , Tsujitani Shunichi , Ito Hisao
Published: January 2004

Objective: COX (cyclooxygenase), a prostaglandin H synthase, catalyzes the rate-limiting step in prostaglandin biosynthesis. Two isoforms of COX have been identified: COX-1 and COX-2. We examined the expression of COX-1 and COX-2 in esophageal normal mucosa, dysplasia and squamous cell carcinoma (SCC). Methods: The expression of COX-1 and COX-2 in 80 surgically removed esophagi due to SCC, as well as in 5 human esophageal SCC cell lines was analyzed, using immunohistochemistry and Western blot analyses. Results: COX-1 and COX-2 were variably expressed in the SCC cell lines. Higher COX-1 expression was noted in 31 (41.9%) of the 74 specimens of normal mucosa, in none of the 40 specimens of dysplastic mucosa and in 15 (18.8%) of the 80 specimens of SCC, the frequency being significantly higher in normal mucosa than in dysplasia or SCC (p < 0.0001, p = 0.0018, respectively). COX-1 expression was significantly higher in well-differentiated SCC than in moderately or poorly differentiated SCC (p < 0.01). Higher COX-2 expression was noted in none (0.0%) of the specimens of normal mucosa, in 12 (30%) of the specimens of dysplastic mucosa, and in 41 (51.3%) of the speciments of SCC, the frequency being significantly higher in SCC than in normal mucosa or dysplasia (p < 0.0001, p = 0.0278, respectively). Conclusions: COX-1 is expressed in normal esophageal mucosa and is occasionally induced in well-differentiated SCC, whereas COX-2 expression is more characteristic of dysplasia and carcinoma than of normal mucosa, implying a possible association with cell differentiation in the former, and esophageal tumorigenesis in the latter.
Metal Contents in the Liver of Patients with Chronic Liver Disease Caused by Hepatitis C Virus
Authors: Ebara Masaaki , Fukuda Hiroyuki , Hatano Ryoji , Yoshikawa Masaharu , Sugiura Nobuyuki , Saisho Hiromitsu , Kondo Fukuo , Yukawa Masae
Published: January 2004

Background/Aims: The aim of this study was to investigate the relationship between trace metals and the prevalence of hepatocellular carcinoma (HCC) in patients with chronic hepatitis or hepatic cirrhosis caused by hepatitis C virus (HCV). Methods: We measured the contents of copper, iron, and zinc in HCC tissue (n = 112), dysplastic nodules (n = 7), and liver parenchyma in patients with (n = 112) and without (n = 12; 7 with grade F3 fibrosis, 5 with grade F4 fibrosis) HCC. Metals were quantified in thin-needle biopsy specimens using the particle-induced X-ray emission method (PIXE). Results: Copper level in liver parenchyma was higher in patients with HCC than in those without HCC (p < 0.01), while there was no such difference in hepatic iron. In patients with grade F4 fibrosis, copper content in the liver parenchyma was higher in the presence of HCC than in its absence (p < 0.05). Multiple regression analysis showed that the only factor significantly associated with the coexistence of HCC in HCV-positive patients with chronic liver disease was the copper level in the liver parenchyma. Conclusions: Hepatic copper overload may contribute to the development of HCC in HCV-positive patients with chronic hepatitis or cirrhosis.
Skp2 and Jab1 Expression Are Associated with Inverse Expression of p27KIP1 and Poor Prognosis in Oral Squamous Cell Carcinomas
Authors: Shintani Satoru , Li Chunnun , Mihara Mariko , Hino Satoshi , Nakashiro Koh-ichi , Hamakawa Hiroyuki
Published: January 2004

Previous studies have shown that low levels of p27KIP1, an inhibitor of G1 cyclin-dependent kinases (CDK), are associated with high aggressiveness and poor prognosis in a variety of cancers. Decreased levels of p27KIP1 are caused, at least in part, by an acceleration of degradation with Skp2 (S-phase kinase-associated protein 2) and Jab1 (Jun activation domain-binding protein 1). This investigation was undertaken to examine whether the Skp2 and Jab1 expression is correlated with p27KIP1 protein levels, and how it is clinically relevant in oral squamous cell carcinoma (OSCC). The correlations between p27KIP1 and Skp2, and p27KIP1 and Jab1 expression were evaluated by Western blot analysis. Immunohistochemical analysis was done in 75 cases of OSCC. A strongly significant inverse correlation was found between levels of p27KIP1 and Skp2, and p27KIP1 and Jab1 (p < 0.0001). Thus, decreased levels of p27KIP1 were associated with strongly increased levels of Skp2 and Jab1, whereas high levels of p27KIP1 coincided with low levels of Skp2 and Jab1. Reductions of p27KIP1 expression and overexpression of Skp2 and Jab1 were significantly associated with cervical lymph node metastasis and poor prognosis. Overexpression of Skp2 and Jab1 is associated with the reduction of p27KIP1 expression, and may have a role in the progression of OSCC.
Loss of p27 Expression Is Associated with Poor Prognosis in Stage I–II Pancreatic Cancer
Authors: Juuti A. , Nordling S. , Louhimo J. , Lundin J. , von Boguslawski K. , Haglund C.
Published: January 2004

Objective: p27 is a cyclin-dependent kinase inhibitor that prevents progression of the cell cycle from G1 phase. Postranscriptional loss of p27 correlates with poor prognosis in various solid tumors. In pancreatic cancer, the loss of p27 expression has been correlated with high tumor grade and advanced clinical stage, but data on its prognostic value are lacking. Method: In this retrospective study, the association between immunohistochemical p27 expression and prognosis was evaluated in 147 patients with pancreatic cancer using a commercial anti-Kip1/p27 monoclonal antibody. Result: p27 expression was generally low; in 103 of the 147 pancreatic cancer tumors examined, no nuclear staining was observed and in only 5 specimens did more than 50% of the nuclei stain, probably reflecting the aggressive nature of the disease. Loss of p27 expression was associated with poor prognosis in stage I–II pancreatic adenocarcinoma; the 5-year survival for p27 negative patients was 3.6% compared with 20% for p27-positive patients (p = 0.03). In a multivariate survival analysis in patients with stage I–II disease, p27 (HR 1.8) was a significant prognostic factor, independent of grade (RR 2.9). There was no association between p27 and other clinical variables. In conclusion, tissue expression of p27 is a significant predictor of 5-year survival in stage I–II pancreatic adenocarcinoma.
Immunomodulation by Polyunsaturated Fatty Acids: Mechanisms and Effects
Authors: Stulnig Thomas M.
Published: January 2004

Polyunsaturated fatty acids (PUFAs) modulate immune responses, thereby exerting beneficial effects in a variety of inflammatory disorders. PUFAs of the n-3 series that are found in marine fish oils are particularly effective. A variety of molecular mechanisms have been found to explain how PUFAs could interfere with immune cell function. PUFAs alter eicosanoid (prostaglandin, leukotriene) synthesis, orphan nuclear receptor activation (e.g. peroxisome proliferator-activated receptors, liver X receptors) and T lymphocyte signaling by changing the molecular composition of special signaling platforms called lipid rafts. This review discusses these mechanisms in detail with respect to their probable relevance in vivo. In addition, the effects of PUFAs on the immune system in general are summarized, as are clinical effects in rheumatoid arthritis, inflammatory bowel disease and sepsis.