bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sensitization of Human Aortic Endothelial Cells to Lipopolysaccharide via Regulation of Toll-Like Receptor 4 by Bacterial Fimbria-Dependent Invasion
Authors: Yumoto Hiromichi , Chou Hsin-Hua , Takahashi Yusuke , Davey Michael , Gibson Frank C. , Genco Caroline A. 
Published: November 2005

ABSTRACTToll-like receptors (TLRs) are differentially up-regulated in response to microbial infection and chronic inflammatory diseases such as atherosclerosis. Epidemiological data support the idea that periodontal disease may be a risk factor for acceleration of atherosclerosis.Porphyromonas gingivalis, the etiological agent of periodontal disease, invades endothelium, has been detected in human atheromatous tissue, and accelerates atheroma formation in apolipoprotein E−/−mice with concurrent induction of TLRs in the aorta. As endothelial cells can present antigen via TLRs and play an important role in the development of atherosclerosis, we examined TLR expression in human aortic endothelial cells (HAEC) cultured with wild-typeP. gingivalis, a fimbria-deficient mutant, and purified antigens. We observed increased TLR expression in HAEC infected with wild-typeP. gingivalisby fluorescence-activated cell sorter, but not with noninvasive, fimbria-deficient mutant or purifiedP. gingivalisantigens. Following a wild-typeP. gingivalischallenge, functional TLR2 and TLR4 activation was assessed by subsequent stimulation with TLR agonistsStaphylococcus aureuslipoteichoic acid (SLTA; TLR2 ligand) andEscherichia colilipopolysaccharide (LPS; TLR4 ligand). Unchallenged HAEC failed to elicit monocyte chemoattractant protein 1 (MCP-1) in response to LPS or SLTA but did so when cultured with wild-typeP. gingivalis. P. gingivalis-induced TLR2 and -4 expression on HAEC functionally reacted to SLTA andE. coliLPS as measured by a further increase in MCP-1 production. Furthermore, MCP-1 expression elicited byE. coliLPS was inhibitable with TLR4-specific antibody and polymyxin B. These results indicate that invasiveP. gingivalisstimulates TLR expression on the surface of endothelium and these primed cells respond to defined TLR-specific ligands.
Toxoplasma gondii-Specific Immunoglobulin M Limits Parasite Dissemination by Preventing Host Cell Invasion
Authors: Couper Kevin N. , Roberts Craig W. , Brombacher Frank , Alexander James , Johnson Lawrence L. 
Published: November 2005

ABSTRACTAn important role for immunoglobulin M (IgM) during early acute virulentToxoplasma gondiiinfection was identified using IgM−/−mice that lack surface and secretory IgM but maintain normal B-cell functionality and isotype class switching. Following intraperitoneal inoculation with the virulent RH strain, IgM−/−mice displayed significantly fewer peritoneal parasites than wild-type (WT) mice, which correlated with increased tachyzoite dissemination to the liver, lung, and spleen in IgM−/−mice compared with WT mice. Early splenic T-cell activation, as measured by CD69 expression, was augmented in IgM−/−mice, and serum and peritoneal cavity gamma interferon levels were also elevated in IgM−/−mice compared with WT controls. Consequently, the difference in parasite dissemination was not attributable to an impaired proinflammatory immune response in the IgM−/−mice. Specific IgM was found to bind to tachyzoites in vivo in WT mice, and this correlated with an increased ability of antiserum collected from WT mice at day 6 postinfection to block tachyzoite cell invasion, compared with comparable serum collected from IgM−/−mice at the same time point. Tachyzoite invasion of host cells was similar if parasites were incubated with WT or IgM−/−nonimmune serum, suggesting that natural IgM does not function to limit parasite dissemination during earlyT. gondiiinfection. Our results highlight an important role for parasite-specific IgM in limiting systemic dissemination of tachyzoites during early acuteT. gondiiinfection.
Vaccination with the RecombinantBrucellaOuter Membrane Protein 31 or a Derived 27-Amino-Acid Synthetic Peptide Elicits a CD4+T Helper 1 Response That Protects againstBrucella melitensisInfection
Authors: Cassataro Juliana , Estein Silvia M. , Pasquevich Karina A. , Velikovsky Carlos A. , de la Barrera Silvia , Bowden Raúl , Fossati Carlos A. , Giambartolomei Guillermo H. 
Published: November 2005

ABSTRACTThe immunogenicity and protective efficacy of the recombinant 31-kDa outer membrane protein fromBrucella melitensis(rOmp31), administered with incomplete Freund's adjuvant, were evaluated in mice. Immunization of BALB/c mice with rOmp31 conferred protection againstB. ovisandB. melitensisinfection. rOmp31 induced a vigorous immunoglobulin G (IgG) response, with higher IgG1 than IgG2 titers. In addition, spleen cells from rOmp31-immunized mice produced interleukin 2 (IL-2) and gamma interferon, but not IL-10 or IL-4, after in vitro stimulation with rOmp31, suggesting the induction of a T helper 1 (Th1) response. Splenocytes from rOmp31-vaccinated animals also induced a specific cytotoxic-T-lymphocyte activity, which led to the in vitro lysis ofBrucella-infected macrophages. In vitro T-cell subset depletion indicated that rOmp31 immunization elicited specific CD4+T cells that secrete IL-2 and gamma interferon, while CD8+T cells induced cytotoxic-T-lymphocyte activity. In vivo depletion of T-cell subsets showed that the rOmp31-elicited protection againstB. melitensisinfection is mediated by CD4+T cells while the contribution of CD8+T cells may be limited. We then evaluated the immunogenicity and protective efficacy of a known exposed region from Omp31 on theBrucellamembrane, a peptide that contains amino acids 48 to 74 of Omp31. Immunization with the synthetic peptide in adjuvant did not elicit a specific humoral response but elicited a Th1 response mediated by CD4+T cells. The peptide in adjuvant induced levels of protection similar to those induced by rOmp31 againstB. melitensisbut less protection than was induced by rOmp31 againstB. ovis. Our results indicate that rOmp31 could be a useful candidate for the development of subunit vaccines againstB. melitensisandB. ovis.
Identification of Novel Antigenic Proteins in a ComplexAnaplasma marginaleOuter Membrane Immunogen by Mass Spectrometry and Genomic Mapping
Authors: Lopez Job E. , Siems William F. , Palmer Guy H. , Brayton Kelly A. , McGuire Travis C. , Norimine Junzo , Brown Wendy C. 
Published: November 2005

ABSTRACTImmunization with purifiedAnaplasma marginaleouter membranes induces complete protection against infection that is associated with CD4+T-lymphocyte-mediated gamma interferon secretion and immunoglobulin G2 (IgG2) antibody titers. However, knowledge of the composition of the outer membrane immunogen is limited. Recent sequencing and annotation of theA. marginalegenome predicts at least 62 outer membrane proteins (OMP), enabling a proteomic and genomic approach for identification of novel OMP by use of IgG serum antibody from outer membrane vaccinates. Outer membrane proteins were separated by two-dimensional electrophoresis, and proteins recognized by total IgG and IgG2 in immune sera of outer membrane-vaccinated cattle were detected by immunoblotting. Immunoreactive protein spots were excised and subjected to liquid chromatography-tandem mass spectrometry. A database search of theA. marginalegenome identified 24 antigenic proteins that were predicted to be outer membrane, inner membrane, or membrane-associated proteins. These included the previously characterized surface-exposed outer membrane proteins MSP2, operon associated gene 2 (OpAG2), MSP3, and MSP5 as well as recently identified appendage-associated proteins. Among the 21 newly described antigenic proteins, 14 are annotated in theA. marginalegenome and include type IV secretion system proteins, elongation factor Tu, and members of the MSP2 superfamily. The identification of these novel antigenic proteins markedly expands current understanding of the composition of the protective immunogen and provides new candidates for vaccine development.
Regulation of Cellular Caveolin-1 Protein Expression in Murine Macrophages by Microbial Products
Authors: Lei Mei G. , Tan Xiaoyu , Qureshi Nilofer , Morrison David C. 
Published: November 2005

ABSTRACTPreviously, we reported that expression of caveolin-1 in elicited peritoneal mouse macrophages was up-regulated by remarkably low (1.0-pg/ml) concentrations ofEscherichia coliO111 lipopolysaccharide (LPS). Here we report that increases in caveolin-1 expression are manifested by different types of LPS, LPS-mimetic taxol, and heat-killedE. coliand to a much lesser extent by zymosan, polysaccharide-peptidoglycan, and heat-killedStaphylococcus aureus. Rhodobacter sphaeroideslipid A (RsDPLA) could not induce caveolin-1 expression in macrophages. Interestingly, polymyxin B (5 μg/ml) and RsDPLA show only a limited capacity to inhibit LPS-induced caveolin-1 expression. These findings suggest that expression of caveolin-1 in response to LPS may only partially be dependent upon lipid A. Recombinant tumor necrosis factor alpha marginally induces caveolin-1, suggesting that the ability of LPS to regulate caveolin-1 is not mediated primarily through an autocrine/paracrine mechanism involving this cytokine. Under conditions in which cellular levels of caveolin-1 are profoundly induced, no significant changes in TLR4 expression are observed. Of interest, caveolin-1 appears to localize to two cellular compartments, one associated with lipid rafts and a second associated with TLR4. Gamma interferon treatment inhibits the induction of caveolin-1 by LPS in macrophages. Inhibition of the p38 kinase-dependent pathway, but not the extracellular signal-regulated kinase pathway, effectively reduced the ability of LPS to mediate caveolin-1 up-regulation. Lactacystin, a potent inhibitor of the proteasome pathway, significantly modulates LPS-independent caveolin-1 expression, and lactacystin inhibits LPS-triggered caveolin-1 responses. These studies suggest that caveolin-1 up-regulation in response to LPS is likely to be proteasome dependent and triggered through the p38 kinase pathway.
Comparative Toll-Like Receptor 4-Mediated Innate Host Defense toBordetellaInfection
Authors: Mann Paul B. , Wolfe Daniel , Latz Eicke , Golenbock Douglas , Preston Andrew , Harvill Eric T. 
Published: November 2005

ABSTRACTBordetella pertussis,B. parapertussis, andB. bronchisepticaare closely related species associated with respiratory disease in humans and other mammals. WhileB. bronchisepticahas a wide host range,B. pertussisandB. parapertussisevolved separately from aB. bronchiseptica-like progenitor to naturally infect only humans. Despite very different doubling times in vitro, all three establish similar levels of infection in the mouse lung within 72 h. Recent work has revealed separate roles for Toll-like receptor 4 (TLR4) in immunity toB. pertussisandB. bronchiseptica, while no role for TLR4 duringB. parapertussisinfection has been described. Here we compared the requirement for TLR4 in innate host defense to these organisms using the same mouse infection model. WhileB. bronchisepticacauses lethal disease in TLR4-deficient mice,B. pertussisandB. parapertussisdo not. Correspondingly, TLR4 is critical in limitingB. bronchisepticabut notB. pertussisorB. parapertussisbacterial numbers during the first 72 h. Interestingly,B. bronchisepticainduces a TLR4-dependent cytokine response that is considerably larger than that induced byB. pertussisorB. parapertussis. Analysis of their endotoxins using RAW cells suggests thatB. bronchisepticalipopolysaccharide (LPS) is 10- and 100-fold more stimulatory thanB. pertussisorB. parapertussisLPS, respectively. The difference in LPS stimulus is more pronounced when using HEK293 cells expressing human TLR4. Thus, it appears that in adapting to infect humans,B. pertussisandB. parapertussisindependently modified their LPS to reduce TLR4-mediated responses, which may compensate for slower growth rates and facilitate host colonization.
Antigenic Specificity of the Mucosal Antibody Response to
Moraxella catarrhalis
in Chronic Obstructive Pulmonary Disease
Authors: Murphy Timothy F. , Brauer Aimee L. , Aebi Christoph , Sethi Sanjay 
Published: November 2005

ABSTRACT

Moraxella catarrhalis
is an important human mucosal pathogen causing otitis media in children and lower respiratory tract infection in adults with chronic obstructive pulmonary disease (COPD). Little is known about the mucosal antibody response to
M. catarrhalis
in adults with COPD. In this study, 10 pairs of well-characterized sputum supernatant samples from adults with COPD who had acquired and subsequently cleared
M. catarrhalis
from their respiratory tracts were studied in detail in an effort to begin to elucidate potentially protective immune responses. Flow cytometry analysis was used to study the distribution of immunoglobulin isotypes in paired preacquisition and postclearance sputum samples. The results showed that immunoglobulin A (IgA) is the predominant
M. catarrhalis
-specific immunoglobulin isotype and that the sputum IgA contains a secretory component, indicating that it is locally produced at the mucosal site. Most patients made new sputum IgA responses to the adhesins UspA1 and Hag, along with the surface protein UspA2. A smaller proportion of patients made new sputum IgA responses to the iron-regulated proteins TbpB and CopB and to lipooligosaccharide. These results have important implications in understanding the mucosal immune response to
M. catarrhalis
in the setting of COPD and in elucidating the elements of a protective immune response.
Iron and Fur Regulation in
Vibrio cholerae
and the Role of Fur in Virulence
Authors: Mey Alexandra R. , Wyckoff Elizabeth E. , Kanukurthy Vanamala , Fisher Carolyn R. , Payne Shelley M. 
Published: November 2005

ABSTRACT

Regulation of iron uptake and utilization is critical for bacterial growth and for prevention of iron toxicity. In many bacterial species, this regulation depends on the iron-responsive master regulator Fur. In this study we report the effects of iron and Fur on gene expression in
Vibrio cholerae
. We show that Fur has both positive and negative regulatory functions, and we demonstrate Fur-independent regulation of gene expression by iron. Nearly all of the known iron acquisition genes were repressed by Fur under iron-replete conditions. In addition, genes for two newly identified iron transport systems, Feo and Fbp, were found to be negatively regulated by iron and Fur. Other genes identified in this study as being induced in low iron and in the
fur
mutant include those encoding superoxide dismutase (
sodA
), fumarate dehydratase (
fumC
), bacterioferritin (
bfr
), bacterioferritin-associated ferredoxin (
bfd
), and multiple genes of unknown function. Several genes encoding iron-containing proteins were repressed in low iron and in the
fur
mutant, possibly reflecting the need to reserve available iron for the most critical functions. Also repressed in the
fur
mutant, but independently of iron, were genes located in the
V. cholerae
pathogenicity island, encoding the toxin-coregulated pilus (TCP), and genes within the
V. cholerae
mega-integron. The
fur
mutant exhibited very weak autoagglutination, indicating a possible defect in expression or assembly of the TCP, a major virulence factor of
V. cholerae
. Consistent with this observation, the
fur
mutant competed poorly with its wild-type parental strain for colonization of the infant mouse gut.
Novel AttenuatedSalmonella entericaSerovar Choleraesuis Strains as Live Vaccine Candidates Generated by Signature-Tagged Mutagenesis
Authors: Ku Yu-We , McDonough Sean P. , Palaniappan Raghavan U. M. , Chang Chao-Fu , Chang Yung-Fu 
Published: November 2005

ABSTRACTSalmonella entericaserovar Choleraesuis is a host-adapted pathogen that causes swine paratyphoid. Signature-tagged mutagenesis (STM) was used to understand the pathogenicity ofS. entericaserovar Choleraesuis in its natural host and also to develop novel attenuated live vaccine candidates against this disease. A library of 960 signature-tagged mutants ofS. entericaserovar Choleraesuis was constructed and screened for attenuation in pigs. Thirty-three mutants were identified by the STM screening, and these mutants were further screened for attenuation by in vivo and in vitro competitive growth. Of these, 20 mutants targeting the outer membrane, type III secretion, transporter, lipopolysaccharide biosynthesis, and other unknown proteins were confirmed for attenuation. Five highly attenuated mutants (SC2D2 [ssaV], SC4A9 [gifsy-1], SC6F9 [dgoT], SC12B12 [ssaJ], and SC10B1[spiA]) were selected and evaluated for safety and protective efficacy in pigs by comparison with a commercially available vaccine strain. STM-attenuated live vaccine strains SC4A9 (gifsy-1) and SC2D2 (ssaV) were superior to commercially available live vaccine because they provided both safety and a protective immune response against challenge in pigs.
Giardia lamblia
-Induced Changes in Gene Expression in Differentiated Caco-2 Human Intestinal Epithelial Cells
Authors: Roxström-Lindquist Katarina , Ringqvist Emma , Palm Daniel , Svärd Staffan 
Published: November 2005

ABSTRACT

The parasitic protozoan
Giardia lamblia
is a worldwide cause of diarrhea, but the mechanism of disease remains elusive. The parasite colonizes the small intestinal epithelium, known to be a sensor for the presence of enteric pathogens, without invading or causing severe inflammation. In this study we investigated the epithelial cell response to
G. lamblia
. Differentiated Caco-2 cells were infected with
G. lamblia
isolate WB-A11, and the transcriptome of the intestinal cells was analyzed after 1.5, 6, and 18 h of interaction, using oligonucleotide microarrays. A large number of genes displayed changed expression patterns, showing the complexity of the interaction between
G. lamblia
and intestinal cells. A novel chemokine profile (CCL2, CCL20, CXCL1, CXCL2, and CXCL3) was induced that was different from the response induced by enteric pathogens causing intestinal inflammation. Several genes involved in stress regulation changed their expression. These findings indicate that the intestinal epithelium senses the
G. lamblia
infection, and this is important for induction of innate and adaptive immunity. The induced stress response can be important in the pathogenesis.
Interferon-Inducible Protein 10, but Not Monokine Induced by Gamma Interferon, Promotes Protective Type 1 Immunity in MurineKlebsiella pneumoniaePneumonia
Authors: Zeng Xianying , Moore Thomas A. , Newstead Michael W. , Deng Jane C. , Kunkel Steven L. , Luster Andrew D. , Standiford Theodore J. 
Published: November 2005

ABSTRACTCXC chemokines that lack the ELR motif, including interferon-inducible protein 10 [IP-10 (CXCL10)] and monokine induced by gamma interferon (IFN-γ) [MIG (CXCL9)], have been shown to mediate the generation of type 1 immune responses. In this study, we found that intrapulmonary administration of the gram-negative bacteriumKlebsiella pneumoniaeresulted in the local and systemic expression of IP-10, followed sequentially by MIG expression. MIG mRNA expression in the lungs ofKlebsiella-infected mice required the endogenous production of IFN-γ, whereas IP-10 was expressed in both an IFN-γ-dependent and an IFN-γ-independent fashion. Antibody-mediated neutralization of IP-10 resulted in reduced bacterial clearance and decreased survival, whereas bacterial clearance was unaltered in mice treated with anti-MIG antibody. Impaired bacterial clearance in anti-IP-10 antibody-treated mice was associated with significant reductions in the number and/or activational status of NK and NK-T cells, CD4+T cells, and γδ T cells, as well as a reduction in the expression of IFN-γ. Conversely, the transient transgenic expression of murine IP-10 using adenovirus-mediated gene transfer resulted in improved bacterial clearance when IP-10 adenovirus was given concomitant with intrapulmonary bacterial challenge. These results indicate that IP-10 is an important component of innate immunity against extracellular bacterial pathogens of the lung and may represent a candidate molecule for immunotherapy in the setting of severe respiratory tract infection.
Cold Shock Response of the UspA1 Outer Membrane Adhesin of
Moraxella catarrhalis
Authors: Heiniger Nadja , Troller Rolf , Meier Patricia Stutzmann , Aebi Christoph 
Published: November 2005

ABSTRACT

Colonization of the human nasopharynx exposes
Moraxella catarrhalis
, a common cause of otitis media in children and exacerbations of chronic obstructive pulmonary disease in adults, to sudden downshifts in temperature, occurring when the host breathes cold air. We investigated whether in vitro cold shock influences the expressions of the outer membrane adhesins UspA1 and hemagglutinin, which are considered virulence factors, and of an
M. catarrhalis
homolog of
recA
, a housekeeping gene, which in
Escherichia coli
is induced by cold shock. Quantitative real-time reverse transcriptase PCR was used for measuring mRNA copy number. A screening experiment revealed that a cold shock at 26°C maximally induced the copy number of
uspA1
. In comparison with 37°C conditions, a 1-hour cold shock at 26°C increased copy numbers of
uspA1
and
recA
by 2.5-fold (11.2 ± 1.8 versus 4.5 ± 0.8 copies/CFU) and 2.7-fold (0.30 ± 0.10 versus 0.11 ± 0.06), respectively, but did not induce transcription of
hag
. Exposure to 26°C increased surface expression of UspA1, as assessed by fluorescence-activated cell sorter analysis, and resulted in a significant increase in adherence of strain O35E to Chang human conjunctival cells (97.1% ± 2.0% versus 48.3% ± 9.2% at 37°C;
P
= 0.01). Cold shock induction of
uspA1
and
recA
was detected in strains belonging to either phylogenetic subpopulation of
M. catarrhalis
(16S rRNA types 1 and 2/3) and was most pronounced in type 2/3 strains (4- to 25-fold for
uspA1
), which do not express detectable amounts of UspA1 protein at 37°C. These data indicate that cold shock at a physiologically relevant temperature of 26°C induces the expression of at least one virulence factor (UspA1). To our knowledge, no similar data are available for other nasopharyngeal pathogens.
Plant-Based Vaccine: Mice Immunized with Chloroplast-Derived Anthrax Protective Antigen Survive Anthrax Lethal Toxin Challenge
Authors: Koya Vijay , Moayeri Mahtab , Leppla Stephen H. , Daniell Henry 
Published: November 2005

ABSTRACT

The currently available human vaccine for anthrax, derived from the culture supernatant of
Bacillus anthracis
, contains the protective antigen (PA) and traces of the lethal and edema factors, which may contribute to adverse side effects associated with this vaccine. Therefore, an effective expression system that can provide a clean, safe, and efficacious vaccine is required. In an effort to produce anthrax vaccine in large quantities and free of extraneous bacterial contaminants, PA was expressed in transgenic tobacco chloroplasts by inserting the
pagA
gene into the chloroplast genome. Chloroplast integration of the
pagA
gene was confirmed by PCR and Southern analysis. Mature leaves grown under continuous illumination contained PA as up to 14.2% of the total soluble protein. Cytotoxicity measurements in macrophage lysis assays showed that chloroplast-derived PA was equal in potency to PA produced in
B. anthracis
. Subcutaneous immunization of mice with partially purified chloroplast-derived or
B. anthracis
-derived PA with adjuvant yielded immunoglobulin G titers up to 1:320,000, and both groups of mice survived (100%) challenge with lethal doses of toxin. An average yield of about 150 mg of PA per plant should produce 360 million doses of a purified vaccine free of bacterial toxins edema factor and lethal factor from 1 acre of land. Such high expression levels without using fermenters and the immunoprotection offered by the chloroplast-derived PA should facilitate development of a cleaner and safer anthrax vaccine at a lower production cost. These results demonstrate the immunogenic and immunoprotective properties of plant-derived anthrax vaccine antigen.