bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two Distinct Antigenic Types of the Polysaccharide Chains of
Helicobacter pylori
Lipopolysaccharides Characterized by Reactivity with Sera from Humans with Natural Infection
Authors: Yokota Shin-Ichi , Amano Ken-Ichi , Shibata Yoshiko , Nakajima Mizuho , Suzuki Miyuki , Hayashi Shunji , Fujii Nobuhiro , Yokochi Takashi 
Published: May 2009

ABSTRACT

We have purified lipopolysaccharides (LPS) from 10
Helicobacter pylori
clinical isolates which were selected on the basis of chemotype and antigenic variation. Data from immunoblotting of the purified LPS with sera from humans with
H. pylori
infection and from absorption of the sera with LPS indicated the presence of two distinct epitopes, termed the highly antigenic and the weakly antigenic epitopes, on the polysaccharide chains. Among 68
H. pylori
clinical isolates, all smooth strains possessed either epitope; the epitopes were each carried by about 50% of the smooth strains. Thus,
H. pylori
strains can be classified into three types on the basis of their antigenicity in humans: those with smooth LPS carrying the highly antigenic epitope, those with smooth LPS carrying the weakly antigenic epitope, and those with rough LPS. Sera from humans with
H. pylori
infection could be grouped into three categories: those containing immunoglobulin G (IgG) antibodies against the highly antigenic epitope, those containing IgG against the weakly antigenic epitope, and those containing both specific IgGs; these groups made up about 50%, less than 10%, and about 40%, respectively, of all infected sera tested. In other words, IgG against the highly antigenic epitope were detected in more than 90% of
H. pylori
-infected individuals with high titers. IgG against the weakly antigenic epitope were detected in about 50% of the sera tested; however, the antibody titers were low. The two human epitopes existed independently from the mimic structures of Lewis antigens, which are known to be an important epitope of
H. pylori
LPS. No significant relationship between the reactivities toward purified LPS of human sera and a panel of anti-Lewis antigen antibodies was found. Moreover, the reactivities of the anti-Lewis antigen antibodies, but not human sera, were sensitive to particular α-
l
-fucosidases. The human epitopes appeared to be located on O-polysaccharide chains containing endo-β-galactosidase-sensitive galactose residues as the backbone. Data from chemical analyses indicated that all LPS commonly contained galactose, glucosamine, glucose, and fucose (except one rough strain) as probable polysaccharide components, together with typical components of inner core and lipid A. We were not able to distinguish between the differences of antigenicity in humans by on the basis of the chemical composition of the LPS.
Contribution of
Escherichia coli
Alpha-Hemolysin to Bacterial Virulence and to Intraperitoneal Alterations in Peritonitis
Authors: May Addison K. , Gleason Thomas G. , Sawyer Robert G. , Pruett Timothy L. 
Published: May 2009

ABSTRACT

Alpha-hemolysin (Hly) is a common exotoxin produced by
Escherichia coli
that enhances virulence in a number of clinical infections. The addition of hemolysin production to laboratory bacterial strains is known to increase the lethality of
E. coli
peritonitis. However, the mechanisms involved have not been determined and the contribution of hemolysin to the alterations in the host intraperitoneal environment and the leukocyte response is not known. Utilizing a rat peritonitis model, we show that wild-type hemolytic
E. coli
strains have a significant competitive advantage over nonhemolytic strains within the peritoneum. To examine the specific contribution of Hly to
E. coli
-induced virulence and alterations within the peritoneum, a mixed peritonitis model of
E. coli
,
Bacteroides fragilis
, and sterile fecal adjuvant was used. Three transformed
E. coli
strains were utilized: one strongly secretes active hemolysin (WAF 270), a second secretes active hemolysin but a reduced amount (WAF 260), and the third does not produce hemolysin (WAF 108). After an equal inoculum of each of the three strains, WAF 270 produced a markedly increased lethality and an increased recovery of both
E. coli
and
B. fragilis
from the host relative to the other strains. Changes in the intraperitoneal pH, degree of erythrocyte lysis, and recruitment and viability of leukocytes within the peritoneum following the induction of peritonitis differed significantly between the strongly hemolytic and nonhemolytic strains. Induction of peritonitis with WAF 270 caused a pronounced decrease in intraperitoneal pH, lysis of most of the intraperitoneal erythrocytes, and a marked decrease in recoverable viable leukocytes compared to WAF 108. Thus, hemolysin production by
E. coli
within the peritoneum may alter not only the host's ability to control the hemolytic strain itself but also other organisms.
Subclinical Chlamydial Infection of the Female Mouse Genital Tract Generates a Potent Protective Immune Response: Implications for Development of Live Attenuated Chlamydial Vaccine Strains
Authors: Su Hua , Messer Ronald , Whitmire William , Hughes Scott , Caldwell Harlan D. 
Published: May 2009

ABSTRACTChlamydia trachomatisis a major cause of sexually transmitted disease (STD) for which a vaccine is needed. CD4+T-helper type 1 (Th1) cell-mediated immunity is an important component of protective immunity against murine chlamydial genital infection. Conventional vaccine approaches have not proven effective in eliciting chlamydial-specific CD4 Th1 immunity at the genital mucosa. Thus, it is possible that the development of a highly efficacious vaccine against genital infection will depend on the generation of a live attenuatedC. trachomatisvaccine. Attenuated strains ofC. trachomatisdo not exist, so their potential utility as vaccines cannot be tested in animal models of infection. We have developed a surrogate model to study the effect of chlamydial attenuation on infection and immunity of the female genital tract by treating mice with a subchlamydiacidal concentration of oxytetracycline following vaginal infection. Compared to untreated control mice, antibiotic-treated mice shed significantly fewer infectious organisms (3 log10) from the cervico-vagina, produced a minimal inflammatory response in urogenital tissue, and did not experience infection-related sequelae. Antibiotic-treated mice generated levels of chlamydia-specific antibody and cell-mediated immunity equivalent to those of control mice. Importantly, antibiotic-treated mice were found to be as immune as control untreated mice when rechallenged vaginally. These findings demonstrate that subclinical chlamydial infection of the murine female genital tract is sufficient to stimulate a potent protective immune response. They also present indirect evidence supporting the possible use of live attenuated chlamydial organisms in the development of vaccines against chlamydial STDs.
Comparative Evaluation of Low-Molecular-Mass Proteins fromMycobacterium tuberculosisIdentifies Members of the ESAT-6 Family as Immunodominant T-Cell Antigens
Authors: Skjøt Rikke Louise Vinther , Oettinger Thomas , Rosenkrands Ida , Ravn Pernille , Brock Inger , Jacobsen Susanne , Andersen Peter 
Published: May 2009

ABSTRACTCulture filtrate fromMycobacterium tuberculosiscontains protective antigens of relevance for the generation of a new antituberculosis vaccine. We have identified two previously uncharacterizedM. tuberculosisproteins (TB7.3 and TB10.4) from the highly active low-mass fraction of culture filtrate. The molecules were characterized, mapped in a two-dimensional electrophoresis reference map of short-term culture filtrate, and compared with another recently identified low-mass protein, CFP10 (F. X. Berthet, P. B. Rasmussen, I. Rosenkrands, P. Andersen, and B. Gicquel. Microbiology 144:3195–3203, 1998), and the well-described ESAT-6 antigen. Genetic analyses demonstrated that TB10.4 as well as CFP10 belongs to the ESAT-6 family of low-mass proteins, whereas TB7.3 is a low-molecular-mass protein outside this family. The proteins were expressed inEscherichia coli, and their immunogenicity was tested in cultures of peripheral blood mononuclear cells from human tuberculosis (TB) patients,Mycobacterium bovisBCG-vaccinated donors, and nonvaccinated donors. The two ESAT-6 family members, TB10.4 and CFP10, were very strongly recognized and induced gamma interferon release at the same level (CFP10) as or at an even higher level (TB10.4) than ESAT-6. The non-ESAT-6 family member, TB7.3, for comparison, was recognized at a much lower level. CFP10 was found to distinguish TB patients from BCG-vaccinated donors and is, together with ESAT-6, an interesting candidate for the diagnosis of TB. The striking immunodominance of antigens within the ESAT-6 family is discussed, and hypotheses are presented to explain this targeting of the immune response during TB infection.
Intracellular and Extracellular Cytokine Production by Human Mixed Mononuclear Cells in Response to Group B Streptococci
Authors: Kwak Daniel J. , Augustine Nancy H. , Borges Wellington G. , Joyner Joanna L. , Green Wayne F. , Hill Harry R. 
Published: May 2009

ABSTRACTGroup B streptococci (GBS) are a major cause of severe infection in newborns, pregnant females, and other immunocompromised hosts. Infection often includes septicemia, shock, pneumonia, and respiratory failure. In previous studies, we have reported that GBS induce marked production of tumor necrosis factor alpha (TNF-α) by human mononuclear cells. The present study was designed to measure the production of TNF-α as well as additional cytokines, including interleukin 1β (IL-1β), IL-6, IL-8, IL-12, and gamma interferon (IFN-γ) but also to determine from what cells and at what time point during incubation with GBS that these cytokines are produced. Mixed mononuclear cells were incubated with heat-killed GBS, media alone, or 1 μg ofEscherichia colilipopolysaccharide (LPS). Brefeldin A was added to each sample prior to staining, which prevented the export of cytokines by the Golgi apparatus. The cells were then stained with the appropriate conjugated antibodies and analyzed by using a flow cytometer. Results indicate that intracellular cytokines appear, in almost all cases, simultaneous to or before secreted proteins are detected. In contrast to the response to LPS, where TNF-α, IL-1β, IL-6, and IL-8 appear almost simultaneously, the human monocyte response to GBS results in the production of TNF-α but delayed appearance of IL-1β, IL-6, and IL-8. The lymphocyte response to GBS was also strikingly different from that to LPS in that both secreted IFN-γ and IL-12 was detected, while LPS failed to induce production of these critical cytokines. This suggests an important role for TNF-α, IFN-γ, and IL-12 in GBS pathogenesis and/or immunity.
Depletion of CD8+T Cells In Vivo Impairs Host Defense of Mice Resistant and Susceptible to Pulmonary Paracoccidioidomycosis
Authors: Cano Luz E. , Singer-Vermes Lúcia M. , Costa Tania A. , Mengel José O. , Xidieh Cynthia F. , Arruda Celina , André Denise C. , Vaz Celidéia A. C. , Burger Eva , Calich Vera L. G. 
Published: May 2009

ABSTRACTUsing a pulmonary model of infection, we demonstrated previously that A/Sn and B10.A mice are, respectively, resistant and susceptible toParacoccidioides brasiliensisinfection. Employing the same experimental model, we examined herein the role of CD8+T cells in the course of paracoccidioidomycosis. Treatment with anti-CD8 monoclonal antibodies caused a selective depletion of pulmonary and splenic CD8+T cells in both mouse strains. The number of pulmonary CD4+T cells and immunoglobulin-positive cells was independent of the number of CD8+T cells. In susceptible mice, the loss of CD8+T cells by in vivo treatment with anti-CD8 monoclonal antibodies impaired the clearance of yeasts from the lungs and increased the fungal dissemination to the liver and spleen. The same treatment in resistant mice increased fungal dissemination to extrapulmonary tissues but did not alter the pulmonary fungal load. Furthermore, CD8+T-cell depletion did not modify delayed-type hypersensitivity reactions of A/Sn mice but increased these reactions in B10.A mice. The production ofP. brasiliensis-specific antibodies by resistant and susceptible mice depleted of CD8+T cells was similar to that of mice given control antibody. Histopathologically, depletion of CD8+T cells did not disorganize the focal granulomatous lesions developed by both mouse strains. These results indicate that CD8+T cells are necessary for optimal clearance of the fungus from tissues of mice infected withP. brasiliensisand demonstrate more prominent protective activity by those cells in the immune responses mounted by susceptible animals.
Interaction of Enteropathogenic or Enterohemorrhagic
Escherichia coli
with HeLa Cells Results in Translocation of Cortactin to the Bacterial Adherence Site
Authors: Cantarelli Vlademir V. , Takahashi Akira , Akeda Yukihiro , Nagayama Kenichi , Honda Takeshi 
Published: May 2009

ABSTRACT

Infection of cultured HeLa epithelial cells with enteropathogenic
Escherichia coli
(EPEC) or enterohemorrhagic
E. coli
(EHEC) O157:H7 results in accumulation of cortactin under the adherent bacteria. Tyrosine phosphorylation of cortactin is not induced following HeLa cell infection with EHEC or EPEC, contrary to what has been reported to occur with
Shigella flexneri.
Plasmodium falciparum
Rosette Formation Is Uncommon in Isolates from Pregnant Women
Authors: Rogerson Stephen J. , Beeson James G. , Mhango Chisale G. , Dzinjalamala Fraction K. , Molyneux Malcolm E. 
Published: May 2009

ABSTRACT

We examined the formation of
Plasmodium falciparum
erythrocyte rosettes using parasite isolates from placental or peripheral blood of pregnant Malawian women and from peripheral blood of children. Five of 23 placental isolates, 23 of 38 maternal peripheral isolates, and 136 of 139 child peripheral isolates formed rosettes. Placental isolates formed fewer rosettes than maternal isolates (range, 0 to 7.5% versus 0 to 33.5%;
P
= 0.002), and both formed fewer rosettes than isolates cultured from children (range, 0 to 56%;
P
< 0.0001). Rosette formation is common in infections of children but uncommon in pregnancy and rarely detected in placental isolates.
High Levels of Inducible Nitric Oxide Synthase mRNA Are Associated with Increased Monocyte Counts in Blood and Have a Beneficial Role inPlasmodium falciparumMalaria
Authors: Chiwakata Collins Batsirai , Hemmer Christoph Josef , Dietrich Manfred 
Published: May 2009

ABSTRACTTo date, there have been conflicting reports concerning the clinical significance of nitric oxide (NO) inPlasmodium falciparummalaria. Some authors have proposed that NO contributes to the development of severe and complicated malaria, while others have argued that NO has a protective role. To investigate these apparently contradictory reports, reverse transcription-coupled PCR was used to study inducible NO synthase (iNOS) in whole-blood RNA samples from patients with severe and complicated malaria or uncomplicated malaria and from healthy donors. This work produced three principal findings. First, samples of patients with severe and complicated malaria were variably positive, with weak to moderate intensity. Markedly higher iNOS RNA levels were observed in samples of patients with uncomplicated malaria than in patients with severe and complicated malaria. Samples of healthy donors were uniformly negative. Second, since we initially demonstrated iNOS expression in whole-blood RNA samples, we extended our investigations to individual blood cells such as monocytes, lymphocytes, neutrophils, and platelets to identify the cellular source of iNOS. We found that iNOS was expressed predominantly in monocytes. Third, retrospective statistical analysis of monocyte counts clearly demonstrated that patients with uncomplicated malaria had higher monocyte counts at the time of presentation than patients with severe and complicated malaria. Taken together, our findings give room to the interpretation that NO may have a beneficial rather than a deleterious role in falciparum malaria.
Archaeosome Vaccine Adjuvants Induce Strong Humoral, Cell-Mediated, and Memory Responses: Comparison to Conventional Liposomes and Alum
Authors: Krishnan Lakshmi , Dicaire Chantal J. , Patel Girishchandra B. , Sprott G. Dennis 
Published: May 2009

ABSTRACTEther glycerolipids extracted from various archaeobacteria were formulated into liposomes (archaeosomes) possessing strong adjuvant properties. Mice of varying genetic backgrounds, immunized by different parenteral routes with bovine serum albumin (BSA) entrapped in archaeosomes (∼200-nm vesicles), demonstrated markedly enhanced serum anti-BSA antibody titers. These titers were often comparable to those achieved with Freund's adjuvant and considerably more than those with alum or conventional liposomes (phosphatidylcholine-phosphatidylglycerol-cholesterol, 1.8:0.2:1.5 molar ratio). Furthermore, antigen-specific immunoglobulin G1 (IgG1), IgG2a, and IgG2b isotype antibodies were all induced. Association of BSA with the lipid vesicles was required for induction of a strong response, and >80% of the protein was internalized within most archaeosome types, suggesting efficient release of antigen in vivo. Encapsulation of ovalbumin and hen egg lysozyme within archaeosomes showed similar immune responses. Antigen-archaeosome immunizations also induced a strong cell-mediated immune response: antigen-dependent proliferation and substantial production of cytokines gamma interferon (Th1) and interleukin-4 (IL-4) (Th2) by spleen cells in vitro. In contrast, conventional liposomes induced little cell-mediated immunity, whereas alum stimulated only an IL-4 response. In contrast to alum and Freund's adjuvant, archaeosomes composed ofThermoplasma acidophilumlipids evoked a dramatic memory antibody response to the encapsulated protein (at ∼300 days) after only two initial immunizations (days 0 and 14). This correlated with increased antigen-specific cell cycling of CD4+T cells: increase in synthetic (S) and mitotic (G2/M) and decrease in resting (G1) phases. Thus, archaeosomes may be potent vaccine carriers capable of facilitating strong primary and memory humoral, and cell-mediated immune responses to the entrapped antigen.
Perturbations in Eosinophil Homeostasis following Treatment of Lymphatic Filariasis
Authors: Gopinath Ramya , Hanna L. E. , Kumaraswami V. , Perumal V. , Kavitha V. , Vijayasekaran V. , Nutman Thomas B. 
Published: May 2009

ABSTRACTTreatment of patients with patentWuchereria bancroftiinfection results in an acute clinical reaction and peripheral eosinophilia. To investigate the dynamics of the eosinophil response, changes in eosinophil activation and degranulation and plasma levels of eosinophil-active chemokines and cytokines were studied in 15 microfilaremic individuals in south India by sequential blood sampling before and after administration of 300 mg of diethylcarbamazine (DEC). Clinical symptoms occurred within 24 h. Plasma interleukin-5 (IL-5) and RANTES levels peaked 1 to 2 days posttreatment, preceding a peak peripheral eosinophil count at day 4. Major basic protein secretion from eosinophils paralleled IL-5 secretion, while levels of eosinophil-derived neurotoxin peaked at day 13 after treatment. Expression of the activation markers HLA-DR and CD25 on eosinophils rose markedly immediately after treatment, while expression of VLA-4 and α4β7 showed an early peak within 24 h and a second peak at day 13. Thus, the posttreatment reactions seen in filarial infections can be divided into an early phase with killing of microfilariae, clinical symptomatology, increases in plasma IL-5 and RANTES levels, and eosinophil activation and degranulation and a later phase with expression of surface integrins on eosinophils, recruitment of eosinophils from the bone marrow to tissues, and clearance of parasite antigen.
X-ray absorption spectroscopy of aqueous solutions in the X-ray energy region from 1800 to 3700 eV
Authors: Jürgensen Astrid 
Published: May 2009

A methodology for the X-ray XANES and EXAFS analyses of aqueous solutions was developed for the Double Crystal Monochromator (DCM) beamline of the Canadian Synchrotron Radiation Facility (CSRF). The technique is based on the implementation of a liquid cell, which is compatible with the standard solid-state sample holding mechanism used at the beamlines of CSRF and the Canadian Light Source (CLS). Aluminized Mylar film with a thickness of 5 μm has been thoroughly investigated for use as a window material for the cell, and found acceptable for the collection of the S, Cl, and K K-edge spectra of ions in aqueous solution, but not for P K-edge or Rb L2,3-edge spectra. Some of the limitations of this methodology, such as diffusion of the solution through the window and the detection limit at low ion concentration, are investigated and discussed.
Matrix effects on mass spectrometric determinations of four pharmaceuticals and personal care products in water, sediments, and biota
Authors: Dussault Ève B. , Balakrishnan Vimal K. , Solomon Keith R. , Sibley Paul K. 
Published: May 2009

Simple analytical methods were developed for the extraction and determination of four pharmaceuticals and personal care products (PPCPs) from water, sediments, and biota. PPCPs were determined using tandem LC–MS in electrospray ionization mode, and interactions with matrix co-eluents were investigated. Extractions of water samples were performed using solid-phase extraction (SPE), sediments were extracted by pressurized liquid extraction (PLE), and biota was extracted by liquid extraction. The selected analytical methods yielded recoveries ≥ 61% in all matrixes. Matrix interactions were investigated throughout the linear range of quantification of each compound, revealing that dissolved salts had relatively minor effects on ionization (between 14% suppression to 12% enhancement), but that sediment and biota extracts caused significant matrix effects (ranging from 56% suppression to 25% enhancement). The direction and magnitude of matrix interactions reflected the physico-chemical properties of each analyte, particularly their pKa. Among the compounds analyzed in electrospray positive mode, carbamazepine was insensitive to matrix interactions, because it is a strong proton acceptor (pKa= 14.0). In contrast, atorvastatin (pKa= 4.5), a weaker proton acceptor, was particularly sensitive to matrix effects. For those compounds analyzed in negative-ion mode, sample alkalinity was found to be important. With a pKaof 10.4, 17α-ethinylestradiol generally exhibited matrix enhancement with increased sample alkalinity. However, the presence of acidic co-eluents contributed to matrix suppression. Lastly, TCS was particularly sensitive to matrix suppression, as its circumneutral pKa(7.9) caused even slight changes in sample pH to considerably impact ionization. We conclude that while different matrixes have clear impacts on ionization of these PPCPs, matrix effects can be quantified and overcome.