bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunogenicity and Protective Immunity Induced by Synthetic Peptides Associated with Putative Immunodominant Regions ofStreptococcus mutansGlucan-Binding Protein B
Authors: Smith Daniel J. , King William F. , Barnes Leigh A. , Peacock Zachary , Taubman Martin A. 
Published: February 2003

ABSTRACTGlucan-binding protein B (GbpB) fromStreptococcus mutanshas been shown to induce protective immunity to dental caries in experimental models. Having recently sequenced thegbpBgene, our objective in this study was to identify immunogenic regions within the GbpB sequence for use in subunit vaccines. Potential regions of immunogenicity were sought by use of a matrix-based algorithm (EpiMatrix) to estimate the binding characteristics of peptides derived from the GbpB sequence by using a database of known major histocompatibility complex class II binding alleles. Screening the entire sequence revealed several peptides with estimated high binding probabilities. Two N-terminal 20-mer peptides (SYI and QGQ) subtending two of these regions were synthesized. A preliminary experiment, in which these peptides were synthesized in the multiple antigenic peptide format and were used to subcutaneously immunize Sprague-Dawley rats twice at a 21-day interval, revealed that the SYI peptide induced a higher percentage of responses to the inciting peptide as well as to intact GbpB, as measured by enzyme-linked immunosorbent assay. The effect of immunization with the SYI peptide construct on the cariogenicity ofS. mutanswas then investigated by immunizing weanling Sprague-Dawley rats twice at a 9-day interval with SYI or with phosphate-buffered saline. All rats were then orally infected withS. mutansstrain SJ. After a 78-day infection period, the SYI-immunized groups had significant reductions in dental caries on both smooth and occlusal surfaces compared with the sham-immunized group. Thus, these experiments indicated that at least one linear sequence, derived from the N-terminal third of GbpB, was sufficiently immunogenic to induce a protective immune response in this experimental rat model for dental caries.
Functional CD40 Expression Induced following Bacterial Infection of Mouse and Human Osteoblasts
Authors: Schrum Laura W. , Marriott Ian , Butler Betsy R. , Thomas Elaine K. , Hudson Michael C. , Bost Kenneth L. 
Published: February 2003

ABSTRACTBacterially induced bone infections often result in significant local inflammatory responses which are coupled with loss of bone. However, the mechanisms necessary for the protective host response, or those responsible for pathogen-induced bone loss, are not clear. Recent evidence demonstrates that bacterially infected osteoblasts secrete chemokines and cytokines, suggesting that these cells may have an unappreciated role in supporting localized inflammation. In this study, mouse and human osteoblasts were investigated for their ability to express functional CD40 upon exposure to two important pathogens of bone,Staphylococcus aureusandSalmonella entericaserovar Dublin. Bacterial infection of cultured mouse or human osteoblasts resulted in increased CD40 mRNA and CD40 protein expression induced by either pathogen. Importantly, CD40 expression by osteoblasts was functional, as assessed by ligation of this molecule with recombinant, soluble CD154. CD40 activity was assessed by induction of interleukin-6 and granulocyte-macrophage colony-stimulating factor in osteoblasts following ligation. Cocultures of activated CD4+T lymphocytes and osteoblasts could interact via CD40 and CD154, since an antibody against CD40 could block macrophage inflammatory protein-1α secretion. Taken together, these studies conclusively demonstrate that infected osteoblasts can upregulate expression of functional CD40 molecules which mediate cytokine secretion. This surprising result further supports the notion that bone-forming osteoblasts can directly interact with CD154-expressing cells (i.e., T lymphocytes) and can contribute to the host response during bone infection.
Analysis of the Role ofBphs/Hrh1in the Genetic Control of Responsiveness to Pertussis Toxin
Authors: Gao Jian Feng , Call Stanford B. , Fillmore Parley D. , Watanabe Takeshi , Meeker Nathan D. , Teuscher Cory 
Published: February 2003

ABSTRACTIn vivo intoxication withBordetella pertussistoxin (PTX) elicits a variety of physiological responses including a marked leukocytosis, disruption of glucose regulation, adjuvant activity, alterations in vascular function, hypersensitivity to vasoactive agents, and death. We recently identifiedBphs, the locus controlling PTX-induced hypersensitivity to the vasoactive amine histamine, as the histamine H1receptor (Hrh1). In this studyBphscongenic mice and mice with a disruptedHrh1gene were used to examine the role ofBphs/Hrh1in the genetic control of susceptibility to a number of phenotypes elicited following in vivo intoxication. We report that the contribution ofBphs/Hrh1to the overall genetic control of responsiveness to PTX is restricted to susceptibility to histamine hypersensitivity and enhancement of antigen-specific delayed-type hypersensitivity responses. Furthermore, the genetic contribution ofBphs/Hrh1to vasoactive amine sensitization is specific for histamine, since hypersensitivity to serotonin was unaffected byBphs/Hrh1. Bphs/Hrh1also did not significantly influence susceptibility to the lethal effects, the leukocytosis response, disruption of glucose regulation, and histamine-independent increases in vascular permeability associated with in vivo intoxication. Nevertheless, significant interstrain differences in susceptibility to the lethal effects of PTX and leukocytosis response were observed. These results indicate that the phenotypic variation in responsiveness to PTX reflects the genetic control of distinct intermediate phenotypes rather than allelic variation in genes controlling overall susceptibility to intoxication.
Human Immune Response to Outer Membrane Protein CD of
Moraxella catarrhalis
in Adults with Chronic Obstructive Pulmonary Disease
Authors: Murphy Timothy F. , Kirkham Charmaine , Liu Dai-Fang , Sethi Sanjay 
Published: February 2003

ABSTRACT

Moraxella catarrhalis
is a common cause of lower respiratory tract infection in adults with chronic obstructive pulmonary disease (COPD). The antibody response to outer membrane protein (OMP) CD, a highly conserved surface protein of
M. catarrhalis
under consideration as a vaccine antigen, was studied in adults with COPD following 40 episodes of infection or colonization. Following infection or colonization, 9 of 40 patients developed new serum immunoglobulin G (IgG) to OMP CD, as measured by enzyme-linked immunosorbent assay. Adsorption assays revealed that a proportion of the serum IgG was directed toward surface-exposed epitopes on OMP CD in six of the nine patients who developed new IgG to OMP CD. Immunoblot assays with fusion peptide constructs indicated that the new antibodies that developed after infection or colonization recognized conformational epitopes, particularly in the carboxy region of the protein. Three of 28 patients developed new mucosal IgA to OMP CD in sputum supernatants. This study establishes that OMP CD is a target of a systemic and mucosal immune response following infection and colonization in some patients with COPD.
Complement Activation InfluencesStaphylococcus aureusAdherence to Endothelial Cells
Authors: Cunnion K. M. , Frank M. M. 
Published: February 2003

ABSTRACTThe ability ofStaphylococcus aureusto adhere to endothelial cells (EC) is a critical step in the development of metastatic infection. The role of complement inS. aureusbinding to EC remains uninvestigated. Log-phaseS. aureus, expressing minimal capsule, was incubated with serum under various conditions, washed, and then incubated at 37°C for 30 min with cultured human umbilical vein EC (ATCC CRL-1730). Adherence was scored visually after staining with acridine orange. Incubation in 10% heat-inactivated human serum increased adherence to endothelial cells by 488% compared to organisms incubated in buffer. IncubatingS. aureusin complement-active normal human serum (NHS) decreased binding to EC by 58% compared to organisms incubated in heat-inactivated serum. The importance of active complement was confirmed by experiments using serum with added EDTA or cobra venom factor, a protein that depletes C3. The expression of capsule byS. aureusstrongly interfered with adherence. It has been shown that an important protein forS. aureusadhesion to EC is fibronectin.S. aureusadherence to purified fibronectin increased by 511% after incubation in heat-inactivated serum, compared to that of organisms incubated in buffer. This decreased by 56% in complement-active serum, suggesting that inhibition ofS. aureusadherence to EC is due, in part, to complement-mediated diminished binding to fibronectin. Interestingly, when EC were exposed toS. aureus-activated serum and then washed, binding byS. aureuswas 234% higher than that of EC exposed to NHS. Thus, complement-activated EC have increasedS. aureusbinding, while complement on the bacterial surface markedly reduces adherence.
ExperimentalPseudomonas aeruginosaKeratitis in Interleukin-10 Gene Knockout Mice
Authors: Cole Nerida , Krockenberger Mark , Stapleton Fiona , Khan Shamila , Hume Emma , Husband Alan J. , Willcox Mark 
Published: February 2003

ABSTRACTPseudomonas aeruginosakeratitis is one of the most destructive diseases of the cornea. The host response to this infection is critical to the outcome. The cytokine interleukin-10 (IL-10) is thought to play an important role in modulating excessive inflammation and antimicrobial defenses. We have found that in IL-10−/−mice there is a significant decrease in bacterial load in corneas at 7 days postchallenge withP. aeruginosa. This decrease was accompanied by a reduction in neutrophil numbers in the cornea and changes in cytokine levels compared to those of wild-type mice. A characteristic increase in neovascularization in the cornea was found in the IL-10−/−mice. This increased angiogenesis correlated with an increased expression of KC, whereas the kinetics of macrophage inflammatory peptide 2 expression correlated with neutrophil numbers. This finding suggests that KC may play a role in corneal angiogenesis. The source of IL-10 in mouse corneas was identified as a subpopulation of infiltrating cells and keratocytes. This study demonstrates that IL-10 plays an important role in regulating the balance of inflammatory mediators duringP. aeruginosainfection of the cornea.
Localized Eosinophil Degranulation Mediates Disease in Tropical Pulmonary Eosinophilia
Authors: O'Bryan Laura , Pinkston Paula , Kumaraswami V. , Vijayan V. , Yenokida Gordon , Rosenberg Helene F. , Crystal Ronald , Ottesen Eric A. , Nutman Thomas B. 
Published: February 2003

ABSTRACTTo explore the mechanisms underlying the eosinophil-mediated inflammation of tropical pulmonary eosinophilia (TPE), bronchoalveolar lavage (BAL) fluid, serum, and supernatants from pulmonary and blood leukocytes (WBC) from patients with acute TPE (n= 6) were compared with those obtained from healthy uninfected individuals (n= 4) and from patients with asthma (n= 4) or elephantiasis (n= 5). Although there were no significant differences in the levels of interleukin-4 (IL-4), IL-5, IL-13, eotaxin, granulocyte-macrophage colony-stimulating factor, RANTES, or eosinophil cationic protein, there was a marked increase in eosinophil-derived neurotoxin (EDN) both systemically and in the lungs of individuals with TPE compared to each of the control groups (P< 0.02). Moreover, there was a compartmentalization of this response, with EDN levels being higher in the BAL fluid than in the serum (P< 0.02). Supernatants from WBC from either whole blood or BAL cells were examined for chemokines, cytokines, eosinophil degranulation products, and arachidonic acid metabolites. Of the many mediators examined—particularly those associated with eosinophil trafficking—only EDN (in BAL fluid and WBC) and MIP-1α (in WBC) levels were higher for TPE patients than for the non-TPE control groups (P< 0.02). These data suggest it is the eosinophilic granular protein EDN, an RNase capable of damaging the lung epithelium, that plays the most important role in the pathogenesis of TPE.
Functional Genomics Approach to the Identification of Virulence Genes Involved in
Edwardsiella tarda
Pathogenesis
Authors: Srinivasa Rao Putanae S. , Lim Tit Meng , Leung Ka Yin 
Published: February 2003

ABSTRACT

Edwardsiella tarda
is an important cause of hemorrhagic septicemia in fish and also of gastro- and extraintestinal infections in humans. Here, we report the identification of 14 virulence genes of pathogenic
E. tarda
that are essential for disseminated infection, via a genome-wide analysis. We screened 490 alkaline phosphatase fusion mutants from a library of 450,000 Tn
phoA
transconjugants derived from strain PPD130/91, using fish as an infection model. Compared to the wild type, 15 mutants showed significant decreases in virulence. Six mutants had insertions in the known virulence-related genes, namely,
fimA
,
gadB
,
katB
,
pstS
,
pstC
, and
ssrB
. Some mutants corresponded to known genes (
astA
,
isor
, and
ompS2
) that had not been previously shown to be involved in pathogenesis, and three had insertions in two novel genes. In vivo infection kinetics experiments confirmed the inability of these attenuated mutants to proliferate and cause fatal infection in fish. Screening for the presence of the above-described virulence genes in six virulent and seven avirulent strains of
E. tarda
indicated that seven of the genes were specific to pathogenic
E. tarda
. The genes identified here may be used to develop vaccines and diagnostic kits as well as for further studying the pathogenesis of
E. tarda
and other pathogenic bacteria.
Two Novel Superantigens Found in Both Group A and Group CStreptococcus
Authors: Proft Thomas , Webb Phillip D. , Handley Vanessa , Fraser John D. 
Published: February 2003

ABSTRACTTwo novel streptococcal superantigen genes (speLSeandspeMSe) were identified from theStreptococcus equigenome database at the Sanger Center. Genotyping of 8S. equiisolates and 40Streptococcus pyogenesisolates resulted in the detection of the orthologous genesspeLandspeMin a restricted number ofS. pyogenesisolates (15 and 5%, respectively). Surprisingly, the novel superantigen genes could not be found in any of the analyzedS. equiisolates. The results suggest that both genes are located on a mobile element that enables gene transfer between individual isolates and between streptococci from different Lancefield groups.S. equipyrogenic exotoxin L (SPE-LSe)/streptococcal pyrogenic exotoxin L (SPE-L) and SPE-MSe/SPE-M are most closely related to SMEZ, SPE-C, SPE-G, and SPE-J, but build a separate branch within this group. Recombinant SPE-L (rSPE-L) and rSPE-M were highly mitogenic for human peripheral blood lymphocytes, with half-maximum responses at 1 and 10 pg/ml, respectively. The results from competitive binding experiments suggest that both proteins bind major histocompatibility complex class II at the β-chain, but not at the α-chain. The most common targets for both toxins were human Vβ1.1 expressing T cells. Seroconversion against SPE-L and SPE-M was observed in healthy blood donors, suggesting that the toxins are expressed in vivo. Interestingly, thespeLgene is highly associated withS. pyogenesM89, a serotype that is linked to acute rheumatic fever in New Zealand.
Primed Peritoneal B Lymphocytes Are Sufficient To Transfer Protection againstBrugia pahangiInfection in Mice
Authors: Paciorkowski Natalia , Shultz Leonard D. , Rajan T. V. 
Published: February 2003

ABSTRACTLymphatic filariasis is a tropical disease caused by the nematode parasitesWuchereria bancroftiandBrugia malayi. Whereas the protective potential of T lymphocytes in filarial infection is well documented, investigation of the role of B lymphocytes in antifilarial immunity has been neglected. In this communication, we examine the role of B lymphocytes in antifilarial immunity, usingBrugia pahangiinfections in the murine peritoneal cavity as a model. We find that B lymphocytes are required for clearance of primary and challenge infections withB. pahangithird-stage larvae (L3). We assessed the protective potential of peritoneal B lymphocytes by adoptive transfer experiments. Primed but not naïve peritoneal B cells from wild-type mice that had been immunized withB. pahangiL3 protected athymic recipients from challenge infection. We evaluated possible mechanisms by which B cells mediate protection. Comparisons of cytokine mRNA expression between B-lymphocyte-deficient and immunocompetent mice followingB. pahangiinfection suggest that B cells are required for the early production of Th2-type cytokines by peritoneal cells. In addition, B-cell-deficient mice demonstrate a defect in inflammatory cell recruitment to the peritoneal cavity followingB. pahangiinfection. The data demonstrate a critical role of B lymphocytes in antifilarial immunity in naïve mice and in the memory response in primed mice.
Attenuated Virulence of a
Burkholderia cepacia
Type III Secretion Mutant in a Murine Model of Infection
Authors: Tomich Mladen , Griffith Adam , Herfst Christine A. , Burns Jane L. , Mohr Christian D. 
Published: February 2003

ABSTRACT

Type III secretion systems are utilized by a number of gram-negative bacterial pathogens to deliver virulence-associated proteins into host cells. Using a PCR-based approach, we identified homologs of type III secretion genes in the gram-negative bacterium
Burkholderia cepacia
, an important pulmonary pathogen in immunocompromised patients and patients with cystic fibrosis. One of the genes, designated
bscN
, encodes a member of a family of ATP-binding proteins believed to generate energy driving virulence protein secretion. Genetic dissection of the regions flanking the
bscN
gene revealed a locus consisting of at least 10 open reading frames, predicted to encode products with significant homology to known type III secretion proteins in other bacteria. A defined null mutation was generated in the
bscN
gene, and the null strain and wild-type parent strain were examined by use of a murine model of
B. cepacia
infection. Quantitative bacteriological analysis of the lungs and spleens of infected C57BL/6 mice revealed that the
bscN
null strain was attenuated in virulence compared to the parent strain, with significantly lower bacterial recovery from the lungs and spleens at 3 days postinfection. Moreover, histopathological changes, including an inflammatory cell infiltrate, were more pronounced in the lungs of mice infected with the wild-type parent strain than in those of mice infected with the isogenic
bscN
mutant. These results implicate type III secretion as an important determinant in the pathogenesis of
B. cepacia
.
Expression of Toll-Like Receptor 2 on Human Schwann Cells: a Mechanism of Nerve Damage in Leprosy
Authors: Oliveira Rosane B. , Ochoa Maria T. , Sieling Peter A. , Rea Thomas H. , Rambukkana Anura , Sarno Euzenir N. , Modlin Robert L. 
Published: February 2003

ABSTRACTNerve damage is a clinical hallmark of leprosy and a major source of patient morbidity. We investigated the possibility that human Schwann cells are susceptible to cell death through the activation of Toll-like receptor 2 (TLR2), a pattern recognition receptor of the innate immune system. TLR2 was detected on the surface of human Schwann cell line ST88-14 and on cultured primary human Schwann cells. Activation of the human Schwann cell line and primary human Schwann cell cultures with a TLR2 agonist, a synthetic lipopeptide comprising the N-terminal portion of the putativeMycobacterium leprae19-kDa lipoprotein, triggered an increase in the number of apoptotic cells. The lipopeptide-induced apoptosis of Schwann cells could be blocked by an anti-TLR2 monoclonal antibody. Schwann cells in skin lesions from leprosy patients were found to express TLR2. It was possible to identify in the lesions Schwann cells that had undergone apoptosis in vivo. The ability ofM. lepraeligands to induce the apoptosis of Schwann cells through TLR2 provides a mechanism by which activation of the innate immune response contributes to nerve injury in leprosy.
Intravenous Mouse Infection Model for Studying the Pathology ofEnterococcus faecalisInfections
Authors: Gentry-Weeks Claudia , Estay Monica , Loui Cindy , Baker Dale 
Published: February 2003

ABSTRACTAn intravenous mouse infection model was used to compare the virulence ofEnterococcus faecalisstrains, to study bacterial localization and organ histopathology, and to examine the effects of Nramp1 and gamma interferon (IFN-γ) on the course of infection. Infection of BALB/c mice with 5 × 108CFU ofE. faecalisJH2-2, MGH-2, 418, DS16C2, or OG1X revealed the following virulence ranking (from highest to lowest): MGH-2, 418, DS16C2, JH2-2, and OG1X. Discernible differences in the number of MGH-2 and JH2-2 bacteria were observed at 7 days (168 h) in the blood (P= 0.037), at 72 h in the liver (P= 0.002), and at 8 h in the spleen (P= 0.036). At these time points, the number of MGH-2 bacteria was higher in the blood and liver while the number of JH2-2 bacteria was higher in the spleen. At 72 h, livers from MGH-2-infected mice had higher numbers of coalescing aggregates of leukocytes and a greater degree of caseous necrosis than those from JH2-2-infected mice. These results indicate a correlation between the virulence of theE. faecalisstrain, the number of bacteria in the liver, and the degree of histopathology of the liver at 72 h postinfection. IFN-γ was important inE. faecalisinfection, since IFN-γ gene knockout mice had reduced mortality and massive coagulative necrosis was observed in wild-type mice. The contribution of Nramp1 was unclear, sinceNramp1−/−mice and the respective control mice were innately resistant toE. faecalis. The mortality of mice in this model is probably due to induction of cytokine release and massive coagulative necrosis.
Role of the NF-κB Signaling Pathway and κBcis-Regulatory Elements on theIRF-1andiNOSPromoter Regions in Mycobacterial Lipoarabinomannan Induction of Nitric Oxide
Authors: Morris Kristin R. , Lutz Ryan D. , Choi Hyung-Seok , Kamitani Tetsu , Chmura Kathryn , Chan Edward D. 
Published: February 2003

ABSTRACTNitric oxide (NO·) produced by inducible nitric oxide synthase (iNOS) is an important host defense molecule againstMycobacterium tuberculosisin mononuclear phagocytes. The objective of this study was to determine the role of the IκBα kinase-nuclear factor κB (IKK-NF-κB) signaling pathway in the induction of iNOS and NO·by a mycobacterial cell wall lipoglycan known as mannose-capped lipoarabinomannan (ManLAM) in mouse macrophages costimulated with gamma interferon (IFN-γ). NF-κB was activated by ManLAM as shown by electrophoretic mobility shift assay, by immunofluorescence of translocated NF-κB in intact cells, and by a reporter gene driven by four NF-κB-binding elements. Transduction of an IκBα mutant (Ser32/36Ala) significantly inhibited NO·expression induced by IFN-γ plus ManLAM. An activated SCF complex, a heterotetramer (Skp1, Cul-1, β-TrCP [F-box protein], and ROC1) involved with ubiquitination, is also required for iNOS-NO·induction. Two NF-κB-binding sites (κBI and κBII) present on the 5′-flanking region of theiNOSpromoter bound ManLAM-induced NF-κB similarly. By use of reporter constructs in which one or both sites are mutated, both NF-κB-binding positions were essential iniNOSinduction by IFN-γ plus ManLAM. IFN-γ-induced activation of the IRF-1 transcriptional complex is a necessary component in host defense against tuberculosis. Although the 5′-flanking region of theIRF-1promoter contains an NF-κB-binding site and ManLAM-induced NF-κB also binds to this site, ManLAM was unable to induce IRF-1 expression. The influence of mitogen-activated protein kinases on IFN-γ plus ManLAM induction of iNOS-NO·is not due to any effects on ManLAM induction of NF-κB.