bluuebunny/crossref_metadata_2025_split huggingface dataset:
CpG Oligodeoxynucleotides and Interleukin-12 Improve the Efficacy ofMycobacterium bovisBCG Vaccination in Mice Challenged withM. tuberculosis
Authors: Freidag Brenda L. , Melton Genevieve B. , Collins Frank , Klinman Dennis M. , Cheever Allen , Stobie Laura , Suen Winnie , Seder Robert A. 
Published: July 2002

ABSTRACTMycobacterium bovisbacillus Calmette-Guérin (BCG) is the only vaccine approved for prevention of tuberculosis. It has been postulated that serial passage of BCG over the years may have resulted in attenuation of its effectiveness. Because interleukin-12 (IL-12) and oligodeoxynucleotides (ODN) containing cytidine phosphate guanosine (CpG) motifs have been shown to enhance Th1 responses in vivo, they were chosen as adjuvants to increase the effectiveness of BCG vaccination. In this report, mice were vaccinated with BCG with or without IL-12 or CpG ODN and then challenged 6 weeks later via the aerosol route with the Erdman strain ofM. tuberculosis. Mice vaccinated with BCG alone showed a 1- to 2-log reduction in bacterial load compared with control mice that did not receive any vaccination prior toM. tuberculosischallenge. Moreover, the bacterial loads of mice vaccinated with BCG plus IL-12 or CpG ODN were a further two- to fivefold lower than those of mice vaccinated with BCG alone. As an immune correlate, the antigen-specific production IFN-γ and mRNA expression in spleen cells prior to challenge were evaluated. Mice vaccinated with BCG plus IL-12 or CpG ODN showed enhanced production of IFN-γ compared with mice vaccinated with BCG alone. Finally, granulomas in BCG-vaccinated mice were smaller and more lymphocyte rich than those in unvaccinated mice; however, the addition of IL-12 or CpG ODN to BCG vaccination did not alter granuloma formation or result in added pulmonary damage. These observations support a role for immune adjuvants given with BCG vaccination to enhance its biologic efficacy.
R1 Region of P97 Mediates Adherence ofMycoplasma hyopneumoniaeto Swine Cilia
Authors: Minion F. Chris , Adams Cary , Hsu Tsungda 
Published: July 2002

ABSTRACTAdherence ofMycoplasma hyopneumoniaeto the swine respiratory tract is mediated by the membrane protein P97. This protein is located on the outer membrane surface, and its role in adherence has been firmly established. The general region of P97 that mediates adherence to swine cilia is thought to be the R1 region near the carboxy terminus of the protein, but it was not clear if this region could mediate adherence to swine cilia independently of other P97 sequences. To examine this in more detail, a series of R1 repeat sequences containing different numbers of repeating units cloned in frame withlacZwas used to produce R1–β-galactosidase fusion proteins. These proteins were then tested for adherence to swine cilia and for reactivity to the adherence-blocking monoclonal antibody F2G5 and convalescent-phase swine sera. In this way it was possible to accurately define the cilium binding epitope of P97 and the minimal epitope recognized by antibody. Our results indicate that eight R1 repeating units are required for cilium binding and that three repeating units are needed for antibody recognition. These results could lead to more effective therapeutic measures against this important swine pathogen.
Interaction of
Listeria monocytogenes
with Human Brain Microvascular Endothelial Cells: an Electron Microscopic Study
Authors: Greiffenberg Lars , Goebel Werner , Kim Kwang Sik , Daniels Justin , Kuhn Michael 
Published: July 2002

ABSTRACT

Internalization of
Listeria monocytogenes
into human brain microvascular endothelial cells (HBMEC) has recently been demonstrated to be dependent upon the
inlB
gene. In the present scanning electron microscopic study we show that
L. monocytogenes
efficiently interacts with the surface of HBMEC in an
inlB
-independent manner which is also different from invasion. The
inlB
-dependent invasion of HBMEC by
L. monocytogenes
is accompanied by intracellular multiplication, movement, and production of bacterium-containing protrusions. These protrusions extend from the cell surface without perturbation of any adjacent cellular membrane.
Characterization of Hemolysin ofMoraxella bovisUsing a Hemolysis-Neutralizing Monoclonal Antibody
Authors: Billson F. Mark , Harbour Colin , Michalski Wojtek P. , Tennent Jan M. , Egerton John R. , Hodgson Jennifer L. 
Published: July 2002

ABSTRACTA concentrated bacterial culture supernatant from the hemolyticMoraxella bovisstrain UQV 148NF was used to immunize mice and generate monoclonal antibodies (MAbs). One, MAb G3/D7, neutralized the hemolytic activity ofM. bovisand recognized a 94-kDa protein by Western blot analysis in hemolyticM. bovisstrains representing each of the different fimbrial serogroups. Exposure of corneal epithelial cells toM. bovisconcentrated culture supernatants demonstrated a role for an exotoxin in the pathogenesis of infectious bovine keratoconjunctivitis, while neutralization of hemolytic and cytotoxic activities by MAb G3/D7 implies that these activities are related or have common epitopes. The action ofM. bovishemolysin was further characterized in sheep erythrocyte preparations with a binding step and Ca2+required for lysis to proceed, similar to the RTX family of bacterial exotoxins. Neutralization of lytic activity in vitro is evidence for the presence ofM. bovisantigens, which may be capable of protecting cattle from the development of infectious bovine keratoconjunctivitis.
Cytocidal and Apoptotic Effects of the ClyA Protein from
Escherichia coli
on Primary and Cultured Monocytes and Macrophages
Authors: Lai Xin-He , Arencibia Ignacio , Johansson Anders , Wai Sun Nyunt , Oscarsson Jan , Kalfas Sotos , Sundqvist Karl-Gösta , Mizunoe Yoshimitsu , Sjöstedt Anders , Uhlin Bernt Eric 
Published: July 2002

ABSTRACT

Cytolysin A (ClyA) is a newly discovered cytolytic protein of
Escherichia coli
K-12 that mediates a hemolytic phenotype. We show here that highly purified ClyA and ClyA-expressing
E. coli
were cytotoxic and apoptogenic to fresh as well as cultured human and murine monocytes/macrophages.
Differential Tumor Necrosis Factor Alpha Expression and Release from Peritoneal Mouse Macrophages In Vitro in Response to Proliferating Gram-Positive versus Gram-Negative Bacteria
Authors: Cui Wei , Morrison David C. , Silverstein Richard 
Published: July 2002

ABSTRACTViableEscherichia coliandStaphylococcus aureusbacteria elicited markedly different in vitro tumor necrosis factor alpha (TNF-α) responses when placed in coculture with peritoneal murine macrophages. These include quantitative differences in TNF-α mRNA expression and corresponding protein product secretion as well as kinetic differences in the profiles of the TNF-α responses. Further, lipopolysaccharide (fromE. coli) is a major contributing factor to these differences, as revealed by comparative experiments with endotoxin-responsive (C3Heb/FeJ) and endotoxin-hyporesponsive (C3H/HeJ) macrophages. Nevertheless, the eventual overall magnitude of the TNF-α secretion of macrophages in response toS. aureuswas at least equivalent to that observed withE. coli, while appearing at time periods hours later than theE. coli-elicited TNF-α response. Both the magnitude and kinetic profile of the TNF-α responses were found to be relatively independent of the rate of bacterial proliferation, at least to the extent that similar results were observed with both viable and paraformaldehyde-killed microbes. Nevertheless,S. aureustreated in culture with the carbapenem antibiotic imipenem manifests markedly altered profiles of TNF-α response, with the appearance of an early TNF-α peak not seen with viable organisms, a finding strikingly similar to that recently reported by our laboratory from in vivo studies (R. Silverstein, J. G. Wood, Q. Xue, M. Norimatsu, D. L. Horn, and D. C. Morrison, Infect. Immun. 68:2301–2308, 2000). In contrast, imipenem treatment ofE. coli-cocultured macrophages does not significantly alter the observed TNF-α response either in vitro or in vivo. In conclusion, our data support the concept that the host inflammatory response of cultured mouse macrophages in response to viable gram-positive versus gram-negative microbes exhibits distinctive characteristics and that these distinctions are, under some conditions, altered on subsequent bacterial killing, depending on the mode of killing. Of potential importance, these distinctive in vitro TNF-α profiles faithfully reflect circulating levels of TNF-α in infected mice. These results suggest that coculture of peritoneal macrophages with viable versus antibiotic-killed bacteria and subsequent assessment of cytokine response (TNF-α) may be of value in clarifying, and ultimately controlling, related host inflammatory responses in septic patients.
Variability of Outer Membrane Protein P1 and Its Evaluation as a Vaccine Candidate against Experimental Otitis Media due to NontypeableHaemophilus influenzae: an Unambiguous, Multifaceted Approach
Authors: Bolduc Gilles R. , Bouchet Valérie , Jiang Ru-Zhang , Geisselsoder Janet , Truong-Bolduc Que Chi , Rice Peter A. , Pelton Stephen I. , Goldstein Richard 
Published: July 2002

ABSTRACTCandidate vaccine antigens for preventing otitis media caused by nontypeableHaemophilus influenzae(NTHI) should possess one or more conserved epitopes. We sought to evaluate the candidacy of P1, a surface-expressed outer membrane protein knowing that this antigen is subject to diversifying selection. Therefore, we selected NTHI strains from among >500 phylogenically variant isolates representative of the diversity found in natural populations ofH. influenzae. Twenty-three variants of P1 (≤95% similarity) were identified among 42 strains. When chinchillas were immunized with recombinant P1 (rP1) obtained from one of these isolates (BCH-3), all animals developed antibodies specific for rP1. Immunized animals were protected against disease when challenged with BCH-3, but not with anompP1mutant of BCH-3 or a strain (BCH-2) possessing a heterologous P1 (91% identity). We conclude that (i) while P1 induces protection against NTHI-mediated otitis media, development of a polyvalent vaccine reflecting the variability of P1 would be necessary to construct an efficacious vaccine and (ii) use of a phylogenically characterized collection of representative isolates in concert with gene sequencing, cloning, gene inactivation, and animal testing offers an efficient, rational, and rigorous strategy for evaluating the potential problems associated with variability of vaccine targets and specificity of related immune responses.
Mediation ofCryptosporidium parvumInfection In Vitro by Mucin-Like Glycoproteins Defined by a Neutralizing Monoclonal Antibody
Authors: Cevallos Ana María , Bhat Najma , Verdon Renaud , Hamer Davidson H. , Stein Barry , Tzipori Saul , Pereira Miercio E. A. , Keusch Gerald T. , Ward Honorine D. 
Published: July 2002

ABSTRACTThe protozoan parasiteCryptosporidium parvumis a significant cause of diarrheal disease worldwide. Attachment to and invasion of host intestinal epithelial cells byC. parvumsporozoites are crucial steps in the pathogenesis of cryptosporidiosis. The molecular basis of these initial interactions is unknown. In order to identify putativeC. parvumadhesion- and invasion-specific proteins, we raised monoclonal antibodies (MAbs) to sporozoites and evaluated them for inhibition of attachment and invasion in vitro. Using this approach, we identified two glycoproteins recognized by 4E9, a MAb which neutralizedC. parvuminfection and inhibited sporozoite attachment to intestinal epithelial cells in vitro. 4E9 recognized a 40-kDa glycoprotein named gp40 and a second, >220-kDa protein which was identified as GP900, a previously described mucin-like glycoprotein. Glycoproteins recognized by 4E9 are localized to the surface and apical region of invasive stages and are shed in trails from the parasite during gliding motility. The epitope recognized by 4E9 contains α-N-acetylgalactosamine residues, which are present in a mucin-type O-glycosidic linkage. Lectins specific for these glycans bind to the surface and apical region of sporozoites and block attachment to host cells. The surface and apical localization of these glycoproteins and the neutralizing effect of the MAb and α-N-acetylgalactosamine-specific lectins strongly implicate these proteins and their glycotopes as playing a role inC. parvum-host cell interactions.
Impaired Control ofBrucella melitensisInfection inRag1-Deficient Mice
Authors: Izadjoo Mina J. , Polotsky Yury , Mense Mark G. , Bhattacharjee Apurba K. , Paranavitana Chrysanthi M. , Hadfield Ted L. , Hoover David L. 
Published: July 2002

ABSTRACTAfter intranasal inoculation,Brucella melitensischronically infects the mononuclear phagocyte system in BALB/c mice, but it causes no apparent illness. Adaptive immunity, which can be transferred by either T cells or antibody from immune to naive animals, confers resistance to challenge infection. The role of innate, non-B-, non-T-cell-mediated immunity in control of murine brucellosis, however, is unknown. In the present study, we documented that BALB/c and C57BL/6 mice had a similar course of infection after intranasal administration of 16M, validating the usefulness of the model in the latter mouse strain. We then compared the course of infection inRag1knockout mice (C57BL/6 background) (referred to here as RAG-1 mice) which have no B or T cells as a consequence of deletion ofRag1(recombination-activating gene 1), with infection in normal C57BL/6 animals after intranasal administration ofB. melitensis16M. C57BL/6 mice cleared brucellae from their lungs by 8 to 12 weeks and controlled infection in the liver and spleen at a low level. In contrast, RAG-1 mice failed to reduce the number of bacteria in any of these organs. From 1 to 4 weeks after inoculation, the number of splenic bacteria increased from 2 to 4.5 logs and remained at that level. In contrast to the consistently high numbers of brucellae observed in the spleens, the number of bacteria rose in the livers sampled for up to 20 weeks. Immunohistologic examination at 8 weeks after infection disclosed foci of persistent pneumonia and large amounts ofBrucellaantigen in macrophages in lung, liver, and spleen in RAG-1, but not C57BL/6, mice. These studies indicate that T- and B-cell-independent immunity can controlBrucellainfection at a high level in the murine spleen, but not in the liver. Immunity mediated by T and/or B cells is required for clearance of bacteria from spleen and lung and for control of bacterial replication in the liver.
New Zealand White Rabbit as a Nonsurgical Experimental Model forSalmonella entericaGastroenteritis
Authors: Hanes D. E. , Robl M. G. , Schneider C. M. , Burr D. H. 
Published: July 2002

ABSTRACTRabbits orally challenged withSalmonella entericadeveloped a dose-dependent diarrheal disease comparable to human salmonellosis. ViableSalmonellaorganisms recovered from the intestine and deep tissues indicate local and systemic infections. Therefore, results show that the rabbit can be used as a model for diarrheal disease and sequelae associated with salmonellosis.
Mouse Cytokine Profiles Associated withBrucella abortusRB51 Vaccination orB. abortus2308 Infection
Authors: Pasquali Paolo , Adone Rosanna , Gasbarre Louis C. , Pistoia Claudia , Ciuchini Franco 
Published: July 2002

ABSTRACTThis study indicated that mice immunized withBrucella abortusRB51 bacteria and subsequently challenged withB. abortus2308 were protected from reinfection. After vaccination, both Th1 and Th2 cytokine patterns were observed. Of those, the early production of gamma interferon seems to have the prominent role in inducing an immunologically based protection.
toxB
Gene on pO157 of Enterohemorrhagic
Escherichia
coli
O157:H7 Is Required for Full Epithelial Cell Adherence Phenotype
Authors: Tatsuno Ichiro , Horie Masanori , Abe Hiroyuki , Miki Takeyoshi , Makino Kozo , Shinagawa Hideo , Taguchi Haruhiko , Kamiya Shigeru , Hayashi Tetsuya , Sasakawa Chihiro 
Published: July 2002

ABSTRACT

Adherence of enterohemorrhagic
Escherichia
coli
(EHEC) to the intestinal epithelium is critical for initiation of a bacterial infection. An in vitro infection study previously indicated that EHEC bacteria initially adhere diffusely and then proliferate to develop MC, a process that is mediated by various secreted proteins, such as EspA, EspB, EspD, Tir, and intimin, as well as other putative adherence factors. In the present study, we investigated the role of a large 93-kb plasmid (pO157) in the adherence of O157:H7 (O157Sakai) and found the
toxB
gene to be involved in the full adherence phenotype. A pO157-cured strain of O157Sakai (O157Cu) developed microcolonies on Caco-2 cells; however, the number of microcolonies was lower than that of O157Sakai, as were the production and secretion levels of EspA, EspB, and Tir. Introduction of a mini-pO157 plasmid (pIC37) composed of the
toxB
and
ori
regions restored full adherence capacity to O157Cu, including production and secretion of the proteins. In contrast, introduction of a pO157 mutant possessing
toxB
::Km into O157Cu could not restore the full adherence phenotype. Expression of truncated versions of His-tagged ToxB also promoted EspB production and/or secretion by O157Cu. These results suggest that ToxB contributes to the adherence of EHEC to epithelial cells through promotion of the production and/or secretion of type III secreted proteins.
Enhanced Antimycobacterial Response to RecombinantMycobacterium bovisBCG Expressing Latency-Associated Peptide
Authors: Marshall Ben G. , Wangoo Arun , O'Gaora Peadar , Cook H. Terry , Shaw Rory J. , Young Douglas B. 
Published: July 2002

ABSTRACTWith a view to exploring the role of transforming growth factor β (TGF-β) during mycobacterial infection, recombinant clones of bacillus Calmette-Guérin (BCG) were engineered to express the natural antagonist of TGF-β, latency-activated peptide (LAP). Induction of TGF-β activity was reduced when macrophages were infected with BCG expressing the LAP construct (LAP-BCG). There was a significant reduction in the growth of LAP-BCG in comparison to that of control BCG following intravenous infection in a mouse model. The enhanced control of mycobacterial replication was associated with an increase in the production of gamma interferon by splenocytes challenged during the acute stage of infection but with a diminished recall response assessed after 13 weeks. Organ weight and hydroxyproline content, representing tissue pathology, were also lower in mice infected with LAP-BCG. The results are consistent with the hypothesis that TGF-β has a detrimental effect on mycobacterial immunity. While a reduction in TGF-β activity augments the initial response to BCG vaccination, early bacterial clearance may adversely affect the induction of a long-term memory response by LAP-BCG.
Staphylococcus aureus
Cap5O Has UDP-ManNAc Dehydrogenase Activity and Is Essential for Capsule Expression
Authors: Portolés Marta , Kiser Kevin B. , Bhasin Navneet , Chan Kenneth H. N. , Lee Jean C. 
Published: July 2002

ABSTRACT

The
Staphylococcus aureus
serotype 5 capsular polysaccharide (CP5) has a repeating unit composed of (→4)-3-
O
-acetyl-β-
d
-ManNAcA-(1→4)-α-
l
-FucNAc (1→3)-β-
d
-FucNAc-(1→)

n

. Sixteen chromosomal genes (
cap5A
through
cap5P
) are involved in the synthesis of CP5. We recently demonstrated that Cap5P, a 2-epimerase, catalyzes the conversion of UDP–
N
-acetyl glucosamine (UDP-GlcNAc) to UDP–
N
-acetylmannosamine (UDP-ManNAc). In this study, we show that UDP-ManNAc is oxidized to UDP–
N
-acetylmannosaminuronic acid (UDP-ManNAcA) by a UDP-ManNAc dehydrogenase encoded by
S. aureus cap5O
. We expressed Cap5O in
Escherichia coli
and purified the recombinant protein. The UDP-ManNAc dehydrogenase activity of purified Cap5O was assessed by incubating Cap5P and UDP-GlcNAc (to produce UDP-ManNAc), together with Cap5O, NAD
+
, and a reducing agent. Enzymatic activity was quantitated indirectly by measuring the increase in absorbance at 340 nm resulting from NADH formation. The product of the reaction was confirmed as UDP-ManNAcA by gas chromatography-mass spectroscopy. A
cap5O
mutation, created by deletion of 727 bp in the 5′ end of the gene, was introduced by allelic replacement into
S. aureus
Reynolds, rendering it CP5 negative. Mice inoculated intravenously or subcutaneously with the wild-type strain Reynolds had greater numbers of
S. aureus
recovered from their kidneys (
P
= 0.019) or their subcutaneous abscesses (
P
= 0.0018), respectively, than did animals inoculated with the
cap5O
mutant. The results of this study indicate that
S. aureus cap5O
is essential for capsule production and that capsule promotes staphylococcal virulence in mouse models of abscess formation.
Molecular Characterization ofStreptococcus pneumoniaeType 4, 6B, 8, and 18C Capsular Polysaccharide Gene Clusters
Authors: Jiang Sheng-Mei , Wang Lei , Reeves Peter R. 
Published: July 2002

ABSTRACTCapsular polysaccharide (CPS) is a major virulence factor inStreptococcus pneumoniae. CPS gene clusters ofS. pneumoniaetypes 4, 6B, 8, and 18C were sequenced and compared with those of CPS types 1, 2, 14, 19F, 19A, 23F, and 33F. All have the same four genes at the 5′ end, encoding proteins thought to be involved in regulation and export. Sequences of these genes can be divided into two classes, and evidence of recombination between them was observed. Next is the gene encoding the transferase for the first step in the synthesis of CPS. The predicted amino acid sequences of these first sugar transferases have multiple transmembrane segments, a feature lacking in other transferases. Sugar pathway genes are located at the 3′ end of the gene cluster. Comparison of the four dTDP-l-rhamnose pathway genes (rmlgenes) of CPS types 1, 2, 6B, 18C, 19F, 19A, and 23F shows that they have the same gene order and are highly conserved. There is a gradient in the nature of the variation ofrmlgenes, the average pairwise difference for those close to the central region being higher than that for those close to the end of the gene cluster and, again, recombination sites can be observed in these genes. This is similar to the situation we observed forrmlgenes of O-antigen gene clusters ofSalmonella enterica. Our data indicate that the conserved first four genes at the 5′ ends and the relatively conservedrmlgenes at the 3′ ends of the CPS gene clusters were sites for recombination events involved in forming new forms of CPS. We have also identifiedwzxandwzygenes for all sequenced CPS gene clusters by use of motifs.
Canine Feces as a Reservoir of Extraintestinal PathogenicEscherichia coli
Authors: Johnson James R. , Stell Adam L. , Delavari Parissa 
Published: July 2002

ABSTRACTTo test the canine reservoir hypothesis of extraintestinal pathogenicEscherichia coli(ExPEC), 63 environmental canine fecal deposits were evaluated for the presence of ExPEC by a combination of selective culturing, extended virulence genotyping, hemagglutination testing, O serotyping, and PCR-based phylotyping. Overall, 30% of canine fecal samples (56% of those that yielded viableE. coli) containedpapG-positiveE. coli, usually as the predominantE. colistrain and always possessingpapGallele III (which encodes variant III of the P-fimbrial adhesin molecule PapG). Multiple other virulence-associated genes typical of human ExPEC were prevalent among the canine fecal isolates. According to serotyping, virulence genotyping, and random amplified polymorphic DNA analysis, over 50% ofpapG-positive fecalE. colicould be directly correlated with specific human clinical isolates from patients with cystitis, pyelonephritis, bacteremia, or meningitis, including archetypal human ExPEC strains 536, CP9, and RS218. Five canine fecal isolates and (clonally related) archetypal human pyelonephritis isolate 536 were found to share a novel allele ofpapA(which encodes the P-fimbrial structural subunit PapA). These data confirm that ExPEC representing known virulent clones are highly prevalent in canine feces, which consequently may provide a reservoir of ExPEC for acquisition by humans.