bluuebunny/crossref_metadata_2025_split huggingface dataset:
RecombinantMycobacterium bovisBCG Expressing Pertussis Toxin Subunit S1 Induces Protection against an Intracerebral Challenge with LiveBordetella pertussisin Mice
Authors: Nascimento Ivan P. , Dias Waldely O. , Mazzantini Rogerio P. , Miyaji Eliane N. , Gamberini Marcia , Quintilio Wagner , Gebara Vera C. , Cardoso Diva F. , Ho Paulo L. , Raw Isaias , Winter Nathalie , Gicquel Brigitte , Rappuoli Rino , Leite Luciana C. C. 
Published: July 2002

ABSTRACTThe recent development of acellular pertussis vaccines has been a significant improvement in the conventional whole-cell diphtheria-pertussis-tetanus toxoid vaccines, but high production costs will limit its widespread use in developing countries. SinceMycobacterium bovisBCG vaccination against tuberculosis is used in most developing countries, a recombinant BCG-pertussis vaccine could be a more viable alternative. We have constructed recombinant BCG (rBCG) strains expressing the genetically detoxified S1 subunit of pertussis toxin 9K/129G (S1PT) in fusion with either the β-lactamase signal sequence or the whole β-lactamase protein, under control of the upregulatedM. fortuitumβ-lactamase promoter, pBlaF*. Expression levels were higher in the fusion with the whole β-lactamase protein, and both were localized to the mycobacterial cell wall. The expression vectors were relatively stable in vivo, since at two months 85% of the BCG recovered from the spleens of vaccinated mice maintained kanamycin resistance. Spleen cells from rBCG-S1PT-vaccinated mice showed elevated gamma interferon (IFN-γ) and low interleukin-4 (IL-4) production, as well as increased proliferation, upon pertussis toxin (PT) stimulation, characterizing a strong antigen-specific Th1-dominant cellular response. The rBCG-S1PT strains induced a low humoral response against PT after 2 months. Mice immunized with rBCG-S1PT strains displayed high-level protection against an intracerebral challenge with liveBordetella pertussis, which correlated with the induction of a PT-specific cellular immune response, reinforcing the importance of cell-mediated immunity in the protection againstB. pertussisinfection. Our results suggest that rBCG-expressing pertussis antigens could constitute an effective, low-cost combined vaccine against tuberculosis and pertussis.
Infection of Fetal Feline Brain Cells in Culture withBartonella henselae
Authors: Muñana Karen R. , Vitek Susanne M. , Hegarty Barbara C. , Kordick Dorsey L. , Breitschwerdt Edward B. 
Published: July 2002

ABSTRACTBartonella henselaeis known to cause central nervous system (CNS) disease in humans, and neurological signs have been observed in experimentally infected cats. However, the pathogenesis of CNS disease remains unclear. This study was undertaken to determine whetherB. henselaeinfects feline fetal brain cells in vitro. Microglial-cell- and astrocyte-enriched cultures were inoculated withB. henselae. Giménez staining identified bacterial organisms within microglial cells by day 7 postinoculation. The viability of the intracellular bacteria was demonstrated by incubating cultures with gentamicin and plating cell lysate on agar. Electron microscopy identified intracellular organisms with characteristicBartonellamorphology but identified no ultrastructural abnormalities within infected microglial cells. No evidence of infection was seen inBartonella-inoculated astrocyte cultures. These findings suggest a role for microglia in the pathogenesis ofB. henselae-associated neurological disease.
Identification of Protective Epitopes by Sequencing of the Major Outer Membrane Protein Gene of a Variant Strain ofChlamydia psittaciSerotype 1 (Chlamydophila abortus)
Authors: Vretou Evangelia , Psarrou Evgenia , Kaisar Maria , Vlisidou Isabella , Salti-Montesanto Viviane , Longbottom David 
Published: July 2002

ABSTRACTProtective monoclonal antibodies (MAbs) to the major outer membrane protein (MOMP) of species of the familyChlamydiaceae, which is the primary vaccine candidate antigen, recognize nonlinear epitopes conferred by the oligomeric conformation of the molecule. Protective MAbs failed to recognize oligomeric MOMP of the variant strain LLG, which bears amino acid substitutions in variable segments (VSs) 1, 2, and 4, and competed with monomer-specific MAbs mapping to these VSs in reference strain 577. The results suggest that multiple sites located in the three VSs contribute to the epitope of protective MAbs.
DNA Immunization withTrypanosoma cruziHSP70 Fused to the KMP11 Protein Elicits a Cytotoxic and Humoral Immune Response against the Antigen and Leads to Protection
Authors: Planelles Lourdes , Thomas M. Carmen , Alonso Carlos , López Manuel C. 
Published: July 2002

ABSTRACTMurine immunization withTrypanosoma cruzi KMP11-HSP70fused genes but not theKMP11gene alone elicited both an immunoglobulin G2a long-lasting humoral immune response against KMP11 protein and activation of CD8+cytotoxic T lymphocytes specific for two KMP11 peptides containing A2 motifs. Moreover, protection against the parasite challenge was observed after immunization with the chimeric gene.
Identification of a Group 1-Like Capsular Polysaccharide Operon for
Vibrio vulnificus
Authors: Wright Anita C. , Powell Jan L. , Kaper James B. , Morris J. Glenn 
Published: July 2002

ABSTRACT

Virulence of
Vibrio vulnificus
correlates with changes in colony morphology that are indicative of a reversible phase variation for expression of capsular polysaccharide (CPS). Encapsulated variants are virulent with opaque colonies, whereas phase variants with reduced CPS expression are attenuated and are translucent. Using Tn
phoA
mutagenesis, we identified a
V
.
vulnificus
CPS locus, which included an upstream
ops
element, a
wza
gene (
wza
Vv
), and several open reading frames with homology to CPS biosynthetic genes. This genetic organization is characteristic of group 1 CPS operons. The
wza
gene product is required for transport of CPS to the cell surface in
Escherichia coli
. Polar transposon mutations in
wza
Vv
eliminated expression of downstream biosynthetic genes, confirming operon structure. On the other hand, nonpolar inactivation of
wza
Vv
was specific for CPS transport, did not alter CPS biosynthesis, and could be complemented in
trans
. Southern analysis of CPS phase variants revealed deletions or rearrangements at this locus. A survey of environmental isolates indicated a correlation between deletions in
wza
Vv
and loss of virulent phenotype, suggesting a genetic mechanism for CPS phase variation. Full virulence in mice required surface expression of CPS and supported the essential role of capsule in the pathogenesis of
V
.
vulnificus
.
Reciprocal Protective Immunity againstBordetella pertussisandBordetella parapertussisin a Murine Model of Respiratory Infection
Authors: Watanabe Mineo , Nagai Masaaki 
Published: July 2002

ABSTRACTThe protective immunity induced by infection withBordetella pertussisand withBordetella parapertussiswas examined in a murine model of respiratory infection. Convalescent mice that had been infected by aerosol withB. pertussisor withB. parapertussisexhibited a protective immune response againstB. pertussisand also againstB. parapertussis. Anti-filamentous hemagglutinin (anti-FHA) serum immunoglobulin G (IgG) and anti-FHA lung IgA antibodies were detected in both mice infected withB. pertussisand those infected withB. parapertussis. Antibodies against pertussis toxin (anti-PT) and against killedB. pertussiscells were detected in mice infected withB. pertussis. Pertactin-specific antibodies and antibodies against killedB. parapertussiscells were detected in mice infected withB. parapertussis. Spleen cells from mice infected withB. pertussissecreted interferon-γ (IFN-γ) in response to stimulation by FHA or PT. Spleen cells from mice infected withB. parapertussisalso secreted IFN-γ in response to FHA. Interleukin-4 was not produced in response to any of the antigens tested. The profiles of cytokine secretion in vitro revealed induction of a Th1-biased immune response during convalescence from infection byB. pertussisand byB. parapertussis. It is possible that Th1 and Th2 responses against FHA might be related to the reciprocal protection achieved in our murine model.
Exaggerated Proinflammatory and Th1 Responses in the Absence of γ/δ T Cells after Infection withListeria monocytogenes
Authors: Skeen Marianne J. , Rix Emily P. , Freeman Molly M. , Ziegler H. Kirk 
Published: July 2002

ABSTRACTWhile γ/δ T cells are involved in host defense and immunopathology in a variety of infectious diseases, their precise role is not yet clearly defined. In the absence of γ/δ T cells, mice die after infection with a dose ofListeriamonocytogenesthat is not lethal in immunologically intact animals. Morbidity might result from insufficient levels of cytokines normally produced by γ/δ T cells or conversely from an excess of cytokines due to a lack of down-regulation of the inflammatory response in the absence of γ/δ T cells. Consistent with a regulatory role, we found that systemic levels of proinflammatory cytokines (interleukin-6 [IL-6], IL-12, and gamma interferon [IFN-γ]) were significantly higher in the absence of γ/δ T cells during the innate phase of the response. Using combinations of genetically altered and immunodepleted mice, we found evidence for γ/δ T-cell-mediated regulation of IFN-γ production by multiple cell types of both lymphoid and myeloid lineages. The antigen-specific α/β T-cell response that followed the exaggerated innate response was also increased in γ/δ T-cell-deficient mice. These findings are consistent with an emerging picture from a variety of immune response models of a critical role for γ/δ T cells in down-modulation of the immune response.
Interleukin-12- and Gamma Interferon-Dependent Protection against Malaria Conferred by CpG Oligodeoxynucleotide in Mice
Authors: Gramzinski Robert A. , Doolan Denise L. , Sedegah Martha , Davis Heather L. , Krieg Arthur M. , Hoffman Stephen L. 
Published: July 2002

ABSTRACTUnmethylated CpG dinucleotides in bacterial DNA or synthetic oligodeoxynucleotides (ODNs) cause B-cell proliferation and immunoglobulin secretion, monocyte cytokine secretion, and activation of natural killer (NK) cell lytic activity and gamma interferon (IFN-γ) secretion in vivo and in vitro. The potent Th1-like immune activation by CpG ODNs suggests a possible utility for enhancing innate immunity against infectious pathogens. We therefore investigated whether the innate immune response could protect against malaria. Treatment of mice with CpG ODN 1826 (TCCATGACGTTCCTGACGTT, with the CpG dinucleotides underlined) or 1585 (ggGGTCAACGTTGAgggggG, with g representing diester linkages and phosphorothioate linkages being to the right of lowercase letters) in the absence of antigen 1 to 2 days prior to challenge withPlasmodium yoeliisporozoites conferred sterile protection against infection. A higher level of protection was consistently induced by CpG ODN 1826 compared with CpG ODN 1585. The protective effects of both CpG ODNs were dependent on interleukin-12, as well as IFN-γ. Moreover, CD8+T cells (but not CD4+T cells), NK cells, and nitric oxide were implicated in the CpG ODN 1585-induced protection. These data establish that the protective mechanism induced by administration of CpG ODN 1585 in the absence of parasite antigen is similar in nature to the mechanism induced by immunization with radiation-attenuatedP. yoeliisporozoites or with plasmid DNA encoding preerythrocytic-stageP. yoeliiantigens. We were unable to confirm whether CD8+T cells, NK cells, or nitric oxide were required for the CpG ODN 1826-induced protection, but this may reflect differences in the potency of the ODNs rather than a real difference in the mechanism of action of the two ODNs. This is the first report that stimulation of the innate immune system by CpG immunostimulatory motifs can confer sterile protection against malaria.
Experimental Model of Human Body Louse Infection Using Green Fluorescent Protein-Expressing
Bartonella quintana
Authors: Fournier Pierre-Edouard , Minnick Michael F. , Lepidi Hubert , Salvo Eric , Raoult Didier 
Published: July 2002

ABSTRACT

A laboratory colony of human body lice was experimentally infected by feeding on rabbits made artificially bacteremic with a green fluorescent protein-expressing
Bartonella quintana. B. quintana
was detected in the gut and feces until death but not in the eggs. The life span of the lice was not modified. The rabbit model should provide valuable clues to the role of lice in the transmission of
B. quintana
.
Antibody against Surface-Bound C5a Peptidase Is Opsonic and Initiates Macrophage Killing of Group B Streptococci
Authors: Cheng Qi , Carlson Brian , Pillai Sub , Eby Ron , Edwards Lorri , Olmsted Stephen B. , Cleary Patrick 
Published: July 2002

ABSTRACTThe capsular polysaccharides of group B streptococci (GBS) are a primary focus of vaccine development. Immunogenicity and long-lasting protection are best achieved by conjugating polysaccharides to a T-cell-dependent protein antigen. Streptococcal C5a peptidase (SCPB) is a conserved surface protein that is expressed by all streptococcal serotypes tested to date, and it is a possible carrier protein that could itself induce a protective immune response. Clearance of GBS from lungs, mucosal surfaces, or blood probably depends on the opsonophagocytic response of tissue-specific macrophages and polymorphonuclear leukocytes (PMNs). In this study, we examined the potential of antibody directed against SCPB from a serotype II strain to enhance the capacity of mouse bone marrow macrophages (from primary cultures) and human PMNs in whole blood to kill GBS in vitro. Our experiments demonstrated thatStreptococcusserotypes Ia, Ib, II, III, and V, preopsonized with anti-SCPB antibody, were killed more rapidly by cultured macrophages and PMNs in whole blood than were nonopsonized GBS. The increased rate of killing was accompanied by an increased macrophage oxidative burst. Furthermore, opsonization was serotype transparent. Immunization with SCPB conjugated to capsular polysaccharide type III produced polysaccharide-specific antibodies. It is interesting that this antiserum promoted serotype-independent killing of streptococci. These data support the use of SCPB in a GBS polysaccharide conjugate vaccine. SCPB not only enhanced the immunogenicity of polysaccharide components of the vaccine, but it might also induce additional serotype-independent protective antibodies.
Stimulation of Dendritic Cells via CD40 Enhances Immune Responses toMycobacterium tuberculosisInfection
Authors: Demangel Caroline , Palendira Umaimainthan , Feng Carl G. , Heath Andrew W. , Bean Andrew G. D. , Britton Warwick J. 
Published: July 2002

ABSTRACTThe resolution of pulmonary tuberculosis (TB) critically depends on the development of the Th1 type of immune responses, as exemplified by the exacerbation of TB in IL-12-deficient mice. Therefore, vaccination strategies optimizing IL-12 production by antigen-presenting cells (APC) in response to mycobacteria may have enhanced protective efficacy. Since dendritic cells (DC) are the critical APC for activation of CD4+and CD8+T cells, we examined whether stimulation ofMycobacterium bovisbacillus Calmette Guérin (BCG)-infected DC via CD40 increased their ability to generate Th1-oriented cellular immune responses. Incubation of DC with an agonistic anti-CD40 antibody activated CD40 signaling in DC, as shown by increased expression of major histocompatibility complex class II and costimulatory molecules, mRNA production for proinflammatory cytokines and interleukin 12 (IL-12) p40. This activation pattern was maintained when DC were stimulated with anti-CD40 antibody and infected with BCG. Importantly, CD40-stimulated BCG-infected DC displayed increased capacity to release bioactive IL-12 and to activate gamma interferon (IFN-γ) producing T cells in vitro. Moreover, when C57BL/6 mice were immunized with these DC and challenged with aerosolMycobacterium tuberculosis, increased levels of mRNA for IL-12 p40, IL-18, and IFN-γ were present in the draining mediastinal lymph nodes. However, the mycobacterial burden in the lungs was not reduced compared to that in mice immunized with BCG-infected non-CD40-stimulated DC. Therefore, although the manipulation of DC via CD40 is effective for enhancing immune responses to mycobacteria in vivo, additional strategies are required to increase protection against virulentM. tuberculosisinfection.
Whole-Cell but Not Acellular Pertussis Vaccines Induce Convulsive Activity in Mice: Evidence of a Role for Toxin-Induced Interleukin-1β in a New Murine Model for Analysis of Neuronal Side Effects of Vaccination
Authors: Donnelly Sheila , Loscher Christine E. , Lynch Marina A. , Mills Kingston H. G. 
Published: July 2002

ABSTRACTImmunization with the whole-cell pertussis vaccine (Pw), while effective at preventing whooping cough in infants, has been associated with local, systemic, and neuronal reactions, including fevers and convulsions in children. In contrast, the new acellular pertussis vaccines (Pa) have a considerably improved safety profile. The lack of an appropriate animal model has restricted investigations into the mechanisms by which neurological reactions are induced by vaccination. Here we describe a novel murine model wherein seizure-like behavioral changes are induced following parenteral administration of Pw. The proinflammatory cytokine interleukin-β (IL-1β), production of which has been associated with many neurodegenerative conditions, was significantly increased in the hippocampus and hypothalamus of vaccinated animals. Accompanying this change was a decrease in release of the inhibitory neurotransmitters γ-aminobutyric acid and adenosine in the hippocampus. Seizure-like behavioral changes were significantly reduced following inhibition of IL-1β production by the administration of an inhibitor of IL-1β-converting enzyme and were almost completely abrogated in IL-1 receptor type I knockout mice. These results suggest a causal relationship between IL-1β induction and convulsive behavior following Pw vaccination. Significantly, Pa neither increased IL-1β nor induced behavioral changes in mice, but did induce the anti-inflammatory cytokine IL-10. In contrast, administration of active pertussis toxin and lipopolysaccharide, residual in Pw but absent from Pa, also induced convulsive activity. Our findings provide the first direct evidence of an immunological basis for pertussis vaccine reactogenicity and suggest that active bacterial toxins are responsible for the neurologic disturbances observed in children immunized with Pw.
Cloning, Expression, and Characterization of a Neuraminidase Gene fromArcanobacterium pyogenes
Authors: Jost B. H. , Songer J. G. , Billington S. J. 
Published: July 2002

ABSTRACTArcanobacterium pyogenesis an opportunistic pathogen, associated with suppurative infections in domestic animals. In addition to pyolysin, a pore-forming, cholesterol-binding toxin,A. pyogenesexpresses a number of putative virulence factors, including several proteases and neuraminidase activity. A 3,009-bp gene,nanH, was cloned and sequenced and conferred neuraminidase activity on anEscherichia colihost strain. The predicted 107-kDa NanH protein displayed similarity to a number of bacterial neuraminidases and contained the RIP/RLP motif and five copies of the Asp box motif found in all bacterial neuraminidases. Recombinant His-tagged NanH was found to have pH and temperature optima of 5.5 to 6.0 and 55°C, respectively. Insertional deletion of thenanHgene resulted in the reduction, but not absence, of neuraminidase activity, indicating the presence of a second neuraminidase gene inA. pyogenes. NanH was localized to theA. pyogenescell wall.A. pyogenesadhered to HeLa, CHO, and MDBK cells in a washing-resistant manner. However, thenanHmutant was not defective for adherence to epithelial cells. The role of NanH in host epithelial cell adherence may be masked by the presence of a second neuraminidase inA. pyogenes.
Expression ofAnaplasma marginaleMajor Surface Protein 2 Variants in Persistently Infected Ticks
Authors: de la Fuente José , Kocan Katherine M. 
Published: July 2002

ABSTRACTAnaplasma marginale, an intraerythrocytic ehrlichial pathogen of cattle, establishes persistent infections in both vertebrate (cattle) and invertebrate (tick) hosts. The ability ofA. marginaleto persist in cattle has been shown to be due, in part, to major surface protein 2 (MSP2) variants which are hypothesized to emerge in response to the bovine immune response. MSP2 antigenic variation has not been studied in persistently infected ticks. In this study we analyzed MSP2 inA. marginalepopulations from the salivary glands of maleDermacentor variabilispersistently infected withA. marginaleafter feeding successively on one susceptible bovine and three sheep. New MSP2 variants appeared in eachA. marginalepopulation, and sequence alignment of the MSP2 variants revealed multiple amino acid substitutions, insertions, and deletions. These results suggest that selection pressure on MSP2 occurred in tick salivary glands independent of the bovine immune response.
Evidence for the Emergence of Non-O1 and Non-O139
Vibrio cholerae
Strains with Pathogenic Potential by Exchange of O-Antigen Biosynthesis Regions
Authors: Li Manrong , Shimada Toshio , Morris J. Glenn , Sulakvelidze Alexander , Sozhamannan Shanmuga 
Published: July 2002

ABSTRACT

The novel epidemic strain
Vibrio cholerae
O139 Bengal originated from a seventh-pandemic O1 El Tor strain by antigenic shift resulting from homologous recombination-mediated exchange of O-antigen biosynthesis (
wb*
) clusters. Conservation of the genetic organization of
wb*
regions seen in other serogroups raised the possibility of the existence of pathogenic non-O1 and non-O139
V. cholerae
strains that emerged by similar events. To test this hypothesis, 300
V. cholerae
isolates of non-O1 and non-O139 serogroups were screened for the presence of virulence genes and an epidemic genetic background by DNA dot blotting, IS
1004
fingerprinting, and restriction fragment length polymorphism (RFLP) analysis. We found four non-O1 strains (serogroups O27, O37, O53, and O65) with an O1 genetic backbone suggesting exchange of
wb*
clusters. DNA sequence analysis of the O37
wb*
region revealed that a novel ∼23.4-kb gene cluster had replaced all but the ∼4.2-kb right junction of the 22-kb O1
wbe
region. In sharp contrast to the backbones, the virulence regions of the four strains were quite heterogeneous; the O53 and O65 strains had the El Tor vibrio pathogenicity island (VPI) cluster, the O37 strain had the classical VPI cluster, and the O27 strain had a novel VPI cluster. Two of the four strains carried CTXφ; the O27 strain possessed a CTXφ with a recently reported immune specificity (
rstR-4
** allele) and a novel
ctxB
allele, and the O37 strain had an El Tor CTXφ (

rstR
ET

allele) and novel
ctxAB
alleles. Although the O53 and O65 strains lacked the
ctxAB
genes, they carried a pre-CTXφ (i.e.,

rstR
cla

). Identification of non-O1 and non-O139 serogroups with pathogenic potential in epidemic genetic backgrounds means that attention should be paid to possible future epidemics caused by these serogroups and to the need for new, rapid vaccine development strategies.