bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunologic Memory Induced by a Glycoconjugate Vaccine in a Murine Adoptive Lymphocyte Transfer Model
Authors: Guttormsen Hilde-Kari , Wetzler Lee M. , Finberg Robert W. , Kasper Dennis L. 
Published: December 2019

ABSTRACT
We have developed an adoptive cell transfer model in mice to study the ability of a glycoprotein conjugate vaccine to induce immunologic memory for the polysaccharide moiety. We used type III capsular polysaccharide from the clinically relevant pathogen group B streptococci conjugated to tetanus toxoid (GBSIII-TT) as our model vaccine. GBS are a major cause of neonatal infections in humans, and type-specific antibodies to the capsular polysaccharide protect against invasive disease. Adoptive transfer of splenocytes from mice immunized with the GBSIII-TT conjugate vaccine conferred anti-polysaccharide immunologic memory to naive recipient mice. The transfer of memory occurred in a dose-dependent manner. The observed anamnestic immune response was characterized by (i) more rapid kinetics, (ii) isotype switching from immunoglobulin M (IgM) to IgG, and (iii) 10-fold-higher levels of type III-specific IgG antibody than for the primary response in animals with cells transferred from placebo-immunized mice. The adoptive cell transfer model described in this paper can be used for at least two purposes: (i) to evaluate conjugate vaccines with different physicochemical properties for their ability to induce immunologic memory and (ii) to study the cellular interactions required for an immune response to these molecules.
Cloning and Characterization ofCAD1/AAF1, a Gene fromCandida albicansThat Induces Adherence to Endothelial Cells after Expression inSaccharomyces cerevisiae
Authors: Fu Yue , Filler Scott G. , Spellberg Bradley J. , Fonzi William , Ibrahim Ashraf S. , Kanbe Toshio , Ghannoum Mahmoud A. , Edwards John E. 
Published: December 2019

ABSTRACTAdherence to the endothelial cell lining of the vasculature is probably a critical step in the egress ofCandida albicansfrom the intravascular compartment. To identify potential adhesins that mediate the attachment of this organism to endothelial cells, a genomic library fromC. albicanswas used to transform a nonadherent strain ofSaccharomyces cerevisiae. The population of transformed yeasts was enriched for highly adherent clones by repeated passages over endothelial cells. One clone which exhibited a fivefold increase in endothelial cell adherence, compared withS. cerevisiaetransformed with vector alone, was identified. This organism also flocculated. The candidal DNA fragment within this adherent/flocculent organism was found to contain a single 1.8-kb open reading frame, which was designatedCAD1. It was found to be identical toAAF1. The predicted protein encoded byCAD1/AAF1contained features suggestive of a regulatory factor. Consistent with this finding, immunoelectron microscopy revealed that CAD1/AAF1 localized to the cytoplasm and nucleus but not the cell wall or plasma membrane of the transformed yeasts. Because yeasts transformed withCAD1/AAF1both flocculated and exhibited increased endothelial cell adherence, the relationship between adherence and flocculation was examined.S. cerevisiaeexpressing either of two flocculation phenotypes, Flo1 or NewFlo, adhered to endothelial cells as avidly as did yeasts expressingCAD1/AAF1. Inhibition studies revealed that the flocculation phenotype induced byCAD1/AAF1was similar to Flo1. Thus,CAD1/AAF1probably encodes a regulatory protein that stimulates endothelial cell adherence inS. cerevisiaeby inducing a flocculation phenotype. WhetherCAD1/AAF1contributes to the adherence ofC. albicansto endothelial cells remains to be determined.
Reduced Response to Multiple Vaccines Sharing Common Protein Epitopes That Are Administered Simultaneously to Infants
Authors: Dagan Ron , Eskola Juhani , Leclerc Claude , Leroy Odile 
Published: December 2019

ABSTRACTThe plethora of newly discovered vaccines implies that, in the future, many vaccines will have to be administered simultaneously to infants. We examined the potential interference with the immune response of several coadministered vaccines containing the same protein component, namely, tetanus toxoid (TT). Infants simultaneously receiving a tetravalent pneumococcal vaccine conjugated to TT (PncT) and a diphtheria-tetanus-pertussis–poliovirus–Haemophilus influenzaetype b-tetanus conjugate vaccine showed significantly lower anti-H. influenzaetype b polysaccharide (polyribosylribitol phosphate [PRP]) antibody concentrations than those receiving either a tetravalent pneumococcal vaccine conjugated to diphtheria toxoid or placebo. A dose range study showed that anti-PRP antibody concentrations were inversely related to the TT content of the PncT vaccines administered in infancy. Postimmunization antitetanus antibody concentrations were also affected adversely as the TT content of the coadministered vaccines was increased. This phenomenon, which we believe derives from interference by a common protein carrier, should be taken into account when the introduction of an immunization program including multiple conjugate vaccines is considered.
Expansion of Vγ9Vδ2 T Cells Is Triggered byFrancisella tularensis-Derived Phosphoantigens in Tularemia but Not after Tularemia Vaccination
Authors: Poquet Yannick , Kroca Michal , Halary Franck , Stenmark Stephan , Peyrat Marie-Alix , Bonneville Marc , Fournié Jean Jacques , Sjöstedt Anders 
Published: December 2019

ABSTRACTTularemia is a disease caused by the facultative intracellular bacteriumFrancisella tularensis. Here we demonstrate that during the first weeks of infection, a significant increase in levels of Vγ9Vδ2 cells occurred in peripheral blood: in 13 patients analyzed 7 to 18 days after the onset of disease, these lymphocytes represented, on average, 30.5% of CD3+cells and nearly 100% of γδ+T cells. By contrast, after vaccination with the live vaccine strain (LVS) ofF. tularensis, only a minor increase occurred. Eleven days after vaccination, γδ T cells represented an average of 6.7% and Vγ9Vδ2 cells represented an average of 5.3% of T cells, as in control subjects. Since derivatives of nonpeptidic pyrophosphorylated molecules, referred to as phosphoantigens, are powerful stimuli for Vγ9Vδ2 cells, this observation prompted an investigation of phosphoantigens inF. tularensisstrains. TheF. tularensisphosphoantigens triggered in vitro a proliferative response of human Vγ9Vδ2 peripheral blood leukocytes as well as a cytotoxic response and tumor necrosis factor release from a Vγ9Vδ2 T-cell clone. Quantitatively similar phosphoantigenic activity was detected in acellular extracts from two clinical isolates (FSC171 and Schu) and from LVS. Taken together, the chemical nature of the stimulus from the clinical isolates and the significant increase in levels of Vγ9Vδ2 cells in peripheral blood of tularemia patients indicate that phosphoantigens produced by virulent strains ofF. tularensistrigger in vivo expansion of γδ T cells in tularemia.
Generation of Neutralizing Antipeptide Antibodies to the Enzymatic Domain of
Pseudomonas aeruginosa
Exotoxin A
Authors: Elzaim Haissam S. , Chopra Ashok K. , Peterson Johnny W. , Goodheart Rick , Heggers John P. 
Published: December 2019

ABSTRACT

Burn patients suffer a break in the physical barrier (skin), which, when combined with their generalized state of immunodeficiency, creates an open window for opportunistic infections, mainly with
Pseudomonas aeruginosa
. Infection of the burn wound has always been a major factor in retardation of wound healing, and sepsis remains the leading cause of death in burn patients. Because studies have shown that topical treatment with antiexotoxin A (ETA) antibodies significantly increases survival in rats infected with toxin-producing strains of
P. aeruginosa
, we examined 11 synthetic peptides encompassing 12 to 45 amino acid (aa) residues, representing what were predicted by computer analysis to be the most hydrophilic and antigenic regions of ETA. These synthetic peptides were injected into rabbits for antibody production. Different groups of rabbits were immunized with a combination of peptides, with each combination representing one of the three distinct domains of ETA. Animals immunized with various peptide combinations produced peptide-specific antibodies that exhibited cross-reactivity to ETA. Two major epitopes were identified on the ETA molecule by experiments with peptide-specific antibodies in enzyme-linked immunosorbent assay and immunoprecipitation. One of these epitopes was located in the translocation domain (II) (aa 297 to 310), while the other was mapped to the last 13 aa residues at the carboxy-terminal end of the enzymatic domain (III) (aa 626 to 638). Of these two regions, the epitope in the enzymatic domain induced a much higher level of neutralizing antibodies that abrogated the cytotoxic activity of ETA in vitro. Antibodies to this epitope blocked the ADP-ribosyltransferase activity of ETA and appeared to interfere with binding of the substrate elongation factor 2 to the enzymatic active site of the ETA molecule. We conclude that polyclonal, as well as monoclonal, antibodies to short peptides, representing small regions of ETA, may have therapeutic potential in passive immunization or topical treatment of burn patients infected with toxin-producing strains of
P. aeruginosa.
Inactivation of the
gbpA
Gene of
Streptococcus mutans
Increases Virulence and Promotes In Vivo Accumulation of Recombinations between the Glucosyltransferase B and C Genes
Authors: Hazlett Karsten R. O. , Michalek Suzanne M. , Banas Jeffrey A. 
Published: December 2019

ABSTRACT

Glucan-binding protein A (GbpA) of
Streptococcus mutans
has been hypothesized to promote sucrose-dependent adherence and the cohesiveness of plaque and therefore to contribute to caries formation. We have analyzed the adherence properties and virulence of isogenic
gbpA
mutants relative to those of wild-type
S. mutans
. Contrary to expectations, the
gbpA
mutant strains displayed enhanced sucrose-dependent adherence in vitro and enhanced cariogenicity in vivo. In vitro,
S. mutans
was grown in the presence of [
3
H]thymidine and sucrose within glass vials. When grown with constant rotation, significantly higher levels of
gbpA
mutant organisms than of wild type remained adherent to the vial walls. Postgrowth vortexing of rotated cultures significantly decreased adherence of wild-type organisms, whereas the adherence of
gbpA
mutant organisms was unaffected. In the gnotobiotic rat model, the
gbpA
mutant strain was hypercariogenic though the colonization levels were not significantly different from those of the wild type. The
gbpA
mutant strain became enriched in vivo with organisms that had undergone a recombination involving the
gtfB
and
gtfC
genes. The incidence of
gtfBC
recombinant organisms increased as a function of dietary sucrose availability and was inversely correlated with caries development. We propose that the absence of GbpA elevates the cariogenic potential of
S. mutans
by altering the structure of plaque. However, the hypercariogenic plaque generated by
gbpA
mutant organisms may be suboptimal for
S. mutans
, leading to the accumulation of
gtfBC
recombinants whose reduced glucosyltransferase activity restores a less cariogenic plaque structure.
Construction of a Functional Single-Chain Variable Fragment Antibody against Hemagglutinin fromPorphyromonas gingivalis
Authors: Shibata Yasuko , Kurihara Kimiyo , Takiguchi Hisashi , Abiko Yoshimitsu 
Published: December 2019

ABSTRACTHemagglutinin is a major glycoprotein ofPorphyromonas gingivalisvesicles and likely confers the ability to adsorb and penetrate into host tissue cells. To protect this bacterial invasion, murine monoclonal antibody (MAb) Pg-vc, which inhibited the hemagglutinating activity, was prepared by usingP. gingivalisvesicles as an antigen. Western blot analysis revealed that when both MAb Pg-vc and anti-HA-Ag2 antibody raised against theP. gingivalishemagglutinin adhesin (M. Deslauriers and C. Mouton, Infect. Immun. 60:2791–2799, 1992) were allowed to react with protein blots fromP. gingivalisvesicles, a superimposable profile was observed. To obtain a recombinant antibody, cDNAs coding for the variable domains of the L and H chains of MAb Pg-vc were cloned by PCR, and a plasmid specifying a single-chain variable fragment (ScFv) was constructed. Following transformation ofEscherichia colicells, a recombinant ScFv protein was successfully expressed. The immunological properties of this protein were identical to those of the parental murine MAb, specifically recognizing the two proteins (43 and 49 kDa) originating fromP. gingivalisvesicles. In addition, the ScFv antibody inhibited theP. gingivalisvesicle-associated hemagglutinating activity. The amino acid sequences deduced from nucleotide sequencing experiments confirmed that variable heavy-chain and variable light-chain regions belonged to VH1 and Vκ12/13 families, respectively. Since the expression system used in this study can readily provide large quantities of single-chain recombinant antibody, it may be a useful in developing a therapeutic agent for passive immunization in humans.
Essential Role of Gamma Interferon in Survival of Colon Ascendens Stent Peritonitis, a Novel Murine Model of Abdominal Sepsis
Authors: Zantl Niko , Uebe Annette , Neumann Brigitte , Wagner Hermann , Siewert Jörg-Rüdiger , Holzmann Bernhard , Heidecke Claus-Dieter , Pfeffer Klaus 
Published: December 2019

ABSTRACTDespite considerable progress, peritonitis and sepsis remain life-threatening conditions. To improve the understanding of the pathophysiology encountered in sepsis, a new standardized and highly reproducible murine model of abdominal sepsis termed colon ascendens stent peritonitis (CASP) was developed. In CASP, a stent is inserted into the ascending colon, which generates a septic focus. CASP employing a stent of 14-gauge diameter (14G stent) results in a mortality of 100% within 18 to 48 h after surgery. By inserting stents of small diameters, mortality can be exactly controlled. Thus, CASP surgery with insertion of a 22G or 18G stent (22G or 18G CASP surgery) results in 38 or 68% mortality, respectively. 14G CASP surgery leads to a rapid invasion of bacteria into the peritoneum and the blood. As a consequence, endotoxemia occurs, inflammatory cells are recruited, and a systemic inflammatory response syndrome develops. Interestingly, the most pronounced upregulation of inflammatory cytokines (gamma interferon [IFN-γ], tumor necrosis factor alpha [TNF-α] and interleukin-12) is observed in spleen and lungs. CASP surgery followed by stent removal at specific time intervals revealed that all animals survived if intervention was performed after 3 h, whereas removal of the septic focus after 9 h did not prevent death, suggesting induction of autonomous mechanisms of a lethal inflammatory response syndrome. 18G CASP surgery in IFN-γ receptor-deficient (IFNγR−/−) mice revealed an essential role of IFN-γ in survival of sepsis, whereas TNF receptor p55-deficient (TNFRp55−/−) mice did not show altered survival rates. In summary, this study describes a novel animal model that closely mimics human sepsis and appears to be highly suitable for the study of the pathophysiology of abdominal sepsis. Importantly, this model demonstrates a protective role of IFN-γ in survival of bacterial sepsis.
Differential Early Interactions betweenSalmonella entericaSerovar Typhi and Two Other PathogenicSalmonellaSerovars with Intestinal Epithelial Cells
Authors: Weinstein Debra L. , O’Neill Barbara L. , Hone David M. , Metcalf Eleanor S. 
Published: December 2019

ABSTRACTSalmonella entericaserovar Typhi (hereafter referred to asS. typhi) is a host-restricted pathogen that adheres to and invades the distal ileum and subsequently disseminates to cause typhoid fever in humans. However,S. typhiappears to be avirulent in small animals. In contrast, other pathogenic salmonellae, such asS. entericaserovars Typhimurium and Dublin (S. typhimuriumandS. dublin, respectively), typically cause localized gastroenteritis in humans but have been used as models for typhoid fever because these organisms cause a disease in susceptible rodents that resembles human typhoid. In vivo,S. typhihas been demonstrated to attach to and invade murine M cells but is rapidly cleared from the Peyer’s patches without destruction of the M cells. In contrast, invasion of M cells byS. typhimuriumis accompanied by destruction of these M cells and subsequently sloughing of the epithelium. These data have furthered our view that the early steps in the pathogenesis of typhoidal and nontyphoidalSalmonellaserovars are distinct. To extend this concept, we have utilized an in vitro model to evaluate three parameters of initial host-pathogen interactions: adherence of threeSalmonellaserovars to human and murine small intestinal epithelial cell (IEC) lines, the capacity of these salmonellae to invade IECs, and the ability of the bacteria to induce interleukin-6 (IL-6) in these cell lines as a measure of host cell activation and the host acute-phase response. The results demonstrate thatS. typhiadheres to and invades human small IECs better than eitherS. typhimuriumorS. dublin. Interestingly,invAandinvEnull mutants ofS. typhiare able neither to adhere to nor to invade IECs, unlikeS. typhimurium invAandinvEmutants, which adhere to but cannot invade IECs.S. typhialso induces significantly greater quantities of IL-6 in human small IEC lines than either of the other twoSalmonellaserovars. These findings suggest that differential host cytokine responses to bacterial pathogens may play an important role in the pathological sequelae that follow infection. Importantly,S. typhimuriumdid not induce IL-6 in murine IECs. SinceS. typhimuriuminfection in mice is often used as a model of typhoid fever, these findings suggest that, at least in this case, the mouse model does not reflect the human disease. Taken together, our studies indicate that (i) marked differences occur in the initial steps ofS. typhi,S. typhimurium, andS. dublinpathogenesis, and (ii) conclusions aboutS. typhipathogenesis that have been drawn from the mouse model of typhoid fever should be interpreted conservatively.
A
Neisseria meningitidis fbpABC
Mutant Is Incapable of Using Nonheme Iron for Growth
Authors: Khun Heng H. , Kirby Shane D. , Lee B. Craig 
Published: December 2019

ABSTRACT

The neisserial
fbpABC
locus has been proposed to act as an iron-specific ABC transporter system. To confirm this assigned function, we constructed an
fbpABC
mutant in
Neisseria meningitidis
by insertional inactivation of
fbpABC
with a selectable antibiotic marker. The mutant was unable to use iron supplied from human transferrin, human lactoferrin, or iron chelates. However, the use of iron from heme and human hemoglobin was unimpaired. These results support the obligatory participation of
fbpABC
in neisserial periplasmic iron transport and do not indicate a role for this genetic locus in the heme iron pathway.
Construction and Characterization of an Isogenic
slt-ii
Deletion Mutant of Enterohemorrhagic
Escherichia coli
Authors: Gunzer Florian , Bohn Ursula , Fuchs Sibylle , Mühldorfer Inge , Hacker Jörg , Tzipori Saul , Donohue-Rolfe Arthur 
Published: December 2019

ABSTRACT

Enterohemorrhagic
Escherichia coli
(EHEC) produces Shiga-like toxins (SLT), potent protein synthesis inhibitors. To further dissect the role of SLT-II in the course of disease, we have constructed
E. coli
TUV86-2, an isogenic SLT-II-negative mutant of EHEC strain 86-24. The
slt-ii
gene was inactivated by suicide vector mutagenesis. We also isolated derivatives of strain 86-24 that were cured of the phage carrying the toxin genes.
Stable Transfection ofTrypanosoma cruziEpimastigotes with the Trypomastigote-Specific Complement Regulatory Protein cDNA Confers Complement Resistance
Authors: Norris Karen A. 
Published: December 2019

ABSTRACTTrypanosoma cruziblood stage trypomastigotes are highly resistant to complement-mediated killing in normal serum. A previously described trypomastigote surface glycoprotein was shown to have binding affinity for human complement components C3b and C4b and restrict activation of the complement cascade, thus preventing lysis of the parasites. Insect stage epimastigotes do not produce detectable levels of this 160-kDa complement regulatory protein (CRP) and are highly sensitive to the lytic effects of complement. Epimastigotes were stably transfected with aT. cruziexpression vector carrying the trypomastigote CRP cDNA and produced fully functional recombinant CRP. The recombinant CRP had binding affinity for C3b, and the transfected epimastigotes were protected from complement-mediated lysis. These results demonstrate for the first time that a developmentally regulated gene ofT. cruzitrypomastigotes can be expressed in noninfectious epimastigotes and that production of CRP by epimastigotes is sufficient to confer a virulence-associated trait. Furthermore, these studies demonstrate the critical role that trypomastigote CRP plays in the protection of parasites from the deleterious effects of complement, thus establishing the protein as a virulence factor ofT. cruzi.
Treatment of Mice with Staphylococcal Enterotoxin B Enhances Resolution of an InducedEscherichia coliUrinary Tract Infection and Stimulates Production of Proinflammatory Cytokines
Authors: Morin Michelle D. , Hopkins Walter J. 
Published: December 2019

ABSTRACTStaphylococcal enterotoxin B (SEB) is a superantigen that causes mass proliferation of murine Vβ8+T cells via major histocompatibility complex (MHC) class II molecules and leads to their apoptosis or anergy. SEB also stimulates other MHC class II-bearing cells to proliferate and secrete cytokines, some of which might enhance early host defenses against urinary tract infections (UTIs). We investigated the effect of SEB administration on the course of an inducedEscherichia coliUTI in mice. Treatment with SEB 3 or 7 days before the infection had no effect on UTI resolution. However, when SEB was administered at the time of infection, bacterial colonization in the bladders was reduced at time points between 6 h and 3 days. This reduction was not due to a physiological effect, such as increased urinary glycosaminoglycans, or altered pH, nor was SEB bactericidal for the inoculum. Cytokine production in the spleens and bladders of SEB-treated and/or infected mice was evaluated by reverse transcription-PCR. SEB treatment resulted in increased levels of interleukin-2 (IL-2), IL-4, IL-6, and IL-10 mRNAs in the spleen and IL-1α, IL-6, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor alpha transcripts in the bladder. Also, liver cells from SEB-treated mice expressed IL-6 mRNA, which induces the production of acute-phase proteins. These data indicate that SEB treatment in vivo leads to enhanced UTI resolution through a mechanism that may include direct stimulation of effector cells in the bladder, the action of cytokines induced in the spleen, or cytokine-mediated induction of acute-phase proteins.