bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immune Response of Children Who Develop Persistent Diarrhea following Rotavirus Infection
Authors: Azim Tasnim , Ahmad S. Meshbahuddin , Khuda Sefat-e- , Sarker M. Safiullah , Unicomb Leanne E. , De Soma , Hamadani Jena D. , Salam Mohammed A. , Wahed M. A. , Albert M. John 
Published: December 2019

ABSTRACT

A prospective study was conducted with Bangladeshi children with rotavirus (RV) diarrhea to assess whether nutritional and clinical parameters, RV serotypes, levels of interleukin-10 (IL-10), tumor necrosis factor alpha (TNF-α), and gamma interferon (IFN-γ), and RV-specific antibody titers in plasma and stool were associated with the development of persistent diarrhea. Children with watery diarrhea for 6 to 8 days, selected from the Dhaka Hospital of the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), were enrolled in the study and monitored until diarrhea improved. Children were classified as having acute diarrhea (AD) if diarrhea resolved within 14 days of onset and as having persistent diarrhea (PD) if diarrhea persisted for more than 14 days after onset. Uninfected, control children (
n
= 13) from the Nutrition Follow-Up Unit of ICDDR,B were also enrolled. Of the 149 children with diarrhea enrolled, 29 had diarrhea with RV alone, of which 19 had AD and 10 developed PD. Samples of stool and blood were collected from all children on enrollment. Stool samples were collected again from children when they developed PD. Of the 10 children who had an initial RV infection and then developed PD, only one had persistent RV infection. Plasma levels of IL-10 and TNF-α were higher in children with diarrhea compared to uninfected controls but were similar in children with AD and PD. Plasma IFN-γ levels were higher in children who developed PD than in those with AD (
P
= 0.008) or uninfected controls (
P
= 0.001). In stools, the levels of TNF-α, the only cytokine detected, were similar in the three groups of children. RV-specific immunoglobulin G (IgG) titers in plasma were higher in uninfected children than in those with AD (
P
< 0.001) or PD (
P
= 0.024) but titers were similar in children with AD and PD. RV-specific IgA titers in plasma and stool were similar in the three groups of children. From all observed parameters, only elevated plasma IFN-γ levels were associated with subsequent development of PD. However, a larger sample size is necessary to substantiate this observation.
Detection of Antibodies to
Brucella
Cytoplasmic Proteins in the Cerebrospinal Fluid of Patients with Neurobrucellosis
Authors: Baldi Pablo C. , Araj George F. , Racaro Graciela C. , Wallach Jorge C. , Fossati Carlos A. 
Published: December 2019

ABSTRACT

The diagnosis of human neurobrucellosis usually relies on the detection of antibodies to
Brucella
lipopolysaccharide (LPS) in cerebrospinal fluid (CSF) by agglutination tests or enzyme-linked immunosorbent assay (ELISA). Here we describe the detection of immunoglobulin G (IgG) to cytoplasmic proteins (CP) of
Brucella
spp. by ELISA and Western blotting in seven CSF samples from five patients with neurobrucellosis. While IgG to CP (titers of 200 to 12,800) and IgG to LPS (800 to 6,400) were found in the CSF of these patients, these antibodies were not detected in CSF samples from two patients who had systemic brucellosis without neurological involvement. The latter, however, had serum IgG and IgM to both LPS and CP. No reactivity to these antigens was found in CSF samples from 14 and 20 patients suffering from nonbrucellar meningitis and noninfectious diseases, respectively. These findings suggest that, in addition to its usefulness in the serological diagnosis of human systemic brucellosis, the ELISA with CP antigen can be used for the specific diagnosis of human neurobrucellosis.
Comparative Analysis of Two Meningococcal Immunotyping Monoclonal Antibodies by Resonant Mirror Biosensor and Antibody Gene Sequencing
Authors: Charalambous Bambos M. , Evans Janet , Feavers Ian M. , Maiden Martin C. J. 
Published: December 2019

ABSTRACT

Lipooligosaccharide (LOS) is a major surface component of the cell walls of
Neisseria meningitidis
, which is important for its roles in pathogenesis and antigenic variation, as a target for immunological typing, and as a possible vaccine component. Although the structures of many antigenic variants have been determined, routine immunological typing of these molecules remains problematic. Resonant mirror analysis was combined with gene sequencing to characterize two monoclonal antibodies (MAbs) used in typing panels that were raised against the same LOS immunotype, L3,7,9. The two MAbs (MAb 4A8-B2 and MAb 9-2-L379) were of the same immunoglobulin subtype, but while MAb 9-2-L379 was more than a 1,000-fold more sensitive in immunotyping assays of both whole meningococcal cells and purified LOS, MAb 4A8-B2 was more specific for immunotype L3,7,9. The differences in sensitivity were a consequence of MAb 9-2-L379 having a 44-fold-faster association constant than MAb 4A8-B2. Comparison of the amino acid sequences of the variable chains of the MAbs revealed that they had very similar heavy chains (81% amino acid sequence identity) but diverse light chains (54% sequence identity). The differential binding kinetics and specificities observed with these MAbs were probably due to differences in the epitopes recognized, and these were probably a consequence of the different immunization protocols used in their production.
Longitudinal Analysis of Lymphocyte Function and Numbers in the First Year of Life in Chromosome 22q11.2 Deletion Syndrome (DiGeorge Syndrome/Velocardiofacial Syndrome)
Authors: Sullivan Kathleen E. , McDonald-McGinn Donna , Driscoll Deborah A. , Emanuel Beverly S. , Zackai Elaine H. , Jawad Abbas F. 
Published: December 2019

ABSTRACTChromosome 22q11.2 deletion syndrome is a common syndrome typically consisting of variable cardiac defects, hypoparathyroidism, developmental delay, and immunodeficiency. The hemizygous deletion has variable effects on the immune system even within the same kindred, and the extent of the immunodeficiency is difficult to predict. Some patients have shown improvement over time; however, this is the first prospective longitudinal study of the dynamic nature of the immunodeficiency. Nineteen patients were studied prospectively between 1994 and 1997. The results of the newborn immunologic studies in the chromosome 22q11.2 deletion group were significantly different from those of a group of newborns with cardiac disease due to other causes. Peripheral blood T-cell numbers were decreased in the chromosome 22q11.2 deletion group, although T-cell function was largely preserved. The group as a whole demonstrated few changes in the first year of life, but a subset of patients with markedly diminished T-cell numbers did demonstrate improvement. Therefore, improvement in peripheral blood T-cell counts is variable in chromosome 22q11.2 deletion syndrome. The patients with the lowest T-cell counts improved the most in the first year of life.
Successful Treatment of Fluconazole-Resistant Oropharyngeal Candidiasis by a Combination of Fluconazole and Terbinafine
Authors: Ghannoum Mahmoud A. , Elewski Boni 
Published: December 2019

ABSTRACT

Increasing incidence of resistance to conventional antifungal therapy has demanded that novel therapies be introduced. Recent in vitro studies have shown that combinations involving azoles and allylamines may be effective in inhibiting fluconazole-resistant fungi. In this report, we describe the case of a 39-year-old woman who presented with white patches on her buccal mucosa, tongue, and palate with a bright erythematous erosive base. A fungal culture revealed
Candida albicans
. The patient failed to respond to the initially prescribed fluconazole therapy. Failure of therapy can be attributed to a developed resistance to fluconazole from the patient’s intermittent use of this antifungal agent at varying dosages for the preceding 2 years due to a diagnosis of onychomycosis. In vitro testing of the culture from the patient showed elevated MICs of fluconazole, itraconzole, and terbinafine (MICs were 32, 0.5, and 64 μg/ml, respectively). Our goal was to combine therapies of fluconazole and terbinafine in an attempt to clear the fungal infection. Impressively, this combination resulted in the clearing of the clinical symptoms and the patient has successfully been asymptomatic for more than 12 months posttreatment.
Antigenic Homology of the Inducible Ferric Citrate Receptor (FecA) of Coliform Bacteria Isolated from Herds with Naturally Occurring Bovine Intramammary Infections
Authors: Lin Jun , Hogan Joseph S. , Smith K. Larry 
Published: December 2019

ABSTRACT

Expression of ferric citrate receptor FecA by
Escherichia coli
and
Klebsiella pneumoniae
isolated from bovine mastitis was investigated. Transformant
E. coli
UT5600/pSV66, which produces large quantities of FecA in the presence of citrate, was constructed. The FecA of
E. coli
UT5600/pSV66 was purified by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis and used to prepare polyclonal antiserum in rabbits. All coliform isolates of
E. coli
(
n
= 18) and
K. pneumoniae
(
n
= 17) from naturally occurring bovine intramammary infections in five herds induced iron-regulated outer membrane proteins when grown in Trypticase soy broth containing 200 μM α-α′-dipyridyl and 1 mM citrate. Polyclonal antiserum against FecA was used in conjunction with an immunoblot technique to determine the degree of antigenic homology of FecA among isolates. In the presence of citrate, each isolate expressed FecA that reacted with the anti-FecA polyclonal antiserum. The molecular mass of FecA (∼80.5 kDa) was also highly conserved among isolates. Therefore, the ferric citrate iron transport may be induced in coliform bacteria and utilized to acquire iron in milk for survival and growth. The FecA is an attractive vaccine component for controlling coliform mastitis during the lactation period.
Identification of a Genetic Locus Essential for Serotype b-Specific Antigen Synthesis in
Actinobacillus actinomycetemcomitans
Authors: Yoshida Yasuo , Nakano Yoshio , Yamashita Yoshihisa , Koga Toshihiko 
Published: December 2019

ABSTRACT

A large gene cluster associated with the biosynthesis of the serotype-specific polysaccharide antigen (SPA) of
Actinobacillus actinomycetemcomitans
Y4 (serotype b) was cloned and characterized. Western blot analysis showed that
Escherichia coli
DH5α, containing a plasmid carrying this cluster, produced a polysaccharide which reacted with a monoclonal antibody directed against the SPA of
A. actinomycetemcomitans
Y4. High-performance liquid chromatography analysis indicated that the polysaccharide produced by an
E. coli
transformant, as well as
A. actinomycetemcomitans
Y4 SPA, was composed of rhamnose and fucose. Furthermore, using various derivatives of the plasmid, we demonstrated that the cloned 13-kb
Bss
HII-
Bsp
HI fragment was indispensable for SPA synthesis in
E. coli
DH5α. The 24,909-bp nucleotide sequence, which included this fragment and its flanking regions, was determined. In the sequenced area, 24 open reading frames (ORFs) with the same orientation were found. Most of these were located sequentially within a short distance of each other. Many of the deduced amino acid sequences were similar to the gene products of the polysaccharide synthetic genes of other bacteria. The average G+C content (37.7%) of all 24 ORFs in the sequenced area was lower than that (45.6%) of the whole chromosome of
A. actinomycetemcomitans
Y4. It is noteworthy the average G+C content of the nine ORFs in the 8.5-kb central region of the 13-kb
Bss
HII-
Bsp
HI fragment indispensable for SPA synthesis in
E. coli
was found to be especially low (27.0%).
Role of BfpF, a Member of the PilT Family of Putative Nucleotide-Binding Proteins, in Type IV Pilus Biogenesis and in Interactions between Enteropathogenic
Escherichia coli
and Host Cells
Authors: Anantha Ravi P. , Stone Kelly D. , Donnenberg Michael S. 
Published: December 2019

ABSTRACT

Adherence of enteropathogenic
Escherichia coli
(EPEC) to epithelial cells is dependent on a type IV fimbria, termed the bundle-forming pilus (BFP). A cluster of 14 genes is required for expression of BFP. The eighth gene in the cluster,
bfpF
, encodes a putative nucleotide-binding protein which resembles the PilT protein of
Pseudomonas aeruginosa
. It has been proposed that PilT is required for the retraction of the
P. aeruginosa
pilus, which results in twitching motility. To test the role of BfpF in BFP function and EPEC pathogenesis, two different mutations were constructed in the
bfpF
gene, one in the cloned gene cluster in a laboratory
E. coli
strain and one in wild-type EPEC. Neither mutation affected prepilin synthesis, leader sequence processing, or pilus biogenesis. However, both mutations resulted in increased localized adherence. In addition, the EPEC
bfpF
mutant displayed increased aggregation. The EPEC
bfpF
mutant was not deficient in attaching and effacing activity or invasion capacity. These results suggest that BfpF decreases aggregation and adherence by EPEC but that subsequent steps in EPEC pathogenesis do not require this protein.
Immunodominant Major Outer Membrane Proteins of
Ehrlichia chaffeensis
Are Encoded by a Polymorphic Multigene Family
Authors: Ohashi Norio , Zhi Ning , Zhang Yilan , Rikihisa Yasuko 
Published: December 2019

ABSTRACT

Several immunodominant major proteins ranging from 23 to 30 kDa were identified in the outer membrane fractions of
Ehrlichia chaffeensis
and
Ehrlichia canis
. The N-terminal amino acid sequence of a 28-kDa protein of
E. chaffeensis
(one of the major proteins) was determined. The gene (
p28
), almost full length, encoding the 28-kDa protein was cloned by PCR with primers designed based on the N-terminal sequence of the
E. chaffeensis
28-kDa protein and the consensus sequence between the C termini of the
Cowdria ruminantium
MAP-1 and
Anaplasma marginale
MSP-4 proteins. The
p28
gene was overexpressed, and antibody to the recombinant protein was raised in a rabbit. The antibody and serum from a patient infected with
E. chaffeensis
reacted with the recombinant protein, three proteins (29, 28, and 25 kDa) of
E. chaffeensis
, and a 30-kDa protein of
E. canis
. Immunoelectron microscopy with the rabbit antibody revealed that the antigenic epitope of the 28-kDa protein was exposed on the surface of
E. chaffeensis
. Southern blot analysis with a
32
P-labeled
p28
gene probe revealed multiple copies of genes homologous to
p28
in the
E. chaffeensis
genome. Six copies of the
p28
gene were cloned and sequenced from the genomic DNA by using the same probe. The open reading frames of these gene copies were tandemly arranged with intergenic spaces. They were nonidentical genes and contained a semivariable region and three hypervariable regions in the predicted protein molecules. One of the gene copies encoded a protein with an internal amino acid sequence identical to the chemically determined N-terminal amino acid sequence of a 23-kDa protein of
E. chaffeensis
. Immunization with the recombinant P28 protein protected mice from infection with
E. chaffeensis
. These findings suggest that the 30-kDa-range proteins of
E. chaffeensis
represent a family of antigenically related homologous proteins encoded by a single gene family.
Cytokine Profiles for Peripheral Blood Lymphocytes from Patients with Active Pulmonary Tuberculosis and Healthy Household Contacts in Response to the 30-Kilodalton Antigen ofMycobacterium tuberculosis
Authors: Torres Martha , Herrera Teresa , Villareal Hector , Rich Elizabeth A. , Sada Eduardo 
Published: December 2019

ABSTRACTPatients with active tuberculosis (TB) have a stronger humoral but a poorer cellular immune response to the secreted 30-kDa antigen (Ag) ofMycobacterium tuberculosisthan do healthy household contacts (HHC), who presumably are more protected against disease. The basis for this observation was studied by examining the Th1 (interleukin 2 [IL-2] and gamma interferon [IFN-γ])- and Th2 (IL-10 and IL-4)-type cytokines produced in response to the 30-kDa Ag by peripheral blood mononuclear cells (PBMC) from patients with active pulmonary TB (n= 7) and from HHC who were tuberculin (purified protein derivative) skin test positive (n= 12). Thirty-kilodalton-Ag-stimulated PBMC from TB patients produced significantly lower levels of IFN-γ (none detectable) than did those from HHC (212 ± 73 pg/ml, mean ± standard error) (P< 0.001). Likewise, 30-kDa-Ag-stimulated PBMC from TB patients failed to express IFN-γ mRNA by reverse transcription-PCR, whereas cells from HHC expressed the IFN-γ gene. In contrast, 30-kDa-Ag-stimulated PBMC from TB patients produced significantly higher levels of IL-10 (403 ± 80 pg/ml) than did those from HHC (187 ± 66 pg/ml) (P< 0.013), although cells from both groups expressed the IL-10 gene. IL-2 and IL-4 were not consistently produced, and their genes were not expressed by 30-kDa-Ag-stimulated cells from either TB patients or HHC. After treatment with antituberculous drugs, lymphocytes from four of the seven TB patients proliferated and three of them expressed IFN-γ mRNA in response to the 30-kDa Ag and produced decreased levels of IL-10.
Endothelial Cell Injury Caused by
Candida albicans
Is Dependent on Iron
Authors: Fratti Rutilio A. , Belanger Paul H. , Ghannoum Mahmoud A. , Edwards John E. , Filler Scott G. 
Published: December 2019

ABSTRACT

Although it is known that
Candida albicans
causes endothelial cell injury, in vitro and in vivo, the mechanism by which this process occurs remains unknown. Iron is critical for the induction of injury in many types of host cells. Therefore, we investigated the role of iron in
Candida
-induced endothelial cell injury. We found that pretreatment of endothelial cells with the iron chelators phenanthroline and deferoxamine protected them from candidal injury, even though the organisms germinated and grew normally. Loading endothelial cells with iron reversed the cytoprotective effects of iron chelation. Moreover, chelation of endothelial cell iron significantly reduced phagocytosis of
C. albicans
by these cells, while candidal adherence to chelator-treated endothelial cells was slightly enhanced. Since endothelial cell phagocytosis of
C. albicans
is required for endothelial cell injury to occur, inhibition of phagocytosis is likely the principal mechanism of the cytoprotective effects of iron chelation. The production of toxic reactive oxygen intermediates by host cells is known to be inhibited by iron chelation. Therefore, we investigated whether treating endothelial cells with antioxidants could mimic the cytoprotective effects of iron chelation. Neither extracellular nor membrane-permeative antioxidants reduced candidal injury of endothelial cells. Furthermore, depleting endothelial cells of the endogenous antioxidant glutathione did not render them more susceptible to damage by
C. albicans
. These results suggest that candidal injury of endothelial cells is independent of the production of reactive oxygen intermediates and that the cytoprotective effects of iron chelation are not due to inhibition of the synthesis of these toxic intermediates.
Levels of Expression and Immunogenicity of Attenuated
Salmonella enterica
Serovar Typhimurium Strains Expressing
Escherichia coli
Mutant Heat-Labile Enterotoxin
Authors: Covone M. Giuseppina , Brocchi Marcelo , Palla Emanuela , da Silveira W. Dias , Rappuoli Rino , Galeotti Cesira L. 
Published: December 2019

ABSTRACT

The effects of heterologous gene dosage as well as
Salmonella typhimurium
strain variability on immune response toward both the heterologous antigen, the nontoxic mutant of the
Escherichia coli
heat-labile enterotoxin LTK63, and the carrier
Salmonella
strain have been analyzed. Effects of a single integration into the host DNA and different-copy-number episomal vectors were compared in
S. typhimurium Δcya Δcrp Δasd
strains of two different serotypes, UK-1 and SR-11. Expression of the enterotoxin in the different
Salmonella
isolates in vitro was found to vary considerably and, for the episomal vectors, to correlate with the plasmid copy number. LTK63-specific serum immunoglobulin G (IgG) and mucosal immunoglobulin A (IgA) antibodies were highest in mice immunized with the high-level-expression strain. High anti-LTK63 IgG and IgA titers were found to correspond to higher anti-
Salmonella
immunity, suggesting that LTK63 exerts an adjuvant effect on response to the carrier. Statistically significant differences in anti-LTK63 immune response were observed between groups of mice immunized with the attenuated Δ
cya Δcrp
UK-1 and SR-11 derivatives producing the antigen at the same rate. These data indicate that the same attenuation in
S. typhimurium
strains of different genetic backgrounds can influence significantly the immune response toward the heterologous antigen. Moreover, delivery of the LTK63 enterotoxin to the immune system by attenuated
S. typhimurium
strains is effective only when synthesis of the antigen is very high during the initial phase of invasion, while persistence of the
S. typhimurium
strain in deep tissues has only marginal influence.
Activated Pulmonary Macrophages Are Insufficient for Resistance againstPneumocystis carinii
Authors: Hanano Ralph , Reifenberg Kurt , Kaufmann Stefan H. E. 
Published: December 2019

ABSTRACTCD4+T cells are pivotal for elimination ofPneumocystis cariniifrom infected lungs, and alveolar macrophages are considered the main effector cells clearing the infected host ofP. cariniiorganisms. To investigate this issue, several mutant mouse strains were used in a previously established experimental setup which facilitates natural acquisition of disease through inhalation of airborne fungal organisms. Mutant mice deficient in major histocompatibility complex class II molecules (Aβ−/−), T-cell receptor αβ cells (TCRβ−/−), or all mature T and B lymphocytes (RAG-1−/−) were naturally susceptible toP. carinii, whereas mouse mutants lacking the gamma interferon (IFN-γ) receptor (IFN-γ-R−/−) or tumor necrosis factor alpha (TNF-α) type I receptor (p55) (TNF-α-RI−/−) resisted disease acquisition. Analysis of pulmonary cytokine patterns and free radical expression revealed the presence of superoxide, nitric oxide, and interleukin-1 (IL-1) mRNA and elevated levels of IFN-γ, TNF-α, and IL-12 in diseased TCRβ−/−and RAG-1−/−mice. Pulmonary macrophages of all diseased mouse mutants expressed scavenger and mannose receptors. Morbid Aβ−/−mutants displayed significant NO levels and IL-1 mRNA only, whereas heterozygous controls did not exhibit any signs of disease. Interestingly, neither IFN-γ nor TNF-α appeared to be essential for resisting natural infection withP. carinii, nor were these cytokines sufficient for mediating resistance during established disease in the absence of CD4+T lymphocytes. Taken together, the results indicated that an activated phagocyte system, as evidenced by cytokine and NO secretion, in diseased mutants was apparently operative but did not suffice for parasite clearance in the absence of CD4+TCRαβ cells. Therefore, additional pathways, possibly involving interactions of inflammatory cytokines with CD4+T lymphocytes, must contribute to successful resistance againstP. carinii.