bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of a Commercially Available Immunoglobulin M Capture Enzyme-Linked Immunosorbent Assay Kit for Diagnosing Acute Dengue Infections
Authors: Porter Kevin R. , Widjaja Susana , Darmawan Handinata , Lohita  , Hadiwijaya Sri Hartati , Maroef Chairin Nisa , Suharyono Wuryadi , Tan Ratna 
Published: December 2019

ABSTRACT
Recently, commercially available kits for the detection of anti-dengue virus (anti-DEN) immunoglobulin M (IgM) antibodies have been developed. These standardized assays have greatly enhanced our ability to effectively diagnose DEN infections. We conducted an evaluation of a test kit manufactured by MRL Diagnostics Inc. that is designed to detect anti-DEN IgM antibodies. Eighty paired samples from DEN-infected individuals were tested by the MRL DEN Fever Virus IgM Capture enzyme-linked immunosorbent assay (ELISA), the PanBio Duo ELISA, the PanBio Rapid Immunochromatographic Test (PRIT), and the IgM-IgG antibody capture (MAC/GAC) ELISA. All infections were confirmed by either PCR-assisted detection of DEN transcripts or by DEN isolation in C6/36 cells. Seventeen paired samples from individuals with no evidence of acute DEN infection were used as negative controls. The PRIT had the best sensitivity (100%), whereas the MAC/GAC ELISA and the PanBio Duo assay had the highest levels of specificity. The MRL ELISA and the PanBio Duo assay were the top performers when taking into consideration both sensitivity and specificity. All assays were able to detect DEN-specific antibodies in samples from patients with either primary or secondary infections, regardless of the infecting DEN serotype.
Validation of a Gastrointestinal Explant System for Measurement of Mucosal Antibody Production
Authors: Losonsky Genevieve A. , Fantry George T. , Reymann Mardi , Lim Yu 
Published: December 2019

ABSTRACTA gastrointestinal explant culture system was developed and compared to the mononuclear cell extraction and enzyme-linked immunospot assay method for measurement of immunoglobulin A (IgA) and IgG antibody-secreting cells (ASCs) in gastric antral and duodenal biopsies of non-Helicobacter pylori-infected volunteers. IgA and IgG were detected in explant supernatants during 6 to 7 days of culture in all subjects. IgA containing secretory component was also detected throughout the culture period, although peak production occurred only in the first 3 days. During 7 days of culture, the cumulative geometric mean IgA levels produced were 2.2 and 8.02 μg/ml/10 mg of antral and duodenal biopsy tissues, respectively, while the cumulative geometric mean IgG levels were 1.54 and 2.92 μg/ml/10 mg of antral and duodenal biopsy tissues, respectively. Cycloheximide treatment resulted in a >90% reduction in both immunoglobulin classes after 6 days of treatment compared to levels in untreated controls. The detection of IgA and IgG ASCs extracted from biopsies on days 1 and 6 of culture confirmed that the antibody detected was derived from mucosal lamina propria. The IgA and IgG ASC responses were positively correlated with antibody concentrations detected in culture supernatants (r= 0.87 and 0.85, respectively). These results validate the potential usefulness of our gastrointestinal explant system for the evaluation of mucosal effector B-cell function.
Enhanced Secretory Leukocyte Protease Inhibitor in Human Immunodeficiency Virus Type 1-Infected Patients
Authors: Baqui A. A. M. A. , Meiller Timothy F. , Falkler William A. 
Published: December 2019

ABSTRACT

Secretory leukocyte protease inhibitor (SLPI) has been found to possess activity against the human immunodeficiency virus type 1 (HIV-1) in vitro at physiological concentrations. A study was undertaken to evaluate SLPI levels in human saliva and plasma among HIV-positive (HIV
+
) patients with various HIV-1 viral loads in comparison to uninfected controls. Whole blood in EDTA and unstimulated saliva samples were collected from 37 HIV
+
patients, of whom 20 had a history of intravenous drug abuse (IVDA). Control samples were collected from 20 appropriate age- and sex-matched HIV-1-negative individuals. SLPI was estimated from both saliva and serum samples by an enzyme-linked immunosorbent assay. HIV viral load was determined using a quantitative reverse transcription-PCR. SLPI levels were increased 16.7% in plasma and 10.3% in saliva among HIV
+
patients in comparison to uninfected controls. SLPI levels were increased 5.9% in saliva and 3.9% in plasma among HIV
+
patients with a high viral load (>10,000 copies/ml) as compared to patients with a low viral load (<400 copies/ml). Only 23% of patients with a high viral load used combination therapy with protease inhibitor drugs, whereas 92.9% of HIV
+
patients with a low viral load used protease inhibitors. SLPI levels did not differ significantly among the IVDA patients, patients with different viral loads, or patients using protease inhibitor drugs. There was a statistically significant increase in SLPI levels in saliva among HIV patients in comparison to non-HIV-infected controls. An increase in SLPI levels among HIV
+
patients may be a natural consequence of HIV pathogenesis and an important factor in preventing oral transmission of HIV, but this increase may not be evident during plasma viremia in patients with a high viral load.
Analysis of the Humoral Immune Response to
Chlamydia pneumoniae
by Immunoblotting and Immunoprecipitation
Authors: Essig Andreas , Simnacher Ulrike , Susa Milorad , Marre Reinhard 
Published: December 2019

ABSTRACT

Chlamydia pneumoniae
is a widely spread agent of respiratory tract infections in humans. A reliable serodiagnosis of the disease is hampered by the poor knowledge about immunodominant antigens in
C. pneumoniae
infections. We applied a novel strategy to identify immunogenic proteins of
C. pneumoniae
TW183 combining metabolic radiolabeling of de novo-synthesized chlamydial antigens with immunoprecipitation. By this technique
C. pneumoniae
antigens of approximately 160, 97 to 99, 60 to 62, 40, 27, and 15 kDa were detected in the vast majority of sera from patients with a current
C. pneumoniae
infection. By immunoblotting purified elementary bodies of
C. pneumoniae
TW183 with the same sera, only the 60- to 62-kDa antigen could be detected consistently. Sequential immunoprecipitation performed at different stages of the chlamydial developmental cycle revealed that the 60- to 62-kDa antigen is strongly upregulated after 24 to 48 h of host cell infection and is presented as a major immunogen in both
C. pneumoniae
-infected patients and mice. We conclude that, due to its high sensitivity and concurrent preservation of conformational epitopes, metabolic radiolabeling of chlamydial antigens combined with immunoprecipitation may be a useful method to reveal important immunogens in respiratory
C. pneumoniae
infection which might have been missed by immunoblot analysis.
Further Characterization of Human Salivary Anticandidal Activities in a Human Immunodeficiency Virus-Positive Cohort by Use of Microassays
Authors: Lin Alan L. , Shi Qinghong , Johnson Dorthea A. , Patterson Thomas F. , Rinaldi Michael G. , Yeh Chih-Ko 
Published: December 2019

ABSTRACT

Salivary anticandidal activities play an important role in oral candidal infection. R. P. Santarpia et al. (Oral Microbiol. Immunol. 7:38–43, 1992) developed in vitro anticandidal assays to measure the ability of saliva to inhibit the viability of
Candida albicans
blastoconidia and the formation of germ tubes by
C. albicans
. In this report, we describe modifications of these assays for use with small volumes of saliva (50 to 100 μl). For healthy subjects, there is strong inhibition of blastoconidial viability in stimulated parotid (75%), submandibular-sublingual (74%), and whole (97%) saliva, as well as strong inhibition of germ tube formation (>80%) for all three saliva types. The susceptibility of several
Candida
isolates to inhibition of viability by saliva collected from healthy subjects is independent of body source of
Candida
isolation (blood, oral cavity, or vagina) or the susceptibility of the isolate to the antifungal drug fluconazole. Salivary anticandidal activities in human immunodeficiency virus (HIV)-infected patients were significantly lower than those in healthy controls for inhibition of blastoconidial viability (
P
< 0.05) and germ tube formation (
P
< 0.001). Stimulated whole-saliva flow rates were also significantly lower (
P
< 0.05) for HIV-infected patients. These results show that saliva of healthy individuals has anticandidal activity and that this activity is reduced in the saliva of HIV-infected patients. These findings may help explain the greater incidence of oral candidal infections for individuals with AIDS.
Hemoglobin Toxicity in Experimental Bacterial Peritonitis Is Due to Production of Reactive Oxygen Species
Authors: Yoo Yeong-Min , Kim Ki-Mo , Kim Sung-Soo , Han Jeong-A , Lea Ho-Zoo , Kim Young-Myeong 
Published: December 2019

ABSTRACT

Hemoglobin (Hb) is a toxic molecule responsible for the extreme lethality associated with experimental
Escherichia coli
peritonitis, but the mechanism has yet to be elucidated. Hb, but not globin, showed toxic effects in a live
E. coli
model but not in a model using killed
E. coli
. Methemoglobin, hematin, and the well-known Fenton reagents iron and iron-EDTA demonstrated the same lethal effect in
E. coli
peritonitis as Hb, while the addition of the Fenton inhibitors desferrioxamine (DF) and diethylenetriamine pentaacetate removed most of the cytotoxic activity of iron. Administration of a combined dose of superoxide dismutase and catalase minimized the action of Hb and iron-EDTA, suggesting that both O
2
⋅
−
and H
2
O
2
are involved in the toxic action of Hb in this rat model. The combination of the antioxidative enzymes and DF further suppressed iron-mediated lethality. An electron spin resonance technique with the spin-trapping reagent 5,5-dimethyl-1-pyroline-
N
-oxide (DMPO) showed O
2
⋅
−
generation in the peritoneal fluid of rats injected with
E. coli
alone or
E. coli
plus iron-DF, and
⋅
OH generation was detected in the peritoneal fluid of the rats injected with iron-EDTA. Hb did not show any spin adduct of oxygen radicals, suggesting that Hb produces non-spin-trapping radical ferryl ion, which decayed the spin adduct of DMPO. In the presence of Hb or iron-EDTA, O
2
−
-generating activity and viability of phagocytes decreased, whereas lipid peroxidation of peritoneal phagocytes increased. Generation of oxygen radicals and lipid peroxidation did not differ in the live and dead bacterial models. Bacterial numbers in the peritoneal cavity and blood were markedly increased in the live bacterial model with Hb and iron-EDTA. The Fenton inhibitor iron-DF prevented the loss of phagocyte function, lipid peroxidation, and bacterial proliferation. These results led us to conclude that the lethal toxicity of Hb in bacterial peritonitis is associated with a Fenton-type reaction, the products of which decrease phagocyte viability, through the induction of lipid peroxidation, allowing bacterial proliferation and resulting in mortality.
Role of theHaemophilus ducreyiTon System in Internalization of Heme from Hemoglobin
Authors: Elkins Christopher , Totten Pat A. , Olsen Bonnie , Thomas Christopher E. 
Published: December 2019

ABSTRACTBy cloning intoEscherichia coliand construction of isogenic mutants ofHaemophilus ducreyi, we showed that the hemoglobin receptor (HgbA) is TonB dependent. AnE. coli hemA tonBmutant expressingH. ducreyi hgbAgrew on low levels of hemoglobin as a source of heme only when an intactH. ducreyiTon system plasmid was present. In contrast, growth on heme by theE. coli hemA tonBmutant expressinghgbAwas observed only at high concentrations of heme, was TonB independent, and demonstrated thatH. ducreyiHgbA was not sufficient to function as a typical TonB-dependent heme receptor inE. coli. Allelic replacement of the wild-typeH. ducreyi exbB,exbD, andtonBloci with theexbB,exbD, andtonBdeletion resulted in anH. ducreyiisogenic mutant unable to utilize hemoglobin but able to utilize hemin at the same levels as the parent strain to fulfill its heme requirement. This finding confirms the TonB dependence of HgbA-mediated hemoglobin utilization and suggests that uptake of hemin inH. ducreyiis TonB independent. Additionally, theH. ducreyiTon system mutant synthesized increased amounts of HgbA and other heme-regulated outer membrane proteins, consistent with derepression of these proteins due to lower intracellular heme and/or iron concentrations in the mutant. Sequencing of the Ton system genes revealed that the arrangement of the genes wasexbB exbD tonB. The proximity and structure of these genes suggested that they are transcribed as an operon. This arrangement, as well as the DNA and deduced amino acid sequences of theseH. ducreyigenes, was most similar to those from other pasteurellae.
Regional Differences in the Cellular Immune Response to Experimental Cutaneous or Visceral Infection withLeishmania donovani
Authors: Melby Peter C. , Yang Yan-Zhu , Cheng Jun , Zhao Weiguo 
Published: December 2019

ABSTRACTInfection with the protozoanLeishmania donovanican cause serious visceral disease or subclinical infection in humans. To better understand the pathogenesis of this dichotomy, we have investigated the host cellular immune response to cutaneous or visceral infection in a murine model. Mice infected in the skin developed no detectable visceral parasitism, whereas intravenous inoculation resulted in hepatosplenomegaly and an increasing visceral parasite burden. Spleen cells from mice with locally controlled cutaneous infection showed strong parasite-specific proliferative and gamma interferon (IFN-γ) responses, but spleen cells from systemically infected mice were unresponsive to parasite antigens. The in situ expression of IFN-γ, interleukin-4 (IL-4), IL-10, IL-12, and inducible nitric oxide synthase (iNOS) mRNAs was determined in the spleen, draining lymph node (LN), and cutaneous site of inoculation. There was considerably greater expression of IFN-γ and IL-12 p40 mRNAs in the LN draining a locally controlled cutaneous infection than in the spleen following systemic infection. Similarly, there was a high level of IFN-γ production by LN cells following subcutaneous infection but no IFN-γ production by spleen cells following systemic infection. Splenic IL-4 expression was transiently increased early after systemic infection, but splenic IL-10 transcripts increased throughout the course of visceral infection. IL-4 and IL-10 mRNAs were also increased in the LN following cutaneous infection. iNOS mRNA was detected earlier in the LN draining a cutaneous site of infection compared to the spleen following systemic challenge. Thus, locally controlled cutaneous infection was associated with antigen-specific spleen cell responsiveness and markedly increased levels of IFN-γ, IL-12, and iNOS mRNA in the draining LN. Progressive splenic parasitism was associated with an early IL-4 response, markedly increased IL-10 but minimal IL-12 expression, and delayed expression of iNOS.
Role of Tumor Necrosis Factor Alpha in Gnotobiotic Mice Infected with an
Escherichia coli
O157:H7 Strain
Authors: Isogai Emiko , Isogai Hiroshi , Kimura Koichi , Hayashi Shunji , Kubota Toru , Fujii Nobuhiro , Takeshi Koichi 
Published: December 2019

ABSTRACT

Gnotobiotic mice inoculated with an enterohemorrhagic
Escherichia coli
(EHEC) O157:H7 strain developed a flaccid paresis, usually culminating in death. The bacteria colonized feces at 10
9
to 10
10
CFU per g (inoculum size: 2.0 × 10
9
CFU/mouse), and Shiga-like toxins (SLTs) were detected in the feces. A microscopic examination of colons showed mild inflammatory cell infiltration, thinning of the intestinal wall, or necrotic foci. Necrosis of tubular cells was noted in these symptomatic mice. Microhemorrhage, thrombosis, and edematous changes of the brain were also seen. Inflammatory cytokines, tumor necrosis factor alpha (TNF-α), interleukin 1α (IL-1α), and IL-6, were detected in the kidney after EHEC infection, but not in the serum. In the brain, only TNF-α was detected. When 2.0 × 10
2
CFU of EHEC O157:H7 was fed to germ-free mice, the number of bacteria began to rise rapidly on day 1 and was maintained at 10
8
to 10
9
CFU/g of feces. SLTs were detected in the feces of the mice. However, the mice showed no histological changes and no cytokine responses, similar to what was found for controls. Treatment with TNF-α modified the clinical neural signs, histopathological changes, and cytokine responses; mice treated with TNF-α developed severe neurotoxic symptoms and had higher frequencies of systemic symptoms and glomerular pathology. Strong cytokine responses were seen in the kidney and brain. Serum cytokines were also detected in this group. In contrast, a TNF-α inhibitor (protease inhibitor) inhibited these responses, especially in the brain. However, local synthesis of the cytokines was observed in the kidney. Thus, TNF-α and the other proinflammatory cytokines could be important in modifying the disease caused by EHEC.
Periplasmic Superoxide Dismutase in Meningococcal Pathogenicity
Authors: Wilks Kathryn E. , Dunn Kate L. R. , Farrant Jayne L. , Reddin Karen M. , Gorringe Andrew R. , Langford Paul R. , Kroll J. Simon 
Published: December 2019

ABSTRACT

Meningococcal
sodC
encodes periplasmic copper- and zinc-cofactored superoxide dismutase (Cu,Zn SOD) which catalyzes the conversion of the superoxide radical anion to hydrogen peroxide, preventing a sequence of reactions leading to production of toxic hydroxyl free radicals. From its periplasmic location, Cu,Zn SOD was inferred to acquire its substrate from outside the bacterial cell and was speculated to play a role in preserving meningococci from the action of microbicidal oxygen free radicals produced in the context of host defense. A
sodC
mutant was constructed by allelic exchange and was used to investigate the role of Cu,Zn SOD in pathogenicity. Wild-type and mutant meningococci grew at comparable rates and survived equally long in aerobic liquid culture. The mutant showed no increased sensitivity to paraquat, which generates superoxide within the cytosol, but was approximately 1,000-fold more sensitive to the toxicity of superoxide generated in solution by the xanthine/xanthine oxidase system. These data support a role for meningococcal Cu,Zn SOD in protection against exogenous superoxide. In experiments to translate this into a role in pathogenicity, wild-type and mutant organisms were used in an intraperitoneal mouse infection model. The
sodC
mutant was significantly less virulent. We conclude that periplasmic Cu,Zn SOD contributes to the virulence of
Neisseria meningitidis
, most likely by reducing the effectiveness of toxic oxygen host defenses.
Borrelia burgdorferiInduces the Production and Release of Proinflammatory Cytokines in Canine Synovial Explant Cultures
Authors: Straubinger Reinhard K. , Straubinger Alix F. , Summers Brian A. , Erb Hollis N. , Härter Luc , Appel Max J. G. 
Published: December 2019

ABSTRACTCanine synovial membrane explants were exposed to high- or low-passageBorrelia burgdorferifor 3, 6, 12, and 24 h. Spirochetes received no treatment, were UV light irradiated for 16 h, or were sonicated prior to addition to synovial explant cultures. In explant tissues, mRNA levels for the proinflammatory cytokines tumor necrosis factor alpha (TNF-α), interleukin-1α (IL-1α), IL-1β, and IL-8 were surveyed semiquantitatively by reverse transcription-PCR. Culture supernatants were examined for numbers of total and motile (i.e., viable) spirochetes, TNF-like and IL-1-like activities, polymorphonuclear neutrophil (PMN) chemotaxis-inducing activities, and IL-8. During exposure to synovial explant tissues, the total number of spirochetes in the supernatants decreased gradually by ∼30%, and the viability also declined. mRNAs for TNF-α, IL-1α, IL-1β, and IL-8 were up-regulated in synovial explant tissues within 3 h after infection with untreated or UV light-irradiatedB. burgdorferi, and mRNA levels corresponded to the results obtained with bioassays. During 24 h of coincubation, cultures challenged with untreated or UV light-irradiated spirochetes produced similar levels of TNF-like and IL-1-like activities. In contrast, explant tissues exposed to untreatedB. burgdorferigenerated significantly higher levels of chemotactic factors after 24 h of incubation than did explant tissues exposed to UV light-treated spirochetes. In identical samples, a specific signal for IL-8 was identified by Western blot analysis. High- and low-passage borreliae did not differ in their abilities to induce proinflammatory cytokines. No difference in cytokine induction between untreated and sonicated high-passage spirochetes was observed, suggesting that fractions of the organism can trigger the production and release of inflammatory mediators. The titration of spirochetes revealed a dose-independent cytokine response, where 103to 107B. burgdorferiorganisms induced similar TNF-like activities but only 107spirochetes induced measurable IL-1-like activities. The release of chemotactic factors was dose dependent and was initiated when tissues were infected with at least 105organisms. We conclude that intactB. burgdorferior fractions of the bacterium can induce the local up-regulation of TNF-α, IL-1α, and IL-1β in the synovium but that the interaction of viable spirochetes with synovial cells leads to the release of IL-8, which probably is a prime initiator of PMN migration during acute Lyme arthritis.
Early Cytokine and Chemokine Gene Expression duringPseudomonas aeruginosaCorneal Infection in Mice
Authors: Kernacki Karen A. , Goebel Dennis J. , Poosch Michael S. , Hazlett Linda D. 
Published: December 2019

ABSTRACTUsing a multiprobe RNase protection assay, we examined cytokine and chemokine mRNAs that were expressed after corneal infection withPseudomonas aeruginosain mice. Cytokines that were upregulated included interleukin-1α (IL-1α) and -1β, IL-1 receptor antagonist, IL-6, IL-11, granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, macrophage colony-stimulating factor, stem cell factor, lymphotoxin β, transforming growth factor β1, and tumor necrosis factor alpha. Chemokine transcripts that were upregulated included Eotaxin; gamma-interferon-inducible protein 10; monocyte chemoattractant protein 1; macrophage inflammatory proteins 1α, 1β, and 2; and RANTES. Peak expression of these cytokines and chemokines was observed between 1 and 3 days after infection. These responses returned to or approached baseline preinfection levels by 7 days after ocular challenge. Identification of the various cytokines and chemokines upregulated during corneal infection provides important information relevant to unraveling the pathogenesis induced by this bacterium and provides hope that specific molecules can be targeted for therapy.