bluuebunny/crossref_metadata_2025_split huggingface dataset:
Validation of a Modified Commercial Enzyme-Linked Immunoassay for Detection of Human Immunodeficiency Virus Type 1 Immunoglobulin G Antibodies in Saliva
Authors: Chohan Bhavna H. , Lavreys Ludo , Mandaliya Kishorchandra N. , Kreiss Joan K. , Bwayo Job J. , Ndinya-Achola Jeckoniah O. , Martin Harold L. 
Published: July 2002

ABSTRACT
This study was performed to evaluate the performance of a saliva collection device (OmniSal) and an enzyme-linked immunoassay (EIA) designed for use on serum samples (Detect HIV1/2) to detect human immunodeficiency virus type 1 (HIV-1) antibodies in the saliva of high-risk women in Mombasa, Kenya. The results of the saliva assay were compared to a “gold standard” of a double-EIA testing algorithm performed on serum. Individuals were considered HIV-1 seropositive if their serum tested positive for antibodies to HIV-1 by two different EIAs. The commercial serum-based EIA was modified to test the saliva samples by altering the dilution and lowering the cutoff point of the assay. Using the saliva sample, the EIA correctly identified 102 of the 103 seropositive individuals, yielding a sensitivity of 99% (95% confidence interval [CI], 94 to 100%), and 96 of the 96 seronegative individuals, yielding a specificity of 100% (95% CI, 95 to 100%). In this high-risk population, the positive predictive value of the assay was 100% and the negative predictive value was 99%. We conclude that HIV-1 antibody testing of saliva samples collected with this device and tested by this EIA is of sufficient sensitivity and specificity to make this protocol useful in epidemiological studies.
Late Hematogenous Infection of Subcutaneous Implants in Rats
Authors: Gottenbos B. , Klatter F. , Van Der Mei H. C. , Busscher H. J. , Nieuwenhuis P. 
Published: July 2002

ABSTRACT
Late biomaterial-centered infection is a major complication associated with the use of biomaterial implants. In this study biomaterials that had been implanted subcutaneously in rats were hematogenously challenged with bacteria 4 weeks after implantation. Bacteria were spread either by intravenous injection or by stimulation of bacterial translocation. It was found that none of the biomaterials was infected by hematogenous spread, whereas 5% of the implants were infected by perioperative contamination. We conclude that late hematogenous infection of subcutaneous biomaterials does not occur in the rat. For humans as well, there are growing doubts whether implants actually become infected through hematogenous routes; it is thought that late infections may be caused by delayed appearance of perioperatively introduced bacteria.
Multiplex Assay for Detection of Strain-Specific Antibodies against the Two Variable Regions of the G Protein of Respiratory Syncytial Virus
Authors: Jones Les P. , Zheng Hao-Qiang , Karron Ruth A. , Peret Teresa C. T. , Tsou Cecelia , Anderson Larry J. 
Published: July 2002

ABSTRACT
The role of strain differences in respiratory syncytial virus (RSV) disease has not been clearly defined. To investigate the possibility that strain differences contribute to susceptibility to repeat infections, we developed assays to detect antibodies to the two variable regions of the RSV G protein by cloning and expressing the internal variable region at amino acids (aa) 60 to 172 (g1) and the carboxy-terminal variable region at aa 193 to the carboxy terminus (g2) from different genotypes of RSV. The purified proteins were covalently linked to beads with different proportions of red and orange fluorescent dyes and reacted against serum specimens. Antibody reacting against the differently colored beads, and thus against different G polypeptides, was detected by use of flow cytometry and the Luminex system. This assay system detected group- and, to some extent, genotype-specific responses to RSV infection and can be used to investigate the role of strain differences in RSV disease.
Assignment of Additional Anticapsular Antibody Concentrations to the
Neisseria meningitidis
Group A, C, Y, and W-135 Meningococcal Standard Reference Serum CDC1992
Authors: Elie Cheryl M. , Holder Patricia K. , Romero-Steiner Sandra , Carlone George M. 
Published: July 2002

ABSTRACT

We assigned additional enzyme-linked immunosorbent assay antibody concentrations (immunoglobulin G [IgG], IgM, and IgA, and total) to the
Neisseria meningitidis
standard reference serum CDC1992 for groups Y and W-135 to 12 Centers for Disease Control and Prevention quality control sera. These assignments will supplement previous assignments and will aid in the evaluation of present and developing vaccines.
Antifungal Susceptibility Testing: Practical Aspects and Current Challenges
Authors: Rex John H. , Pfaller Michael A. , Walsh Thomas J. , Chaturvedi Vishnu , Espinel-Ingroff Ana , Ghannoum Mahmoud A. , Gosey Linda L. , Odds Frank C. , Rinaldi Michael G. , Sheehan Daniel J. , Warnock David W. 
Published: July 2002

SUMMARYDevelopment of standardized antifungal susceptibility testing methods has been the focus of intensive research for the last 15 years. Reference methods for yeasts (NCCLS M27-A) and molds (M38-P) are now available. The development of these methods provides researchers not only with standardized methods for testing but also with an understanding of the variables that affect interlaboratory reproducibility. With this knowledge, we have now moved into the phase of (i) demonstrating the clinical value (or lack thereof) of standardized methods, (ii) developing modifications to these reference methods that address specific problems, and (iii) developing reliable commercial test kits. Clinically relevant testing is now available for selected fungi and drugs: Candida spp. against fluconazole, itraconazole, flucytosine, and (perhaps) amphotericin B; Cryptococcus neoformans against (perhaps) fluconazole and amphotericin B; and Aspergillus spp. against (perhaps) itraconazole. Expanding the range of useful testing procedures is the current focus of research in this area.
NO Contributes to Proliferative Suppression in a Murine Model of Filariasis
Authors: O'Connor Richard A. , Jenson Jessica S. , Devaney Eileen 
Published: July 2002

ABSTRACTInfection of BALB/c mice with microfilariae (mf) ofBrugia pahangileads to the suppression of antigen (Ag)-specific proliferative responses in the spleen. The proliferative defect is dependent on inducible nitric oxide synthase (iNOS) activity, since inhibition of iNOS with eitherl-N-monomethyl arginine (l-NMMA) or aminoguanidine reversed defective proliferation. Splenocytes from mf-infected animals produce high levels of gamma interferon (IFN-γ) upon in vitro restimulation with Ag, and experiments in IFN-γ receptor-deficient (IFN-γR−/−) mice demonstrated that signaling via the IFN-γR is essential in the induction of NO production and subsequent proliferative suppression. Restimulation of splenocytes from mf-infected animals with an extract ofAcanthocheilonema viteae, a related filarial worm which lacks endosymbiotic bacteria, also resulted in NO production and proliferative suppression, demonstrating that lipopolysaccharide of bacterial origin is not essential to the induction of iNOS activity. These results extend previous observations that infection with different life cycle stages ofBrugialeads to the development of differentially polarized immune responses and demonstrate one method by which these differences may exert their effects on the proliferative potential of cells from infected animals.
Role of Neutrophil Leukocytes in Cutaneous Infection Caused byStaphylococcus aureus
Authors: Mölne Lena , Verdrengh Margareta , Tarkowski Andrzej 
Published: July 2002

ABSTRACTDespite the high prevalence of cutaneous infections, little is known about the role of host immune responsiveness duringStaphylococcus aureusdermatitis. We have recently described a murine model of infectious dermatitis induced by superantigen-producingS. aureus. To assess the role of neutrophils in staphylococcal dermatitis, mice were given granulocyte-depleting monoclonal antibody prior to and on several occasions following intracutaneous inoculation with staphylococci. The granulocyte-depleted mice that had been intradermally inoculated withS. aureusdeveloped crusted ulcerations which tended not to heal, whereas animals injected with control monoclonal antibody displayed only minor and transient skin lesions. The finding of severe ulcerations in neutropenic mice correlated with a significantly higher burden of bacteria in the blood and skin during the early phase of the infection. Importantly, while mice with an intact granulocyte population showed only limited skin infection, bacteremia occurred in the great majority of the neutrophil-depleted animals. As a consequence, the latter individuals exhibited significantly increased levels of the proinflammatory cytokine interleukin-6 and specific antibodies to staphylococcal cell wall components and toxic shock syndrome toxin-1 in the serum. Our data point to a crucial protective role of granulocytes inS. aureusdermatitis.
Detection and Characterization of Autoagglutination Activity by
Campylobacter jejuni
Authors: Misawa Naoaki , Blaser Martin J. 
Published: July 2002

ABSTRACT

In several gram-negative bacterial pathogens, autoagglutination (AAG) activity is a marker for interaction with host cells and virulence.
Campylobacter jejuni
strains also show AAG, but this property varies considerably among strains. To examine the characteristics of
C. jejuni
AAG, we developed a quantitative in vitro assay. For strain 81-176, which shows high AAG, activity was optimal for cells grown for ≤24 h, was independent of growth temperature, and was best measured for cells suspended in phosphate-buffered saline at 25°C for 24 h. AAG activity was heat labile and was abolished by pronase or acid-glycine (pH 2.2) treatment but not by lipase, DNase, or sodium metaperiodate. Strain 4182 has low AAG activity, but extraction with water increased AAG, suggesting the loss of an inhibitor. Strain 6960 has weak AAG with no effect due to water extraction. Our study with clinical isolates suggests that
C. jejuni
strains may be grouped into three AAG phenotypes. A variant derived from strain 81116 that is flagellate but immotile showed the strong AAG exhibited by the parent strain, suggesting that motility per se is not necessary for the AAG activity. AAG correlated with both bacterial hydrophobicity and adherence to INT407 cells. Mutants which lack flagella (
flaA
,
flaB
, and
flbA
) or common cell surface antigen (
peb1A
) were constructed in strain 81-176 by natural transformation-mediated allelic exchange. Both AAG activity and bacterial hydrophobicity were abolished in the aflagellate mutants but not the
peb1A
mutant. In total, these findings indicate that
C. jejuni
AAG is highly associated with flagellar expression.
Genetic Diversity of the Capsular Polysaccharide C Biosynthesis Region of
Bacteroides fragilis
Authors: Comstock Laurie E. , Pantosti Annalisa , Kasper Dennis L. 
Published: July 2002

ABSTRACT

A genetic approach was used to assess the heterogeneity of the capsular polysaccharide C (PS C) biosynthesis locus of
Bacteroides fragilis
and to determine whether distinct loci contain genes whose products are likely to be involved in conferring charged groups that enable the
B. fragilis
capsular polysaccharides to induce abscesses. A collection of 50
B. fragilis
strains was examined. PCR analysis demonstrated that the genes flanking the PS C biosynthesis region are conserved, whereas the genes within the loci are heterogeneous. Only
cfiA
+
B. fragilis
strains, which represent 3% of the clinical isolates of
B. fragilis
, displayed heterogeneity in the regions flanking the polysaccharide biosynthesis genes. Primers were designed in the conserved regions upstream and downstream of the PS C locus and were used to amplify the region from 45 of the 50
B. fragilis
strains studied. Fourteen PS C genetic loci could be differentiated by a combination of PCR and extended PCR. These loci ranged in size from 14 to 26 kb. Hybridization analysis with genes from the PS C loci of strains 9343 and 638R revealed that the majority of strains contain homologs of
wcgC
(
N
-acetylmannosamine dehydrogenase),
wcfF
(putative dehydrogenase), and
wcgP
(putative aminotransferase). The data suggest that the synthesis of polysaccharides that have zwitterionic characteristics rendering them able to induce abscesses is common in
B. fragilis
.
The
Cryptococcus neoformans
Gene
DHA1
Encodes an Antigen That Elicits a Delayed-Type Hypersensitivity Reaction in Immune Mice
Authors: Mandel M. Alejandra , Grace Greg G. , Orsborn Kris I. , Schafer Fredda , Murphy Juneann W. , Orbach Marc J. , Galgiani John N. 
Published: July 2002

ABSTRACT

When mice are vaccinated with a culture filtrate from
Cryptococcus neoformans
(CneF), they mount a protective cell-mediated immune response as detected by dermal delayed-type hypersensitivity (DTH) to CneF. We have identified a gene (
DHA1
) whose product accounts at least in part for the DTH reactivity. Using an acapsular mutant (Cap-67) of
C. neoformans
strain B3501, we prepared a culture filtrate (CneF-Cap67) similar to that used for preparing the commonly used skin test antigen made with
C. neoformans
184A (CneF-184A). CneF-Cap67 elicited DTH in mice immunized with CneF-184A. Deglycosylation of CneF-Cap67 did not diminish its DTH activity. Furthermore, size separation by either chromatography or differential centrifugation identified the major DTH activity of CneF-Cap67 to be present in fractions that contained proteins of approximately 19 to 20 kDa. Using N-terminal and internal amino acid sequences derived from the 20-kDa band, oligonucleotide primers were designed, two of which produced a 776-bp amplimer by reverse transcription-PCR (RT-PCR) using RNA from Cap-67 to prepare cDNA for the template. The amplimer was used as a probe to isolate clones containing the full-length
DHA1
gene from a phage genomic library prepared from strain B3501. The full-length cDNA was obtained by 5′ rapid amplification of cDNA ends and RT-PCR. Analysis of
DHA1
revealed a similarity between the deduced open reading frame and that of a developmentally regulated gene from
Lentinus edodes
(shiitake mushroom) associated with fruiting-body formation. Also, the gene product contained several amino acid sequences identical to those determined biochemically from the purified 20-kDa peptide encoded by
DHA1
. Recombinant DHA1 protein expressed in
Escherichia coli
was shown to elicit DTH reactions similar to those elicited by CneF-Cap67 in mice immunized against
C. neoformans
. Thus,
DHA1
is the first gene to be cloned from
C. neoformans
whose product has been shown to possess immunologic activity.
Preparation and Preclinical Evaluation of a Novel Liposomal Complete-Core Lipopolysaccharide Vaccine
Authors: Bennett-Guerrero Elliott , McIntosh Thomas J. , Barclay G. Robin , Snyder D. Scott , Gibbs Richard J. , Mythen Michael G. , Poxton Ian R. 
Published: July 2002

ABSTRACT

Our objective is to develop a prophylactic vaccine strategy that can be evaluated for surgical and other high-risk hospitalized patients. In this paper, we describe the preparation and preclinical evaluation of a liposomal complete-core lipopolysaccharide (LPS) vaccine that is nontoxic and broadly antigenic. Complete-core (Ra-chemotype) LPSs were isolated from four gram-negative bacterial strains (
Escherichia coli
K-12,
E. coli
R1,
Pseudomonas aeruginosa
PAC608, and
Bacteroides fragilis
), mixed together to form a cocktail of complete-core LPSs, and then incorporated into multilamellar liposomes consisting of dimyristoyl phosphatidyl choline, dimyristoyl phosphatidylglycerol, and cholesterol in a 4:1:4 molar ratio. The endotoxic activities of these LPS-containing liposomes were less than 0.1% of the endotoxicities of the original free LPSs as measured by the
Limulus
amoebocyte lysate assay. In vivo administration of liposomal complete-core LPS mixed with Al(OH)
3
to rabbits resulted in no pyrogenicity or overt toxicity over a 7-day period. In immunoblots, sera from rabbits following active immunization elicited cross-reactive antibodies to a large panel of rough and smooth LPSs from numerous clinically relevant gram-negative bacteria, including
E. coli
(serotypes O1, O4, O6, O8, O12, O15, O18, O75, O86, O157, and O111),
P. aeruginosa
(Fisher-Devlin serotypes 1, 2, and 3, which correspond to International Antigenic Typing Scheme types 6, 11, and 2, respectively),
Klebsiella pneumoniae
(serotypes O1, O2ab, and O3),
B. fragilis
, and
Bacteroides vulgatus
. Active immunization of mice with liposomal complete-core LPS provided protection against a lethal challenge with
E. coli
O18 LPS. The vaccine tested was nontoxic, nonpyrogenic, and immunogenic against a wide variety of pathogens found in clinical settings.
Distribution of Open Reading Frames of Plasticity Region of Strain J99 in
Helicobacter pylori
Strains Isolated from Gastric Carcinoma and Gastritis Patients in Costa Rica
Authors: Occhialini Alessandra , Marais Armelle , Alm Richard , Garcia Fernando , Sierra Rafaela , Mégraud Francis 
Published: July 2002

ABSTRACT

The plasticity region of
Helicobacter pylori
strain J99 is a large chromosomal segment containing 33 strain-specific open reading frames (ORFs) with characteristics of a pathogenicity island. To study the diversity of the plasticity region, 22 probes corresponding to 20 ORFs inside the plasticity region and two ORFs on its boundaries were hybridized to genomic DNA isolated from clinical strains of
H. pylori
from patients with gastritis or gastric adenocarcinoma. Highly variable hybridization patterns were observed. The majority of the clinical strains presented a hybridization profile similar to that of J99; thus, these ORFs are not J99 strain specific. No association was found between a particular hybridization pattern and the clinical origin of the strain. Nevertheless, two single ORFs (JHP940 and JHP947) were more likely to be found in gastric cancer strains. They may be new pathogenicity markers. An in vitro expression study of these ORFs was also performed for the J99 strain, under different conditions. Thirteen ORFs were consistently expressed, six were consistently shut off, and three were expressed differentially. Most of the constitutionally expressed genes were located on the 3′ part of the plasticity region. Our results show that the plasticity region, rather than being considered a pathogenicity island per se, should be considered a genomic island, which represents a large fragment of foreign DNA integrated into the genome and not necessarily implicated in the pathogenic capacity of the strain.
Antigenic Structure of Outer Membrane Protein E of
Moraxella catarrhalis
and Construction and Characterization of Mutants
Authors: Murphy Timothy F. , Brauer Aimee L. , Yuskiw Norine , Hiltke Thomas J. 
Published: July 2002

ABSTRACT

Outer membrane protein E (OMP E) is a 50-kDa protein of
Moraxella catarrhalis
which possesses several characteristics indicating that the protein will be an effective vaccine antigen. To study the antigenic structure of OMP E, eight monoclonal antibodies were developed and characterized. Three of the antibodies recognized epitopes which are present on the bacterial surface. Fusion peptides corresponding to overlapping regions of OMP E were constructed, and immunoblot assays were performed to localize the areas of the molecule bound by the monoclonal antibodies. These studies identified a surface-exposed epitope in the region of amino acids 80 through 180. To further study the protein, two mutants which lack OMP E were constructed. In bactericidal assays, the mutants were more readily killed by normal human serum compared to the isogenic parent strains. These results indicate that OMP E is involved in the expression of serum resistance of
M. catarrhalis
.
Modulation of Innate Cytokine Responses by Products ofHelicobacter pylori
Authors: Meyer Frank , Wilson Keith T. , James Stephen P. 
Published: July 2002

ABSTRACTThe gastric inflammatory and immune response inHelicobacter pyloriinfection may be due to the effect of differentH. pyloriproducts on innate immune mechanisms. The aim of this study was to determine whether bacterial components could modulate cytokine production in vitro and thus contribute to Th1 polarization of the gastric immune response observed in vivo. The effect ofH. pylorirecombinant urease, bacterial lysate, intact bacteria, and bacterial DNA on proliferation and cytokine production by peripheral blood mononuclear cells (PBMCs) fromH. pylori-negative donors was examined as a model for innate cytokine responses. Each of the differentH. pyloripreparations induced gamma interferon (IFN-γ) and interleukin-12p40 (IL-12p40), but not IL-2 or IL-5, production, and all butH. pyloriDNA stimulated release of IL-10. Addition of anti-IL-12 antibody to cultures partially inhibited IFN-γ production. In addition, each bacterial product inhibited mitogen-stimulated IL-2 production by PBMCs and Jurkat T cells. The inhibitory effect of bacterial products on IL-2 production correlated with inhibition of mitogen-stimulated lymphocyte proliferation, although urease inhibited IL-2 production without inhibiting proliferation, suggesting that inhibition of IL-2 production alone is not sufficient to inhibit lymphocyte proliferation. The results of these studies demonstrate that Th1 polarization of the gastric immune response may be due in part to the direct effects of multiple differentH. pyloricomponents that enhance IFN-γ and IL-12 production while inhibiting both IL-2 production and cell proliferation that may be necessary for Th2 responses.
Visceral Leishmaniasis in Mice Devoid of Tumor Necrosis Factor and Response to Treatment
Authors: Murray Henry W. , Jungbluth Achim , Ritter Erika , Montelibano Christina , Marino Michael W. 
Published: July 2002

ABSTRACTTumor necrosis factor (TNF)-deficient mice were challenged withLeishmania donovanito characterize TNF in the response of visceral intracellular infection to antileishmanial chemotherapy. In wild-type controls (i) liver infection peaked at week 2 and resolved, (ii) discrete liver granulomas developed at weeks 2 to 4 and involuted, and (iii) leishmanicidal responses to antimony (Sb), amphotericin B (AmB), and miltefosine were intact. In TNF knockout (KO) mice (i) initial liver infection was unrestrained, plateaued, and then declined somewhat by week 6, (ii) an absent early granulomatous reaction abruptly accelerated with striking tissue inflammation, widespread hepatic necrosis, and 100% mortality by week 10, and (iii) while the initial response to AmB and miltefosine was intact, killing induced by Sb therapy was reduced by >50%. Although initial AmB treatment during weeks 2 to 3 killed 98% of liver parasites, 75% of AmB-treated KO mice subsequently relapsed and died by week 12; however, additional maintenance AmB preserved long-term survival. These results for a model of visceral infection indicate that endogenous TNF is required early on to control intracellularL. donovani, support granuloma development, and mediate optimal initial effects of Sb and prevent relapse after ordinarily curative AmB treatment. A compensatory, TNF-independent antileishmanial mechanism developed in TNF KO mice; however, its effect was uncontrolled fatal inflammation. Chemotherapeutic elimination of the parasite stimulus reversed the hyperinflammatory response and preserved survival.