bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of a Monoclonal Antibody-Blocking Enzyme-Linked Immunoassay and a Strip Immunoblot Assay for Identifying Type-Specific Herpes Simplex Virus Type 2 Serological Responses
Authors: Van Doornum G. J. J. , Slomka M. J. , Buimer M. , Groen J. , Van den Hoek J. A. R. , Cairo I. , Vyse A. , Brown D. W. G. 
Published: July 2002

ABSTRACT
Detection of herpes simplex virus type 2 (HSV-2)-specific antibodies by a monoclonal antibody (MAb)-blocking enzyme-linked immunoassay (EIA) was compared with detection by a strip immunoblot assay (SIA) in a sexually transmitted disease (STD) clinic population. The study population consisted of 1,683 genitourinary medicine clinic attendees (582 women and 1,101 men). Sera were tested for the presence of HSV-2 antibody by use of the blocking EIA, in which binding of the MAb AP-1 to HSV-2 glycoprotein G-2 (gG-2) is blocked by HSV-2-specific antibody. The Chiron RIBA HSV-1 and -2 strip immunoassay (SIA) utilizes HSV-1- and HSV-2-specific or cross-reactive antigens immobilized on nitrocellulose strips (HSV gB-1 and HSV gG-1 peptide bands specific for HSV-1 antibody, HSV-2 gG-2 band specific for HSV-2 antibody, and HSV gD-2 band cross-reactive for HSV-1 and HSV-2 antibodies). A total of 1,612 sera were tested by MAb-blocking EIA for HSV-2 antibody and by SIA for HSV-1 and HSV-2 antibodies. By EIA, 541 (33.6%) sera were positive for HSV-2 antibody and 1,068 sera were negative for HSV-2 antibody; 3 sera gave equivocal results. HSV-2 antibody was detected in 555 (34.4%) sera by SIA; 144 (26%) of these sera possessed only HSV-2 antibody, and 411 (74%) sera contained both HSV-1 and HSV-2 antibodies. SIA detected HSV-1 antibody in 1,155 (71.6%) sera; 744 (64%) of these sera contained HSV-1 antibody alone. Sixteen sera contained antibody against HSV but could not be typed by SIA. A total of 512 sera were positive for HSV-2 antibody by both the EIA and SIA. We concluded that the blocking EIA and SIA showed a high level of agreement in detecting HSV-2 antibody in this population. In contrast to the SIA, the blocking EIA is a useful tool for large epidemiological studies, though the SIA proved to be slightly more sensitive once sera with discrepant results were further tested.
Rapid Detection of
Salmonella enterica
Serovar Choleraesuis in Blood Cultures by a Dot Blot Enzyme-Linked Immunosorbent Assay
Authors: Janyapoon Kritsana , Korbsrisate Sunee , Thamapa Hatairat , Thongmin Sittichai , Kanjanahareutai Suwattana , Wongpredee Niramol , Sarasombath Suttipant 
Published: July 2002

ABSTRACT

A dot blot enzyme-linked immunosorbent assay (ELISA) with a monoclonal antibody specific to phase1-c
Salmonella
was developed for the direct detection of
Salmonella enterica
serovar Choleraesuis in blood cultures. This system was applied to the identification of serovar Choleraesuis, and the results were compared with those obtained by a conventional biochemical method. It was revealed that all 12 samples identified to be infected with serovar Choleraesuis were positive on testing by the ELISA. In contrast, 77 samples infected with bacteria commonly isolated from the blood were not reactive by the ELISA. The calculated sensitivity and specificity of the established assay are 100%.
Development of a Novel In Vitro Assay (ALS Assay) for Evaluation of Vaccine-Induced Antibody Secretion from Circulating Mucosal Lymphocytes
Authors: Chang H. Sunny , Sack David A. 
Published: July 2002

ABSTRACT

We describe here a novel method for measuring in vitro antibody secretion from the tissue culture of human B lymphocytes in peripheral blood mononuclear cells (PBMC) after oral vaccination with a killed cholera vaccine. Enzyme-linked immunosorbent assay (ELISA) titers of the antibody secreted in the cell supernatant were determined. The validation results demonstrated that human PBMC remained viable and continued to secrete antibodies (total immunoglobulin A [IgA] and IgG) for up to 4 days of incubation at 37°C with 5% CO
2
in cell cultures. The secreted antibody concentration correlated positively with the PBMC concentration and incubation time in the tissue culture and correlated negatively with the storage time of the whole blood at room temperature. In vitro assay of secreting antibody in the lymphocyte supernatant (i.e., the ALS assay) is capable of the detecting specific antibody response after oral vaccination with a killed whole-cell-plus-B-subunit cholera vaccine (WC-B) in healthy adults in a phase I clinical trial. Postimmunization PBMC secreted antibodies to cholera toxin in the cell supernatants. Antibody production did not require any in vitro antigen stimulation. In the ALS assay, antigen-specific antibody titers of prevaccination samples were barely detectable, whereas serum antitoxin ELISA titers in background of prevaccine samples were significantly higher than the ALS titers. We conclude that, without any in vitro antigen stimulation after vaccination, PBMC secrete antibodies into the supernatants in the ALS assay. This assay can quantitatively measure the antigen-specific antibody production from the PBMC culture in postvaccination blood samples.
Simplified Assay for Measuring
Toxoplasma gondii
Immunoglobulin G Avidity
Authors: Prince Harry E. , Wilson Marianna 
Published: July 2002

ABSTRACT

A
Toxoplasma gondii
immunoglobulin G (IgG) avidity enzyme-linked immunosorbent assay (ELISA) was developed that combines the accuracy of assays based on end point titers and the relative ease of assays based on optical density values. Like published procedures, the new assay's avidity index (AI) was based on differential
T. gondii
-specific IgG reactivity in serum-treated wells washed with urea buffer versus that in wells washed with control buffer; unlike previous assays, however, the IgG reactivity was measured quantitatively using a standard curve. The assay was evaluated using 24 IgG-positive and IgM-positive sera collected within 5 months of the onset of symptoms (recent-infection group) and 25 IgG-positive and IgM-negative sera (past-infection group). All sera in the recent-infection group exhibited AI values of <0.18, whereas all sera in the past-infection group exhibited AI values of >0.27. The AI values of the recent-infection group showed significant correlation with the number of days after the onset of symptoms. A subset of 16 sera (8 recent and 8 past) was tested using a commercially available
T. gondii
IgG avidity ELISA based on end point titration; the results of the two assays showed highly significant correlation (
R
2
= 0.9125). In addition, we confirmed and extended the findings of other investigators, showing that AI values calculated using optical density values, but not AI values calculated using quantitative IgG values, varied significantly depending on the serum dilution used. This new assay should facilitate the accurate measurement of
T. gondii
IgG avidity in a reference laboratory setting.
Comparison of Serologic Assays for Detection of Antibodies against Human Herpesvirus 8
Authors: Corchero Jose L. , Mar Eng-Chun , Spira Thomas J. , Pellett Philip E. , Inoue Naoki 
Published: July 2002

ABSTRACT
Improvement of serologic assays for detection of antibodies against human herpesvirus 8 (HHV-8) is critical to better understand its epidemiology and biology. We produced the HHV-8 latent (ORF73) and lytic (ORF65, K8.1, and glycoprotein B) antigens in the Semliki Forest virus system and evaluated their performance in immunofluorescence assays (IFAs) and enzyme-linked immunosorbent assays (ELISAs). These assays were compared with other latent antigen-based assays, including an IFA based on primary effusion lymphoma (PEL) cells and an ELISA based on bacterially expressed ORF73 antigen, as well as with other lytic antigen-based assays, including an IFA based on induced PEL cells, a commercial ELISA based on purified virions, and ELISAs based on K8.1- and ORF65-derived oligopeptides. We used a panel of 180 serum specimens obtained from three groups expected to have high, intermediate, and low HHV-8 prevalences. Using three different evaluation methods, we found that (i) the performances of the lytic antigen-based ELISAs were almost equivalent, (ii) the lytic antigen-based assays were more sensitive than the latent antigen-based assays, and (iii) in general, IFAs were more sensitive than ELISAs based on the same open reading frame. We also found that serum specimens from healthy individuals contained antibodies cross-reactive with HHV-8 glycoprotein B that can potentially cause false-positive reactions in lytic PEL-based IFAs. Although this is not a substantial problem in most epidemiologic studies, it may confound the interpretation of data in studies that require high assay specificity. Because the K8.1-based IFA provides sensitivity similar to that of lytic PEL-based IFAs and improved specificity, it can be a useful alternative to the PEL-based IFAs.
Augmentation of Cellular Immunity and Reduction of Influenza Virus Titer in Aged Mice FedLactobacillus caseiStrain Shirota
Authors: Hori Tetsuji , Kiyoshima Junko , Shida Kan , Yasui Hisako 
Published: July 2002

ABSTRACTWe investigated whether oral administration ofLactobacillus caseistrain Shirota activates the cellular immune system and ameliorates influenza virus (IFV) titer in the nasal site in upper respiratory IFV infection by using aged mice. Natural killer activity of splenocytes and lung cells of aged mice fed anL. caseistrain Shirota diet (L.caseistrain Shirota group) was significantly (P< 0.01 andP< 0.05) increased compared to those fed a control diet (control group). The increases were 1.5- and 2.5-fold, respectively. In aged mice fed an XL.caseistrain Shirota diet, potent induction of gamma interferon (IFN-γ) and tumor necrosis factor alpha (TNF-α), which play a very important role in excluding IFV, was evident in nasal lymphocytes. IFN-γ and TNF-α production increased 12- and 3.5-fold, respectively. In this model of upper respiratory IFV infection, the titer of IFV in the nasal washings of aged mice fed anL.caseistrain Shirota diet was significantly (P< 0.05) lower than that in aged mice fed a control diet (101.6 ± 0.6and 102.2 ± 0.5, respectively). These findings suggest that oral administration ofL.caseistrain Shirota activates not only systemic cellular immunity but also local cellular immunity and that it ameliorates IFV infection.
Indeterminate Human Immunodeficiency Virus Western Blot Profiles in Ethiopians with Discordant Screening-Assay Results
Authors: Meles Hailu , Wolday Dawit , Fontanet Arnaud , Tsegaye Aster , Tilahun Tesfaye , Aklilu Mathias , Sanders Eduard , De Wit Tobias F. Rinke 
Published: July 2002

ABSTRACT

The Western blot (WB) assay is the most widely accepted confirmatory assay for the detection of antibodies to human immunodeficiency virus type 1 (HIV-1). However, indeterminate WB reactivity to HIV-1 proteins may occur in individuals who do not appear to be infected with HIV. The profiles of WB reactivity among Ethiopians are hardly known. Here, we describe the profiles of indeterminate WB reactivity in Ethiopians with discordant screening assays. Between 1996 and 2000, a total of 12,124 specimens were tested for HIV-1 antibodies. Overall, 1,437 (11.9%) were positive for HIV-1 antibody. Ninety-one (≈0.8%) gave equivocal results because of discordant results among the various screening assays and indeterminate WB profiles by the American Red Cross (ARC) criteria. Most (30.4%) of these indeterminate WB results were due to p24 reactivity. However, 12 samples (13.2%) displayed reactivity to p24 and gp41 or to p24 and gp120/160 proteins (positive by Centers for Disease Control and Prevention [CDC] criteria). Only two samples (2.2%) were reactive to both
env
glycoproteins gp41 and gp120/160 (positive by the World Health Organization [WHO] criteria). Of 31 WB assays initially indeterminate by the ARC criteria and with follow-up samples, 29 (93.5%) became negative when retested subsequently while 2 (6.5%) remained indeterminate for more than a year and were thus considered negative. Using CDC and WHO criteria, 6 (19.4%) and 2 (6.5%), respectively, of these WB assays would have been considered falsely positive. In addition, 17 indeterminate samples were negative when assessed by a nucleic acid-based amplification assay for HIV-1 viremia. In general, there was 97.8% concordance between the ARC and WHO criteria and 85.7% concordance between the ARC and CDC criteria for an indeterminate WB result. The ARC criteria best met the specified objectives for diagnosis in our setting.
Use of
Taenia crassiceps
Cysticercus Antigen Preparations for Detection of Antibodies in Cerebrospinal Fluid Samples from Patients with Neurocysticercosis (
Taenia solium
)
Authors: Pardini Alessandra Xavier , Peralta Regina Helena , Vaz Adelaide José , Machado Luis dos Ramos , Peralta José Mauro 
Published: July 2002

ABSTRACT

Antigen extracts obtained from the vesicular fluid of
Taenia crassiceps
cysticerci and from fractions purified by affinity chromatography with the lectin concanavalin A and the glycoprotein antigen separated by electrophoresis were used for the detection of
Taenia solium
anticysticercus antibodies. The sensitivity and specificity obtained for all antigens were 100% in enzyme-linked immunosorbent assay with good reproducibility. Using immunoblotting of the three antigens, low-molecular-mass peptides (18 and 14 kDa) were characterized only in cerebrospinal fluid samples from patients with neurocysticercosis. The results confirm that antigen fractions purified from
T. crassiceps
cisticerci are important sources of specific peptides and proved to be efficient in detecting anti-
T. solium
antibodies.
Levels of Soluble CD40 Ligand (CD154) in Serum Are Increased in Human Immunodeficiency Virus Type 1-Infected Patients and Correlate with CD4+T-Cell Counts
Authors: Sipsas Nikolaos V. , Sfikakis Petros P. , Kontos Athanasios , Kordossis Theodore 
Published: July 2002

ABSTRACTCD40 ligand (CD40L or CD154) is a costimulatory molecule expressed mainly on activated CD4+T cells. Concentrations of the soluble form of CD40L (sCD40L) in serum were determined for a cohort of 77 human immunodeficiency virus type 1 (HIV-1)-infected patients before and after initiation of highly active antiretroviral treatment (HAART) by a quantitative enzyme-linked immunosorbent assay. Circulating sCD40L levels were higher by twofold in untreated patients than in healthy controls (means ± standard deviations [SD]: 1.41 ± 1.48 versus 0.69 ± 0.59 ng/ml;P< 0.001). HIV-1-infected patients classified as CD4 T-cell category 1 had significantly higher sCD40L levels than patients classified as CD4 categories 2 and 3 (mean ± SD: 2.08 ± 1.46 ng/ml versus 1.57 ± 1.58 [category 2] and 0.94 ± 1.25 ng/ml [category 3];P= 0.046), while no correlation with clinical categories A, B, and C was found. Individual serum sCD40L levels correlated with CD4+T-cell counts (P= 0.039) but not with viral load, gamma globulin levels, or acute-inflammatory-response markers. After 8 to 12 months of HAART, a further threefold increase of serum sCD40L levels, which paralleled the increase of CD4+T-cell counts, was observed. These novel findings suggest that sCD40L measurement in HIV-1-infected patients could serve as a new surrogate marker useful in the assessment of treatment efficacy, especially in settings where well-equipped laboratories and funding required for CD4+T-cell count and viral load measurements are not available.
Quantitative Detection of
Helicobacter pylori
Gene Expression In Vivo and Relationship to Gastric Pathology
Authors: Peek Richard M. , van Doorn Leen-Jan , Donahue John P. , Tham Kyi T. , Figueiredo Ceu , Blaser Martin J. , Miller Geraldine G. 
Published: July 2002

ABSTRACT

The
iceA
locus of
Helicobacter pylori
includes one of two mutually exclusive gene families,
iceA1
and
iceA2
. Colonization with
iceA1
strains is associated with enhanced acute mucosal inflammation, and adherence to gastric epithelial cells in vitro induces expression of
iceA1
but not
iceA2
mRNA; however, both transcripts can be detected in vivo. The aim of this study was to determine whether differing levels of
iceA
transcription in vivo may contribute to disease pathogenesis. RNA from 41
H. pylori-positive gastric biopsy specimens was reverse transcribed to cDNA. Quantitative PCR was performed using biotinylated iceA1
,
iceA2
, and 16S rRNA primers, and binding of biotinylated products to streptavidin-coated plates was detected by hybridization with a fluorescein-labeled probe.
iceA
genotypes were determined by PCR and sequence analysis. All 41 samples contained detectable
H. pylori
16S rRNA, with similar levels in
iceA1
- (
n
= 10) and
iceA2
(
n
= 31)-colonized patients (
P
= 0.34). Biopsy specimens from four (40%) and 19 (61%) persons colonized with
iceA1
or
iceA2
strains, respectively, had detectable
iceA
RNA. Acute inflammatory scores were significantly higher in
iceA1
RNA-positive patients than in
iceA1
RNA-negative,
iceA2
RNA-positive, or
iceA2
RNA-negative subjects (
P
≤ 0.05 for each). Within the
iceA2
RNA-positive group,
H. pylori
strains with a single 35-amino-acid cassette were associated with significantly higher mucosal
iceA2
transcript levels (
P
= 0.014 versus strains with two cassettes). These results indicate that the levels of transcription of
H. pylori iceA1
and
iceA2
and of 16S rRNA are independent and that particular
iceA2
gene structures are associated with enhanced transcription. The finding that
iceA1
transcription levels are significantly associated with the intensity of neutrophilic infiltration suggests that heterogeneity in inflammatory scores among persons colonized with
H. pylori iceA1
strains reflects levels of
iceA1
transcription in vivo.
New Method To Generate Enzymatically Deficient
Clostridium difficile
Toxin B as an Antigen for Immunization
Authors: Genth Harald , Selzer Jörg , Busch Christian , Dumbach Jürgen , Hofmann Fred , Aktories Klaus , Just Ingo 
Published: July 2002

ABSTRACT

The family of the large clostridial cytotoxins, encompassing
Clostridium difficile
toxins A and B as well as the lethal and hemorrhagic toxins from
Clostridium sordellii
, monoglucosylate the Rho GTPases by transferring a glucose moiety from the cosubstrate UDP-glucose. Here we present a new detoxification procedure to block the enzyme activity by treatment with the reactive UDP-2′,3′-dialdehyde to result in alkylation of toxin A and B. Alkylation is likely to occur in the catalytic domain, because the native cosubstrate UDP-glucose completely protected the toxins from inactivation and the alkylated toxin competes with the native toxin at the cell receptor. Alkylated toxins are good antigens resulting in antibodies recognizing only the C-terminally located receptor binding domain, whereas formaldehyde treatment resulted in antibodies recognizing both the receptor binding domain and the catalytic domain, indicating that the catalytic domain is concealed under native conditions. Antibodies against the native catalytic domain (amino acids 1 through 546) and those holotoxin antibodies recognizing the catalytic domain inhibited enzyme activity. However, only antibodies against the receptor binding domain protected intact cells from the cytotoxic activity of toxin B, whereas antibodies against the catalytic domain were protective only when inside the cell.
Endotoxin-Induced Lung Inflammation Is Independent of the Complement Membrane Attack Complex
Authors: Brauer R. B. , Gegenfurtner C. , Neumann B. , Stadler M. , Heidecke C. D. , Holzmann B. 
Published: July 2002

ABSTRACTSeveral products of the activated complement system are known to modulate endothelial cell function in vitro. It has been shown that the membrane attack complex (MAC) (C5b-C9) can enhance tumor necrosis factor alpha (TNF-α)-induced expression of P- and E-selectin and intercellular adhesion molecule type 1 in cell cultures of human umbilical vein endothelial cells. In the present study the potential role of this synegism for lung injury during endotoxin-mediated septic shock in vivo was examined using a model of C6-deficient PVG (C−) (RT1C) rats and the congenic PVG (C+) (RT1C) strain. Following administration of a high (5 mg/kg) or low (0.5 mg/kg) dose of lipopolysaccharide (LPS) (Escherichia coliO55:B5), we determined the expression of cytokines, chemokines, and adhesion molecules as well as the recruitment of leukocytes in the lung. Challenge with intraperitoneal i.p. injections of LPS resulted in a strong induction of TNF-α, interleukin-1α/β, cytokine-induced neutrophil chemoattractant, interferon-inducible protein 10, macrophage inflammatory proteins 1α and 2, macrophage chemotactic protein 1, and P-selectin. However, there were no significant differences between PVG (C−) and PVG (C+) rats. Immunoperoxidase staining showed a similar increase of lung infiltration by CD11b/c+leukocytes in both rat strains. We therefore conclude that the described synergism between TNF-α and the MAC of the complement system on the induction of endothelial adhesion molecules is dispensable for inflammatory processes during endotoxin-mediated septic shock in vivo.
Cloning, Sequencing, and Role in Serum Susceptibility of Porin II from MesophilicAeromonas hydrophila
Authors: Nogueras Maria Mercé , Merino Susana , Aguilar Alicia , Benedi Vicente Javier , Tomás Juan M. 
Published: July 2002

ABSTRACTWe cloned and sequenced the structural gene forAeromonas hydrophilaporin II from strain AH-3 (serogroup O:34). The genetic position of this gene, like that ofompFinEscherichia coli, is adjacent toaspCand transcribed in the same direction. However, upstream of the porin II gene no similarities withE. coliwere found. We obtained defined insertion mutants in porin II gene either inA. hydrophila(O:34) orA. veronii sobria(serogroup O:11) serum-resistant or -sensitive strains. Furthermore, we complemented these mutants with a plasmid harboring only the porin II gene, which allowed us to define the role of porin II as an important surface molecule involved in serum susceptibility and C1q binding in these strains.
Molecular and Biological Analysis of Eight Genetic Islands That Distinguish
Neisseria meningitidis
from the Closely Related Pathogen
Neisseria gonorrhoeae
Authors: Klee Silke R. , Nassif Xavier , Kusecek Barica , Merker Petra , Beretti Jean-Luc , Achtman Mark , Tinsley Colin R. 
Published: July 2002

ABSTRACT

The pathogenic species
Neisseria meningitidis
and
Neisseria gonorrhoeae
cause dramatically different diseases despite strong relatedness at the genetic and biochemical levels.
N. meningitidis
can cross the blood-brain barrier to cause meningitis and has a propensity for toxic septicemia unlike
N. gonorrhoeae
. We previously used subtractive hybridization to identify DNA sequences which might encode functions specific to bacteremia and invasion of the meninges because they are specific to
N. meningitidis
and absent from
N. gonorrhoeae
. In this report we show that these sequences mark eight genetic islands that range in size from 1.8 to 40 kb and whose chromosomal location is constant. Five of these genetic islands were conserved within a representative set of strains and/or carried genes with homologies to known virulence factors in other species. These were deleted, and the mutants were tested for correlates of virulence in vitro and in vivo. This strategy identified one island, region 8, which is needed to induce bacteremia in an infant rat model of meningococcal infection. Region 8 encodes a putative siderophore receptor and a disulfide oxidoreductase. None of the deleted mutants was modified in its resistance to the bactericidal effect of serum. Neither were the mutant strains altered in their ability to interact with endothelial cells, suggesting that such interactions are not encoded by large genetic islands in
N. meningitidis
.