bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of Synthetic Peptides Derived from the Antigens ESAT-6 and CFP-10 for Differential Diagnosis of Bovine Tuberculosis in Cattle
Authors: Vordermeier H. M. , Whelan A. , Cockle P. J. , Farrant L. , Palmer N. , Hewinson R. G. 
Published: July 2002

ABSTRACTIn Great Britain an independent scientific review for the government has concluded that the development of a cattle vaccine againstMycobacterium bovisinfection holds the best long-term prospect for tuberculosis control in British herds. A precondition for vaccination is the development of a complementary diagnostic test to differentiate between vaccinated animals and those infected withM. bovisso that testing and slaughter-based control strategies can continue alongside vaccination. To date bacillus Calmette-Guérin (BCG), an attenuated strain ofM. bovis, is the only available vaccine for the prevention of tuberculosis. However, tests based on tuberculin purified protein derivative cannot distinguish betweenM. bovisinfection and BCG vaccination. Therefore, specific antigens expressed byM. bovisbut absent from BCG constitute prime candidates for differential diagnostic reagents. Recently, two such antigens, ESAT-6 and CFP-10, have been reported to be promising candidates as diagnostic reagents for the detection ofM. bovisinfection in cattle. Here we report the identification of promiscuous peptides of CFP-10 that were recognized byM. bovis-infected cattle. Five of these peptides were formulated into a peptide cocktail together with five peptides derived from ESAT-6. Using this peptide cocktail in T-cell assays,M. bovis-infected animals were detected, while BCG-vaccinated orMycobacterium avium-sensitized animals did not respond. The sensitivity of the peptide cocktail as an antigen in a whole-blood gamma interferon assay was determined using naturally infected field reactor cattle, and the specificity was determined using blood from BCG-vaccinated and noninfected, nonvaccinated animals. The sensitivity of the assay in cattle with confirmed tuberculosis was found to be 77.9%, with a specificity of 100% in BCG-vaccinated or nonvaccinated animals. This compares favorably with the specificity of tuberculin when tested in noninfected or vaccinated animals. In summary, our results demonstrate that this peptide cocktail can discriminate betweenM. bovisinfection and BCG vaccination with a high degree of sensitivity and specificity.
Anemia and Interleukin-10, Tumor Necrosis Factor Alpha, and Erythropoietin Levels among Children with Acute, UncomplicatedPlasmodium falciparumMalaria
Authors: Nussenblatt Veronique , Mukasa Gelasius , Metzger Amy , Ndeezi Grace , Garrett Elizabeth , Semba Richard D. 
Published: July 2002

ABSTRACTAnemia is an important complication of malaria, and its pathogenesis is not well understood. To gain insight into potential age-related relationships between tumor necrosis factor alpha (TNF-α), interleukin 10 (IL-10), erythropoietin, and anemia during acute malaria, 273 children of ages 12 to 120 months presenting with acute, uncomplicated malaria in Kampala, Uganda, were monitored at enrollment and 3 and 7 days later. Younger children had higher geometric mean erythropoietin, TNF-α, and α1-acid glycoprotein (AGP) concentrations than older children. Univariate regression analysis revealed that age, log10erythropoietin levels, IL-10/TNF-α ratio, and AGP levels were each significantly associated with hemoglobin levels at baseline. Hemoglobin concentrations were inversely correlated with the log10erythropoietin level at all three visits. For the older age groups, higher levels of TNF-α were significantly associated with higher IL-10 levels at all three visits, but this relationship was significant only at baseline for younger children. These data suggest that younger children do not maintain IL-10 production in response to the inflammatory process, and this mechanism may contribute to the more severe anemia found in younger children. Acute malaria is an illness whose incidence and severity are largely age dependent. Further studies are needed to understand the relationships between age-related immune responses to malaria and their role in the pathogenesis of malarial anemia.
Development of Internal Controls for the Luminex Instrument as Part of a Multiplex Seven-Analyte Viral Respiratory Antibody Profile
Authors: Martins Thomas B. 
Published: July 2002

ABSTRACT
The ability of the Luminex system to simultaneously quantitate multiple analytes from a single sample source has proven to be a feasible and cost-effective technology for assay development. In previous studies, my colleagues and I introduced two multiplex profiles consisting of 20 individual assays into the clinical laboratory. With the Luminex instrument’s ability to classify up to 100 distinct microspheres, however, we have only begun to realize the enormous potential of this technology. By utilizing additional microspheres, it is now possible to add true internal controls to each individual sample. During the development of a seven-analyte serologic viral respiratory antibody profile, internal controls for detecting sample addition and interfering rheumatoid factor (RF) were investigated. To determine if the correct sample was added, distinct microspheres were developed for measuring the presence of sufficient quantities of immunoglobulin G (IgG) or IgM in the diluted patient sample. In a multiplex assay of 82 samples, the IgM verification control correctly identified 23 out of 23 samples with low levels (<20 mg/dl) of this antibody isotype. An internal control microsphere for RF detected 30 out of 30 samples with significant levels (>10 IU/ml) of IgM RF. Additionally, RF-positive samples causing false-positive adenovirus and influenza A virus IgM results were correctly identified. By exploiting the Luminex instrument’s multiplexing capabilities, I have developed true internal controls to ensure correct sample addition and identify interfering RF as part of a respiratory viral serologic profile that includes influenza A and B viruses, adenovirus, parainfluenza viruses 1, 2, and 3, and respiratory syncytial virus. Since these controls are not assay specific, they can be incorporated into any serologic multiplex assay.
Diagnostic Usefulness of Antibodies against Ribosome Recycling Factor from
Brucella melitensis
in Human or Canine Brucellosis
Authors: Cassataro Juliana , Delpino M. Victoria , Velikovsky Carlos A. , Bruno Laura , Fossati Carlos A. , Baldi Pablo C. 
Published: July 2002

ABSTRACT

The diagnostic usefulness of an enzyme-linked immunosorbent assay (ELISA) using a purified recombinant ribosome recycling factor from
Brucella melitensis
(CP24 antigen) was tested in human and canine infections caused by smooth and rough
Brucella
species, respectively. Anti-CP24 antibodies were detected in 9 (43%) of 21 consecutive cases of canine brucellosis and in 8 (53%) of 15 dogs followed for 60 days after the diagnosis of acute brucellosis. Among eight patients with acute brucellosis, anti-CP24 antibodies were detected in four in the 10 weeks following diagnosis, but the remaining four were negative during the whole follow-up (22 weeks). The frequency of anti-CP24 antibodies was also low among 24 patients with subacute brucellosis and 23 patients with chronic illness (29 and 26%, respectively). While all patients positive for anti-CP24 antibodies were also positive for antibodies to total cytoplasmic proteins of
Brucella
(CP), five were negative for antibodies to another cytoplasmic protein, the
Brucella
lumazine synthase (BLS). When a larger sample of 35 human sera negative for anti-BLS antibodies was assayed, 85.7% were positive for anti-CP24 antibodies, suggesting that the combined measurement of both reactivities could yield a higher sensitivity than any test alone. To test this hypothesis, an ELISA combining both antigens was designed. The percentage of positive results among chronic cases was higher for this assay than for the individual measurement of anti-CP24 or anti-BLS antibodies (83 versus 26 and 65%, respectively) and was closer to the value obtained for anti-CP antibodies (91%). The frequency of anti-CP24 antibodies is low in both canine and human brucellosis. In the latter case, however, an ELISA combining CP24 and BLS is more sensitive than assays measuring anti-CP24 or anti-BLS antibodies separately and almost as sensitive as the ELISA using CP.
Effect of Contaminating Red Blood Cells on OKT3-Mediated Polyclonal Activation of Peripheral Blood Mononuclear Cells
Authors: Song Samuel , Goodwin Joseph , Zhang Jenny , Babbitt Bruce , Lathey Janet L. 
Published: July 2002

ABSTRACT

Erythrocytes are typically present as impurities in the majority of peripheral blood mononuclear cell (PBMC) preparations. This study was undertaken to investigate the effects of contaminating red blood cells (RBC) on the ability of OKT3 to activate CD4
+
and CD8
+
T cells. Surprisingly, the levels of gamma interferon, tumor necrosis factor alpha, and interleukin-1β (IL-1β) produced by PBMC upon stimulation by OKT3 were increased (
P
< 0.05) in a dose-dependent manner when increasing amounts of autologous RBC (RBC-to-PBMC ratios of 2:1, 10:1, and 50:1) were spiked into PBMC preparations. The OKT3-driven induction of the IL-2 receptor (CD25) and the proliferation of T lymphocytes in response to phorbol myristate acetate were not affected by the addition of RBC.
Antibodies to Malaria Vaccine Candidates Pvs25 and Pvs28 Completely Block the Ability ofPlasmodium vivaxTo Infect Mosquitoes
Authors: Hisaeda Hajime , Stowers Anthony W. , Tsuboi Takafumi , Collins William E. , Sattabongkot Jetsumon S. , Suwanabun Natavadee , Torii Motomi , Kaslow David C. 
Published: July 2002

ABSTRACTTransmission-blocking vaccines are one strategy for controlling malaria, whereby sexual-stage parasites are inhibited from infecting mosquitoes by human antibodies. To evaluate whether the recently clonedPlasmodium vivaxproteins Pvs25 and Pvs28 are candidates for a transmission-blocking vaccine, the molecules were expressed in yeast as secreted recombinant proteins. Mice vaccinated with these proteins adsorbed to aluminum hydroxide developed strong antibody responses against the immunogens, although for Pvs28, this response was genetically restricted. Antisera against both recombinant Pvs25 and Pvs28 recognized the corresponding molecules expressed by cultured sexual-stage parasites isolated from patients withP. vivaxmalaria. The development of malaria parasites in mosquitoes was completely inhibited when these antisera were ingested with the infected blood meal. Pvs25 and Pvs28, expressed inSaccharomyces cerevisiae, are as yet the only fully characterized transmission-blocking vaccine candidates againstP. vivaxthat induce such a potent antiparasite response.
Human CD8+T Cells Specific forMycobacterium tuberculosisSecreted Antigens in Tuberculosis Patients and Healthy BCG-Vaccinated Controls in The Gambia
Authors: Smith Steven M. , Klein Michèl R. , Malin Adam S. , Sillah Jackson , Huygen Kris , Andersen Peter , McAdam Keith P. W. J. , Dockrell Hazel M. 
Published: July 2002

ABSTRACTIntracellular flow cytometry analysis of perforin production by CD8+T cells showed levels were greatly reduced in tuberculosis (TB) patients compared to healthy controls. Reduced cytotoxic-T-lymphocyte activity was also obtained with CD8+T cells from TB patients compared to healthy controls in The Gambia. A change in antigen recognition was noted between the two groups of donors: in addition to recognition of Ag85A and Ag85B, as seen in healthy donors, a prominent ESAT-6 response was found in TB patients.
Construction and Characterization of an Effector Strain of
Streptococcus mutans
for Replacement Therapy of Dental Caries
Authors: Hillman J. D. , Brooks T. A. , Michalek S. M. , Harmon C. C. , Snoep J. L. , van der Weijden C. C. 
Published: July 2002

ABSTRACT

An effector strain has been constructed for use in the replacement therapy of dental caries. Recombinant DNA methods were used to make the
Streptococcus mutans
supercolonizing strain, JH1140, lactate dehydrogenase deficient by deleting virtually all of the
ldh
open reading frame (ORF). To compensate for the resulting metabolic imbalance, a supplemental alcohol dehydrogenase activity was introduced by substituting the
adhB
ORF from
Zymomonas mobilis
in place of the deleted
ldh
ORF. The resulting clone, BCS3-L1, was found to produce no detectable lactic acid during growth on a variety of carbon sources, and it produced significantly less total acid due to its increased production of ethanol and acetoin. BCS3-L1 was significantly less cariogenic than JH1140 in both gnotobiotic- and conventional-rodent models. It colonized the teeth of conventional rats as well as JH1140 in both aggressive-displacement and preemptive-colonization models. No gross or microscopic abnormalities of major organs were associated with oral colonization of rats with BCS3-L1 for 6 months. Acid-producing revertants of BCS3-L1 were not observed in samples taken from infected animals (reversion frequency, <10
−3
) or by screening cultures grown in vitro, where no revertants were observed among 10
5
colonies examined on pH indicator medium. The reduced pathogenic potential of BCS3-L1, its strong colonization potential, and its genetic stability suggest that this strain is well suited to serve as an effector strain in the replacement therapy of dental caries in humans.
AMycobacterium ulceransToxin, Mycolactone, Causes Apoptosis in Guinea Pig Ulcers and Tissue Culture Cells
Authors: George Kathleen M. , Pascopella Lisa , Welty Diane M. , Small P. L. C. 
Published: July 2002

ABSTRACTMycobacterium ulceransis the causative agent of Buruli ulcer, a tropical ulcerative skin disease. One of the most intriguing aspects of this disease is the presence of extensive tissue damage in the absence of an acute inflammatory response. We recently purified and characterized a macrolide toxin, mycolactone, fromM. ulcerans. Injection of this molecule into guinea pig skin reproduced cell death and lack of acute inflammatory response similar to that seen following the injection of viable bacteria. We also showed that mycolactone causes a cytopathic effect on mouse fibroblast L929 cells that is characterized by cytoskeletal rearrangements and growth arrest within 48 h. However, these results could not account for the extensive cell death which occurs in Buruli ulcer. The results presented here demonstrate that L929 and J774 mouse macrophage cells die via apoptosis after 3 to 5 days of exposure to mycolactone. Treatment of cells with a pan-caspase inhibitor can inhibit mycolactone-induced apoptosis. We demonstrate that injection of mycolactone into guinea pig skin results in cell death via apoptosis and that the extent of apoptosis increases as the lesion progresses. These results may help to explain why tissue damage in Buruli ulcer is not accompanied by an acute inflammatory response.
Serum Amyloid P Component Bound to Gram-Negative Bacteria Prevents Lipopolysaccharide-Mediated Classical Pathway Complement Activation
Authors: de Haas Carla J. C. , van Leeuwen Ester M. M. , van Bommel Toon , Verhoef Jan , van Kessel Kok P. M. , van Strijp Jos A. G. 
Published: July 2002

ABSTRACTAlthough serum amyloid P component (SAP) is known to bind many ligands, its biological function is not yet clear. Recently, it was demonstrated that SAP binds to lipopolysaccharide (LPS). In the present study, SAP was shown to bind to gram-negative bacteria expressing short types of LPS or lipo-oligosaccharide (LOS), such asSalmonella entericaserovar Copenhagen Re andEscherichia coliJ5, and also to clinical isolates ofHaemophilus influenzae. It was hypothesized that SAP binds to the bacteria via the lipid A part of LPS or LOS, since thehtrBmutant of the nontypeableH. influenzaestrain NTHi 2019-B29-3, which expresses a nonacetylated lipid A, did not bind SAP. This was in contrast to the parental strain NTHi 2019. The binding of SAP resulted in a clear inhibition of the deposition of complement component C3 on the bacteria. SAP inhibited only the activation of the classical complement pathway; the alternative route remained unaffected. In the classical route, SAP prevented the deposition of the first complement component, Clq, probably by interfering with the binding of Clq to LPS. Since antibody-mediated Clq activation was not inhibited by SAP, SAP seems to inhibit only the LPS-induced classical complement pathway activation. The SAP-induced inhibition of C3 deposition strongly diminished the complement-mediated lysis as well as the phagocytosis of the bacteria. The binding of SAP to gram-negative bacteria, therefore, might influence the pathophysiology of an infection with such bacteria.
γδ T Cells Are a Component of Early Immunity against Preerythrocytic Malaria Parasites
Authors: McKenna Kyle C. , Tsuji Moriya , Sarzotti Marcella , Sacci John B. , Witney Adam A. , Azad Abdu F. 
Published: July 2002

ABSTRACTWe tested the hypothesis that γδ T cells are a component of an early immune response directed against preerythrocytic malaria parasites that are required for the induction of an effector αβ T-cell immune response generated by irradiated-sporozoite (irr-spz) immunization. γδ T-cell-deficient (TCRδ−/−) mice on a C57BL/6 background were challenged withPlasmodium yoelii(17XNL strain) sporozoites, and then liver parasite burden was measured at 42 h postchallenge. Liver parasite burden was measured by quantification of parasite-specific 18S rRNA in total liver RNA by quantitative-competitive reverse transcription-PCR and by an automated 5′ exonuclease PCR. Sporozoite-challenged TCRδ−/−mice showed a significant (P< 0.01) increase in liver parasite burden compared to similarly challenged immunocompetent mice. In support of this result, TCRδ−/−mice were also found to be more susceptible than immunocompetent mice to a sporozoite challenge when blood-stage parasitemia was used as a readout. A greater percentage of TCRδ−/−mice than of immunocompetent mice progressed to a blood-stage infection when challenged with five or fewer sporozoites (odds ratio = 2.35,P= 0.06). TCRδ−/−mice receiving a single irr-spz immunization showed percent inhibition of liver parasites comparable to that of immunized immunocompetent mice following a sporozoite challenge. These data support the hypothesis that γδ T cells are a component of early immunity directed against malaria preerythrocytic parasites and suggest that γδ T cells are not required for the induction of an effector αβ T-cell immune response generated by irr-spz immunization.
Escherichia coli
O157:H7 Causes More-Severe Systemic Disease in Suckling Piglets than in Colostrum-Deprived Neonatal Piglets
Authors: Dean-Nystrom Evelyn A. , Pohlenz Joachim F. L. , Moon Harley W. , O'Brien Alison D. 
Published: July 2002

ABSTRACT

Our objective was to determine if suckling neonatal piglets are susceptible to enterohemorrhagic
Escherichia coli
(EHEC) O157:H7 disease. Surprisingly, EHEC O157:H7 caused more-rapid and more-severe neurological disease in suckling neonates than in those fed an artificial diet. Shiga toxin-negative O157:H7 did not cause neurological disease but colonized and caused attaching-and-effacing intestinal lesions.
Effects of
Enterococcus faecalis fsr
Genes on Production of Gelatinase and a Serine Protease and Virulence
Authors: Qin Xiang , Singh Kavindra V. , Weinstock George M. , Murray Barbara E. 
Published: July 2002

ABSTRACT

Three
agr
-like genes (
fsrA
,
fsrB
, and
fsrC
, for
Enterococcus faecalis
regulator) were found upstream of the previously reported gelatinase gene (
gelE
) and a downstream putative serine protease gene (
sprE
; accession number
Z12296
) of
Enterococcus faecalis
OG1RF. The deduced amino acid sequence of
fsrA
shows 26% identity and 38% similarity to
Staphylococcus aureus
AgrA (the response regulator of the accessory gene regulator system in the
agr
locus), FsrB shows 23% identity and 41% similarity to
S. aureus
AgrB, and FsrC shows 23% identity and 36% similarity to
S. aureus
AgrC (the sensor transducer of Agr system). Northern blot analysis suggested that
gelE
and
sprE
are cotranscribed and that
fsrB
and
fsrC
are also cotranscribed in OG1RF. Northern blot analysis of
fsrA
,
fsrB
,
fsrC
,
gelE
, and
sprE
insertion mutants showed that
fsrB
,
fsrC
,
gelE
, and
sprE
are not expressed in
fsrA
,
fsrB
, and
fsrC
mutants, while insertion in an open reading frame further upstream of
fsrA
did not effect the expression of these genes, suggesting that
agr
-like genes may be autoregulated and that they regulate
gelE
and
sprE
expression, as further confirmed by complementation of
fsr
gene mutations with a 6-kb fragment which contains all three
fsr
genes in the shuttle vector, pAT18. Testing of 95 other isolates of
E. faecalis
showed that 62% produced gelatinase (Gel
+
), while 91% (including all Gel
+
strains) hybridized to a
gelE
probe; 71% (including all Gel
+
strains) hybridized to an
fsr
probe, corroborating the conclusion that both
gelE
and
fsr
are necessary for gelatinase production. Testing of
fsrA
,
fsrB
, and
sprE
mutants in a mouse peritonitis model showed that
sprE
and
agr
-like gene mutants resulted in highly significantly prolonged survival compared to the parent strain OG1RF, a finding similar to what we had previously shown for a
gelE
mutant. These results suggest that
sprE
and
agr
-like genes contribute to the virulence of
E. faecalis
OG1RF in this model.
Naturally Acquired and Vaccine-Elicited Antibodies Block Erythrocyte Cytoadherence of the
Plasmodium vivax
Duffy Binding Protein
Authors: Michon Pascal , Fraser Tresa , Adams John H. 
Published: July 2002

ABSTRACT

Malaria merozoites require the presence of specific surface receptors on the red blood cell for invasion.
Plasmodium vivax
, requires the Duffy blood group antigen as an obligate receptor for invasion. The parasite Duffy binding protein (DBP) is the ligand involved in this process, making the DBP a potential vaccine candidate. A preliminary objective was to study whether people exposed to vivax malaria acquire antibodies that have the ability to block erythrocyte cytoadherence to the PvDBP. In comparison, we studied the immunogenicity of various recombinant DBP vaccines and investigated their potential to induct antifunctional antibodies. In order to do so, recombinant proteins to different regions of the putative ectodomain of the DBP and a DNA vaccine were used to immunize laboratory animals. An in vitro cytoadherence assay was used to investigate the presence of antifunctional antibodies in plasmas from people naturally exposed to vivax malaria, as well as in antisera obtained by animal vaccination. Our results showed that human plasma from populations naturally exposed to vivax malaria, as well as antisera obtained by vaccination using recombinant proteins, a DNA vaccine, and a synthetic peptide to DBP, inhibited in vitro binding of human erythrocytes to the DBP ligand domain (DBP
II
) in correlation to their previously measured antibody titer. Our results provide further evidence for the vaccine potential of this essential parasite adhesion molecule.