bluuebunny/crossref_metadata_2025_split huggingface dataset:
Minimum Infective Dose of
Mycobacterium bovis
in Cattle
Authors: Dean Gillian S. , Rhodes Shelley G. , Coad Michael , Whelan Adam O. , Cockle Paul J. , Clifford Derek J. , Hewinson R. Glyn , Vordermeier H. Martin 
Published: September 2005

ABSTRACT

The aim of this work was to determine the minimum infective dose of
Mycobacterium bovis
necessary to stimulate specific immune responses and generate pathology in cattle. Four groups of calves (20 animals) were infected by the intratracheal route with 1,000, 100, 10, or 1 CFU of
M. bovis
. Specific immune responses (gamma interferon [IFN-γ] and interleukin-4 [IL-4] responses) to mycobacterial antigens were monitored throughout the study, and the responses to the tuberculin skin test were assessed at two times. Rigorous post mortem examinations were performed to determine the presence of pathology, and samples were taken for microbiological and histopathological confirmation of
M. bovis
infection. One-half of the animals infected with 1 CFU of
M. bovis
developed pulmonary pathology typical of bovine tuberculosis. No differences in the severity of pathology were observed for the different
M. bovis
doses. All animals that developed pathology were skin test positive and produced specific IFN-γ and IL-4 responses. No differences in the sizes of the skin test reactions, the times taken to achieve a positive IFN-γ result, or the levels of the IFN-γ and IL-4 responses were observed for the different
M. bovis
doses, suggesting that diagnostic assays (tuberculin skin test and IFN-γ test) can detect cattle soon after
M. bovis
infection regardless of the dose. This information should be useful in modeling the dynamics of bovine tuberculosis in cattle and in assessing the risk of transmission.
Legionella pneumophila
NudA Is a Nudix Hydrolase and Virulence Factor
Authors: Edelstein Paul H. , Hu Baofeng , Shinzato Takashi , Edelstein Martha A. C. , Xu Wenlian , Bessman Maurice J. 
Published: September 2005

ABSTRACT

We studied the identity and function of the 528-bp gene immediately upstream of
Legionella pneumophila
F2310
ptsP
(enzyme I
Ntr
). This gene,
nudA
, encoded for a Nudix hydrolase based on the inferred protein sequence. NudA had hydrolytic activity typical of other Nudix hydrolases, such as
Escherichia coli
YgdP, in that Ap

n

A’s, in particular diadenosine pentaphosphate (Ap
5
A), were the preferred substrates. NudA hydrolyzed Ap
5
A to ATP plus ADP. Both
ptsP
and
nudA
were cotranscribed. Bacterial two-hybrid analysis showed no PtsP-NudA interactions. Gene
nudA
was present in 19 of 20 different
L. pneumophila
strains tested and in 5 of 10 different
Legionella
spp. other than
L. pneumophila
. An in-frame
nudA
mutation was made in
L. pneumophila
F2310 to determine the phenotype. The
nudA
mutant was an auxotroph that grew slowly in liquid and on solid media and had a smaller colony size than its parent. In addition, the mutant was more salt resistant than its parent and grew very poorly at 25°C; all of these characteristics, as well as auxotrophy and slow-growth rate, were reversed by transcomplementation with
nudA
. The
nudA
mutant was outcompeted by about fourfold by the parent in competition studies in macrophages; transcomplementation almost completely restored this defect. Competition studies in guinea pigs with
L. pneumophila
pneumonia showed that the
nudA
mutant was outcompeted by its parent in both lung and spleen. NudA is of major importance for resisting stress in
L. pneumophila
and is a virulence factor.
Antigen Requirements for Efficient Priming of CD8+T Cells byLeishmania major-Infected Dendritic Cells
Authors: Bertholet Sylvie , Debrabant Alain , Afrin Farhat , Caler Elisabeth , Mendez Susana , Tabbara Khaled S. , Belkaid Yasmine , Sacks David L. 
Published: September 2005

ABSTRACTCD4+and CD8+T-cell responses have been shown to be critical for the development and maintenance of acquired resistance to infections with the protozoan parasiteLeishmania major. Monitoring the development of immunodominant or clonally restricted T-cell subsets in response to infection has been difficult, however, due to the paucity of known epitopes. We have analyzed the potential ofL. majortransgenic parasites, expressing the model antigen ovalbumin (OVA), to be presented by antigen-presenting cells to OVA-specific OT-II CD4+or OT-I CD8+T cells. Truncated OVA was expressed inL. majoras part of a secreted or nonsecreted chimeric protein withL. donovani3′ nucleotidase (NT-OVA). Dendritic cells (DC) but not macrophages infected withL. majorthat secreted NT-OVA could prime OT-I T cells to proliferate and release gamma interferon. A diminished T-cell response was observed when DC were infected with parasites expressing nonsecreted NT-OVA or with heat-killed parasites. Inoculation of mice with transgenic parasites elicited the proliferation of adoptively transferred OT-I T cells and their recruitment to the site of infection in the skin. Together, these results demonstrate the possibility of targeting heterologous antigens to specific cellular compartments inL. majorand suggest that proteins secreted or released byL. majorin infected DC are a major source of peptides for the generation of parasite-specific CD8+T cells. The ability ofL. majortransgenic parasites to activate OT-I CD8+T cells in vivo will permit the analysis of parasite-driven T-cell expansion, differentiation, and recruitment at the clonal level.
Analysis of the Behavior of
eryC
Mutants of
Brucella suis
Attenuated in Macrophages
Authors: Burkhardt Sonja , Jiménez de Bagüés Maria P. , Liautard Jean-Pierre , Köhler Stephan 
Published: September 2005

ABSTRACT

The facultatively intracellular pathogen
Brucella
, characterized by its capacity to replicate in professional and non professional phagocytes, also causes abortion in ruminants. This property has been linked to the presence of erythritol in the placenta, as brucellae preferentially utilize erythritol. The
ery
operon encodes enzymes involved in erythritol metabolism, and a link with virulence has since been discussed. Allelic exchange mutants in
eryC
of
Brucella suis
were erythritol sensitive in vitro with a MIC of 1 to 5 mM of erythritol. Their multiplication in macrophage-like cells was 50- to 90-fold reduced, but complementation of the mutant restored wild-type levels of intracellular multiplication and the capacity to use erythritol as a sole carbon source. In vivo, the
eryC
mutant colonized the spleens of infected BALB/c mice to a significantly lower extent than the wild type and the complemented strain. Interestingly,
eryC
mutants that were in addition spontaneously erythritol tolerant nevertheless exhibited wild-type-like intramacrophagic and intramurine replication. We concluded from our results that erythritol was not an essential carbon source for the pathogen in the macrophage host cell but that the inactivation of the
eryC
gene significantly reduced the intramacrophagic and intramurine fitness of
B. suis
.
Antibodies to the Iron Uptake ABC Transporter Lipoproteins PiaA and PiuA Promote Opsonophagocytosis of
Streptococcus pneumoniae
Authors: Jomaa Maha , Yuste Jose , Paton James C. , Jones Christopher , Dougan Gordon , Brown Jeremy S. 
Published: September 2005

ABSTRACT

PiaA and PiuA are the lipoprotein components of the Pia and Piu
Streptococcus pneumoniae
iron uptake ABC transporters and are required for full virulence in mouse models of infection. Active or passive vaccination with recombinant PiuA and PiaA protects mice against invasive
S. pneumoniae
disease. In this study we have analyzed the antibody responses and mechanism of protection induced by PiuA and PiaA in more detail. For both proteins, two booster vaccinations induced stronger antibody responses in mice than a single or no booster vaccinations, and 5 μg of protein induced similar levels of antibody responses as 20 μg. Immunoglobulin G (IgG) subclass-specific enzyme-linked immunosorbent assays demonstrated that the antibody response to PiuA and PiaA was predominantly IgG1, with induction of only low levels of IgG2a. Anti-PiaA and anti-PiuA polyclonal rabbit antibodies bound to the surface of live
S. pneumoniae
when assessed by flow cytometry but did not inhibit growth of
S. pneumoniae
in cation-depleted medium or bacterial susceptibility to the iron-dependent antibiotic streptonigrin. However, anti-PiaA and anti-PiuA did increase complement-independent and -dependent opsonophagocytosis of different serotypes of
S. pneumoniae
by the human neutrophil cell line HL60. Hence, vaccination with PiaA and PiuA protects against
S. pneumoniae
infection by inducing antibodies that promote bacterial opsonophagocytosis rather than inhibiting iron transport.
Homologues of Insecticidal Toxin Complex Genes in
Yersinia enterocolitica
Biotype 1A and Their Contribution to Virulence
Authors: Tennant Sharon M. , Skinner Narelle A. , Joe Angela , Robins-Browne Roy M. 
Published: September 2005

ABSTRACT

Yersinia enterocolitica
is an enteric pathogen that consists of six biotypes: 1A, 1B, 2, 3, 4, and 5. Strains of the latter five biotypes can carry a virulence plasmid, known as pYV, and several well-characterized chromosomally encoded virulence determinants.
Y. enterocolitica
strains of biotype 1A lack the virulence-associated markers of pYV-bearing strains and were once considered to be avirulent. There is growing epidemiological, clinical, and experimental evidence, however, to suggest that some biotype 1A strains are virulent and can cause gastrointestinal disease. To identify potential virulence genes of pathogenic strains of
Y. enterocolitica
biotype 1A, we used genomic subtractive hybridization to determine genetic differences between two biotype 1A strains: an environmental isolate,
Y. enterocolitica
IP2222, and a clinical isolate,
Y. enterocolitica
T83. Among the
Y. enterocolitica
T83-specific genes we identified were three,
tcbA
,
tcaC
, and
tccC
, that showed homology to the insecticidal toxin complex (TC) genes first discovered in
Photorhabdus luminescens
. The
Y. enterocolitica
T83 TC gene homologues were expressed by
Y. enterocolitica
T83 and were significantly more prevalent among clinical biotype 1A strains than other
Yersinia
isolates. Inactivation of the TC genes in
Y. enterocolitica
T83 resulted in mutants which were attenuated in the ability to colonize the gastrointestinal tracts of perorally infected mice. These results indicate that products of the TC gene complex contribute to the virulence of some strains of
Y. enterocolitica
biotype 1A, possibly by facilitating their persistence in vivo.
Biochemical Characterization and Vaccine Potential of a Heme-Binding Glutathione Transferase from the Adult Hookworm
Ancylostoma caninum
Authors: Zhan Bin , Liu Sen , Perally Samirah , Xue Jian , Fujiwara Ricardo , Brophy Peter , Xiao Shuhua , Liu Yueyuan , Feng Jianjun , Williamson Angela , Wang Yan , Bueno Lilian L. , Mendez Susana , Goud Gaddam , Bethony Jeffrey M. , Hawdon John M. , Loukas Alex , Jones Karen , Hotez Peter J. 
Published: September 2005

ABSTRACT

We report the cloning and expression of
Ac
-GST-1, a novel glutathione
S
-transferase from the adult hookworm
Ancylostoma caninum
, and its possible role in parasite blood feeding and as a vaccine target. The predicted
Ac
-GST-1 open reading frame contains 207 amino acids (mass, 24 kDa) and exhibited up to 65% amino acid identity with other nematode GSTs. mRNA encoding
Ac
-GST-1 was detected in adults, eggs, and larval stages, but the protein was detected only in adult hookworm somatic extracts and excretory/secretory products. Using antiserum to the recombinant protein,
Ac
-GST-1 was immunolocalized to the parasite hypodermis and muscle tissue and weakly to the intestine. Recombinant
Ac
-GST-1 was enzymatically active, as determined by conjugation of glutathione to a model substrate, and exhibited a novel high-affinity binding site for hematin. The possible role of
Ac
-GST-1 in parasite heme detoxification during hemoglobin digestion or heme uptake prompted interest in evaluating it as a potential vaccine antigen. Vaccination of dogs with
Ac
-GST-1 resulted in a 39.4% reduction in the mean worm burden and 32.3% reduction in egg counts compared to control dogs following larval challenge, although the reductions were not statistically significant. However, hamsters vaccinated with
Ac
-GST-1 exhibited statistically significant worm reduction (53.7%) following challenge with heterologous
Necator americanus
larvae. These studies suggest that
Ac
-GST-1 is a possible drug and vaccine target for hookworm infection.
Innate Refractoriness of the Lewis Rat to Toxoplasmosis Is a Dominant Trait That Is Intrinsic to Bone Marrow-Derived Cells
Authors: Sergent Véronique , Cautain Bastien , Khalife Jamal , Deslée Didier , Bastien Patrick , Dao Anne , Dubremetz Jean-François , Fournié Gilbert J. , Saoudi Abdelhadi , Cesbron-Delauw Marie-France 
Published: September 2005

ABSTRACTToxoplasmosis is a ubiquitous parasitic infection causing a wide spectrum of diseases. It is usually asymptomatic but can lead to severe ocular and neurological disorders. Among the small-animal models available to study factors that determine susceptibility to toxoplasmosis, the rat appears to be rather similar to humans, particularly in terms of resistance to acute infection. Here, we demonstrate that the Lewis (LEW) rat strain displays an unexpected refractoriness toToxoplasmainfection. Complete resistance was assessed by both negative anti-Toxoplasmaserology and lack of detection of the parasite during the course of infection. In this model, sex, age, major histocompatibility complex, and inoculum size had no effect on resistance. Interestingly, progeny from F1hybrid crosses between Fischer (F344) or Brown Norway susceptible rats and LEW resistant rats were also fully resistant, showing a dominant effect of the gene or set of genes. Furthermore, resistance of the LEW rat was shown to be dependent on hematopoietic cells and partially abrogated by neutralization of endogenous gamma interferon. To our knowledge, this is the first observation of a rodent strain that is refractory toToxoplasmainfection. This model is therefore an attractive and powerful tool to dissect host genetic factors involved in susceptibility to toxoplasmosis.
Pathophysiological Manifestations in Mice Exposed to Anthrax Lethal Toxin
Authors: Culley Nathan C. , Pinson David M. , Chakrabarty Anuradha , Mayo Matthew S. , LeVine Steven M. 
Published: September 2005

ABSTRACT
Pathophysiological changes associated with anthrax lethal toxin included loss of plasma proteins, decreased platelet count, slower clotting times, fibrin deposits in tissue sections, and gross and histopathological evidence of hemorrhage. These findings suggest that blood vessel leakage and hemorrhage lead to disseminating intravascular coagulation and/or circulatory shock as an underlying pathophysiological mechanism.
Protective Role of Neutrophils in Mice Experimentally Infected with
Rhodococcus equi
Authors: Martens Ronald J. , Cohen Noah D. , Jones Samuel L. , Moore Thomas A. , Edwards John F. 
Published: September 2005

ABSTRACT

Neutrophils are important in controlling early infections with the intracellular bacterium
Rhodococcus equi
. Antineutrophil monoclonal antibody (RB6-8C5)-induced neutrophil deficiency during the first week after experimental infection of mice with
R. equi
resulted in more severe disease and significantly increased tissue concentrations of
R. equi.
Relationship of Virulence Factor Expression to Evolved Virulence in Mouse-Passaged
Cryptococcus neoformans
Lines
Authors: McClelland Erin E. , Perrine Wesley T. , Potts Wayne K. , Casadevall Arturo 
Published: September 2005

ABSTRACT

Serial passage of
Cryptococcus neoformans
in mice increases virulence relative to the nonpassaged line. Postpassaged lines showed no difference in the expression of most known virulence factors, with the exception that the more virulent lines had smaller capsules in vitro. These data imply that other mechanisms of virulence remain to be discovered.
Effects of Dexamethasone and Transient Malnutrition on Rabbits Infected with AerosolizedMycobacterium tuberculosisCDC1551
Authors: Kesavan Anup K. , Mendez Susana E. , Hatem Christine L. , Lopez-Molina Javier , Aird Katherine , Pitt M. Louise M. , Dannenberg Arthur M. , Manabe Yukari C. 
Published: September 2005

ABSTRACTMalnutrition is common in the developing world, where tuberculosis is often endemic. Rabbits infected with aerosolizedMycobacterium tuberculosisthat subsequently became inadvertently and transiently malnourished had compromised cell-mediated immunity comparable to that of the rabbits immunosuppressed with dexamethasone. They had significant leukopenia and reduced delayed-type hypersensitivity responses. Malnutrition dampened cell-mediated immunity and would interfere with diagnostic tests that rely on intact CD4 T-cell responses.
gp100209–2M Peptide Immunization of Human Lymphocyte Antigen-A2+ Stage I-III Melanoma Patients Induces Significant Increase in Antigen-Specific Effector and Long-Term Memory CD8+ T Cells
Authors: Walker Edwin B. , Haley Daniel , Miller William , Floyd Kevin , Wisner Ketura P. , Sanjuan Nelson , Maecker Holden , Romero Pedro , Hu Hong-Ming , Alvord W. Gregory , Smith John W. , Fox Bernard A. , Urba Walter J. 
Published: September 2005

AbstractThirty-five HLA-A2+ patients with completely resected stage I-III melanoma were vaccinated multiple times over 6 months with a modified melanoma peptide, gp100209–2M, emulsified in Montanide adjuvant. Direct ex vivo gp100209–2M tetramer analysis of pre- and postvaccine peripheral blood mononuclear cells (PBMCs) demonstrated significant increases in the frequency of tetramer+ CD8+ T cells after immunization for 33 of 35 evaluable patients (median, 0.36%; range, 0.05–8.9%). Ex vivo IFN-γ cytokine flow cytometry analysis of postvaccine PBMCs after brief gp100209–2M in vitro activation showed that for all of the patients studied tetramer+ CD8+ T cells produced IFN-γ; however, some patients had significant numbers of tetramer+ IFN-γ− CD8+T cells suggesting functional anergy. Additionally, 8 day gp100209–2M in vitro stimulation (IVS) of pre- and postvaccine PBMCs resulted in significant expansion of tetramer+ CD8+ T cells from postvaccine cells for 34 patients, and these IVS tetramer+ CD8+ T cells were functionally responsive by IFN-γ cytokine flow cytometry analysis after restimulation with either native or modified gp100 peptide. However, correlated functional and phenotype analysis of IVS-expanded postvaccine CD8+ T cells demonstrated the proliferation of functionally anergic gp100209–2M- tetramer+ CD8+ T cells in several patients and also indicated interpatient variability of gp100209–2M stimulated T-cell proliferation. Flow cytometry analysis of cryopreserved postvaccine PBMCs from representative patients showed that the majority of tetramer+ CD8+ T cells (78.1 ± 4.2%) had either an “effector” (CD45 RA+/CCR7−) or an “effector-memory” phenotype (CD45RA−/CCR7−). Notably, analysis of PBMCs collected 12–24 months after vaccine therapy demonstrated the durable presence of gp100209–2M-specific memory CD8+ T cells with high proliferation potential. Overall, this report demonstrates that after vaccination with a MHC class I-restricted melanoma peptide, resected nonmetastatic melanoma patients can mount a significant antigen-specific CD8+ T-cell immune response with a functionally intact memory component. The data further support the combined use of tetramer binding and functional assays in correlated ex vivo and IVS settings as a standard for immunomonitoring of cancer vaccine patients.
Elevated Cyclooxygenase-2 Expression Is Associated with Altered Expression of p53 and SMAD4, Amplification of HER-2/neu, and Poor Outcome in Serous Ovarian Carcinoma
Authors: Erkinheimo Tiina-Liisa , Lassus Heini , Finne Patrik , van Rees Bastiaan P. , Leminen Arto , Ylikorkala Olavi , Haglund Caj , Butzow Ralf , Ristimäki Ari 
Published: September 2005

Abstract
Purpose and Experimental Design: Cyclooxygenase-2 (COX-2) is frequently expressed in human adenocarcinomas and inhibition of COX-2 suppresses tumor formation in various animal models of carcinogenesis. We analyzed expression of COX-2 protein in human serous ovarian carcinomas by immunohistochemistry (n = 442) and by Western blotting (n = 12) and COX-2 mRNA by reverse transcriptase PCR (n = 12). COX-2 immunoreactivity was correlated to clinicopathological variables and to expression of p53 and SMAD4 as detected by immunohistochemistry and to amplification of HER-2/neu as detected by in situ hybridization.
Results: COX-2 mRNA expression was detected in 75% (9 of 12) and COX-2 protein in 42% (5 of 12) of the serous ovarian adenocarcinoma specimens as detected by reverse transcriptase-PCR and Western blot analysis, respectively. Moderate to strong (elevated) immunoreactivity for COX-2 was detected in 70% (310 of 442) of the tumors. Elevated COX-2 expression associated with reduced disease-specific survival (P = 0.0011), high histological grade (P &lt; 0.0001), residual tumor size &gt; 1 cm (P = 0.0111), and age &gt; 57 years (P = 0.0099). Tumors with altered immunostaining pattern for p53 or SMAD4 expressed more frequently elevated levels of COX-2 when compared with the tumors with normal staining pattern of these tumor suppressor genes (P &lt; 0.0001 and P = 0.0004, respectively). In addition, elevated COX-2 expression associated with amplification of HER-2/neu oncogene (P = 0.0479).
Conclusions: Our results suggest that elevated expression of COX-2 associates with reduced survival in serous ovarian carcinomas and that expression of COX-2 may be induced in these tumors by loss of tumor suppressor genes such as p53and SMAD4and by amplification of HER-2/neuoncogene.