bluuebunny/crossref_metadata_2025_split huggingface dataset:
MICA‐STR, HLA‐B haplotypic diversity and linkage disequilibrium in the Hunan Han population of southern China
Authors: Tian W. , Li L‐X. , Wang F. , Luo Q‐Z. , Yan M‐Y. , Yu P. , Guo S‐S. , Cao Y. 
Published: June 2006

SummaryMajor histocompatibility complex (MHC) class I chain‐related gene A (MICA) is located 46 kb centromeric to HLA‐B and encodes a stress‐inducible protein. MICA allelic variation is thought to be associated with disease susceptibility and immune response to transplants. This study was aimed to investigate the haplotypic diversity and linkage disequilibrium between human leukocyte antigen (HLA)‐B and (GCT)n short tandem repeat in exon 5 of MICA gene (MICA‐STR) in a southern Chinese Han population. Fifty‐eight randomly selected nuclear families with 183 members including 85 unrelated parental samples were collected in Hunan province, southern China. HLA‐B generic typing was performed by polymerase chain reaction–sequence‐specific priming (PCR–SSP), and samples showing novel HLA‐B‐MICA‐STR linkage were further typed for HLA‐B allelic variation by high‐resolution PCR–SSP. MICA‐STR allelic variation and MICA gene deletion (MICA*Del) were detected by fluorescent PCR–size sequencing and PCR–SSP. Haplotype was determined through family segregation analysis. Statistical analysis was applied to the data of the 85 unrelated parental samples. Nineteen HLA‐B specificities and seven MICA‐STR allelic variants were observed in 85 unrelated parental samples, the most predominant of which were HLA‐B*46, ‐B60, ‐B*13, and ‐B*15, and MICA*A5, MICA*A5.1 and MICA*A4, respectively. Genotype distributions of HLA‐B, MICA‐STR loci were consistent with Hardy–Weinberg proportions. The HLA‐B‐MICA‐STR haplotypic phases of all 85 unrelated parental samples were unambiguously assigned, which contained 30 kinds of HLA‐B, MICA‐STR haplotypic combinations, nine of them have not been reported in the literature. Significant positive linkage disequilibria between certain HLA‐B and MICA‐STR alleles, including HLA‐B*13 and MICA*A4, HLA‐B*38 and MICA*A9, HLA‐B*58 and MICA*A9, HLA‐B*46 and MICA*A5, HLA‐B*51 and MICA*A6, HLA‐B*52 and MICA*A6, and HLA‐B60 and MICA*A5.1, were observed. HLA‐B*48 was linked to MICA*A5, MICA*A5.1 and MICA*Del. HLA‐B*5801‐MICA*A10 linkage was found in a family. Our data indicated a high degree of haplotypic diversity and strong linkage disequilibrium between MICA‐STR and HLA‐B in a southern Chinese Han population, the data will inform future studies on anthropology, donor–recipient HLA matching in clinical transplantation and HLA‐linked disease association.
Role of
Porphyromonas gingivalis
FeoB2 in Metal Uptake and Oxidative Stress Protection
Authors: He Jia , Miyazaki Hiroshi , Anaya Cecilia , Yu Fan , Yeudall W. Andrew , Lewis Janina P. 
Published: June 2006

ABSTRACT

Porphyromonas gingivalis
, a gram-negative anaerobic bacterium, is a recognized periodontopathogen. It exhibits a high degree of aerotolerance and is able to survive in host cells, indicating that efficient oxidative stress protection mechanisms must be present in this organism. Manganese homeostasis plays a major role in oxidative stress protection in a variety of organisms; however, the transport and role of this metal in
P. gingivalis
is not well understood. Analysis of the genome of
P. gingivalis
W83 revealed the presence of two genes encoding homologs of a ferrous iron transport protein, FeoB1 and FeoB2. FeoB2 has been implicated in manganese accumulation in
P. gingivalis
. We sought to determine the role of the FeoB2 protein in metal transport as well as its contribution to resistance to oxygen radicals. Quantitative reverse transcriptase PCR analyses demonstrated that expression of
feoB2
is induced in the presence of oxygen. The role of FeoB2 was investigated using an isogenic mutant strain deficient in the putative transporter. We characterized the FeoB2-mediated metal transport using
55
Fe
2+
and
54
Mn
2+
. The FeoB2-deficient mutant had dramatically reduced rates of manganese uptake (0.028 pmol/min/10
7
bacteria) compared with the parental strain (0.33 pmol/min/10
7
bacteria) (after 20 min of uptake using 50 nM of
54
Mn
2+
). The iron uptake rates, however, were higher in the mutant strain (0.75 pmol/min/10
7
bacteria) than in the wild type (0.39 pmol/min/10
7
bacteria). Interestingly, reduced survival rates were also noted for the mutant strain after exposure to H
2
O
2
and to atmospheric oxygen compared to the parental strain cultured under the same conditions. In addition, in vitro infection of host cells with the wild type, the FeoB2-deficient mutant, and the same-site revertant revealed that the mutant had a significantly decreased capability for intracellular survival in the host cells compared to the wild-type strain. Our results demonstrate that
feoB2
encodes a major manganese transporter required for protection of the bacterium from oxidative stress generated by atmospheric oxygen and H
2
O
2
. Furthermore, we show that FeoB2 and acquisition of manganese are required for intracellular survival of
P. gingivalis
in host cells.
A Monoclonal Antibody to
Bacillus anthracis
Protective Antigen Defines a Neutralizing Epitope in Domain 1
Authors: Rivera Johanna , Nakouzi Antonio , Abboud Nareen , Revskaya Ekaterina , Goldman David , Collier R. John , Dadachova Ekaterina , Casadevall Arturo 
Published: June 2006

ABSTRACT

Antibody (Ab) responses to
Bacillus anthracis
toxins are protective, but relatively few protective monoclonal antibodies (MAbs) have been reported. Protective antigen (PA) is essential for the action of
B. anthracis
lethal toxin (LeTx) and edema toxin. In this study, we generated two MAbs to PA, MAbs 7.5G and 10F4. These MAbs did not compete for binding to PA, consistent with specificities for different epitopes. The MAbs were tested for their ability to protect a monolayer of cultured macrophages against toxin-mediated cytotoxicity. MAb 7.5G, the most-neutralizing MAb, bound to domain 1 of PA and reduced LeTx toxicity in BALB/c mice. Remarkably, MAb 7.5G provided protection without blocking the binding of PA or lethal factor or the formation of the PA heptamer complex. However, MAb 7.5G slowed the proteolytic digestion of PA by furin in vitro, suggesting a potential mechanism for Ab-mediated protection. These observations indicate that some Abs to domain 1 can contribute to host protection.
Search for
Bacillus anthracis
Potential Vaccine Candidates by a Functional Genomic-Serologic Screen
Authors: Gat Orit , Grosfeld Haim , Ariel Naomi , Inbar Itzhak , Zaide Galia , Broder Yehoshua , Zvi Anat , Chitlaru Theodor , Altboum Zeev , Stein Dana , Cohen Sara , Shafferman Avigdor 
Published: June 2006

ABSTRACT

Bacillus anthracis
proteins that possess antigenic properties and are able to evoke an immune response were identified by a reductive genomic-serologic screen of a set of in silico-preselected open reading frames (ORFs). The screen included in vitro expression of the selected ORFs by coupled transcription and translation of linear PCR-generated DNA fragments, followed by immunoprecipitation with antisera from
B. anthracis-
infected animals. Of the 197 selected ORFs, 161 were chromosomal and 36 were on plasmids pXO1 and pXO2, and 138 of the 197 ORFs had putative functional annotations (known ORFs) and 59 had no assigned functions (unknown ORFs). A total of 129 of the known ORFs (93%) could be expressed, whereas only 38 (64%) of the unknown ORFs were successfully expressed. All 167 expressed polypeptides were subjected to immunoprecipitation with the anti-
B. anthracis
antisera, which revealed 52 seroreactive immunogens, only 1 of which was encoded by an unknown ORF. The high percentage of seroreactive ORFs among the functionally annotated ORFs (37%; 51/129) attests to the predictive value of the bioinformatic strategy used for vaccine candidate selection. Furthermore, the experimental findings suggest that surface-anchored proteins and adhesins or transporters, such as cell wall hydrolases, proteins involved in iron acquisition, and amino acid and oligopeptide transporters, have great potential to be immunogenic. Most of the seroreactive ORFs that were tested as DNA vaccines indeed appeared to induce a humoral response in mice. We list more than 30 novel
B. anthracis
immunoreactive virulence-related proteins which could be useful in diagnosis, pathogenesis studies, and future anthrax vaccine development.
Role of Tumor Necrosis Factor Alpha in Development of Immunity againstCryptosporidium parvumInfection
Authors: Lean I-Sarah , Lacroix-Lamandé Sonia , Laurent Fabrice , McDonald Vincent 
Published: June 2006

ABSTRACTTumor necrosis factor (TNF-α) significantly reducedCryptosporidium parvumdevelopment in a murine enterocyte cell line, and a key mechanism of action appeared to be inhibition of parasite invasion. However, TNF-α-deficient mice controlled infection as effectively as wild-type mice. This suggests that TNF-α might have only a redundant role for establishing immunity againstC. parvum.
Burkholderia cenocepacia
ZmpB Is a Broad-Specificity Zinc Metalloprotease Involved in Virulence
Authors: Kooi C. , Subsin B. , Chen R. , Pohorelic B. , Sokol P. A. 
Published: June 2006

ABSTRACT

In previous studies we characterized the
Burkholderia cenocepacia
ZmpA zinc metalloprotease. In this study, we determined that
B. cenocepacia
has an additional metalloprotease, which we designated ZmpB. The
zmpB
gene is present in the same species as
zmpA
and was detected in
B. cepacia
,
B. cenocepacia
,
B. stabilis
,
B. ambifaria
, and
B. pyrrocinia
but was absent from
B. multivorans
,
B. vietnamiensis
,
B. dolosa
, and
B. anthina
. The
zmpB
gene was expressed, and ZmpB was purified from
Escherichia coli
by using the pPROEXHTa His
6
Tag expression system. ZmpB has a predicted preproenzyme structure typical of thermolysin-like proteases and is distantly related to
Bacillus cereus
bacillolysin. ZmpB was expressed as a 63-kDa preproenzyme precursor that was autocatalytically cleaved into mature ZmpB (35 kDa) and a 27-kDa prepropeptide. EDTA, 1,10-phenanthroline, and Zn
2+
cations inhibited ZmpB enzyme activity, indicating that it is a metalloprotease. ZmpB had proteolytic activity against α-1 proteinase inhibitor, α
2
-macrogobulin, type IV collagen, fibronectin, lactoferrin, transferrin, and immunoglobulins.
B. cenocepacia zmpB
and
zmpA zmpB
mutants had no proteolytic activity against casein and were less virulent in a rat agar bead chronic infection model, indicating that
zmpB
is involved in
B. cenocepacia
virulence. Expression of
zmpB
was regulated by both the CepIR and CciIR quorum-sensing systems.
Phenotypic and Functional Characterization of Vaginal Dendritic Cells in a Rat Model ofCandida albicansVaginitis
Authors: De Bernardis Flavia , Lucciarini Roberta , Boccanera Maria , Amantini Consuelo , Arancia Silvia , Morrone Stefania , Mosca Michela , Cassone Antonio , Santoni Giorgio 
Published: June 2006

ABSTRACTThis study analyzes the phenotype of vaginal dendritic cells (VDCs), their antigenic presentation and activation of T-cell cytokine secretion, and their protective role in a rat model ofCandidavaginitis. Histological observation demonstrated a significant accumulation of OX62+VDCs in the mucosal epithelium ofCandida albicans-infected rats at the third round of infection. We identified two subsets of OX62+VDCs differing in the expression of CD4 molecule in both noninfected andCandida-infected rats. The OX62+CD4+subset of VDCs displayed a lymphoid cell-like morphology and expressed the T-cell antigen CD5, whereas the OX62+CD4−VDC subset exhibited a myeloid morphology and was CD5 negative.Candidainfection resulted in VDC maturation with enhanced expression of CD80 and CD134L on both CD4+and CD4−VDC subsets at 2 and 6 weeks afterCandidainfection. CD5−CD4−CD86−CD80−CD134L+VDCs from infected, but not noninfected, rats spontaneously released large amounts of interleukin-12 (IL-12) and tumor necrosis factor alpha, whereas all VDC subsets released comparable levels of IL-10 and IL-2 cytokines. Furthermore, OX62+VDCs from infected rats primed naïve CD4+T-cell proliferation and release of cytokines, including gamma interferon, IL-2, IL-6, and IL-10, in response to staphylococcal enterotoxin B stimulation in vitro. Adoptive transfer of highly purified OX62+VDCs from infected rats induced a significant acceleration of fungal clearance compared with that in rats receiving naive VDCs, suggesting a protective role of VDCs in the anti-Candidamucosal immunity. Finally, VDC-mediated protection was associated with their ability to rapidly migrate to the vaginal mucosa and lymph nodes, as assessed by adoptive transfer of OX62+VDCs labeled with 5 (and 6-)-carboxyfluorescein diacetate succinimidyl ester.
LuxS Involvement in the Regulation of Genes Coding for Hemin and Iron Acquisition Systems inPorphyromonas gingivalis
Authors: James Chloe E. , Hasegawa Yoshiaki , Park Yoonsuk , Yeung Vincent , Tribble Gena D. , Kuboniwa Masae , Demuth Donald R. , Lamont Richard J. 
Published: June 2006

ABSTRACTThe periodontal pathogenPorphyromonas gingivalisemploys a variety of mechanisms for the uptake of hemin and inorganic iron. Previous work demonstrated that hemin uptake inP. gingivalismay be controlled by LuxS-mediated signaling. In the present study, the expression of genes involved in hemin and iron uptake was determined in parent andluxSmutant strains by quantitative real-time reverse transcription-PCR. Compared to the parental strain, theluxSmutant showed reduced levels of transcription of genes coding for the TonB-linked hemin binding protein Tlr and the lysine-specific protease Kgp, which can degrade host heme-containing proteins. In contrast, there was up-regulation of the genes for another TonB-linked hemin binding protein, HmuR; a hemin binding lipoprotein, FetB; a Fe2+ion transport protein, FeoB1; and the iron storage protein ferritin. Differential expression of these genes in theluxSmutant was maximal in early-exponential phase, which corresponded with peak expression ofluxSand AI-2 signal activity. Complementation of theluxSmutation with wild-typeluxSintransrescued expression ofhmuR. Mutation of the GppX two-component signal transduction pathway caused an increase in expression ofluxSalong withtlrand lower levels of message forhmuR. Moreover, expression ofhmuRwas repressed, and expression oftlrstimulated, when theluxSmutant was incubated with AI-2 partially purified from the culture supernatant of wild-type cells. A phenotypic outcome of the altered expression of genes involved in hemin uptake was impairment of growth of theluxSmutant in hemin-depleted medium. The results demonstrate a role of LuxS/AI-2 in the regulation of hemin and iron acquisition pathways inP. gingivalisand reveal a novel control pathway forluxSexpression.
Evaluation of Protection Afforded by
Brucella abortus
and
Brucella melitensis
Unmarked Deletion Mutants Exhibiting Different Rates of Clearance in BALB/c Mice
Authors: Kahl-McDonagh M. M. , Ficht T. A. 
Published: June 2006

ABSTRACT

Research for novel
Brucella
vaccines has focused upon the development of live vaccine strains, which have proven more efficacious than killed or subunit vaccines. In an effort to develop improved vaccines, signature-tagged mutant banks were screened to identify mutants attenuated for survival. Mutants selected from these screens exhibited various degrees of attenuation characterized by the rate of clearance, ranging from a failure to grow in macrophages after 24 h of infection to a failure to persist in the mouse model beyond 8 weeks. Ideal vaccine candidates should be safe to the host, while evoking protective immunity. In the present work, we constructed unmarked deletion mutants of three gene candidates,
manBA
,
virB2
, and
asp24
, in both
Brucella abortus
and
Brucella melitensis
. The Δ
asp24
mutants, which persist for extended periods in vivo, are superior to current vaccine strains and to other deletion strains tested in the mouse model against homologous challenge infection after 12, 16, and 20 weeks postvaccination. The Δ
asp24
mutants also display superior protection compared to Δ
manBA
and Δ
virB2
mutants against heterologous challenge in mice. From this study, a direct association between protection against infection and cytokine response was not apparent between all vaccine groups and, therefore, correlates of protective immunity will need to be considered further. A distinct correlation between persistence of the vaccine strain and protection against infection was corroborated.
Effect of a CD4-Depleting Antibody on the Development ofCryptococcus neoformans-Induced Allergic Bronchopulmonary Mycosis in Mice
Authors: Arora Shikha , McDonald Roderick A. , Toews Galen B. , Huffnagle Gary B. 
Published: June 2006

ABSTRACTAllergic bronchopulmonary mycosis (ABPM) is a hypersensitivity lung disease in which fungal colonization is accompanied by an allergic response to the fungus. Using a mouse model of ABPM caused byCryptococcus neoformansinfection of C57BL/6 mice, the goal of the present studies was to determine the effect of the CD4-depleting monoclonal antibody GK1.5 on the development of the allergic responses seen during active fungal infection. These results would provide insight into the role of CD4+T cells in this disease. Our results show that GK1.5 treatment resulted in attenuation of pulmonary inflammation and eosinophilia in these animals. These mice also had reduced T2 cytokine production and no serum immunoglobulin E production. Absence of CD4+T cells did not affect recruitment of CD8+T cells to the site of infection; however, the numbers of CD19+B cells were severely reduced in the lungs of CD4+T-cell-depleted animals. We also examined changes in the pulmonary architecture and found that depletion of CD4+T cells was associated with a significant reduction in mucus production and goblet cell metaplasia in these mice. Interestingly, attenuation of Th2 responses in CD4+T-cell-depleted animals did not increase the fungal load in their lungs. We also compared development of ABPM in young and mature mice and did not find any differences at any of the time points. Overall, our results show that depletion of CD4+T cells prevents the development of Th2 responses seen during ABPM.
The Novel
Helicobacter pylori
CznABC Metal Efflux Pump Is Required for Cadmium, Zinc, and Nickel Resistance,Urease Modulation, and Gastric Colonization
Authors: Stähler Frank Nils , Odenbreit Stefan , Haas Rainer , Wilrich Julia , Vliet Arnoud H. M. Van , Kusters Johannes G. , Kist Manfred , Bereswill Stefan 
Published: June 2006

ABSTRACT

Maintaining
metal homeostasis is crucial for the adaptation of
Helicobacter
pylori
to the gastric environment. Iron, copper, and nickel
homeostasis has recently been demonstrated to be required for the
establishment of
H. pylori
infection in animal models. Here we
demonstrate that the HP0969-0971 gene cluster encoding the Czc-type
metal export pump homologs HP0969, HP0970, and the
H.
pylori
-specific protein HP0971 forms part of a novel
H.
pylori
metal resistance determinant, which is required for gastric
colonization and for the modulation of urease activity. Insertional
mutagenesis of the HP0971, HP0970, or HP0969 genes in
H.
pylori
reference strain 26695 resulted in increased sensitivity to
cadmium, zinc, and nickel (czn), suggesting that the encoded proteins
constitute a metal-specific export pump. Accordingly, the genes were
designated
cznC
(HP0971),
cznB
(HP0970), and
cznA
(HP0969). The CznC and CznA proteins play a predominant
role in nickel homeostasis, since only the
cznC
and
cznA
mutants but not the
cznB
mutant displayed an 8-
to 10-fold increase in urease activity. Nickel-specific affinity
chromatography demonstrated that recombinant versions of CznC and CznB
can bind to nickel and that the purified CznB protein interacted with
cadmium and zinc, since both metals competitively inhibited nickel
binding. Finally, single
cznA
,
cznB
, and
cznC
mutants did not colonize the stomach in a Mongolian
gerbil-based animal model. This demonstrates that the metal export
functions of
H. pylori cznABC
are essential for gastric
colonization and underlines the extraordinary importance of metal ion
homeostasis for the survival of
H. pylori
in the gastric
environment.
T-Cell Expression Cloning ofPorphyromonas gingivalisGenes Coding for T Helper-Biased Immune Responses during Infection
Authors: Gonçalves Reginaldo B. , Leshem Onir , Bernards Karen , Webb John R. , Stashenko Philip P. , Campos-Neto Antonio 
Published: June 2006

ABSTRACTExposure of the mouse oral cavity toPorphyromonas gingivalisresults in the development of gingivitis and periapical bone loss, which apparently are associated with a Th1 response to bacterial antigens. We have used this infection model in conjunction with direct T-cell expression cloning to identify bacterial antigens that induce a preferential or biased T helper response during the infectious process. AP. gingivalis-specific CD4 T-cell line derived from mice at 3 weeks postchallenge was used to directly screen aP. gingivalisgenomic expression library. This screen resulted in the identification of five genes coding for previously identified proteins and three other putative protein antigens. One of the identified proteins,P. gingivalisthiol peroxidase, was studied in detail because this molecule belongs to a protein family that is apparently involved in microbial pathogenesis. Infection of mice withP. gingivalis, either via the subcutaneous route or after exposure of the animal's oral cavity to viable bacteria, resulted in the induction of a strong thiol peroxidase-specific immune response characterized by the production of high titers of specific serum immunoglobulin G2a antibody and the production of gamma interferon by antigen-stimulated lymphoid cells, a typical Th1-biased response. Thus, the use of a proven T-cell expression cloning approach and a mouse model of periodontal disease resulted in the identification and characterization ofP. gingivalisproteins that might be involved in pathogenesis.
Transient Neonatal
Cryptosporidium parvum
Infection Triggers Long-Term Jejunal Hypersensitivity to Distension in Immunocompetent Rats
Authors: Marion Rachel , Baishanbo Asiya , Gargala Gilles , François Arnaud , Ducrotté Philippe , Duclos Celia , Fioramonti Jean , Ballet Jean Jacques , Favennec Loïc 
Published: June 2006

ABSTRACT

In 5-day-old immunocompetent Sprague-Dawley rats infected with either 10
2
or 10
5
Cryptosporidium parvum
oocysts, transient infection resulted 120 days later in increased cardiovascular depressor response to jejunal distension and jejunal myeloperoxidase activity (
P
< 0.05). Nitazoxanide treatment normalized jejunal sensitivity (
P
< 0.001) but not myeloperoxidase levels (
P
> 0.05). Data warrant further evaluation of the role of early cryptosporidiosis in the development of chronic inflammatory gut conditions.