bluuebunny/crossref_metadata_2025_split huggingface dataset:
A DNA Prime-
Mycobacterium bovis
BCG Boost Vaccination Strategy for Cattle Induces Protection against Bovine Tuberculosis
Authors: Skinner Margot A. , Buddle Bryce M. , Wedlock D. Neil , Keen Denise , de Lisle Geoffrey W. , Tascon Ricardo E. , Candido Ferraz Jose , Lowrie Douglas B. , Cockle Paul J. , Vordermeier H. Martin , Glyn Hewinson R. 
Published: August 2003

ABSTRACT

The variable efficacy of bacillus Calmette-Guérin (
Mycobacterium bovis
BCG) in protecting humans and cattle against tuberculosis has prompted a search for a more effective vaccination regimen. A prime-boost strategy was investigated in cattle naturally sensitized to environmental mycobacteria by using a combination of three DNA vaccines coding for Hsp 65, Hsp 70, and Apa for priming, followed by a boost with BCG prior to experimental challenge with virulent
M. bovis.
Controls were vaccinated with DNA or BCG alone or were not vaccinated. The immune responses were monitored throughout the study, and protection was assessed based on reductions in the numbers of lesions and viable mycobacteria in lymph node samples. Vaccination with BCG alone or with a DNA prime-BCG boost regimen induced high levels of antigen-specific gamma interferon (IFN-γ) in whole-blood cultures. In the prime-boost group there were fewer animals with severe lung lesions, fewer lymph nodes with lesions per animal, a smaller proportion of animals with lesions, lower mean lung and lymph node lesion scores, and less
M. bovis
isolated from retropharyngeal and thoracic lymph nodes compared to the results obtained for the nonvaccinated animals. The prime-boost regimen induced significant enhancement of protection in six parameters, compared with significant enhancement of protection in only two parameters for BCG alone. In addition, following challenge, in vitro IFN-γ responses against ESAT-6 and CFP-10, as well as bovine tuberculin-induced skin test and in vitro IFN-γ responses, were identified as immunological markers that predicted protection. The use of the prime-boost strategy suggested that a combination of vaccines may be better than a single vaccine for protection against tuberculosis.
Effect of Transcription Factor GATA-2 on Phagocytic Activity of Alveolar Macrophages fromPneumocystis carinii-Infected Hosts
Authors: Lasbury Mark E. , Tang Xing , Durant Pamela J. , Lee Chao-Hung 
Published: August 2003

ABSTRACTAlveolar macrophages fromPneumocystis carinii-infected hosts are defective in phagocytosis (W. Chen, J. W. Mills, and A. G. Harmsen, Int. J. Exp. Pathol. 73:709-720, 1992; H. Koziel et al., J. Clin. Investig. 102:1332-1344, 1998). Experiments were performed to determine whether this defect is specific forP. cariniiorganisms. The results showed that these macrophages were unable to phagocytose bothP. cariniiorganisms and fluorescein isothiocyanate (FITC)-conjugated latex beads, indicating that alveolar macrophages fromP. carinii-infected hosts have a general defect in phagocytosis. To determine whether this defect correlates with the recently discovered down-regulation of the GATA-2 transcription factor gene duringP. cariniiinfection, alveolar macrophages from dexamethasone-suppressed or healthy rats were treated with anti-GATA-2 oligonucleotides and then assayed for phagocytosis. Aliquots of the alveolar macrophages were also treated with the sense oligonucleotides as the control. Cells treated with the antisense oligonucleotides were found to have a 46% reduction in phagocytosis ofP. cariniiorganisms and a 65% reduction in phagocytosis of FITC-latex beads compared to those treated with the sense oligonucleotides. To determine whether the defect in phagocytosis in alveolar macrophages fromP. carinii-infected hosts can be corrected by overexpression of GATA-2, a plasmid containing the rat GATA-2 gene in the sense orientation driven by the cytomegalovirus (CMV) promoter was introduced into alveolar macrophages fromP. carinii-infected rats. Aliquots of the same cells transfected with a plasmid containing GATA-2 in the antisense orientation relative to the CMV promoter served as the control. Alveolar macrophages treated with the sense GATA-2 expression construct were found to increase their phagocytic activity by 66% in phagocytosis ofP. cariniiorganisms and by 280% in phagocytosis of FITC-latex beads compared to those that received the antisense GATA-2 construct. The results of this study indicate that GATA-2 plays an important role in the regulation of phagocytosis in alveolar macrophages duringP. cariniiinfection.
Importance of a Developmentally Regulated Pheromone Receptor of
Cryptococcus neoformans
for Virulence
Authors: Chang Yun C. , Miller Georgina F. , Kwon-Chung K. J. 
Published: August 2003

ABSTRACT

Cryptococcus neoformans
is the etiologic agent of cryptococcosis. Two mating types exist in this fungus,
MAT
α and
MAT
a
. The
CPR
a
gene of
C. neoformans
is a
MAT
a
strain-specific gene and encodes a putative seven-transmembrane domain pheromone receptor. Unlike the other reported fungal pheromone receptors,
CPR
a
shows functional diversity. Deletion of
CPR
a
drastically affects mating efficiency but does not abolish mating.
CPR
a
expression is developmentally regulated and is not affected by deletion of the transcriptional regulator
STE12
a
. The expression of
CPR
a
is markedly increased by shifting cultures from liquid to solid media.
CPR
a
also plays a significant role in virulence. Δ
cpr
a
cells produce smaller capsules in the brains of mice than the wild-type cells, and the mice infected with Δ
cpr
a
survive significantly longer than those receiving the wild-type strain. Our results suggest that the
MAT
a
pheromone receptor of
C. neoformans
is not only required for mating but also important for survival and growth of the fungus in host tissue.
Effect of Codon Optimization on Expression Levels of a Functionally Folded Malaria Vaccine Candidate in Prokaryotic and Eukaryotic Expression Systems
Authors: Yadava Anjali , Ockenhouse Christian F. 
Published: August 2003

ABSTRACT

We have produced two synthetic genes that code for the F2 domain located within region II of the 175-kDa
Plasmodium falciparum
erythrocyte binding antigen (EBA-175) to determine the effects of codon alteration on protein expression in homologous and heterologous host systems. EBA-175 plays a key role in the process of merozoite invasion into erythrocytes through a specific receptor-ligand interaction. The F2 domain of EBA-175 is the ligand that binds to the glycophorin A receptor on human erythrocytes and is therefore a target of vaccine development efforts. We designed synthetic genes based on
P. falciparum
,
Escherichia coli
, and
Pichia
codon usage and expressed recombinant F2 in
E. coli
and
Pichia pastoris.
Compared to the expression of the native F2 sequence, conversion to prokaryote (
E. coli
)- or eukaryote (
Pichia
)-based codon usage dramatically improved the levels of recombinant protein expression in both
E. coli
and
P. pastoris
. The majority of the protein expressed in
E. coli
, however, was produced as inclusion bodies. The protein expressed in
P. pastoris
, on the other hand, was expressed as a secreted, soluble protein. The
P. pastoris-
produced protein was superior to that produced in
E. coli
based on its ability to bind to red blood cells. Consistent with these observations, the antibodies generated against the
Pichia
-produced protein prevented the binding of recombinant EBA to red blood cells. These antibodies recognize EBA-175 present on merozoites as well as in sporozoites by immunofluorescence. Our results suggest that the
Pichia
-based EBA-F2 vaccine construct has further potential to be developed for clinical use.
Stimulation of T-Helper Cell Gamma Interferon and Immunoglobulin G Responses Specific forBabesia bovisRhoptry-Associated Protein 1 (RAP-1) or a RAP-1 Protein Lacking the Carboxy-Terminal Repeat Region Is Insufficient To Provide Protective Immunity against VirulentB. bovisChallenge
Authors: Norimine Junzo , Mosqueda Juan , Suarez Carlos , Palmer Guy H. , McElwain Terry F. , Mbassa Gabriel , Brown Wendy C. 
Published: August 2003

ABSTRACTRhoptry-associated protein 1 (RAP-1) is a targeted vaccine antigen forBabesia bovisandBabesia bigeminainfections of cattle. The 60-kDaB. bovisRAP-1 is recognized by antibodies and T lymphocytes from cattle that recovered from infection and were immune to subsequent challenge. Immunization with native or recombinant protein was reported to reduce parasitemias in challenged animals. We recently reported that the NT domain ofB. bovisRAP-1 contained immunodominant T-cell epitopes, whereas the repeat-rich CT domain was less immunostimulatory for T lymphocytes from cattle immune toB. bovis.The present study was therefore designed to test the hypothesis that the NT region of RAP-1, used as a vaccine with interleukin-12 and RIBI (catalog no. R-730; RIBI Immunochem Research, Inc., Hamilton, Mont. [now Corixa, Seattle, Wash.]) adjuvant to induce a type 1 response, would prime calves for antibody and T-helper cell responses comparable to or greater than those induced by full-length RAP-1 containing the C-terminal repeats. Furthermore, a type 1 immune response to RAP-1 was hypothesized to induce protection against challenge. Following four inoculations of either recombinant full-length RAP-1 or RAP-1 NT protein, RAP-1-specific immunoglobulin G (IgG) titers, T-lymphocyte proliferation, and gamma interferon production were similar. Similar numbers of NT region peptides were recognized. However, in spite of the presence of strong RAP-1-specific IgG and CD4+-T-lymphocyte responses that were recalled upon challenge, neither antigen stimulated a protective immune response. We conclude that successful priming of calves with recombinant RAP-1 and adjuvants that elicit strong Th1 cell and IgG responses is insufficient to protect calves against virulentB. bovischallenge.
Borrelia burgdorferi
Population Dynamics and Prototype Gene Expression during Infection of Immunocompetent and Immunodeficient Mice
Authors: Hodzic Emir , Feng Sunlian , Freet Kim J. , Barthold Stephen W. 
Published: August 2003

ABSTRACT

The population dynamics of
Borrelia burgdorferi
were quantified by real-time PCR targeting the
flaB
gene in skin (inoculation site, noninoculation site, and ear), heart (heart base and ventricle), quadriceps muscle, and the tibiotarsal joint at 1, 2, 4, 6, and 8 weeks after intradermal inoculation in C3H and C3H-
scid
mice. In addition, RNA transcription was assessed for several prototype genes, including
flaB
,
ospA
,
ospC
,
dbpA
,
arp
,
vlsE
,
fbp
,
oppA-2
, and
p37-42
. Spirochete numbers were equivalent in C3H and C3H-
scid
mice at 1 or 2 weeks and then declined in C3H mice, but they continued to rise and then plateaued in C3H-
scid
mice. Gene transcription was likewise higher in C3H-
scid
mice than in C3H mice, particularly at 4 or more weeks of infection. Gene transcription showed variation among tissues, with the highest levels of transcription in heart and joint tissue, which are sites of inflammation.
A Novel Pathogenicity Island Integrated Adjacent to the
thrW
tRNA Gene of Avian Pathogenic
Escherichia coli
Encodes a Vacuolating Autotransporter Toxin
Authors: Parreira V. R. , Gyles C. L. 
Published: August 2003

ABSTRACT

We report the complete nucleotide sequence and genetic organization of the Vat-encoding pathogenicity island (PAI) of avian pathogenic
Escherichia coli
strain Ec222. The 22,139-bp PAI is situated adjacent to the 3′ terminus of the
thrW
tRNA gene, has a G+C content of 41.2%, and includes a bacteriophage SfII integrase gene, mobile genetic elements, two open reading frames with products exhibiting sequence similarity to known proteins, and several other open reading frames of unknown function. The PAI encodes an autotransporter protein, Vat (vacuolating autotransporter toxin), which induces the formation of intracellular vacuoles resulting in cytotoxic effects similar to those caused by the VacA toxin from
Helicobacter pylori
. The predicted 148.3-kDa protein product possesses the three domains that are typical of serine protease autotransporters of
Enterobacteriaceae
: an N-terminal signal sequence of 55 amino acids, a 111.8-kDa passenger domain containing a modified serine protease site (ATSGSG), and a C-terminal outer membrane translocator of 30.5 kDa. Vat has 75% protein homology with the hemagglutinin Tsh, an autotransporter of avian pathogenic
E. coli
. A
vat
deletion mutant of Ec222 showed no virulence in respiratory and cellulitis infection models of disease in broiler chickens. We conclude that the newly described PAI and Vat may be involved in the pathogenicity of avian septicemic
E. coli
strain Ec222 and other avian pathogenic
E. coli
strains.
Preparation and Characterization of Group A Meningococcal Capsular Polysaccharide Conjugates and Evaluation of Their Immunogenicity in Mice
Authors: Jin Zhigang , Chu Chiayung , Robbins John B. , Schneerson Rachel 
Published: August 2003

ABSTRACTEpidemic and endemic meningitis caused by group ANeisseria meningitidisremains a problem in sub-Saharan Africa. Although group A meningococcal capsular polysaccharide (GAMP) vaccine confers immunity at all ages, the improved immunogenicity of a conjugate and its compatibility with the World Health Organization's Extended Program on Immunization offers advantages over GAMP alone. Conjugates of GAMP bound to bovine serum albumin (BSA) were synthesized, characterized, and evaluated for their immunogenicities in mice. Two methods, involving adipic acid dihydrazide (ADH) as a linker, were used. First, ADH was bound to GAMP activated with cyanogen bromide (CNBr) or with 1-cyano-4(dimethylamino)-pyridinium tetrafluoroborate (CDAP) to form GAMPCNBrAHand GAMPCDAPAH. These derivatives were bound to BSA by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) to form GAMPCNBrAH-BSA and GAMPCDAPAH-BSA. Second, ADH was bound to BSA with EDC to formAHBSA.AHBSA was bound to activated GAMP to form GAMPCNBr-AHBSA and GAMPCDAP-AHBSA. The yield of GAMPCDAP-AHBSA (35 to 40%) was higher than those of the other conjugates (5 to 20%). GAMP conjugates elicited immunoglobulin G (IgG) anti-GAMP in all mice after three injections of 2.5 or 5.0 μg of GAMP: the geometric mean (GM) was highest in recipients of GAMPCDAP-AHBSA (11.40 enzyme-linked immunosorbent assay units). Although the difference was not statistically significant, the 5.0-μg dose elicited a higher GM IgG anti-GAMP than the 2.5-μg dose. Low levels of anti-GAMP were elicited by GAMP alone. GAMPCDAP-AHBSA elicited bactericidal activity roughly proportional to the level of IgG anti-GAMP.
SarT Influences
sarS
Expression in
Staphylococcus aureus
Authors: Schmidt Katherine A. , Manna Adhar C. , Cheung Ambrose L. 
Published: August 2003

ABSTRACT

Staphylococcus aureus
is a gram-positive pathogen that is capable of expressing a variety of virulence proteins in response to environmental signals. Virulence protein expression in
S. aureus
is controlled by a network of regulatory loci including
sarA
and
agr
. The
sarA/agr
network is associated with the expression of cell wall-associated adhesins during exponential growth and the expression of secreted enzymes and toxins in the transition to post-exponential growth. A number of
sarA
homologs, including
sarT
and
sarS
, have been identified in the
S. aureus
genome. Previous studies have shown that
sarA
influences expression of both
sarT
and
sarS
in the global regulatory network. SarS has been shown to bind to the
spa
promoter to induce expression of protein A. SarT, one of the SarA homologs that represses
hla
expression and is repressible by SarA and
agr
, was found to induce
sarS
expression in this report. Northern blot analysis of
sarS
and
spa
expression in
S. aureus
RN6390, and the isogenic
sarT
,
sarT sarA
, and
sarT agr
mutants showed that while
sarA
regulated
spa
expression directly, the
agr
locus used
sarT
as an intermediary to regulate
sarS
, thus leading to
spa
repression in
agr
-activated cells. Gel shift and footprinting analysis showed that SarT binds to the
sarS
promoter, indicating that the interaction of the
sarT
gene product with the upstream region of
sarS
is likely direct. Induction of
sarS
and
spa
by SarT in

agr
+

strains was confirmed by a tetracycline-inducible system to titrate
sarT
expression.
Porphyromonas gingivalisInfection in Pregnant Mice Is Associated with Placental Dissemination, an Increase in the Placental Th1/Th2 Cytokine Ratio, and Fetal Growth Restriction
Authors: Lin Dongming , Smith Mary Alice , Elter John , Champagne Catherine , Downey Christine Lynn , Beck James , Offenbacher Steven 
Published: August 2003

ABSTRACTOur previous animal studies showed that maternalPorphyromonas gingivalisinfection in a subcutaneous chamber is associated with hepatic and uterine translocation, as well as systemic induction of maternal inflammatory responses, both of which were associated with fetal growth restriction (FGR). However,P. gingivalis-challenged dams had fetuses with either FGR (2 standard deviations below mean weight of nonchallenged dams) or normal weight. Therefore, the objective of this study was to determine whether maternal infection withP. gingivaliscompromises normal fetal development via direct placental invasion and induction of fetus-specific placental immune responses characterized by a proinflammatory Th1-type cytokine profile.P. gingivalis-specific DNA was detected in placentas and fetuses of FGR and normal littermates fromP. gingivalis-infected dams. Th1- and Th2-type cytokine mRNA as well as tumor necrosis factor alpha and transforming growth factor β2 mRNA were examined in placental tissue by using reverse transcription-PCR to determine Th1/Th2 ratios. For eight litters containing both normal-weight and FGR fetuses,P. gingivalisDNA was detected only in the placentas of FGR fetuses. All fetuses and all amniotic fluid samples from infected and control dams were negative forP. gingivalisDNA. mRNA levels of gamma interferon and interleukin-2 (IL-2) were significantly increased in placentas of FGR fetuses, while expression of IL-10 was significantly decreased in the same group. These data indicate that, inP. gingivalis-challenged dams, within each litter there is placenta-specific translocation ofP. gingivalisthat results in growth restriction of the targeted fetus, which is associated with a shift in the placental Th1/Th2 cytokine balance.
Vaccination with Novel Immunostimulatory Adjuvants against Blood-Stage Malaria in Mice
Authors: Su Zhong , Tam Mi-Fong , Jankovic Dragana , Stevenson Mary M. 
Published: August 2003

ABSTRACTAn important aspect of malaria vaccine development is the identification of an appropriate adjuvant which is both capable of stimulating a protective immune response and safe for use by humans. Here, we investigated the feasibility of using novel immunostimulatory molecules as adjuvants combined with a crude antigen preparation and coadsorbed to aluminum hydroxide (alum) as a vaccine against blood-stagePlasmodium chabaudiAS malaria. Prior to challenge infection, immunization of genetically susceptible A/J mice with the combination of malaria antigen plus recombinant interleukin-12 (IL-12) in alum induced a Th1 immune response with production of high levels of gamma interferon (IFN-γ) and diminished IL-4 levels by spleen cells stimulated in vitro with parasite antigen compared to mice immunized with antigen alone, antigen in alum, or antigen plus IL-12. Mice immunized with malaria antigen plus recombinant IL-12 in alum had high levels of total malaria-specific antibody and immunoglobulin G2a. Compared to unimmunized mice, immunization with antigen plus IL-12 in alum induced the highest level of protective immunity against challenge infection withP. chabaudiAS, which was evident as a significantly decreased peak parasitemia level and 100% survival. Protective immunity was dependent on CD4+T cells, IFN-γ, and B cells and was long-lasting. Replacement of IL-12 as an adjuvant by synthetic oligodeoxynucleotides (ODN) containing CpG motifs induced a similar level of vaccine-induced protection against challenge infection withP. chabaudiAS. These results illustrate that it is possible to enhance the potency of a crude malaria antigen preparation delivered in alum by inclusion of immunostimulatory molecules, such as IL-12 or CpG-ODN.
Cytotoxic Necrotizing Factor 1 ofEscherichia coliStimulates Rho/Rho-Kinase-Dependent Myosin Light-Chain Phosphorylation without Inactivating Myosin Light-Chain Phosphatase in Endothelial Cells
Authors: Essler Markus , Linder Stefan , Schell Barbara , Hüfner Katharina , Wiedemann Agnès , Randhahn Katharina , Staddon James M. , Aepfelbacher Martin 
Published: August 2003

ABSTRACTCytotoxic necrotizing factor 1 (CNF-1) is an exotoxin ofEscherichia colithat constitutively activates the GTPases Rho, Rac, and CDC42. Stimulation of Rho was shown to enhance myosin light-chain (MLC) phosphorylation via Rho kinase-mediated inhibition of MLC phosphatase in endothelial cells. Here we report that 3 h after CNF stimulation of endothelial cells, RhoA was activated and MLC phosphorylation was increased in a Rho/Rho-kinase-dependent manner, but no decrease in MLC phosphatase activity could be detected. Despite continuous RhoA activation, MLC phosphatase activity was doubled after 24 h of CNF stimulation, and this coincided with decreased MLC phosphorylation and cell spreading. Rac was also activated at 3 to 24 h but did not contribute to MLC phosphorylation, and its amount gradually decreased in the CNF-stimulated cells. CDC42Hs was not activated above control values by CNF. These results suggest that CNF can induce specific decoupling (Rho kinase from MLC phosphatase) and deactivation events in Rho GTPase signaling, potentially reflecting cellular protection mechanisms against permanently active Rho GTPases.
Influence of Pregnancy on the Pathogenesis of Listeriosis in Mice Inoculated Intragastrically
Authors: Hamrick Terri S. , Horton John R. , Spears Patricia A. , Havell Edward A. , Smoak Ida W. , Orndorff Paul E. 
Published: August 2003

ABSTRACTPregnancy increases the risk of listeriosis, a systemic disease caused byListeria monocytogenes. However, there is incomplete agreement on the reasons for this increased risk. We examined two features of listeriosis in gravid and nongravid female mice following intragastric (gavage) inoculation, namely, (i) disease severity (measured by lethality) and (ii) listerial infectivity (measured by liver and spleen colonization levels up to 120 h postinoculation). Two listerial strains of differing serotype (1/2a and 4nonb) were initially employed. Neither strain produced a lethal infection in nonpregnant female mice (dose range, 106to 109CFU/mouse), and only the 4nonb strain produced lethalities in pregnant mice (dose range, 106to 108CFU/mouse). The 4nonb strain also produced a higher level of liver and spleen colonization than the 1/2a strain following gavage administration. (The two strains showed similar levels of colonization if parenterally administered.) Both strains were equally capable of binding to and forming plaques upon cultured mouse enterocytes. The ability of the 4nonb strain to produce a lethal infection in pregnant animals did not correlate with an increased incidence or level of liver and spleen colonization over that in nonpregnant females. However, the lethality rate did correlate well with the rate at which embryos and their surrounding decidual covering became infected, suggesting that intrauterine infection could be responsible for the increased disease severity in the gravid females.