bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interactions of Surfactant Proteins A and D withSaccharomyces cerevisiaeandAspergillus fumigatus
Authors: Allen Martin J. , Voelker Dennis R. , Mason Robert J. 
Published: July 2002

ABSTRACTSurfactant proteins A (SP-A) and D (SP-D) are members of the collectin family of calcium-dependent lectins and are important pulmonary host defense molecules. Human SP-A and SP-D and rat SP-D bind toAspergillus fumigatusconidia, but the ligand remains unidentified. To identify a fungal ligand for SP-A and/or SP-D, we examined the interactions of the proteins withSaccharomyces cerevisiae. SP-D but not SP-A bound yeast cells, and EDTA inhibited the binding. SP-D also aggregated yeast cells and isolated yeast cell walls. Treating yeast cells to remove cell wall mannoprotein did not reduce SP-D binding, and SP-D failed to aggregate chitin. However, SP-D aggregated yeast glucan before and after treatment with a β(1→3)-glucanase, suggesting a specific interaction between the collectin and β(1→6)-glucan. In support of this idea, SP-D-induced yeast aggregation was strongly inhibited by pustulan [a β(1→6)-linked glucose homopolymer] but was not inhibited by laminarin [a β(1→3)-linked glucose homopolymer]. Additionally, pustulan but not laminarin strongly inhibited SP-D binding toA. fumigatus. The pustulan concentration for 50% inhibition of SP-D binding toA. fumigatusis 1.0 ± 0.3 μM glucose equivalents. Finally, SP-D showed reduced binding to the β(1→6)-glucan-deficientkre6yeast mutant. Taken together, these observations demonstrate that β(1→6)-glucan is an important fungal ligand for SP-D and that glycosidic bond patterns alone can determine if an extended carbohydrate polymer is recognized by SP-D.
Specific Antibodies to
Porphyromonas gingivalis
Lys-Gingipain by DNA Vaccination Inhibit Bacterial Binding to Hemoglobin and Protect Mice from Infection
Authors: Kuboniwa Masae , Amano Atsuo , Shizukuishi Satoshi , Nakagawa Ichiro , Hamada Shigeyuki 
Published: July 2002

ABSTRACT

Lys-gingipain (KGP), a lysine-specific cysteine proteinase, is one of the major virulence factors of
Porphyromonas gingivalis
. Here we examined the involvement of the catalytic domain of KGP (KGP
cd
) in hemoglobin binding by
P. gingivalis
, using a specific immunoglobulin G (IgG) elicited by the administration of plasmid DNA encoding KGP
cd
or the catalytic domain of Arg-gingipain (RGP
cd
). The pSeq2A/
kgp
cd
and pSeq2B/
rgp
cd
plasmids were constructed by the ligation of
kgp
cd
and
rgp
cd
DNA fragments, respectively. Female BALB/c mice were immunized with each of these plasmids. pSeq2A/
kgp
cd
elicited a strong response to recombinant KGP
cd
(rKGP
cd
), as well as to comparably produced rRGP
cd
-reactive antibodies. The serum antibodies elicited by pSecTag2B/
rgp
cd
also cross-reacted with rKGP
cd
as well as rRGP
cd
. Anti-KGP
cd
IgG significantly inhibited hemoglobin binding by
P. gingivalis
. Furthermore, the inhibition of hemoglobin binding was markedly enhanced by a combination of anti-KGP
cd
and anti-fimbriae. Anti-RGP
cd
IgG showed a negligible inhibitory effect, while both anti-KGP
cd
and anti-RGP
cd
IgGs showed significant inhibitory effects on Lys- and Arg-specific proteolytic activities and on the growth of
P. gingivalis
under iron-restricted conditions where supplemented hemoglobin was the sole iron source. Immunized mice were challenged by intraperitoneal inoculation with
P. gingivalis
. All nonimmunized mice died within 72 h; however, vaccination with pSeq2A/
kgp
cd
and pSeq2B/
rgp
cd
prevented inflammatory responses and prolonged the survival rate of immunized mice by 43 and 27%, respectively. These results suggest that KGP
cd
acts as a hemoglobin-binding protein and can also be useful as an immunogen inducing a protective response to
P. gingivalis
infection.
Monoclonal Antibodies Specific forNeisseria meningitidisGroup B Polysaccharide and Their Peptide Mimotopes
Authors: Shin J. S. , Lin J. S. , Anderson P. W. , Insel R. A. , Nahm M. H. 
Published: July 2002

ABSTRACTFrom five mice immunized withEscherichia coliK1 bacteria, we produced 12 immunoglobulin M hybridomas secreting monoclonal antibodies (MAbs) that bind toNeisseria meningitidisgroup B (NMGB). The 12 MAbs also bound the capsular polysaccharide (PS) ofE. coliK1 [which, like NMGB, is α(2-8)-linked polysialic acid (PSA)] and bound to EV36, a nonpathogenicE. coliK-12 strain producing α(2-8) PSA. Except for HmenB5, which cross-reacted withN. meningitidisgroup C, none of the MAbs bound toN. meningitidisgroups A, C, and Y. Of the 12 MAbs, 6 were autoantibodies as defined by binding to CHP-134, a neuroblastoma cell line expressing short-chain α(2-8) PSA; five of these MAbs killed NMGB in the presence of rabbit complement, and two also killed NMGB with human complement. The other six MAbs, however, were nonautoreactive; all killed NMGB with rabbit complement, and five killed NMGB with human complement. To obtain peptide mimotopes of NMGB PS, four of the nonautoreactive MAbs (HmenB2, HmenB3, HmenB13, and HmenB14) were used to screen two types of phage libraries, one with a linear peptide of 7 amino acids and the other with a circular peptide of 7 amino acids inserted between two linked cysteines. We obtained 86 phage clones that bound to the screening MAb in the absence but not in the presence ofE. coliK1 PSA in solution. The clones contained 31 linear and 4 circular mimotopes expressing unique sequences. These mimotopes nonrandomly expressed amino acids and were different from previously described mimotopes for NMGB PS. The new mimotopes may be useful in producing a vaccine(s) capable of eliciting anti-NMGB antibodies not reactive with neuronal tissue.
Timing, Localization, and Persistence of Colonization by Segmented Filamentous Bacteria in the Neonatal Mouse Gut Depend on Immune Status of Mothers and Pups
Authors: Jiang Han-Qing , Bos Nicolaas A. , Cebra John J. 
Published: July 2002

ABSTRACTAs a member of the indigenous gut mucosal microbiota, segmented filamentous bacteria (SFB) colonize the guts of a variety of vertebrates and invertebrates. They are potent microbial stimuli of the gut mucosal immune system. In the small intestines of mice and rats, it has been observed that SFB are absent during the suckling period and appear in high numbers shortly after weaning, then quickly retreat to the cecum and large intestine. In this study, we explored whether this microecological phenomenon resulted from the interaction between SFB and the passively acquired maternal mucosal immunity and/or the actively acquired mucosal immunity. We set up a mouse model by reciprocal crossings and backcrossings of SFB-monoassociated, formerly germ-free, immunocompetent (+/+) BALB/c mice and immunodeficient (scid/scid) mice to produce pups which are either immunocompetent (scid/+) or immunodeficient (scid/scid) and are born either to immunocompetent (scid/+) mothers or to immunodeficient (scid/scid) mothers. We monitored the number of SFB on the mucosa of the small intestine in the four different groups of mice after birth, as well as the level of passively acquired antibodies, the active gut mucosal immune responses, and immunoglobulin A (IgA) coating of SFB in the gut. The results showed that, irrespective of whether the pups were scid/scid or scid/+, SFB could be found earlier on the mucosa of the small intestine in pups born to scid/scid mothers, appearing from day 13 and rapidly reaching a climax around weaning time on day 28, compared to the significantly delayed colonization in the pups of scid/+ mothers, starting from day 16 and peaking around days 28 to 32. After the climax, SFB quickly declined to very low levels in the small intestines of scid/+ pups of either scid/scid mothers or scid/+ mothers, whereas they remained at high levels in scid/scid pups at least until day 70, the last observation time in this study. The dynamic changes in SFB colonization of the small intestines of the different groups of pups may be related to the dynamic changes in the levels of SFB coated with secretory IgA (sIgA), which resulted from the significantly different levels of sIgA obtained from the mothers' milk during the suckling period and, later, of self-produced sIgA in the small intestine. Nevertheless, it is evident that the timing, localization, and persistence of colonization of the neonatal gut by SFB depends on the immune status of both mothers and pups.
Presence ofLpsdMutation Influences Cytokine Regulation In Vivo by theMycoplasma arthritidisMitogen Superantigen and Lethal Toxicity in Mice Infected withM. arthritidis
Authors: Mu Hong-Hua , Sawitzke Allen D. , Cole Barry C. 
Published: July 2002

ABSTRACTTheMycoplasma arthritidismitogen (MAM) superantigen (SAg) is a potent activator of human and murine cells and is produced by an organism that is a cause of acute and chronic arthritis of rodents. It is phylogenetically unrelated to other bacterial SAgs and exhibits a number of unique features. We recently demonstrated that MAM differentially regulates the cytokine responses of different mouse strains following in vivo administration. Here we show that the presence in inbred C3H/HeJ mice of the mutantLpsdgene, which is associated with a defect in Toll-like receptor 4 (TLR4), influences MAM regulation of cytokine profiles in vivo.Whereas the levels of type 1 cytokines (interleukin-2 [IL-2], gamma interferon, IL-12, and tumor necrosis factor alpha) were depressed in cells from MAM-injected wild-type C3H/HeSnJ mice, they were elevated in cells from C3H/HeJ mice. Furthermore, the levels of type 2 cytokines (IL-4, IL-6, and IL-10) were elevated inLpsnC3H/HeSnJ mice but depressed inLpsdC3H/HeJ mice. The transcript for IL-12 p40 was highly expressed in C3H/HeJ but not C3H/HeSnJ mice. F1mice exhibited the same cytokine profile as C3H/HeJ mice, indicating that the mutant gene exhibited dominant-negative inheritance. In addition, C3H/HeJ mice were highly susceptible to toxic death in comparison with C3H/HeSnJ mice after injection with liveM. arthritidisorganisms. Our results suggest that MAM interacts with the lipopolysaccharide signaling pathway, possibly involving TLR4 or a combinatorial Toll complex.
Hyphae and Yeasts ofCandida albicansDifferentially Regulate Interleukin-12 Production by Human Blood Monocytes: Inhibitory Role ofC. albicansGermination
Authors: Liu Liming , Kang Kefei , Takahara Masakazu , Cooper Kevin D. , Ghannoum Mahmoud A. 
Published: July 2002

ABSTRACTThe role ofCandida albicansyeast-to-hypha transition in interleukin-12 (IL-12) production by monocytes was investigated. GerminatingC. albicansnot only failed to induce IL-12 p70 but also suppressed IL-12 production induced by heat-killedC. albicans. Comparison of the abilities of germinatingC. albicansand agerminating mutants to inhibit IL-12 production showed that germination ofC. albicansplays a critical role in the inhibition of IL-12 production.
Assessment of
Helicobacter pylori
Gene Expression within Mouse and Human Gastric Mucosae by Real-Time Reverse Transcriptase PCR
Authors: Rokbi Bachra , Seguin Delphine , Guy Bruno , Mazarin Véronique , Vidor Emmanuel , Mion François , Cadoz Michel , Quentin-Millet Marie-José 
Published: July 2002

ABSTRACT

Despite increasing knowledge on the biology of
Helicobacter pylori
, little is known about the expression pattern of its genome during infection. While mouse models of infection have been widely used for the screening of protective antigens, the reliability of the mouse model for gene expression analysis has not been assessed. In an attempt to address this question, we have developed a quantitative reverse transcriptase PCR (RT-PCR) that allowed the detection of minute amounts of mRNA within the gastric mucosa. The expression of four genes, 16S rRNA,
ureA
(encoding urease A subunit),
katA
(catalase), and
alpA
(an adhesin), was monitored during the course of a 6-month infection of mice and in biopsy samples from of 15 infected humans. We found that the selected genes were all expressed within both mouse and human infected mucosae. Moreover, the relative abundance of transcripts was the same (16S rRNA >
ureA
>
katA
>
alpA
), in the two models. Finally, results obtained with the mouse model suggest a negative effect of bacterial burden on the number of transcripts of each gene expressed per CFU (
P
< 0.05 for 16S rRNA,
alpA
, and
katA
). Overall, this study demonstrates that real-time RT-PCR is a powerful tool for the detection and quantification of
H. pylori
gene expression within the gastric mucosa and strongly indicates that mice experimentally infected with
H. pylori
provide a valuable model for the analysis of bacterial gene expression during infection.
Facilitated Intranasal Induction of Mucosal and Systemic Immunity to Mutans Streptococcal Glucosyltransferase Peptide Vaccines
Authors: Smith Daniel J. , King William F. , Barnes Leigh A. , Trantolo Debra , Wise Donald L. , Taubman Martin A. 
Published: July 2002

ABSTRACTSynthetic peptide vaccines which are derived from functional domains ofStreptococcus mutansglucosyltransferases (GTF) have been shown to induce protective immunity in Sprague-Dawley rats after subcutaneous injection in the salivary gland region. Since mucosal induction of salivary immunity would be preferable in humans, we explored methods to induce mucosal antibody in the rat to the GTF peptide vaccines HDS and HDS-GLU after intranasal administration. Several methods of facilitation of the immune response were studied: the incorporation of peptides in bioadhesive poly(d,l-lactide-coglycolide) (PLGA) microparticles, the use of monoepitopic (HDS) or diepitopic (HDS-GLU) peptide constructs, or the use of mucosal adjuvants. Salivary immunoglobulin A (IgA) responses were not detected after intranasal administration of diepitopic HDS-GLU peptide constructs in alum or after incorporation into PLGA microparticles. However, significant primary and secondary salivary IgA and serum IgG antibody responses to HDS were induced in all rats when cholera holotoxin (CT) or a detoxified mutantEscherichia coliheat-labile enterotoxin (R192G LT) were intranasally administered with HDS peptide constructs in PLGA. Coadministration of LT with HDS resulted in predominantly IgG2a responses in the serum, while coadministration with CT resulted in significant IgG1 and IgG2a responses to HDS. Serum IgG antibody, which was induced to the HDS peptide construct by coadministration with these adjuvants, also bound intact mutans streptococcal GTF in an enzyme-linked immunosorbent assay and inhibited its enzymatic activity. Thus, immune responses which are potentially protective for dental caries can be induced to peptide-based GTF vaccines after mucosal administration if combined with the CT or LT R192G mucosal adjuvant.
Immunogenicity of Well-Characterized SyntheticPlasmodium falciparumMultiple Antigen Peptide Conjugates
Authors: Joshi Manju B. , Gam Albert A. , Boykins Robert A. , Kumar Sanjai , Sacci John , Hoffman Stephen L. , Nakhasi Hira L. , Kenney Richard T. 
Published: July 2002

ABSTRACTGiven the emerging difficulties with malaria drug resistance and vector control, as well as the persistent lack of an effective vaccine, new malaria vaccine development strategies are needed. We used a novel methodology to synthesize and fully characterize multiple antigen peptide (MAP) conjugates containing protective epitopes fromPlasmodium falciparumand evaluated their immunogenicity in four different strains of mice. A di-epitope MAP (T3-T1) containing two T-cell epitopes of liver stage antigen-1 (LSA-1), a di-epitope MAP containing T-cell epitopes from LSA-1 and from merozoite surface protein-1, and a tri-epitope MAP (T3-CS-T1) containing T3-T1 and a potent B-cell epitope from the circumsporozoite protein central repeat region were tested in this study. Mice of all four strains produced peptide-specific antibodies; however, the magnitude of the humoral response indicated strong genetic restriction between the different strains of mice. Anti-MAP antibodies recognized stage-specific proteins on the malaria parasites in an immunofluorescence assay. In addition, serum from hybrid BALB/cJ × A/J CAF1 mice that had been immunized with the tri-epitope MAP T3-CS-T1 successfully inhibited the malaria sporozoite invasion of hepatoma cells in vitro. Spleen cells from immunized mice also showed a genetically restricted cellular immune response when stimulated with the immunogen in vitro. This study indicates that well-characterized MAPs combining solid-phase synthesis and conjugation chemistries are potent immunogens and that this approach can be utilized for the development of subunit vaccines.
Brucella abortus
HtrA Functions as an Authentic Stress Response Protease but Is Not Required for Wild-Type Virulence in BALB/c Mice
Authors: Phillips Robert W. , Roop R. Martin 
Published: July 2002

ABSTRACT

A second mutation has recently been identified in the previously described
Brucella abortus htrA
mutant PHE1. As a result of this finding, a new
B. abortus htrA
mutant, designated RWP11, was constructed to evaluate the biological function of the
Brucella
HtrA protease. RWP11 is more sensitive to oxidative killing in vitro and less resistant to killing by cultured murine neutrophils and macrophages than the virulent parental strain 2308 but is not attenuated in BALB/c mice through 4 weeks postinfection. The in vitro phenotype of
B. abortus
RWP11 is consistent with the proposed function of bacterial HtrA proteases as components of a secondary line of defense against oxidative damage. The in vivo phenotype of this mutant, however, indicates that, unlike the corresponding
Salmonella
and
Yersinia
proteins,
Brucella
HtrA does not play a critical role in virulence in the mouse model.
The Extracytoplasmic Sigma Factor, ς
E
, Is Required for Intracellular Survival of Nontypeable
Haemophilus influenzae
in J774 Macrophages
Authors: Craig Jane E. , Nobbs Angela , High Nicola J. 
Published: July 2002

ABSTRACT

Nontypeable
Haemophilus influenzae
(NTHi) causes a wide variety of respiratory tract infections in humans. It is capable of invading and surviving in epithelial cells and has also been shown to persist in macrophage-like cell line J774A.1. To determine the molecular mechanisms which enable NTHi to survive in an intracellular environment, differential display reverse transcriptase PCR was used to identify genes which were either induced or upregulated by NTHi residing in macrophages. Using this approach, we identified one transcript which was consistently amplified from intracellular NTHi cDNA. Nucleotide sequence analysis of this product revealed that it spanned the 3′ and 5′ ends of
rpoE
and
rseB
, respectively, which form part of the extracytoplasmic stress operon that encodes and regulates expression of alternate sigma factor sigma E (ς
E
). To confirm that expression of
rpoE
was upregulated following uptake of NTHi by macrophages, an
rpoE-lacZ
transcriptional fusion was constructed, and expression of β-galactosidase activity in broth-grown NTHi was compared with expression of β-galactosidase activity in intracellular NTHi. The level of β-galactosidase activity in NTHi 4 h after phagocytosis by macrophages was found to be 100-fold higher than that of broth-grown organisms, suggesting that genes of the ς
E
regulon may be important for persistence of NTHi in mammalian cells. The hypothesis that ς
E
plays a role in the intracellular survival of NTHi was subsequently confirmed by the decreased ability of an
rpoE
insertion mutant to survive in macrophages.
Nitric Oxide and Apoptosis Induced in Peyer's Patches by Attenuated Strains ofSalmonella entericaSerovar Enteritidis
Authors: Cerquetti M. C. , Goren N. B. , Ropolo A. J. , Grasso D. , Giacomodonato M. N. , Vaccaro M. I. 
Published: July 2002

ABSTRACTNitric oxide (NO) is a toxic molecule of the immune system which contributes to the control of microbial pathogens. Additional functions of NO in innate and adaptive immunity have recently been described; these functions include the modulation of the cytokine response of lymphocytes and the regulation of immune cell apoptosis. In addition to direct microbicidal actions, NO has immunoregulatory effects relevant to the control of infections. In turn, infected macrophages and macrophage-regulating lymphocytes may undergo apoptosis during infection bySalmonellaspp. In this work we investigated the ability of attenuated strains ofSalmonella entericaserovar Enteritidis with different protective capacities to induce intestinal inducible nitric oxide synthase (iNOS) and apoptosis in Peyer's patches (PP) in mice. Results showed that the intestinal iNOS activity correlated with increased apoptosis in PP. Furthermore, the ability to induce intestinal NO production and apoptosis within the first few hours after immunization seemed to correlate with the protective capacity of mutant E/1/3 ofS. entericaserovar Enteritidis. It was found that nonprotective mutant C/2/2, which was unable to induce intestinal NO production, also failed to induce apoptosis in PP. Moreover, aminoguanidine treatment at the time of immunization resulted in inhibition of the NO production and apoptosis induced by protective mutant E/1/3 and completely abolished protection against challenge. These results suggest that the induction of iNOS in the intestinal mucosa by attenuated mutant E/1/3 ofS. entericaserovar Enteritidis at the time of immunization is necessary to generate a protective immune response.
Contribution of Fibronectin-Binding Protein to Pathogenesis of
Streptococcus suis
Serotype 2
Authors: de Greeff Astrid , Buys Herma , Verhaar Robin , Dijkstra Janny , van Alphen Loek , Smith Hilde E. 
Published: July 2002

ABSTRACT

In the present study we investigated the role of the fibronectin (FN)- and fibrinogen (FGN)-binding protein (FBPS) in the pathogenesis of
Streptococcus suis
serotype 2 in piglets. The complete gene encoding FBPS from
S. suis
serotype 2 was cloned in
Escherichia coli
and sequenced. The occurrence of the gene in various serotypes was analyzed by hybridization studies. The FBPS protein was expressed in
E. coli
and purified, and binding to human FN and FGN was demonstrated. The induction of antibodies in piglets was studied upon infection. An isogenic mutant unable to produce FBPS was constructed, and the levels of virulence of the wild-type and mutant strains were compared in a competitive infection model in young piglets. Organ cultures showed that FBPS was not required for colonization of the tonsils but that FBPS played a role in the colonization of the specific organs involved in an
S. suis
infection. Therefore, the FBPS mutant was considered as an attenuated mutant.
Analyses of the Evolutionary Distribution of
Salmonella
Translocated Effectors
Authors: Hansen-Wester Imke , Stecher Bärbel , Hensel Michael 
Published: July 2002

ABSTRACT

The type III secretion system encoded by
Salmonella
pathogenicity island 2 (SPI2) translocates
Salmonella
translocated effectors (STE) into host cells. STE are encoded by genes outside of SPI2. The distribution of STE loci within the salmonellae was investigated. In contrast to the SPI2 locus that is conserved within
Salmonella enterica
, STE loci show a variable distribution. In addition to other virulence determinants, the possession of various sets of STE loci may contribute to the different host ranges and pathogenic potentials of
S. enterica
serovars.