bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immune Responses in Ileostomy Fluid and Serum after Oral Cholera Vaccination of Patients Colectomized because of Ulcerative Colitis
Authors: Kilhamn Jan , Brevinge Hans , Svennerholm Ann-Mari , Jertborn Marianne 
Published: December 2019

ABSTRACT
The capacity of an oral inactivated B-subunit–whole-cell cholera vaccine to induce immune responses in patients colectomized due to ulcerative colitis was studied. Two doses of vaccine induced significant mucosal immunoglobulin A (IgA) antibody responses in ileostomy fluid against cholera toxin in 14 of 15 (93%) patients and against whole vibrios in 9 of 15 (60%) cases. The serological responses were lower (but not significantly) than those observed in healthy Swedish volunteers. Increased IgA antitoxin levels were found in ileostomy fluid as late as 2 years after vaccination.
Symbiosis of
Aeromonas veronii
Biovar sobria and
Hirudo medicinalis
, the Medicinal Leech: a Novel Model for Digestive Tract Associations
Authors: Graf Joerg 
Published: December 2019

ABSTRACT

Hirudo medicinalis
, the medicinal leech, is applied postoperatively in modern medicine. Infections by
Aeromonas
occur in up to 20% of patients unless a preemptive antibiotic treatment is administered. The associated infections demonstrate the need for a better understanding of the digestive tract flora of
H. medicinalis
. Early studies reported the presence of a single bacterial species in the digestive tract and suggested that these bacteria were endosymbionts contributing to the digestion of blood. In this study, we cultivated bacteria from the digestive tract and characterized them biochemically. The biochemical test results identified the isolates as
Aeromonas veronii
biovar sobria. This species identification was supported by sequence comparison of a variable region of the genes coding for 16S rRNA. In a colonization assay, a rifampin-resistant derivative of a symbiotic isolate was fed in a blood meal to
H. medicinalis
. The strain colonized the digestive tract rapidly and reached a concentration similar to that of the native bacterial flora. For the first 12 h, the in vivo doubling time was 1.2 h at 23°C. After 12 h, at a density of 5 × 10
7
CFU/ml, the increase in viable counts ceased, suggesting a dramatic reduction in the bacterial growth rate. Two human fecal isolates, identified as
Aeromonas hydrophila
and
A. veronii
biovar sobria, were also able to colonize the digestive tract. These data demonstrate that the main culturable bacterium in the crop of
H. medicinalis
is
A. veronii
biovar sobria and that the medicinal leech can be used as a model for digestive tract association of
Aeromonas
species.
Induction of Pro- and Anti-Inflammatory Cytokines byBorrelia burgdorferiLipoproteins in Monocytes Is Mediated by CD14
Authors: Giambartolomei Guillermo H. , Dennis Vida A. , Lasater Barbara L. , Philipp Mario T. 
Published: December 2019

ABSTRACTWe previously showed that heat-killedBorrelia burgdorferispirochetes and lipidated outer surface protein A (L-OspA) stimulated the in vitro production of interleukin-10 (IL-10) in peripheral blood mononuclear cells (PBMC) from uninfected humans and rhesus monkeys (G. Giambartolomei et al., Infect. Immun. 66:2691–2697, 1998). Here we demonstrate that uninfected human peripheral blood monocytes, but not B or T cells, are the cells that transcribe the IL-10 cytokine gene in response to heat-killedB. burgdorferi.B. burgdorferisimilarly induced an upregulation of the IL-1β and IL-6 cytokine genes in monocytes and the production of IL-10 and IL-6 in culture supernatants of the human monocytic cell line THP-1. Purified L-OspA (but not unlipidated OspA [U-OspA] or U-OspC) also stimulated the production of both cytokines in THP-1 cells in a dose-dependent fashion, suggesting that acylation of the OspA protein molecule is required for the production of both anti- and pro-inflammatory cytokines in naive monocytes. A lipohexapeptide that contained the tripalmitoyl-modified cysteine motif (Pam3Cys-Hex) ofB. burgdorferilipoproteins but with an arbitrary peptide sequence had the same effect. Monoclonal antibodies (MAbs) MY4 and 60bca, both of which bind to CD14 and are known to block lipopolysaccharide (LPS)-mediated cytokine production, were able to block L-OspA-mediated IL-10 and IL-6 cytokine production. In contrast, MAb 26ic, which also binds to CD14 but does not block LPS function, failed to inhibit L-OspA-mediated cytokine production. These data suggest that activation of monocytes and production of both anti- and pro-inflammatory cytokines induced by lipoproteins proceeds via the CD14 receptor. LPS binding protein was not required for OspA-induced cytokine production. Our results demonstrate that pro- and anti-inflammatory cytokines induced byB. burgdorferilipoproteins in PBMC are produced by monocytes and that lipoprotein and LPS signaling pathways share at least the initial signaling event that involves the CD14 receptor.
Resurgent
Vibrio cholerae
O139: Rearrangement of Cholera Toxin Genetic Elements and Amplification of
rrn
Operon
Authors: Khetawat Gopal , Bhadra Rupak K. , Nandi Suvobroto , Das Jyotirmoy 
Published: December 2019

ABSTRACT

The unprecedented genesis of a novel non-O1
Vibrio cholerae
strain belonging to serogroup O139, which caused an epidemic in late 1992 in the Indian subcontinent, and its subsequent displacement by El Tor O1 vibrios after 18 months initiated a renewed investigation of the aspects of the organism that are related to pathogenesis. The reappearance of
V. cholerae
O139 with altered antibiotic sensitivity compared to O139 Bengal (O139B) in late 1996 has complicated the epidemiological scenario of
V. cholerae
and has necessitated an examination of possible rearrangements in the genome underlying such rapid changes in the phenotypic traits. With a view to investigating whether the phenotypic changes that have occurred are associated with alteration in the genome, the genome of the resurgent
V. cholerae
O139 (O139R) strains were examined. Pulsed-field gel electrophoresis analysis of
Not
I- and
Sfi
I-digested genomic DNA of O139R isolates showed restriction fragment length polymorphism including in the cholera toxin (CTX) genetic element locus and with O139B isolates. Analyses of the organization of the CTX genetic elements in O139R strains showed that in contrast to two copies of the elements connected by two direct-repeat sequences (RS) in most of the genomes of O139B isolates, the genomes of all O139R strains examined, except strain AS192, have three such elements connected by a single RS. While the RS present in the upstream of the CTX genetic elements in the genome of O139R is of O139B origin, the RS connecting the cores of the elements has several new restriction sites and has lost the
Bgl
II site which is supposed to be conserved in all O1 strains and O139B. The endonuclease I-
Ceu
I, which has sites only in the
rrn
operons in the genomes of all organisms examined so far, has 10 sites in the genomes of O139R strains, compared to 9 in the genomes of O139B strains. The recent isolates of
V. cholerae
O139 have thus gained one
rrn
operon. This variation in the number of
rrn
operons within a serogroup has not been reported for any other organism. The results presented in this report suggest that like the pathogenic El Tor O1 strains, the genomes of O139 strains are undergoing rapid alterations.
Bovine CD4+T-Lymphocyte Clones Specific for Rhoptry-Associated Protein 1 ofBabesia bigeminaStimulate Enhanced Immunoglobulin G1 (IgG1) and IgG2 Synthesis
Authors: Brown Wendy C. , McElwain Terry F. , Palmer Guy H. , Chantler Sue Ellen , Estes D. Mark 
Published: December 2019

ABSTRACTOptimal protective immunity against babesial infection is postulated to require both complement-fixing and opsonizing antibodies in addition to gamma interferon (IFN-γ)-mediated macrophage activation. The rhoptry-associated protein 1 (RAP-1) ofBabesia bigeminainduces partial protective immunity and is a candidate vaccine antigen. Previous studies demonstrated that cattle immunized with native protein that were subsequently protected against challenge had a strong IFN-γ and weaker interleukin-4 (IL-4) response in immune lymph node lymphocytes that reflected the cytokine profile of the majority of CD4+T-cell clones obtained from peripheral blood. RAP-1-specific T helper (Th) cell clones that coexpress IFN-γ and IL-4 are typical of numerous parasite-specific clones examined. However, the function of such cells as helper cells to enhance immunoglobulin secretion by bovine B cells has not been reported. In cattle, both immunoglobulin G1 (IgG1) and IgG2 can fix complement, but IgG2 is the superior opsonizing subclass. Therefore, studies were undertaken to ascertain the functional relevance of RAP-1-specific, CD4+Th0 cells as helper cells to enhance IgG1 and/or IgG2 production by autologous B lymphocytes. For comparison, Th0 clones specific for the metazoan parasiteFasciola hepaticathat expressed relatively more IL-4 than theB. bigemina-specific Th cells were similarly assayed.B. bigeminaRAP-1-specific clones could enhance production of both IgG1 and IgG2 by autologous B cells, whereas Th cell clones specific forF. hepaticaenhanced predominantly IgG1 production. The capacity to enhance IgG2 production was associated with production of IFN-γ by Th cells cocultured with B cells, antigen, and IL-2. The in vitro helper T-cell activity of these T-cell clones was representative of the in vivo serologic responses, which were composed of a mixed IgG1-IgG2 response inB. bigeminaRAP-1 immune cattle and a biased IgG1 response inF. hepatica-immune cattle.
Infection-Derived
Enterococcus faecalis
Strains Are Enriched in
esp
, a Gene Encoding a Novel Surface Protein
Authors: Shankar Viswanathan , Baghdayan Arto S. , Huycke Mark M. , Lindahl Gunnar , Gilmore Michael S. 
Published: December 2019

ABSTRACT

We report the identification of a new cell wall-associated protein of
Enterococcus faecalis
. Studies on the distribution of the gene encoding this novel surface protein, Esp, reveal a significant (
P
< 0.001) enrichment in infection-derived
E. faecalis
isolates. Interestingly, the
esp
gene was not identified in any of 34 clinical
E. faecium
isolates or in 4 other less pathogenic enterococcal species tested. Analysis of the structural gene among various
E. faecalis
isolates reveals the existence of alternate forms of expression of the Esp protein. The deduced primary structure of the Esp protein from strain MMH594, inferred to be 1,873 amino acids (aa) with a predicted mass of ∼202 kDa, reveals a core region consisting of repeat units that make up 50% of the protein. Esp bears global organizational similarity to the Rib and C alpha proteins of group B streptococci. Identity among Esp, Rib, and C alpha proteins is strikingly localized to a stretch of 13 aa within repeats of similar length. The high degree of conservation of this 13-residue sequence suggests that it plays an important role in the natural selection for this trait among infection-derived
E. faecalis
and group B streptococcal isolates.
Lipopolysaccharide Stimulates Butyric Acid-Induced Apoptosis in Human Peripheral Blood Mononuclear Cells
Authors: Kurita-Ochiai Tomoko , Fukushima Kazuo , Ochiai Kuniyasu 
Published: December 2019

ABSTRACTWe previously reported that butyric acid, an extracellular metabolite from periodontopathic bacteria, induced apoptosis in murine thymocytes, splenic T cells, and human Jurkat T cells. In this study, we examined the ability of butyric acid to induce apoptosis in peripheral blood mononuclear cells (PBMC) and the effect of bacterial lipopolysaccharide (LPS) on this apoptosis. Butyric acid significantly inhibited the anti-CD3 monoclonal antibody- and concanavalin A-induced proliferative responses in a dose-dependent fashion. This inhibition of PBMC growth by butyric acid depended on apoptosis in vitro. It was characterized by internucleosomal DNA digestion and revealed by gel electrophoresis followed by a colorimetric DNA fragmentation assay to occur in a concentration-dependent fashion. Butyric acid-induced PBMC apoptosis was accompanied by caspase-3 protease activity but not by caspase-1 protease activity. LPS potentiated butyric acid-induced PBMC apoptosis in a dose-dependent manner. Flow-cytometric analysis revealed that LPS increased the proportion of sub-G1cells and the number of late-stage apoptotic cells induced by butyric acid. Annexin V binding experiments with fractionated subpopulations of PBMC in flow cytometory revealed that LPS accelerated the butyric acid-induced CD3+-T-cell apoptosis followed by similar levels of both CD4+- and CD8+-T-cell apoptosis. The addition of LPS to PBMC cultures did not cause DNA fragmentation, suggesting that LPS was unable to induce PBMC apoptosis directly. These data suggest that LPS, in combination with butyric acid, potentiates CD3+PBMC T-cell apoptosis and plays a role in the apoptotic depletion of CD4+and CD8+cells.
Polarized Helper-T-Cell Responses againstLeishmania majorin the Absence of B Cells
Authors: Brown Daniel R. , Reiner Steven L. 
Published: December 2019

ABSTRACTB-cell-to-T-cell signaling can shape helper T (Th) cell responses. During infection withLeishmania major, Th response is critical in determining the outcome of disease. Resistance depends on the generation of a protective Th1 response, while susceptibility is mediated by the generation of a Th2 response. In this study, we determined whether B cells are required for the development of polarized Th1 and Th2 responses during infection withL. major. Mice lacking B cells due to disruption of the immunoglobulin M locus (μMT) were infected withL. major, and disease progression and Th cell development were assessed. On the genetically resistant C57BL background, both wild-type and μMT mice controlled the infection and mounted a Th1 response. On the genetically susceptible BALB/c background, both wild-type and μMT mice were susceptible to infection and generated Th2 responses. Thus, duringL. majorinfection, neither direct antigen presentation or costimulation by B cells nor antibody-mediated effector functions are essential for the development of polarized Th responses.
Cloning and Characterization of a Novel Membrane-Associated Antigenic Protein ofHelicobacter pylori
Authors: Yoshida Masaru , Wakatsuki Yoshio , Kobayashi Yoshinao , Itoh Toshiyuki , Murakami Kazuhisa , Mizoguchi Akira , Usui Takashi , Chiba Tsutomu , Kita Toru 
Published: December 2019

ABSTRACTInfection byHelicobacter pylori, a noninvasive bacterium, induces chronic leukocyte infiltration in the stomach by still largely unknown molecular mechanisms. We investigated the possibility that a membrane protein ofH. pyloriinduces an inflammatory reaction in the subepithelial tissue of the stomach. By generating an expression library ofH. pylorichromosomal DNA and screening with rabbit antiserum raised to a membrane fraction ofH. pyloriand sera of infected patients, we cloned a 16.0-kDa protein (HP-MP1) which appeared to attach to the inner membrane of theH. pyloriin a homodimeric form. Anti-HP-MP1 antibodies were detected in the sera of infected patients but not in those of uninfected controls. Coincubation of monocytes with recombinant HP-MP1 led to cell activation and production of interleukin-1α (IL-1α), tumor necrosis factor alpha, IL-8, and macrophage inflammatory protein 1α. The results indicate that HP-MP1 is an antigenic membrane-associated protein ofH. pyloriwhich potentially activates monocytes. This suggests that HP-MP1 may play roles in the pathogenesis of perpetual tissue inflammation associated withH. pyloriinfection.
Mucin-Related Epitopes Distinguish M Cells and Enterocytes in Rabbit Appendix and Peyer’s Patches
Authors: Lelouard Hugues , Reggio Hubert , Mangeat Paul , Neutra Marian , Montcourrier Philippe 
Published: December 2019

ABSTRACT
The biochemical composition of the apical membranes of epithelial M cells overlying the gut-associated lymphoid tissues (GALT) is still largely unknown. We have prepared monoclonal antibodies (MAbs) directed against carbonate-washed plasma membranes from epithelial cells detached with EDTA from rabbit appendix, a tissue particularly rich in GALT. As determined by immunofluorescence microscopy, several MAbs specifically recognized either M cells or enterocyte-like cells of the domes from rabbit appendix, sacculus rotundus, and Peyer’s patches. M cells were identified by their large ventral pocket containing lymphoid cells and by specific labeling with antivimentin. Among various characterized MAbs, MAb 104 recognized rabbit immunoglobulins and was used as an apical marker for M cells in the rabbit appendix, MAb 58 selectively stained an integral membrane glycoprotein of greater than 205 kDa located at the apex of M cells, and MAb 214 stained a smaller soluble glycoprotein associated with the apical surfaces from neighboring enterocytes. In addition, both MAbs 58 and 214 also labeled luminal mucus and secretory granules in goblet cells. The selective association of mucin-related molecules at the surfaces of either M cells or enterocyte-like cells of the follicle-associated epithelium suggests that specific carbohydrate antigens are differentially expressed by epithelial cells and could account for the differential binding properties of pathogens.
Identification of Two Novel Genes Encoding 97- to 99-Kilodalton Outer Membrane Proteins of
Chlamydia pneumoniae
Authors: Knudsen Katrine , Madsen Anna Sofie , Mygind Per , Christiansen Gunna , Birkelund Svend 
Published: December 2019

ABSTRACT

Two genes encoding 97- to 99-kDa
Chlamydia pneumoniae
VR1310 outer membrane proteins (Omp4 and Omp5) with mutual similarity were cloned and sequenced. The proteins were shown to be constituents of the
C. pneumoniae
outer membrane complex, and the deduced amino acid sequences were similar to those of putative outer membrane proteins encoded by the
Chlamydia psittaci
and
Chlamydia trachomatis
gene families. By use of a monospecific polyclonal antibody against purified recombinant Omp4, it was shown that without heating, the protein migrated at 65 to 75 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Immunoelectron microscopy showed that epitopes of Omp4 were exposed on the surface of
C. pneumoniae
elementary bodies, reticulate bodies, and outer membrane complex. Proteins encoded by the
C. pneumoniae
gene family seem to be dominant antigens in experimentally infected mice.
Characterization ofemb, a Gene Encoding the Major Adhesin ofStreptococcus defectivus
Authors: Manganelli Riccardo , van de Rijn Ivo 
Published: December 2019

ABSTRACTStreptococcus defectivusis one of the nutritionally variant streptococci, a class of viridans group streptococci first isolated from patients with endocarditis and otitis media. In previous studies, NVS-47, a clinical isolate ofS. defectivus, was shown to bind to the extracellular matrix. A high-molecular-weight surface protein was identified and proposed to be responsible for mediating this binding. In the present study, the gene encoding this protein was identified by transposon mutagenesis and characterized. The gene (emb) was found to be larger than 14 kb and was partially sequenced. It encodes a protein containing at least 50 repeats of 77 amino acids predicted to assume an alternating coiled-coil conformation. The domain responsible for extracellular matrix binding was mapped to the N terminus of the protein. From sequence analysis, Emb is proposed to be the prototype of a new family of streptococcal fibrillar proteins.
Novel Target Antigens of the Variant-Specific Immune Response toPlasmodium falciparumIdentified by Differential Screening of an Expression Library
Authors: Le Scanf Cécile , Fandeur Thierry , Bonnefoy Serge , Guillotte Micheline , Mercereau-Puijalon Odile 
Published: December 2019

ABSTRACTA primary infection by thePlasmodium falciparumPalo Alto O and R antigenic variants induces a variant-specific immunity in theSaimiri sciureusmonkey. We have shown that these variants express distinct PfEMP1 antigens and differ in their levels of expression of additional antigens, including two conserved erythrocyte membrane-associated proteins, HRP1 and PfEMP3. To identify the antigens eliciting a variant-specific response, we conducted a differential screening of a λgt11 library with variant-specific sera. We report here the analysis of the 46 anti-R-specific clones. Two specific targets of the anti-R response were identified: (i) PfEMP3, suggesting that immunogenicity of this antigen is modulated by its relative abundance in different variants, and (ii) Asn-rich motifs. Most anti-R-specific clones, derived from so-far-undescribed genes, were detected by a cross-reaction on poly(Asn) stretches, as indicated by elimination of the signal after absorption on Asn-rich sequences. Reverse transcription-PCR (RT-PCR) showed that expression of the gene defined by clone 13 was R specific. Pepscan analysis of clone 13 identified three Asn-rich polypeptides and one unique peptide reacting specifically with antibodies eluted from the R-infected erythrocyte surface. Antisera raised to the unique peptide reacted with an R-specific protein. Attempts to demonstrate that clone 13 was derived from avargene by using PCRs combining clone 13 andvar-derived primers were unsuccessful. Thevargenes expressed by O and R parasites were identified not by this strategy but by RT-PCR withvar-specific primers. This work has provided novel insights into immunity to antigenic variants and has identified a novel gene switched on during antigenic variation.
Nucleotide Sequences of Genes Coding for Fimbrial Proteins in a Cryptic Genospecies of
Haemophilus
spp. Isolated from Neonatal and Genital Tract Infections
Authors: Gousset Nathalie , Rosenau Agnes , Sizaret Pierre-Yves , Quentin Roland 
Published: December 2019

ABSTRACT

Nineteen isolates belonging to a cryptic genospecies of
Haemophilus
(referred to here as genital strains) isolated from genital tract infections (6 strains) and from neonatal infections (13 strains) were studied for fimbrial genes. Sixteen strains exhibit peritrichous fimbriae observed by electron microscopy. By PCR with primers corresponding to the extreme ends of the
Haemophilus influenzae
type b (Hib)
hifA
and
hifD
genes and Southern blotting, a
hifA
-like gene (named
ghfA
) and a
hifD
-like gene (named
ghfD
) were identified in 6 of the 19 strains. Five of these six strains were from the genital tracts of adults, and one was from a neonate. For each gene, the nucleotide sequence was identical for the six strains. A
hifE
-like gene (named
ghfE
) was amplified from only one of the 19 genital strains of
Haemophilus
, but the
ghfE
probe gave a signal in Southern hybridization with the five other strains positive for
ghfA
and
ghfD
. Therefore, these strains may carry a
ghfE
-like gene. The Hib fimbrial gene cluster is located between the
purE
and
pepN
genes as previously described. For the 13 genital
Haemophilus
strains that lack fimbrial genes, this region corresponds to a noncoding sequence. Another major fimbrial gene designated the fimbrin gene was previously identified in a nontypeable
H. influenzae
strain. A fimbrin-like gene was identified for all of our 19 genital strains. This gene is similar to the
ompP5
gene of many
Haemophilus
strains. Therefore, other, unidentified genes may explain the piliation observed in electron microscopy on genital
Haemophilus
strains which do not possess LKP-like fimbrial genes. Fimbrial genes were significantly associated with strains isolated from the genital tract. They may confer on the strain the ability to survive in the genital tract.