bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mucosal and Systemic Immune Responses in Humans after Primary and Booster Immunizations with Orally Administered Invasive and Noninvasive Live Attenuated Bacteria
Authors: Viret Jean-Francois , Favre Didier , Wegmüller Bernhard , Herzog Christian , Que John U. , Cryz Stanley J. , Lang Alois B. 
Published: December 2019

ABSTRACTThe mucosal and systemic immune responses after primary and booster immunizations with two attenuated live oral vaccine strains derived from a noninvasive (Vibrio cholerae) and an invasive (Salmonella typhi) enteric pathogen were comparatively evaluated. Vaccination withS. typhiTy21a elicited antibody-secreting cell (ASC) responses specific forS. typhiO9, 12 lipopolysaccharide (LPS), as well as significant increases in levels of immunoglobulin G (IgG) and IgA antibodies to the same antigen in serum. A strong systemic CD4+T-helper type 1 cell-mediated immune (CMI) response was also induced. In contrast to results with Ty21a, no evidence of a CMI response was obtained after primary immunization withV. choleraeCVD 103-HgR in spite of the good immunogenicity of the vaccine. Volunteers who received a single dose of CVD 103-HgR primarily developed an IgM ASC response against whole vaccine cells and purifiedV. choleraeInaba LPS, and seroconversion of serum vibriocidal antibodies occurred in four of five subjects. Serum IgG anti-cholera toxin antibody titers were of lower magnitude. For both live vaccines, the volunteers still presented significant local immunity 14 months after primary immunization, as revealed by the elevated baseline antibody titers at the time of the booster immunization and the lower ASC, serum IgG, and vibriocidal antibody responses after the booster immunization. These results suggest that local immunity may interfere with colonization of the gut by both vaccine strains at least up to 14 months after basis immunization. Interestingly, despite a low secondary ASC response, Ty21a was able to boost both humoral (anti-LPS systemic IgG and IgA) and CMI responses. Evidence of a CMI response was also observed for one of three volunteers given a cholera vaccine booster dose. The direct comparison of results with two attenuated live oral vaccine strains in human volunteers clearly showed that the capacity of the vaccine strain to colonize specific body compartments conditions the pattern of vaccine-induced immune responses.
Identification of Functional Domains of
Bordetella
Dermonecrotizing Toxin
Authors: Kashimoto Takashige , Katahira Jun , Cornejo Willian R. , Masuda Minako , Fukuoh Atsushi , Matsuzawa Takeshi , Ohnishi Takahiro , Horiguchi Yasuhiko 
Published: December 2019

ABSTRACT

Bordetella
dermonecrotizing toxin (DNT) stimulates the assembly of actin stress fibers and focal adhesions by deamidating Gln63 of the small GTPase Rho. To clarify the functional and structural organization of DNT, we cloned and sequenced the DNT gene and examined the functions of various DNT mutants. Our analyses of the nucleotide and amino acid sequences revealed that the start codon of the DNT gene is a GTG triplet located 39 bp upstream of the reported putative initiation ATG codon; consequently, DNT contains an additional 13 amino acids at its N-terminal end. All of the N-terminally truncated mutants were found to modify Rho. The shortest fragment of DNT possessing the Rho modification activity consists of amino acids from Ile1176 to the C-terminal end. This fragment overlaps the region homologous to
Escherichia coli
cytotoxic necrotizing factors (CNFs), which show activity similar to that of DNT. The introduction of a mutation at Cys1305 located in the highly conserved region between CNFs and DNT eliminated the activity, indicating that this domain is the catalytic center of DNT. The N-terminal fragment (1 to 531) of DNT failed to modify Rho but reduced the DNT-induced polynucleation in MC3T3-E1 cells when simultaneously added with the holotoxin, suggesting competitive inhibition in the receptor-binding or internalizing step. Our finding that DNT consists of an N-terminal receptor-binding and/or internalizing domain and a C-terminal catalytically active domain may facilitate analysis of the overall action of the toxin on the mammalian target cells.
Analysis of the Immunological Responses to Transferrin and Lactoferrin Receptor Proteins from
Moraxella catarrhalis
Authors: Yu Rong-hua , Bonnah Robert A. , Ainsworth Samuel , Schryvers Anthony B. 
Published: December 2019

ABSTRACT

Moraxella catarrhalis
expresses surface receptor proteins that specifically bind host transferrin (Tf) and lactoferrin (Lf) in the first step of the iron acquisition pathway. Acute- and convalescent-phase antisera from a series of patients with
M. catarrhalis
pulmonary infections were tested against Tf and Lf receptor proteins purified from the corresponding isolates. After the purified proteins had been separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting, we observed strong reactivity against Tf-binding protein B (TbpB; also called OMP1) and Lf-binding protein B (LbpB) but little or no reactivity against Tf-binding protein A (TbpA) or Lf-binding protein A (LbpA), using the convalescent-phase antisera. Considerable antigenic heterogeneity was observed when TbpBs and LbpBs isolated from different strains were tested with the convalescent-phase antisera. Comparison to the reactivity against electroblotted total cellular proteins revealed that the immune response against LbpB and TbpB constitutes a significant portion of the total detectable immune response to
M. catarrhalis
proteins. Preparations of affinity-isolated TbpA and LbpA reacted with convalescent-phase antisera in a solid-phase binding assay, but blocking with soluble TbpB, soluble LbpB, or extracts from an LbpA
−
mutant demonstrated that this reactivity was attributed to contaminants in the TbpA and LbpA preparations. These studies demonstrate the immunogenicity of
M. catarrhalis
TbpB and LbpB in humans and support their potential as vaccine candidates.
Genetic Characterization of a Tn5-Disrupted Glycosyltransferase Gene Homolog inBrucella abortusand Its Effect on Lipopolysaccharide Composition and Virulence
Authors: McQuiston J. R. , Vemulapalli R. , Inzana T. J. , Schurig G. G. , Sriranganathan N. , Fritzinger D. , Hadfield T. L. , Warren R. A. , Snellings N. , Hoover D. , Halling S. M. , Boyle S. M. 
Published: December 2019

ABSTRACTWe constructed a rough mutant ofBrucella abortus2308 by transposon (Tn5) mutagenesis. Neither whole cells nor extracted lipopolysaccharide (LPS) from this mutant, designated RA1, reacted with aBrucellaO-side-chain-specific monoclonal antibody (MAb), Bru-38, indicating the absence of O-side-chain synthesis. Compositional analyses of LPS from strain RA1 showed reduced levels of quinovosamine and mannose relative to the levels in the parental, wild-type strain, 2308. We isolated DNA flanking the Tn5insertion in strain RA1 by cloning a 25-kbXbaI genomic fragment into pGEM-3Z to create plasmid pJM6. Allelic exchange of genomic DNA inB. abortus2308 mediated by electroporation of pJM6 produced kanamycin-resistant clones that were not reactive with MAb Bru-38. Southern blot analysis of genomic DNA from these rough clones revealed Tn5in a 25-kbXbaI genomic fragment. A homology search with the deduced amino acid sequence of the open reading frame disrupted by Tn5revealed limited homology with various glycosyltransferases. ThisB. abortusgene has been namedwboA. Transformation of strain RA1 with a broad-host-range plasmid bearing the wild-typeB. abortus wboAgene resulted in the restoration of O-side-chain synthesis and the smooth phenotype.B. abortusRA1 was attenuated for survival in mice. However, strain RA1 persisted in mice spleens for a longer time than theB. abortusvaccine strain RB51, but as expected, neither strain induced antibodies specific for the O side chain.
The Cysteine-Rich Region of theEntamoeba histolyticaAdherence Lectin (170-Kilodalton Subunit) Is Sufficient for High-Affinity Gal/GalNAc-Specific Binding In Vitro
Authors: Pillai Dylan R. , Wan Peter S. K. , Yau Yvonne C. W. , Ravdin Jonathan I. , Kain Kevin C. 
Published: December 2019

ABSTRACTAdherence ofEntamoeba histolyticatrophozoites to colonic mucin, epithelium, and other target cells is mediated by the amebic Gal/GalNAc lectin. We constructed in vitro expression vectors containing full-length (residues 1 to 1280), cysteine-poor (1 to 353 and 1 to 480), and cysteine-rich (356 to 1143 and 480 to 900) fragments of the gene encoding the heavy subunit of the adherence lectin,hgl2. In vitro transcription followed by translation using a nuclease-treated rabbit reticulocyte lysate system was carried out. Immunoreactivity of in vitro-translated Hgl2 was confirmed by immunoprecipitation with lectin-specific monoclonal antibodies (MAbs) 1G7 and 8A3, which recognize linear epitopes. Protein disulfide isomerase (PDI) refolding of Hgl2 enhanced immunoreactivity (P< 0.05) with the conformationally dependent MAb 3F4. Binding of PDI-refolded full-length (P< 0.001) and cysteine-rich (P= 0.005) Hgl2 to CHO cells was galactose dependent and competitively inhibited by native hololectin (50% inhibitory concentration of 39.6 ng/ml). The cysteine-poor region (1 to 353) did not bind CHO cells. Both full-length (1 to 1280) and cysteine-rich (356 to 1143) Hgl2 bound the glyconeoconjugate GalNAc19BSA in a GalNAc-specific manner. The smaller cysteine-rich fragment (480 to 900) also exhibited GalNAc-specific binding but to a lesser extent (P< 0.05) than residues 1 to 1280 and 356 to 1143. Neither the cysteine-poor fragment (1 to 480), luciferase (protein control), nor control translation reactions (withouthgl2lectin mRNA) bound GalNAc19BSA. Binding to GalNAc19BSA was shown to be dependent on the concentration of GalNAc19BSA coated in each well or35S-lectin added (KD= 0.85 ± 0.37 pM). Binding was competitively inhibited by the terminal GalNAc-containing glycoprotein asialofetuin (P< 0.005). Taken together, these data provide direct evidence that the cysteine-rich region of the Gal/GalNAc lectin heavy subunit contains one or more carbohydrate-binding domains.
Gamma Interferon Modulates CD95 (Fas) and CD95 Ligand (Fas-L) Expression and Nitric Oxide-Induced Apoptosis during the Acute Phase ofTrypanosoma cruziInfection: a Possible Role in Immune Response Control
Authors: Martins Gislâine A. , Vieira Leda Q. , Cunha Fernando Q. , Silva João S. 
Published: December 2019

ABSTRACTWe have previously shown that splenocytes from mice acutely infected withTrypanosoma cruziexhibit high levels of nitric oxide (NO)-mediated apoptosis. In the present study, we used the gamma interferon (IFN-γ)-knockout (IFN-γ−/−) mice to investigate the role of IFN-γ in modulating apoptosis induction and host protection duringT. cruziinfection in mice. IFN-γ−/−mice were highly susceptible to infection and exhibited significant reduction of NO production and apoptosis levels in splenocytes but normal lymphoproliferative response compared to the infected wild-type (WT) mice. Furthermore, IFN-γ modulates an enhancement of Fas and Fas-L expression after infection, since the infected IFN-γ−/−mice showed significantly lower levels of Fas and Fas-L expression. The addition of recombinant murine IFN-γ to spleen cells cultures from infected IFN-γ−/−mice increased apoptosis levels, Fas expression, and NO production. In the presence of IFN-γ and absence of NO, although Fas expression was maintained, apoptosis levels were significantly reduced but still higher than those found in splenocytes from uninfected mice, suggesting that Fas–Fas-L interaction could also play a role in apoptosis induction inT. cruzi-infected mice. Moreover, in vivo, the treatment of infected WT mice with the inducible nitric oxide synthase inhibitor aminoguanidine also led to decreased NO and apoptosis levels but not Fas expression, suggesting that IFN-γ modulates apoptosis induction by two independent and distinct mechanisms: induction of NO production and of Fas and Fas-L expression. We suggest that besides being of crucial importance in mediating resistance to experimentalT. cruziinfection, IFN-γ could participate in the immune response control through apoptosis modulation.
Evidence of Thymus-Independent Local and Systemic Antibody Responses toCryptosporidium parvumInfection in Nude Mice
Authors: Adjei Andrew A. , Jones Janet T. , Riggs Michael W. , Enriquez F. Javier 
Published: December 2019

ABSTRACTDifferences in susceptibility to persistent cryptosporidial infection between two strains of adult athymic nude mice prompted us to investigate the immune mechanism(s) that may control resistance to infection in these T-cell-deficient mice. We studied fecal oocyst shedding, serum and fecal parasite-specific antibody responses, and fecal immunoglobulin levels in athymic C57BL/6J nude and athymic BALB/cJ nude mice following oral inoculation withCryptosporidium parvumoocysts at 8 to 9 weeks of age. C57BL/6J nude mice had significantly higher fecal parasite-specific immunoglobulin A (IgA) (days 27, 31, 35, and 42 postinoculation) and IgM (days 10, 17, 24, 28, 31, 38, 42, and 48 postinoculation) levels than BALB/cJ nude mice (P< 0.05) and significantly higher serum parasite-specific IgA levels at 63 days postinoculation (P< 0.03). Moreover, C57BL/6J nude mice shed significantly fewerC. parvumoocysts than BALB/cJ nude mice from days 52 to 63 postinoculation (P< 0.05). In contrast, BALB/cJ nude mice had higher levels of non-parasite-specific IgA (days 38 to 63 postinoculation) and IgM (days 24, 35, 38, and 52 postinoculation) than C57BL/6J nude mice in feces (P< 0.05). These data suggest that parasite-specific fecal antibodies may be associated with resistance toC. parvumin C57BL/6J nude mice.
Molecular and Functional Characteristics of a Protective Human Monoclonal Antibody to Serotype 8Streptococcus pneumoniaeCapsular Polysaccharide
Authors: Zhong Z. , Burns T. , Chang Q. , Carroll M. , Pirofski L. 
Published: December 2019

ABSTRACTThe structural characteristics and biological activity of human antibodies that are reactive with the capsular polysaccharides of most serotypes ofStreptococcus pneumoniae, including serotype 8, are unknown. This paper describes the generation, molecular structure, and protective efficacy of a human monoclonal antibody (MAb) reactive with the capsular polysaccharide of serotype 8Streptococcus pneumoniae. We generated the immunoglobulin M(κ) [IgM(κ)] MAb D11 by Epstein-Barr virus transformation of peripheral lymphocytes from a Pneumovax recipient. Nucleic acid sequence analysis revealed that MAb D11 uses V3-15/VH3 and A20/Vκgene segments with evidence of somatic mutation. In vitro studies revealed MAb D11-dependent complement deposition on the capsule of serotype 8 organisms via either the classical or the alternative complement pathway. In vivo, MAb D11 prolonged the survival of both normal and C4-deficient mice with lethal serotype 8S. pneumoniaeinfection. Our findings demonstrate that a serotype-specific human IgM with certain structural and functional characteristics was protective in mice lacking a functional classical complement pathway and show that alternative complement pathway activation is an important determinant of pneumococcal protection.
Infection of Mice Lacking Interleukin-7 (IL-7) Reveals an Unexpected Role for IL-7 in the Development of the ParasiteSchistosoma mansoni
Authors: Wolowczuk Isabelle , Nutten Sophie , Roye Olivier , Delacre Myriam , Capron Monique , Murray Richard M. , Trottein François , Auriault Claude 
Published: December 2019

ABSTRACTA single intradermal administration of recombinant interleukin-7 (IL-7) has been shown to aggravate the course of murine schistosomiasis, to favor the development of Th2-associated antibodies specific for the parasite, and to alter migration kinetics and/or migratory route of the parasite within its vertebrate host. Here we show that after infection of IL-7-deficient mice withSchistosoma mansoni, the predominant parasite-specific humoral response follows a Th1 pattern, and the development of the parasite is greatly impaired. In IL-7-deficient mice, increased numbers of larvae reach the lungs and fewer larvae reach the liver, compared to control mice. In the absence of IL-7, female worms show an altered fecundity, leading to decreased numbers of eggs trapped in the tissues and to an amelioration of the pathology of the infected host. The most striking observation is the blockade of parasite growth in an IL-7-defective environment, leading to dwarf male and female worms. The results of this study have important implications for the role of IL-7 in the host-parasite relationship and show how parasites can disable or evade the host immune response.
Attenuated Host Resistance againstMycobacterium bovisBCG Infection in Mice Lacking Osteopontin
Authors: Nau Gerard J. , Liaw Lucy , Chupp Geoffrey L. , Berman Jeffrey S. , Hogan Brigid L. M. , Young Richard A. 
Published: December 2019

ABSTRACTExpression of the cytokine osteopontin (OPN) is elevated in granulomas caused byMycobacterium tuberculosis. We tested the hypothesis that OPN contributes to host protection in a mouse model of mycobacterial infection. When infected withMycobacterium bovisBCG, mice lacking a functional OPN gene had more severe infections characterized by heavier bacterial loads and a delayed clearance of the bacteria. The OPN-null mice had greater granuloma burdens consistent with the elevated bacterial load. The ability of osteopontin to facilitate the clearance of mycobacteria was most pronounced early after infection and appeared to be independent of known mediators of resistance to infection by mycobacteria: antigen-specific T-cell immunity, gamma interferon production, and nitric oxide production. BCG grew more rapidly in macrophages derived from OPN-null mice than in those from wild-type mice, demonstrating that the null phenotype was due to an intrinsic macrophage defect. These results indicate that osteopontin augments the host response against a mycobacterial infection and that it acts independently from other antimycobacterial resistance mechanisms.
Protection againstMycobacterium aviumby DNA Vaccines Expressing Mycobacterial Antigens as Fusion Proteins with Green Fluorescent Protein
Authors: Velaz-Faircloth Maria , Cobb Alison J. , Horstman Amanda L. , Henry Stanley C. , Frothingham Richard 
Published: December 2019

ABSTRACTMycobacterium aviumcauses disseminated disease in humans with AIDS, paratuberculosis in ruminants, lymphadenopathy in swine, and tuberculosis in birds. We constructed DNA vaccines expressing mycobacterial antigens as fusion proteins with enhanced green fluorescent protein (EGFP). Plasmids p65K-EGFP, p85A-EGFP, and p85B-EGFP expressed theM. avium65-kDa antigen, theMycobacterium bovisBCG 85A antigen, and theM. avium85B antigen, respectively, as EGFP fusion proteins. We visualized protein expression directly in cultured murine fibroblasts and intact muscle. p65K-EGFP expressed fusion protein in a diffuse cytoplasmic pattern, and p85A-EGFP and p85B-EGFP produced a speckled pattern. We vaccinated C57BL/6 mice with three doses of plasmid DNA and then challenged them intraperitoneally withM. avium. Negative controls received saline, and positive controls received one dose of BCG vaccine. Mice in all groups developed disseminated infection with a high burden of organisms. Compared to negative controls, mice vaccinated with p85A-EGFP had an eightfold reduction in spleenM. aviumCFU at 4 weeks after infection and a fourfold reduction at 8 weeks, reductions similar to those generated by BCG vaccine. Mice vaccinated with p65K-EGFP had a fourfold CFU reduction at 4 weeks and no effect at 8 weeks. This is the first report of DNA vaccines expressing foreign antigens as fusion proteins with EGFP and the first report of successful DNA vaccination againstM. avium.
Detection of Als Proteins on the Cell Wall of
Candida albicans
in Murine Tissues
Authors: Hoyer L. L. , Clevenger J. , Hecht J. E. , Ehrhart E. J. , Poulet F. M. 
Published: December 2019

ABSTRACT

A murine model of disseminated candidiasis was utilized to determine whether
Candida albicans
Als proteins are produced in vivo. The kidneys, spleen, heart, liver, and lungs were collected from mice inoculated with one of three
C. albicans
strains (SC5314, B311, or WO-1). Immunohistochemical analysis of murine tissues by using a rabbit polyclonal anti-Als serum indicated that Als proteins were produced by each
C. albicans
cell in the tissues examined. Patterns of staining with the anti-Als serum were similar among the
C. albicans
strains tested. These data indicated that Als protein production was widespread in disseminated candidiasis and that, despite strain differences in
ALS
gene expression previously noted in vitro, Als protein production in vivo was similar among
C. albicans
strains. The extensive production of Als proteins in vivo and their presence on the
C. albicans
cell wall position these proteins well for a role in host-pathogen interaction.
The Cloned Locus of Enterocyte Effacement from Enterohemorrhagic
Escherichia coli
O157:H7 Is Unable To Confer the Attaching and Effacing Phenotype upon
E. coli
K-12
Authors: Elliott Simon J. , Yu Jie , Kaper James B. 
Published: December 2019

ABSTRACT

The locus of enterocyte effacement (LEE) pathogenicity island of enterohemorrhagic
Escherichia coli
(EHEC) O157:H7 possesses the same genes in identical order and orientation as the LEE of enteropathogenic
E. coli
(EPEC) O127:H6 but is unable to form attaching and effacing (A/E) lesions or to secrete Esp proteins when it is cloned in an
E. coli
K-12 background. The A/E phenotype could not be restored by
trans
complementation with a variety of cloned EPEC LEE fragments, suggesting functional and/or regulatory differences between the LEE pathogenicity islands of EPEC O127:H6 and EHEC O157:H7.
Infectivity ofPlasmodium bergheiSporozoites Delivered by Intravenous Inoculation versus Mosquito Bite: Implications for Sporozoite Vaccine Trials
Authors: Vaughan Jefferson A. , Scheller Libia F. , Wirtz Robert A. , Azad Abdu F. 
Published: December 2019

ABSTRACTPlasmodium bergheisporozoites delivered by mosquito bite were more infectious to outbred CD-1 mice than were sporozoites delivered by intravenous inoculation. The route of challenge also affected vaccine efficacy. In view of these findings and the fact that mosquito bites are the natural mode of sporozoite delivery, infectious mosquito bites should be considered the challenge protocol of choice for sporozoite vaccine efficacy trials.
CpG Motifs inPorphyromonas gingivalisDNA Stimulate Interleukin-6 Expression in Human Gingival Fibroblasts
Authors: Takeshita Akira , Imai Kenichi , Hanazawa Shigemasa 
Published: December 2019

ABSTRACTWe suggest here thatPorphyromonas gingivalisDNA may function as a virulence factor in periodontal disease through expression of inflammatory cytokine. The bacterial DNA markedly stimulated in a dose-dependent manner interleukin-6 (IL-6) production by human gingival fibroblasts. The stimulatory action was eliminated by treatment with DNase but not RNase. The stimulatory effect was not observed in the fibroblasts treated with eucaryotic DNAs. The bacterial DNA also stimulated in dose- and treatment time-dependent manners the expression of the IL-6 gene in the cells. In addition, the stimulatory effect was eliminated when the DNA was methylated with CpG motif methylase. Interestingly, a 30-base synthetic oligonucleotide containing the palindromic motif GACGTC could stimulate expression of the IL-6 gene and production of its protein in the cells. Furthermore, the synthetic oligonucleotide-induced expression of this cytokine gene was blocked by pyrrolidine dithiocarbamate andN-acetyl-l-cystine, potent inhibitors of transcriptional factor NF-κB. Gel mobility shift assay showed increased binding of NF-κB to its consensus sequence in the synthetic oligonucleotide-treated cells. Also, using specific antibody against p50 and p65, which compose NF-κB, we showed the consensus sequence-binding proteins to be NF-κB. These results are the first to demonstrate that the internal CpG motifs inP. gingivalisDNA stimulate IL-6 expression in human gingival fibroblasts via stimulation of NF-κB.