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  • Spinola, S  (34)
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  • 1
    In: Infection and Immunity, 2001, Vol. 69(3), p.1483
    Description: Haemophilus ducreyi expresses several putative virulence factors in vitro. Isogenic mutant-to-parent comparisons have been performed in a human model of experimental infection to examine whether specific gene products are involved in pathogenesis. Several mutants (momp, ftpA, losB, lst, cdtC, and hhdB) were as virulent as the parent in the human model, suggesting that their gene products did not play a major role in pustule formation. However, we could not exclude the possibility that the gene of interest was not expressed during the initial stages of infection. Biopsies of pustules obtained from volunteers infected with H. ducreyi were subjected to reverse transcription-PCR. Transcripts corresponding to momp, ftpA, losB, lst, cdtB, and hhdA were expressed in vivo. In addition, transcripts for other putative virulence determinants such as ompA2, tdhA, lspA1, and lspA2 were detected in the biopsies. These results indicate that although several candidate virulence determinants are expressed during experimental infection, they do not have a major role in the initial stages of pathogenesis.
    Keywords: Chancroid -- Microbiology ; Haemophilus Ducreyi -- Genetics ; RNA, Bacterial -- Biosynthesis ; RNA, Messenger -- Biosynthesis;
    ISSN: 0019-9567
    ISSN: 00199567
    E-ISSN: 10985522
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  • 2
    In: Journal of Bacteriology, Feb, 1996, Vol.178(3-4), p.808(9)
    Description: A study was conducted to determine the role of the pili expressed by Haemophilus ducreyi in the pathogenesis of the genital ulcer disease chancroid. A gene encoding the 24K protein of fine, tangled pili, termed ftpA, was isolated and examined by molecular techniques. The results showed that the FtpA protein lacked homology with other pilins, but shared homoloy with proteins that polymerize ordered rings in Escherichia coli and Treponema pallidum.
    Keywords: Hemophilus Infections -- Genetic Aspects
    ISSN: 0021-9193
    E-ISSN: 10985530
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  • 3
    In: Infection and Immunity, 2001, Vol. 69(7), p.4224
    Description: Haemophilus ducreyi is the etiologic agent of chancroid, a sexually transmitted genital ulcer disease that facilitates the transmission of human immunodeficiency virus. In the human model of infection, the histopathology of infected sites in part resembles a delayed-type hypersensitivity (DTH) response. In this study, T cells were isolated from skin biopsy specimens obtained from 24 subjects who were infected for 7 to 14 days. One clone and 12 lines that responded to H. ducreyi antigens were obtained from 12 of the subjects. Fluorescence-activated cell sorter analysis showed that the antigen-responsive lines and clone were predominantly CD3 super(+) and CD4 super(+). The lines and clone responded to H. ducreyi antigen in a dose-dependent manner and produced gamma interferon (IFN- gamma ) alone or IFN- gamma and interleukin-10 (IL- 10) but no IL-4 or IL-5 in response to H. ducreyi. Proliferation of T cells was dependent on the presence of autologous antigen- presenting cells. The lines showed little response to antigens prepared from other members of the Pasteurellaceae and responded to different fractions of H. ducreyi separated by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. We conclude that T cells that recognize H. ducreyi antigens are recruited to sites experimentally infected with the organism. The lack of cross-reactivity to the Pasteurellaceae and the response of the lines to different antigen fractions suggest that subjects are sensitized to H. ducreyi during the course of infection.
    Keywords: Haemophilus Ducreyi ; Pasteurellaceae ; Lymphocytes T ; Hypersensitivity (Delayed) ; Cytokines ; Interleukin 10 ; Interleukin 4 ; Interleukin 5 ; Lymphocytes T ; Hypersensitivity (Delayed) ; Cytokines ; Interleukin 10 ; Interleukin 4 ; Interleukin 5 ; ^G-Interferon ; Haemophilus Ducreyi ; Pasteurellaceae ; Bacteria ; Immune Response and Immune Mechanisms ; Function ; Man ; Man ; Haemophilus Ducreyi ; Pasteurellaceae ; Gamma -Interferon ; Man;
    ISSN: 0019-9567
    ISSN: 00199567
    E-ISSN: 10985522
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  • 4
    In: Infection and Immunity, 2001, Vol. 69(4), p.2549
    Description: In a previous study, Haemophilus ducreyi was found in the pustule and dermis of samples obtained at the clinical end point in the human model of infection. To understand the kinetics of localization, we examined infected sites at 0, 24, and 48 h after inoculation and at the clinical end point. Immediately after inoculation, bacteria were found predominantly in the dermis but also in the epidermis. Few bacteria were detectable at 24 h; however, by 48 h, bacteria were readily seen in the pustule and dermis. H. ducreyi was associated with polymorphonuclear leukocytes and macrophages in the pustule and at its base, but was not associated with T cells, Langerhans' cells, or fibroblasts. H. ducreyi colocalized with collagen and fibrin but not laminin or fibronectin. Association with phagocytes, collagen, and fibrin was seen as early as 48 h and persisted at the pustular stage of disease. Optical sectioning by confocal microscopy and transmission electron microscopy both failed to demonstrate intracellular H. ducreyi. These data identify collagen and fibrin as potentially important targets of adherence in vivo and strongly suggest that H. ducreyi remains extracellular throughout infection and survives by resisting phagocytic killing in vivo.
    Keywords: Bacterial Adhesion ; Collagen -- Physiology ; Fibrin -- Physiology ; Haemophilus Ducreyi -- Physiology ; Phagocytes -- Microbiology;
    ISSN: 0019-9567
    ISSN: 00199567
    E-ISSN: 10985522
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  • 5
    Language: English
    In: The Journal of infectious diseases, 15 April 2008, Vol.197(8), pp.1103-9
    Description: Haemophilus ducreyi contains 3 TonB-dependent receptors: the hemoglobin receptor HgbA, which is required for virulence in humans; the heme receptor TdhA; and an uncharacterized conserved hypothetical protein TdX (HD0646). A double tdX/tdhA mutant (FX527) was constructed on the background of a human-passaged variant of strain 35000 (35000HP). Six volunteers were infected with 35000HP at 3 sites on one arm and with FX527 at 3 sites on the other. The pustule formation rate was 55.6% (95% confidence interval [CI], 35.7%-75.4%) at 18 parent-strain sites and 44.4% (95% CI, 15.0%-73.9%) at 18 mutant-strain sites (P = .51). Similar amounts of 35000HP and FX527 were recovered from pustules in semiquantitative culture. Thus, TdX and TdhA are not necessary for virulence, whereas HgbA is both necessary and sufficient for virulence in humans. The data suggest that hemoglobin is the sole source of heme/iron used by H. ducreyi in vivo and has implications for the potential of HgbA as a vaccine.
    Keywords: Bacterial Outer Membrane Proteins -- Biosynthesis ; Bacterial Proteins -- Biosynthesis ; Chancroid -- Microbiology ; Haemophilus Ducreyi -- Pathogenicity ; Membrane Proteins -- Biosynthesis
    ISSN: 0022-1899
    E-ISSN: 15376613
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  • 6
    In: Journal of Bacteriology, March, 1997, Vol.179(5-6), p.1764(10)
    Description: The nucleotide sequence of the gene encoding the major outer membrane protein (MOMP) of Haemophilus ducreyi was analyzed by sodium dodecyl sulfate-polyacrilamide gel electrophoresis. Nucleotide sequence analysis of the MOMP gene of Haemophilus ducreyi indicated the presence of two OmpA homologs that were encoded by momp and ompA2 genes. Southern blot analysis also indicated the high degree of similarity between MOMP and OmpA2 which existed in tandem in the different strains of Haemophilus ducreyi.
    Keywords: Pathogenic Bacteria -- Genetic Aspects ; Membrane Proteins -- Analysis ; Bacterial Proteins -- Analysis
    ISSN: 0021-9193
    E-ISSN: 10985530
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  • 7
    In: Infection and Immunity, 1999, Vol. 67(12), p.6394
    Description: The immune response to Haemophilus ducreyi is mediated in part by T cells infiltrating the site of infection. In this study, we show that H. ducreyi antigen preparations inhibited the proliferation of peripheral blood mononuclear cells and primary human T-cell lines. H. ducreyi also inhibited Jurkat T-cell proliferation and induced apoptosis of Jurkat T cells, confirmed through the detection of DNA degradation and membrane unpacking. The cytotoxic product(s) was present in cell-free culture supernatant and whole-cell preparations of H. ducreyi and was heat labile. H. ducreyi produces two known heat-labile toxins, a hemolysin and a cytolethal distending toxin (CDT). Whole cells and supernatants prepared from a hemolysin-deficient mutant had the same inhibitory and apoptotic effects on Jurkat T cells as did its isogenic parent. Preparations made from an H. ducreyi cdtC mutant were less toxic and induced less apoptosis than the parent. The toxic activity of the cdtC mutant was restored by complementation in trans. CdtC-neutralizing antibodies also inhibited H. ducreyi-induced toxicity and apoptosis. The data suggest that CDT may interfere with T-cell responses to H. ducreyi by induction of apoptosis.
    Keywords: Medicine ; Biology;
    ISSN: 0019-9567
    ISSN: 00199567
    E-ISSN: 10985522
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  • 8
    Language: English
    In: The Journal of Infectious Diseases, 1 February 1990, Vol.161(2), pp.336-339
    Description: The development of vaccines to prevent Neisseria infections has been impeded by antigenic diversity of most Neisseria surface components. The lipid-modified azurin (Laz), one of two distinct surface proteins recognized by the H.8 monoclonal antibody, is present in all pathogenic Neisseria. The mature protein has two domains; one contains an H.8 epitope and the other has extensive homology to azurins, a class of bacterial copper-binding proteins. The cellular location of Laz and the serum immune response to Laz were examined in patients with disseminated Neisseria infections. The data demonstrated that Laz is probably contained in the Neisseria outer membrane, although unlike most outer membrane proteins it is Sarkosyl soluble. By probing recombinant bacteriophages encoding the H.8 and azurin domains of Laz, results showed that whereas the H.8 epitope is immunogenic in patients with disseminated Neisseria infections, the azurin domain of Laz plays little role in eliciting an antibody response in these patients.
    Keywords: Biological sciences -- Biology -- Microbiology -- Epitopes ; Physical sciences -- Chemistry -- Chemical compounds -- Polyclonal antibodies ; Health sciences -- Medical conditions -- Infections -- Monoclonal antibodies ; Health sciences -- Medical sciences -- Immunology -- Monoclonal antibodies ; Health sciences -- Medical sciences -- Immunology -- Monoclonal antibodies ; Health sciences -- Medical sciences -- Immunology -- Monoclonal antibodies ; Physical sciences -- Astronomy -- Astronomical cosmology -- Monoclonal antibodies ; Physical sciences -- Chemistry -- Chemical compounds -- Monoclonal antibodies ; Health sciences -- Medical sciences -- Immunology -- Monoclonal antibodies ; Health sciences -- Medical sciences -- Immunology -- Monoclonal antibodies
    ISSN: 00221899
    E-ISSN: 15376613
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  • 9
    Language: English
    In: The Journal of Infectious Diseases, 1 June 1997, Vol.175(6), pp.1390-1395
    Description: The performance of two EIAs (adsorption EIA and lipooligosaccharide [LOS] EIA) that detect antibodies to Haemophilus ducreyi was evaluated with serum specimens obtained from 163 patients (96 with genital ulcer disease [GUD]). Paired serum specimens (initial and follow-up) were obtained from 52 of the GUD patients. By use of initial serum specimens from 82 GUD patients whose etiologic agents for their ulcers had been identified, the adsorption EIA had a sensitivity and specificity for chancroid of 53% and 71%, while the LOS EIA had a sensitivity and specificity of 48% and 89%, respectively. Sensitivity and specificity of the adsorption EIA increased to 78% and 84%, respectively, when the results of follow-up serum specimens were used to calculate optimal performance. The proportion of patients testing positive for H. ducreyi who had anti-H. ducreyi IgG antibodies, as determined by adsorption EIA, increased with the duration of infection, thus limiting the role of EIAs in the diagnosis of chancroid.
    Keywords: Health sciences -- Medical conditions -- Physical trauma -- Haemophilus ducreyi ; Health sciences -- Medical conditions -- Infections -- Haemophilus ducreyi ; Physical sciences -- Chemistry -- Chemical reactions -- Haemophilus ducreyi ; Health sciences -- Medical sciences -- Immunology -- Haemophilus ducreyi ; Biological sciences -- Biology -- Microbiology -- Haemophilus ducreyi ; Health sciences -- Medical conditions -- Diseases -- Haemophilus ducreyi ; Biological sciences -- Biology -- Anatomy -- Haemophilus ducreyi ; Health sciences -- Medical conditions -- Infections -- Haemophilus ducreyi ; Health sciences -- Medical sciences -- Immunology -- Haemophilus ducreyi ; Physical sciences -- Earth sciences -- Geology -- Haemophilus ducreyi
    ISSN: 00221899
    E-ISSN: 15376613
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  • 10
    Language: English
    In: The Journal of infectious diseases, 15 May 2007, Vol.195(10), pp.1443-51
    Description: We infected 11 HIV-seropositive volunteers whose CD4(+) cell counts were 〉350 cells/ microL (7 of whom were receiving antiretrovirals) with Haemophilus ducreyi. The papule and pustule formation rates were similar to those observed in HIV-seronegative historical control subjects. No subject experienced a sustained change in CD4(+) cell count or HIV RNA level. The cellular infiltrate in biopsy samples obtained from the HIV-seropositive and HIV-seronegative subjects did not differ with respect to the percentage of leukocytes, neutrophils, macrophages, or T cells. The CD4(+):CD8(+) cell ratio in biopsy samples from the HIV-seropositive subjects was 1:3, the inverse of the ratio seen in the HIV-seronegative subjects (P〈.0001). Although CD4(+) cells proliferated in lesions, in situ hybridization and reverse-transcription polymerase chain reaction for HIV RNA was negative. We conclude that experimental infection in HIV-seropositive persons is clinically similar to infection in HIV-seronegative persons and does not cause local or augment systemic viral replication. Thus, prompt treatment of chancroid may abrogate increases in viral replication associated with natural disease.
    Keywords: Chancroid -- Complications ; HIV Infections -- Complications ; Haemophilus Ducreyi -- Physiology
    ISSN: 0022-1899
    E-ISSN: 15376613
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