scholarly journals Trimeric Autotransporter DsrA Is a Major Mediator of Fibrinogen Binding in Haemophilus ducreyi

2013 ◽  
Vol 81 (12) ◽  
pp. 4443-4452 ◽  
Author(s):  
William G. Fusco ◽  
Christopher Elkins ◽  
Isabelle Leduc
Keyword(s):  
Binding Protein ◽  
Blood Clot ◽  
Etiologic Agent ◽  
Haemophilus Ducreyi ◽  
Dependent Manner ◽  
Passenger Domain ◽  
Content Type ◽  
Ulcer Disease ◽  
Sexually Transmitted ◽  
Terminal Section

ABSTRACTHaemophilus ducreyiis the etiologic agent of the sexually transmitted genital ulcer disease chancroid. In both natural and experimental chancroid,H. ducreyicolocalizes with fibrin at the base of the ulcer. Fibrin is obtained by cleavage of the serum glycoprotein fibrinogen (Fg) by thrombin to initiate formation of the blood clot. Fg binding proteins are critical virulence factors in medically important Gram-positive bacteria.H. ducreyihas previously been shown to bind Fg in an agglutination assay, and theH. ducreyiFg binding protein FgbA was identified in ligand blotting with denatured proteins. To better characterize the interaction ofH. ducreyiwith Fg, we examined Fg binding to intact, viableH. ducreyibacteria and identified a novel Fg binding protein.H. ducreyibound unlabeled Fg in a dose-dependent manner, as measured by two different methods. In ligand blotting with total denatured cellular proteins, digoxigenin (DIG)-Fg bound only twoH. ducreyiproteins, the trimeric autotransporter DsrA and the lectin DltA; however, only the isogenicdsrAmutant had significantly less cell-associated Fg than parental strains in Fg binding assays with intact bacteria. Furthermore, expression of DsrA, but not DltA or an empty vector, rendered the non-Fg-bindingH. influenzaestrain Rd capable of binding Fg. A 13-amino-acid sequence in the C-terminal section of the passenger domain of DsrA appears to be involved in Fg binding byH. ducreyi. Taken together, these data suggest that the trimeric autotransporter DsrA is a major determinant of Fg binding at the surface ofH. ducreyi.

scholarly journals A Humoral Immune Response Confers Protection against Haemophilus ducreyi Infection

2003 ◽  
Vol 71 (12) ◽  
pp. 6971-6977 ◽  
Author(s):  
Leah E. Cole ◽  
Kristen L. Toffer ◽  
Robert A. Fulcher ◽  
Lani R. San Mateo ◽  
Paul E. Orndorff ◽  
...  
Keyword(s):  
Immune Response ◽  
Humoral Immune Response ◽  
Etiologic Agent ◽  
Haemophilus Ducreyi ◽  
Swine Model ◽  
Ulcer Disease ◽  
Sexually Transmitted ◽  
Humoral Immune ◽  
The Third ◽  
The Impact

ABSTRACT Haemophilus ducreyi is the etiologic agent of the sexually transmitted genital ulcer disease chancroid. Neither naturally occurring chancroid nor experimental infection with H. ducreyi results in protective immunity. Likewise, a single inoculation of H. ducreyi does not protect pigs against subsequent infection. Accordingly, we used the swine model of chancroid infection to examine the impact of multiple inoculations on a host's immune response. After three successive inoculations with H. ducreyi, pigs developed a modestly protective immune response evidenced by the decreased recovery of viable bacteria from lesions. All lesions biopsied 2 days after the first and second inoculations contained viable H. ducreyi cells, yet only 55% of the lesions biopsied 2 days after the third inoculation did. Nearly 90% of the lesions biopsied 7 days after the first inoculation contained viable H. ducreyi cells, but this percentage dropped to only 16% after the third inoculation. Between the first and third inoculations, the average recovery of CFU from lesions decreased approximately 100-fold. The reduced recovery of bacteria corresponded directly with a fivefold increase in H. ducreyi-specific antibody titers and the emergence of bactericidal activity. These immune sera were protective when administered to naïve pigs prior to challenge with H. ducreyi. These data suggest that pigs mount an effective humoral immune response to H. ducreyi after multiple exposures to the organism.

scholarly journals The Haemophilus ducreyi LspA1 Protein Inhibits Phagocytosis By Using a New Mechanism Involving Activation of C-Terminal Src Kinase

mBio ◽  
2014 ◽  
Vol 5 (3) ◽  
Author(s):  
Dana A. Dodd ◽  
Randall G. Worth ◽  
Michael K. Rosen ◽  
Sergio Grinstein ◽  
Nicolai S. C. van Oers ◽  
...  
Keyword(s):  
Immune Response ◽  
Catalytic Activity ◽  
Mammalian Cells ◽  
Src Kinase ◽  
Innate Immune ◽  
Haemophilus Ducreyi ◽  
Dependent Manner ◽  
Content Type ◽  
Sexually Transmitted ◽  
Tyrosine Residues

ABSTRACTHaemophilus ducreyicauses chancroid, a sexually transmitted infection. A primary means by which this pathogen causes disease involves eluding phagocytosis; however, the molecular basis for this escape mechanism has been poorly understood. Here, we report that the LspA virulence factors ofH. ducreyiinhibit phagocytosis by stimulating the catalytic activity of C-terminal Src kinase (Csk), which itself inhibits Src family protein tyrosine kinases (SFKs) that promote phagocytosis. Inhibitory activity could be localized to a 37-kDa domain (designated YL2) of the 456-kDa LspA1 protein. The YL2 domain impaired ingestion of IgG-opsonized targets and decreased levels of active SFKs when expressed in mammalian cells. YL2 contains tyrosine residues in two EPIYG motifs that are phosphorylated in mammalian cells. These tyrosine residues were essential for YL2-based inhibition of phagocytosis. Csk was identified as the predominant mammalian protein interacting with YL2, and a dominant-negative Csk rescued phagocytosis in the presence of YL2. Purified Csk phosphorylated the tyrosines in the YL2 EPIYG motifs. Phosphorylated YL2 increased Csk catalytic activity, resulting in positive feedback, such that YL2 can be phosphorylated by the same kinase that it activates. Finally, we found that theHelicobacter pyloriCagA protein also inhibited phagocytosis in a Csk-dependent manner, raising the possibility that this may be a general mechanism among diverse bacteria. Harnessing Csk to subvert the Fcγ receptor (FcγR)-mediated phagocytic pathway represents a new bacterial mechanism for circumventing a crucial component of the innate immune response and may potentially affect other SFK-involved cellular pathways.IMPORTANCEPhagocytosis is a critical component of the immune system that enables pathogens to be contained and cleared. A number of bacterial pathogens have developed specific strategies to either physically evade phagocytosis or block the intracellular signaling required for phagocytic activity.Haemophilus ducreyi, a sexually transmitted pathogen, secretes a 4,153-amino-acid (aa) protein (LspA1) that effectively inhibits FcγR-mediated phagocytic activity. In this study, we show that a 294-aa domain within this bacterial protein binds to C-terminal Src kinase (Csk) and stimulates its catalytic activity, resulting in a significant attenuation of Src kinase activity and consequent inhibition of phagocytosis. The ability to inhibit phagocytosis via Csk is not unique toH. ducreyi, because we found that theHelicobacter pyloriCagA protein also inhibits phagocytosis in a Csk-dependent manner. Harnessing Csk to subvert the FcγR-mediated phagocytic pathway represents a new bacterial effector mechanism for circumventing the innate immune response.

scholarly journals Haemophilus ducreyi Infection Induces Activation of the NLRP3 Inflammasome in Nonpolarized but Not in Polarized Human Macrophages

2013 ◽  
Vol 81 (8) ◽  
pp. 2997-3008 ◽  
Author(s):  
Wei Li ◽  
Barry P. Katz ◽  
Margaret E. Bauer ◽  
Stanley M. Spinola
Keyword(s):  
Nlrp3 Inflammasome ◽  
Interleukin 1 ◽  
Study Data ◽  
Human Infection ◽  
Haemophilus Ducreyi ◽  
Inflammasome Activation ◽  
Microbial Infection ◽  
Content Type ◽  
Ulcer Disease ◽  
Caspase 1

ABSTRACTRecognition of microbial infection by certain intracellular pattern recognition receptors leads to the formation of a multiprotein complex termed the inflammasome. Inflammasome assembly activates caspase-1 and leads to cleavage and secretion of the proinflammatory cytokines interleukin-1 beta (IL-1β) and IL-18, which help control many bacterial pathogens. However, excessive inflammation mediated by inflammasome activation can also contribute to immunopathology. Here, we investigated whetherHaemophilus ducreyi, a Gram-negative bacterium that causes the genital ulcer disease chancroid, activates inflammasomes in experimentally infected human skin and in monocyte-derived macrophages (MDM). AlthoughH. ducreyiis predominantly extracellular during human infection, several inflammasome-related components were transcriptionally upregulated inH. ducreyi-infected skin. Infection of MDM with live, but not heat-killed,H. ducreyiinduced caspase-1- and caspase-5-dependent processing and secretion of IL-1β. Blockage ofH. ducreyiuptake by cytochalasin D significantly reduced the amount of secreted IL-1β. Knocking down the expression of the inflammasome components NLRP3 and ASC abolished IL-1β production. Consistent with NLRP3-dependent inflammasome activation, blocking ATP signaling, K+efflux, cathepsin B activity, and lysosomal acidification all inhibited IL-1β secretion. However, inhibition of the production and function of reactive oxygen species did not decrease IL-1β production. Polarization of macrophages to classically activated M1 or alternatively activated M2 cells abrogated IL-1β secretion elicited byH. ducreyi. Our study data indicate thatH. ducreyiinduces NLRP3 inflammasome activation via multiple mechanisms and suggest that the heterogeneity of macrophages within human lesions may modulate inflammasome activation during human infection.

scholarly journals Passive Immunization with a Polyclonal Antiserum to the Hemoglobin Receptor of Haemophilus ducreyi Confers Protection against a Homologous Challenge in the Experimental Swine Model of Chancroid

2011 ◽  
Vol 79 (8) ◽  
pp. 3168-3177 ◽  
Author(s):  
Isabelle Leduc ◽  
William G. Fusco ◽  
Neelima Choudhary ◽  
Patty A. Routh ◽  
Deborah M. Cholon ◽  
...  
Keyword(s):  
Lipid A ◽  
Polyclonal Antibodies ◽  
Passive Immunization ◽  
Etiologic Agent ◽  
Polyclonal Antiserum ◽  
Haemophilus Ducreyi ◽  
Human Model ◽  
Swine Model ◽  
Content Type ◽  
Monophosphoryl Lipid A

ABSTRACTHaemophilus ducreyi, the etiologic agent of chancroid, has an obligate requirement for heme. Heme is acquired byH. ducreyifrom its human host via TonB-dependent transporters expressed at its bacterial surface. Of 3 TonB-dependent transporters encoded in the genome ofH. ducreyi, only the hemoglobin receptor, HgbA, is required to establish infection during the early stages of the experimental human model of chancroid. Active immunization with a native preparation of HgbA (nHgbA) confers complete protection in the experimental swine model of chancroid, using either Freund's or monophosphoryl lipid A as adjuvants. To determine if transfer of anti-nHgbA serum is sufficient to confer protection, a passive immunization experiment using pooled nHgbA antiserum was conducted in the experimental swine model of chancroid. Pigs receiving this pooled nHgbA antiserum were protected from a homologous, but not a heterologous, challenge. Passively transferred polyclonal antibodies elicited to nHgbA bound the surface ofH. ducreyiand partially blocked hemoglobin binding by nHgbA, but were not bactericidal. Taken together, these data suggest that the humoral immune response to the HgbA vaccine is protective against anH. ducreyiinfection, possibly by preventing acquisition of the essential nutrient heme.

Etiology of Genital Ulcer Disease in Dakar, Senegal, and Comparison of PCR and Serologic Assays for Detection of Haemophilus ducreyi

2000 ◽  
Vol 38 (1) ◽  
pp. 268-273
Author(s):  
Patricia A. Totten ◽  
Jane M. Kuypers ◽  
Cheng-Yen Chen ◽  
Michelle J. Alfa ◽  
Linda M. Parsons ◽  
...  
Keyword(s):  
Transmitted Disease ◽  
Haemophilus Ducreyi ◽  
Genital Ulcer ◽  
Serological Tests ◽  
Past Infection ◽  
Ulcer Disease ◽  
Sexually Transmitted ◽  
Genital Ulcer Disease ◽  
Pcr Assays ◽  
Simplex Virus

ABSTRACT We used PCR assays to determine the etiology of genital ulcers in patients presenting to a sexually transmitted disease clinic in Dakar, Senegal, and evaluated the ability of two PCR tests ( groEL and recD ) and two serological tests (adsorption enzyme immunoassay [EIA] and lipooligosaccharide [LOS] EIA) to detect current Haemophilus ducreyi infection. We found that in this population, H. ducreyi , T. pallidum , and herpes simplex virus HSV DNA were detected in 56, 15, and 13% of 39 genital ulcer specimens, respectively, and H. ducreyi DNA was detected in 60% (3 of 5) of samples from ulcerated bubos. Among 40 consecutive patients with genital ulcer disease and with sufficient sample for both PCR assays, the recD and groEL H. ducreyi PCR assays were 83% concordant, with the recD PCR assay detecting six (15%) additional positive specimens and the groEL assay detecting one (3%) additional positive specimen. Compared to PCR, the adsorption EIA and LOS EIA tests had sensitivities of 71 and 59% and specificities of 57 and 90%, respectively, for the diagnosis of current H. ducreyi infection. While these differences in specificity could be due either to previous infection with H. ducreyi or to the detection of cross-reacting antibodies, only 6% of patients from a nearby family planning clinic gave a positive reaction in both the adsorption EIA and LOS EIA assays, indicating that cross-reacting antibodies are not prevalent among clinic attendees in this city. Our studies indicate that the adsorption EIA detects both current and past infection, while the LOS EIA assay is more specific for current infection with H. ducreyi in this population.

scholarly journals Sialylation of Lipooligosaccharides Is Dispensable for the Virulence of Haemophilus ducreyi in Humans

2011 ◽  
Vol 80 (2) ◽  
pp. 679-687 ◽  
Author(s):  
Stanley M. Spinola ◽  
Wei Li ◽  
Kate R. Fortney ◽  
Diane M. Janowicz ◽  
Beth Zwickl ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Cell Activation ◽  
Molecular Mimicry ◽  
Etiologic Agent ◽  
Human Infection ◽  
Haemophilus Ducreyi ◽  
Dendritic Cell Activation ◽  
Content Type ◽  
Self Recognition ◽  
Serum Killing

ABSTRACTSialylated glycoconjugates on the surfaces of mammalian cells play important roles in intercellular communication and self-recognition. The sialic acid preferentially expressed in human tissues isN-acetylneuraminic acid (Neu5Ac). In a process called molecular mimicry, many bacterial pathogens decorate their cell surface glycolipids with Neu5Ac. Incorporation of Neu5Ac into bacterial glycolipids promotes bacterial interactions with host cell receptors called Siglecs. These interactions affect bacterial adherence, resistance to serum killing and phagocytosis, and innate immune responses.Haemophilus ducreyi, the etiologic agent of chancroid, expresses lipooligosaccharides (LOS) that are highly sialylated. However, anH. ducreyisialyltransferase (lst) mutant, whose LOS contain reduced levels of Neu5Ac, is fully virulent in human volunteers. Recently, a second sialyltransferase gene (Hd0053) was discovered inH. ducreyi, raising the possibility thatHd0053compensated for the loss oflstduring human infection. CMP-Neu5Ac is the obligate nucleotide sugar donor for all bacterial sialyltransferases; LOS derived from anH. ducreyiCMP-Neu5Ac synthetase (neuA) mutant has no detectable Neu5Ac. Here, we compared anH. ducreyi neuAmutant to its wild-type parent in several models of pathogenesis. In human inoculation experiments, theneuAmutant formed papules and pustules at rates that were no different than those of its parent. When grown in media with and without Neu5Ac supplementation, theneuAmutant and its parent had similar phenotypes in bactericidal, macrophage uptake, and dendritic cell activation assays. Although we cannot preclude a contribution of LOS sialylation to ulcerative disease, these data strongly suggest that sialylation of LOS is dispensable forH. ducreyipathogenesis in humans.

scholarly journals Haemophilus ducreyi Is Susceptible to Protegrin

1998 ◽  
Vol 42 (10) ◽  
pp. 2690-2693 ◽  
Author(s):  
Kate Fortney ◽  
Patricia A. Totten ◽  
Robert I. Lehrer ◽  
Stanley M. Spinola
Keyword(s):  
Human Immunodeficiency Virus ◽  
Sexually Transmitted Diseases ◽  
Type Strain ◽  
Etiologic Agent ◽  
Haemophilus Ducreyi ◽  
Sexually Transmitted ◽  
Immunodeficiency Virus ◽  
Resistance Patterns ◽  
Test Organisms

ABSTRACT Protegrins, potent antimicrobial peptides found in porcine leukocytes, have activity against the sexually transmitted pathogens Neisseria gonorrhoeae,Chlamydia trachomatis, and human immunodeficiency virus type 1. We tested synthetic protegrin 1 (PG-1) for activity against nine isolates of Haemophilus ducreyi, the etiologic agent of chancroid. The test organisms included CIP 542 (the type strain), 35000HP (a human-passaged variant of 35000), 35000HP-RSM2 (an isogenicd-glycero-d-manno-heptosyltransferase mutant of 35000HP), and six clinical isolates. The isolates were epidemiologically unrelated, represented three HindIII ribotypes, and had varying antimicrobial resistance patterns. In bactericidal assays, five isolates were rapidly killed by synthetic PG-1. In radial diffusion assays, all nine isolates were exquisitely sensitive to PG-1. These data highlight the potential of protegrins for development as topical agents to prevent many sexually transmitted diseases, including chancroid.

scholarly journals Interleukin-22 (IL-22) Binding Protein Constrains IL-22 Activity, Host Defense, and Oxidative Phosphorylation Genes during Pneumococcal Pneumonia

2019 ◽  
Vol 87 (11) ◽  
Author(s):  
Giraldina Trevejo-Nunez ◽  
Waleed Elsegeiny ◽  
Felix E. Y. Aggor ◽  
Jamie L. Tweedle ◽  
Zoe Kaplan ◽  
...  
Keyword(s):  
Oxidative Phosphorylation ◽  
Pneumococcal Pneumonia ◽  
Binding Protein ◽  
Pneumococcal Infection ◽  
Community Acquired Pneumonia ◽  
Dependent Manner ◽  
Rna Seq ◽  
Content Type ◽  
Interleukin 22 ◽  
Oxphos Gene

ABSTRACT Streptococcus pneumoniae is the most common cause of community-acquired pneumonia worldwide, and interleukin-22 (IL-22) helps contain pneumococcal burden in lungs and extrapulmonary tissues. Administration of IL-22 increases hepatic complement 3 and complement deposition on bacteria and improves phagocytosis by neutrophils. The effects of IL-22 can be tempered by a secreted natural antagonist, known as IL-22 binding protein (IL-22BP), encoded by Il22ra2. To date, the degree to which IL-22BP controls IL-22 in pulmonary infection is not well defined. Here, we show that Il22ra2 inhibits IL-22 during S. pneumoniae lung infection and that Il22ra2 deficiency favors downregulation of oxidative phosphorylation (OXPHOS) genes in an IL-22-dependent manner. Il22ra2−/− mice are more resistant to S. pneumoniae infection, have increased IL-22 in lung tissues, and sustain longer survival upon infection than control mice. Transcriptome sequencing (RNA-seq) analysis of infected Il22ra2−/− mouse lungs revealed downregulation of genes involved in OXPHOS. Downregulation of this metabolic process is necessary for increased glycolysis, a crucial step for transitioning to a proinflammatory phenotype, in particular macrophages and dendritic cells (DCs). Accordingly, we saw that macrophages from Il22ra2−/− mice displayed reduced OXPHOS gene expression upon infection with S. pneumoniae, changes that were IL-22 dependent. Furthermore, we showed that macrophages express IL-22 receptor subunit alpha-1 (IL-22Ra1) during pneumococcal infection and that Il22ra2−/− macrophages rely more on the glycolytic pathway than wild-type (WT) controls. Together, these data indicate that IL-22BP deficiency enhances IL-22 signaling in the lung, thus contributing to resistance to pneumococcal pneumonia by downregulating OXPHOS genes and increasing glycolysis in macrophages.

Haemophilus ducreyi

1985 ◽  
Vol 6 (5) ◽  
pp. 203-205
Author(s):  
Judy A. Daly
Keyword(s):  
Transmitted Disease ◽  
Haemophilus Ducreyi ◽  
Causative Organism ◽  
Ulcer Disease ◽  
Sexually Transmitted ◽  
Genital Ulcer Disease ◽  
Direct Inoculation ◽  
Ulcus Molle ◽  
Multiple Antibiotics

Chancroid, or soft chancre (ulcus molle), was first differentiated from syphilis by Bassereau in 1852. The causative organism,Haemophilus ducreyi, was first described by Ducrey in 1889, although he was unable to grow the organism in vitro. The first successful culture has been attributed to Petersen (1895).Haemophilus ducreyihas been clinically associated only with genital ulcer disease and direct inoculation infections. There is no difficulty acceptingHaemophilus ducreyias a legitimate clinical and taxonomic species because it is the sole humanHaemophilusspecies with a requirement only for X factor as determined by the porphyrin test. The emergence ofHaemophilus ducreyistrains resistant to multiple antibiotics has restricted efforts to curb the spread of this increasingly prevalent sexually transmitted disease.

scholarly journals The Haemophilus ducreyi Serum Resistance Antigen DsrA Confers Attachment to Human Keratinocytes

2002 ◽  
Vol 70 (11) ◽  
pp. 6158-6165 ◽  
Author(s):  
Leah E. Cole ◽  
Thomas H. Kawula ◽  
Kristen L. Toffer ◽  
Christopher Elkins
Keyword(s):  
Cell Line ◽  
Immune Cell ◽  
Outer Membrane Proteins ◽  
Protein A ◽  
Etiologic Agent ◽  
Haemophilus Ducreyi ◽  
Serum Resistance ◽  
Hacat Cells ◽  
Wild Type ◽  
Ulcer Disease

ABSTRACT Haemophilus ducreyi is the etiologic agent of the sexually transmitted genital ulcer disease chancroid. H. ducreyi serum resistance protein A (DsrA) is a member of a family of multifunctional outer membrane proteins that are involved in resistance to killing by human serum complement. The members of this family include YadA of Yersinia species, the UspA proteins of Moraxella catarrhalis, and the Eib proteins of Escherichia coli. The role of YadA, UspA1, and UspA2H as eukaryotic cell adhesins and the function of UspA2 as a vitronectin binder led to our investigation of the cell adhesion and vitronectin binding properties of DsrA. We found that DsrA was a keratinocyte-specific adhesin as it was necessary and sufficient for attachment to HaCaT cells, a keratinocyte cell line, but was not required for attachment to HS27 cells, a fibroblast cell line. We also found that DsrA was specifically responsible for the ability of H. ducreyi to bind vitronectin. We then theorized that DsrA might use vitronectin as a bridge to bind to human cells, but this hypothesis proved to be untrue as eliminating HaCaT cell binding of vitronectin with a monoclonal antibody specific to integrin αvβ5 did not affect the attachment of H. ducreyi to HaCaT cells. Finally, we wanted to examine the importance of keratinocyte adhesion in chancroid pathogenesis so we tested the wild-type and dsrA mutant strains of H. ducreyi in our swine models of chancroid pathogenesis. The dsrA mutant was less virulent than the wild type in both the normal and immune cell-depleted swine models of chancroid infection.

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