scholarly journals Characterization of a Novel Intracellularly Activated Gene from Salmonella enterica Serovar Typhi

2002 ◽  
Vol 70 (10) ◽  
pp. 5404-5411 ◽  
Author(s):  
Holger Basso ◽  
Faiza Rharbaoui ◽  
Lothar H. Staendner ◽  
Eva Medina ◽  
Francisco García-Del Portillo ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Lethal Dose ◽  
Human Monocyte ◽  
Integral Membrane Protein ◽  
Intracellular Survival ◽  
Peritoneal Macrophages ◽  
Bacterial Invasion ◽  
Bacterial Survival ◽  
Human Macrophages

ABSTRACT A Salmonella enterica serovar Typhi gene that is selectively up-regulated upon bacterial invasion of eukaryotic cells was characterized. The open reading frame encodes a 298-amino-acid hydrophobic polypeptide (30.8 kDa), which is predicted to be an integral membrane protein with nine membrane-spanning domains. The protein is closely related (87 to 94% reliability) to different transport and permease systems. Gene expression under laboratory conditions was relatively weak; however, sevenfold induction was observed in a high-osmolarity medium (300 mM NaCl). The growth pattern in a laboratory medium of a serovar Typhi strain Ty2 derivative containing a 735-bp in-frame deletion in this gene, named gaiA (for gene activated intracellularly), was not affected. In contrast, the mutant was partially impaired in intracellular survival in murine peritoneal macrophages, as well as in human monocyte-derived macrophages. However, in the case of human macrophages, this survival defect was modest and evident only at late infection times (24 h). Despite the distinct intracellular survival kinetics displayed in macrophages of different species, the gaiA null mutant was significantly affected in its potential to trigger apoptosis in both murine and human macrophages. Provision of the gaiA gene in trans resulted in complementation of these phenotypes. Interestingly, the absence of a functional gaiA gene caused a marked attenuation in the mouse mucin model, as shown by the increase (3 orders of magnitude) in the 50% lethal dose of the mutant strain over that of the parental strain Ty2 (P ≤ 0.05). Altogether, these data indicate that the product encoded by the gaiA gene is required for triggering apoptosis and bacterial survival within murine macrophages, which is consistent with the in vivo results obtained in the mouse mucin model. However, gaiA was not required for initial intracellular survival in human cells, indicating that its role in the natural host might be more complex than is suggested by the studies performed in the murine system.

scholarly journals Differential Bacterial Survival, Replication, and Apoptosis-Inducing Ability of Salmonella Serovars within Human and Murine Macrophages

2000 ◽  
Vol 68 (3) ◽  
pp. 1005-1013 ◽  
Author(s):  
William R. Schwan ◽  
Xiao-Zhe Huang ◽  
Lan Hu ◽  
Dennis J. Kopecko
Keyword(s):  
Typhoid Fever ◽  
Systemic Infection ◽  
Peritoneal Macrophages ◽  
Human Macrophage ◽  
U937 Cells ◽  
Bacterial Survival ◽  
Human Macrophages ◽  
Macrophage Cells ◽  
Serovar Typhimurium ◽  
Murine Peritoneal Macrophages

ABSTRACT Salmonella serovars are associated with human diseases that range from mild gastroenteritis to host-disseminated enteric fever. Human infections by Salmonella enterica serovar Typhi can lead to typhoid fever, but this serovar does not typically cause disease in mice or other animals. In contrast, S. enterica serovar Typhimurium and S. entericaserovar Enteritidis, which are usually linked to localized gastroenteritis in humans and some animal species, elicit a systemic infection in mice. To better understand these observations, multiple strains of each of several chosen serovars of Salmonellawere tested for the ability in the nonopsonized state to enter, survive, and replicate within human macrophage cells (U937 and elutriated primary cells) compared with murine macrophage cells (J774A.1 and primary peritoneal cells); in addition, death of the infected macrophages was monitored. The serovar Typhimurium strains all demonstrated enhanced survival within J774A.1 cells and murine peritoneal macrophages, compared with the significant, almost 100-fold declines in viable counts noted for serovar Typhi strains. Viable counts for serovar Enteritidis either matched the level of serovar Typhi (J774A.1 macrophages) or were comparable to counts for serovar Typhimurium (murine peritoneal macrophages). Apoptosis was significantly higher in J774A.1 cells infected with serovar Typhimurium strain LT2 compared to serovar Typhi strain Ty2. On the other hand, serovar Typhi survived at a level up to 100-fold higher in elutriated human macrophages and 2- to 3-fold higher in U937 cells compared to the serovar Typhimurium and Enteritidis strains tested. Despite the differential multiplication of serovar Typhi during infection of U937 cells, serovar Typhi caused significantly less apoptosis than infections with serovar Typhimurium. These observations indicate variability in intramacrophage survival and host cytotoxicity among the various serovars and are the first to show differences in the apoptotic response of distinctSalmonella serovars residing in human macrophage cells. These studies suggest that nonopsonized serovar Typhimurium enters, multiplies within, and causes considerable, acute death of macrophages, leading to a highly virulent infection in mice (resulting in death within 14 days). In striking contrast, nonopsonized serovar Typhi survives silently and chronically within human macrophages, causing little cell death, which allows for intrahost dissemination and typhoid fever (low host mortality). The type of disease associated with any particular serovar of Salmonellais linked to the ability of that serovar both to persist within and to elicit damage in a specific host's macrophage cells.

Abstract WMP105: Human Monocyte Derived Macrophage Phagocytize Eryptotic Erythrocytes in a Phosphotidylserine Dependent Mechanism

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Arthur F Steinschneider ◽  
Che-Feng Chang ◽  
Michael H Askenase ◽  
Youxi Ai ◽  
Lauren H Sansing
Keyword(s):  
Autologous Blood ◽  
Annexin V ◽  
Human Monocyte ◽  
Human Macrophages ◽  
Receptor Interactions ◽  
Autologous Blood Injection ◽  
Blood Injection ◽  
Fresh Rbcs ◽  
Dependent Mechanism

Introduction: After intracerebral hemorrhage (ICH), erythrocytes contribute to secondary injury by releasing toxic hemoproteins. Our lab has previously shown that blood derived macrophages play an important role in ICH clearance but mechanisms of phagocytosis by human macrophages are unknown. This study aims to quantify eryptotic (phosphatidylserine (PtdSer)-expressing) red blood cells (RBCs) in an in vivo model of ICH, and to investigate the mechanisms that play a role in autologous eryptotic phagocytosis by human monocyte derived macrophages (huMDMs). Methods: ICH was induced in mice by autologous blood injection. The mice were sacrificed at 1 day after ICH. The brains were separated into hemispheres and digested into a single cell suspension for analysis by flow cytometry. Cells were stained with antibodies to cell surface markers and annexin V to quantify externalized PtdSer expression. Human monocytes were cultured with M-CSF for 7 days to generate huMDMs. Autologous RBCs were heat shocked (HS) to induce eryptosis. The huMDMs were cocultured with HS RBCs, HS RBCs treated with annexin V, or control RBCs. After 1 hour of coculture, the huMDMs were washed, stained and erythrophagocytosis quantified by microscopy. Results: The proportion of cells that externalized PtdSer increased by almost 20 fold at day 1 after ICH. Control brains mixed with fresh RBCs and subjected to tissue prep did not show PtdSer expression, ensuring that the PtdSer expression detected was induced in vivo (Fig A). HS RBCs increased PtdSer expression and were efficiently phagocytosed by huMDMs. Treatment of HS RBCs with annexin V to antagonize PtdSer-receptor interactions decreased RBC phagocytosis to levels comparable to control RBCs (Figs B and C). Conclusions: In vivo after ICH, erythrocytes externalize PtdSer, a cue to be engulfed by macrophages. Human macrophages phagocytose RBCs in a PtdSer-dependent mechanism. These findings highlight potential targets to enhance ICH clearance.

scholarly journals In Vitro and In Vivo Assessment of Salmonella enterica Serovar Typhimurium DT104 Virulence

2001 ◽  
Vol 69 (7) ◽  
pp. 4673-4677 ◽  
Author(s):  
Chris A. Allen ◽  
Paula J. Fedorka-Cray ◽  
Andrés Vazquez-Torres ◽  
Mitsu Suyemoto ◽  
Craig Altier ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Phage Type ◽  
Multidrug Resistant ◽  
Peritoneal Macrophages ◽  
Lethal Infection ◽  
Animal Infection ◽  
Serovar Typhimurium ◽  
Clinical Illness

ABSTRACT Multidrug-resistant Salmonella enterica serovar Typhimurium phage type DT104 has become a widespread cause of human and other animal infection worldwide. The severity of clinical illness inS. enterica serovar Typhimurium DT104 outbreaks has led to the suggestion that this strain possesses enhanced virulence. In the present study, in vitro and in vivo virulence-associated phenotypes of several clinical isolates of S. enterica serovar Typhimurium DT104 were examined and compared to S. entericaserovar Typhimurium ATCC 14028s. The ability of these DT104 isolates to survive within murine peritoneal macrophages, invade cultured epithelial cells, resist antimicrobial actions of reactive oxygen and nitrogen compounds, and cause lethal infection in mice were assessed. Our results failed to demonstrate that S. enterica serovar Typhimurium DT104 isolates are more virulent than S. enterica serovar Typhimurium ATCC 14028s.

scholarly journals The Immunomodulatory Effects of AlbuminIn VitroandIn Vivo

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Derek S. Wheeler ◽  
John S. Giuliano ◽  
Patrick M. Lahni ◽  
Alvin Denenberg ◽  
Hector R. Wong ◽  
...  
Keyword(s):  
Gene Expression ◽  
Lethal Dose ◽  
Intraperitoneal Administration ◽  
Peritoneal Macrophages ◽  
Luciferase Reporter Assay ◽  
Luciferase Reporter ◽  
Reporter Assay ◽  
Dose Dependent

Albumin appears to have proinflammatory effectsin vitro. We hypothesized that albumin would induce a state of tolerance to subsequent administration of lipopolysaccharide (LPS)in vitroandin vivo. RAW264.7 and primary peritoneal macrophages were treated with increasing doses of bovine serum albumin (BSA) and harvested for NF-κB luciferase reporter assay or TNF-αELISA. In separate experiments, RAW264.7 cells were preconditioned with 1 mg/mL BSA for 18 h prior to LPS (10 μg/mL) treatment and harvested for NF-κB luciferase reporter assay or TNF-αELISA. Finally, C57Bl/6 mice were preconditioned with albumin via intraperitoneal administration 18 h prior to a lethal dose of LPS (60 mg/kg body wt). Blood was collected at 6 h after LPS administration for TNF-αELISA. Albumin produced a dose-dependent and TLR-4-dependent increase in NF-κB activation and TNF-αgene expressionin vitro. Albumin preconditioning abrogated the LPS-mediated increase in NF-κB activation and TNF-αgene expressionin vitroandin vivo. The clinical significance of these findings remains to be elucidated.

scholarly journals Genetic Requirements for Salmonella-Induced Cytopathology in Human Monocyte-Derived Macrophages

2002 ◽  
Vol 70 (12) ◽  
pp. 7126-7135 ◽  
Author(s):  
Sara H. Browne ◽  
Marc L. Lesnick ◽  
Donald G. Guiney
Keyword(s):  
Salmonella Enterica ◽  
Human Monocyte ◽  
Intracellular Bacteria ◽  
Wild Type ◽  
Site Specific ◽  
Human Macrophages ◽  
Serovar Typhimurium ◽  
Protein Secretion System ◽  
Type Iii Protein Secretion ◽  
A Site

ABSTRACT Infection of human macrophages with Salmonella enterica serovar Typhimurium or Salmonella enterica serovar Dublin produces delayed cytotoxicity characterized by cell detachment and associated apoptosis. Using a site-specific mutant in the SpvB active site, we verify that the ADP-ribosylation activity of SpvB is required for delayed cytotoxicity in human macrophages infected with Salmonella. SipB and the type III protein secretion system (TTSS) encoded by Salmonella pathogenicity island 1 (SPI1) are not involved, whereas the SPI2 TTSS is absolutely required for SpvB-dependent cytotoxicity. Furthermore, we show that infection of macrophage cultures with wild-type or sipB mutant bacteria led to a complete loss of polymerized actin in over half of the cells after 24 h. In contrast, macrophages infected with the spvB or SPI2 (ssaV or ssaJ) mutant strain retained normal F-actin filaments, despite similar numbers of intracellular bacteria. We conclude that SpvB and a functional SPI2 TTSS are essential for Salmonella-induced delayed cytotoxicity of human macrophages.

Tannic Acid Exhibits Adjuvant Activity by Enhancing Humoral and Cell-Mediated Immunity Against BSA as a Protein Antigen

2021 ◽  
Vol 28 ◽  
Author(s):  
Nidia Cabral-Hipólito ◽  
Brenda Sarahí Molina-Ramírez ◽  
Irais Castillo-Maldonado ◽  
Rocío Meza-Velázquez ◽  
Rubén García-Garza ◽  
...  
Keyword(s):  
Tannic Acid ◽  
Wistar Rats ◽  
Lethal Dose ◽  
Peritoneal Macrophages ◽  
Protein Antigen ◽  
Cell Mediated Immunity ◽  
Vaccine Adjuvants ◽  
Adjuvant Activity ◽  
Toxic Dose

Background: Immunization or vaccination is the process of inducing artificial immunity against an antigen taking advantage of the mechanisms of immunological memory. Current vaccines include substances known as adjuvants, which tend to improve the immunogenicity of the antigen, reduce the antigen quantity employed, and boost the immune response in weak responders. Unfortunately, only a few vaccine adjuvants are approved for human use. Objective: Thus, the objective of this study was to investigate the effect of Tannic acid on humoral and cell-mediated immunity against bovine serum albumin (BSA) as a protein antigen in Wistar rats. Method: In order to establish the Tannic acid concentration to test it as an adjuvant, the lethal dose 50 and maximum non-toxic dose were calculated through cytotoxicity and hemolytic assays with J774 A.1 cell line and rat erythrocytes by resazurin reduction method and UV/vis spectrophotometry. Thirty Wistar rats were divided into 5 groups that included two controls without antigen and three treatment groups of adjuvants plus BSA as a protein antigen. The rats were immunized in a 30-day scheme. Blood samples were collected for humoral immunity analysis by means of immunoglobulin quantification, isotyping and antigen-antibody precipitation inhibition analysis. Rat peritoneal macrophages and splenocytes were isolated for cell-mediated immunity analysis by means of nitric oxide quantification from adjuvant stimulated peritoneal macrophages and lymphocytes proliferation assay. Results: Tannic acid was capable of increasing the immunogenicity of the antigen; besides, it was able to stimulate cell-mediated immunity by means of increased lymphocyte proliferation. Moreover, Tannic acid improved the humoral response by means of increased specific antibodies titers. These activities may be attributed to pattern recognition receptors stimulation. Conclusion: Tannic acid was considered biocompatible when tested in vivo because the concentration tested did not show cytotoxicity or hemolytic effect, and there was no detrimental effect observed on the animals’ health. These results show Tannic acid as a promising candidate for vaccine adjuvant.

scholarly journals Salmonella Extracellular Matrix Components Influence Biofilm Formation and Gallbladder Colonization

2016 ◽  
Vol 84 (11) ◽  
pp. 3243-3251 ◽  
Author(s):  
Haley E. Adcox ◽  
Erin M. Vasicek ◽  
Varun Dwivedi ◽  
Ky V. Hoang ◽  
Joanne Turner ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Typhoid Fever ◽  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Bacterial Survival ◽  
Content Type ◽  
Extracellular Matrix Components ◽  
Matrix Components

Salmonella enterica serovar Typhi, the causative agent of typhoid fever in humans, forms biofilms encapsulated by an extracellular matrix (ECM). Biofilms facilitate colonization and persistent infection in gallbladders of humans and mouse models of chronic carriage. Individual roles of matrix components have not been completely elucidated in vitro or in vivo . To examine individual functions, strains of Salmonella enterica serovar Typhimurium, the murine model of S . Typhi, in which various ECM genes were deleted or added, were created to examine biofilm formation, colonization, and persistence in the gallbladder. Studies show that curli contributes most significantly to biofilm formation. Expression of Vi antigen decreased biofilm formation in vitro and virulence and bacterial survival in vivo without altering the examined gallbladder pro- or anti-inflammatory cytokines. Oppositely, loss of all ECM components (Δ wcaM Δ csgA Δ yihO Δ bcsE ) increased virulence and bacterial survival in vivo and reduced gallbladder interleukin-10 (IL-10) levels. Colanic acid and curli mutants had the largest defects in biofilm-forming ability and contributed most significantly to the virulence increase of the Δ wcaM Δ csgA Δ yihO Δ bcsE mutant strain. While the Δ wcaM Δ csgA Δ yihO Δ bcsE mutant was not altered in resistance to complement or growth in macrophages, it attached and invaded macrophages better than the wild-type (WT) strain. These data suggest that ECM components have various levels of importance in biofilm formation and gallbladder colonization and that the ECM diminishes disseminated disease in our model, perhaps by reducing cell attachment/invasion and dampening inflammation by maintaining/inducing IL-10 production. Understanding how ECM components aid acute disease and persistence could lead to improvements in therapeutic treatment of typhoid fever patients.

scholarly journals Construction, Genotypic and Phenotypic Characterization, and Immunogenicity of Attenuated ΔguaBA Salmonella enterica Serovar Typhi Strain CVD 915

2001 ◽  
Vol 69 (8) ◽  
pp. 4734-4741 ◽  
Author(s):  
Jin Yuang Wang ◽  
Marcela F. Pasetti ◽  
Fernando R. Noriega ◽  
Richard J. Anderson ◽  
Steven S. Wasserman ◽  
...  
Keyword(s):  
Vaccine Strain ◽  
Salmonella Enterica ◽  
Phase 1 ◽  
Lethal Dose ◽  
Phenotypic Characterization ◽  
Typhoid Vaccine ◽  
Wild Type ◽  
Gene Encoding

ABSTRACT A promising live attenuated typhoid vaccine candidate strain for mucosal immunization was developed by introducing a deletion in theguaBA locus of pathogenic Salmonella entericaserovar Typhi strain Ty2. The resultant ΔguaBA mutant, serovar Typhi CVD 915, has a gene encoding resistance to arsenite replacing the deleted sequence within guaBA, thereby providing a marker to readily identify the vaccine strain. CVD 915 was compared in in vitro and in vivo assays with wild-type strain Ty2, licensed live oral typhoid vaccine strain Ty21a, or attenuated serovar Typhi vaccine strain CVD 908-htrA (harboring mutations inaroC, aroD, and htrA). CVD 915 was less invasive than CVD 908-htrA in tissue culture and was more crippled in its ability to proliferate after invasion. In mice inoculated intraperitoneally with serovar Typhi and hog gastric mucin (to estimate the relative degree of attenuation), the 50% lethal dose of CVD 915 (7.7 × 107 CFU) was significantly higher than that of wild-type Ty2 (1.4 × 102 CFU) and was only slightly lower than that of Ty21a (1.9 × 108CFU). Strong serum O and H antibody responses were recorded in mice inoculated intranasally with CVD 915, which were higher than those elicited by Ty21a and similar to those stimulated by CVD 908-htrA. CVD 915 also elicited potent proliferative responses in splenocytes from immunized mice stimulated with serovar Typhi antigens. Used as a live vector, CVD 915(pTETlpp) elicited high titers of serum immunoglobulin G anti-fragment C. These encouraging preclinical data pave the way for phase 1 clinical trials with CVD 915.

scholarly journals Acquisition of Mn(II) in Addition to Fe(II) Is Required for Full Virulence of Salmonella enterica Serovar Typhimurium

2002 ◽  
Vol 70 (11) ◽  
pp. 6032-6042 ◽  
Author(s):  
E. Boyer ◽  
I. Bergevin ◽  
D. Malo ◽  
P. Gros ◽  
M. F. M. Cellier
Keyword(s):  
Salmonella Enterica ◽  
Ferrous Iron ◽  
Double Mutant ◽  
Divalent Cations ◽  
Intracellular Survival ◽  
Iron Transporter ◽  
Serovar Typhimurium ◽  
Increased Sensitivity

ABSTRACT The roles of the genes feoB (ABC ferrous iron transporter), mntH (proton-dependent manganese transporter), and sitABCD (putative ABC iron and/or manganese transporter) in Salmonella pathogenicity were investigated by using mutant strains deficient in one, two, or three transporters. Our results indicated that sitABCD encodes an important transporter of Mn(II) and Fe(II) which is required for full virulence in susceptible animals (Nramp1 −/−) and for replication inside Nramp1 −/− macrophages in vitro. The mntH sitABCD double mutant (mutant MS) showed minimal Mn(II) uptake and increased sensitivity to H2O2 and to the divalent metal chelator 2,2′-dipyridyl (DP) and was defective for replication in macrophages. In vivo MS appeared to be as virulent as the sitABCD mutant in Nramp1 −/− animals. The ferrous iron transporter Feo was required for full virulence in 129/Sv Nramp1 −/− mice, and infection with multiple mutants lacking FeoB was not fatal. The sitABCD feoB mutant (mutant SF) and the mntH sitABCD feoB mutant (mutant MSF) showed minimal Fe(II) uptake and were slightly impaired for replication in susceptible macrophages. MSF showed reduced growth in minimal medium deficient in divalent cations. The role of the mntH gene, which is homologous to mammalian Nramp genes, was also investigated after overexpression in the double mutant MS. MntH preferred Mn(II) over Fe(II) and could suppress MS sensitivity to H2O2 and to DP, and it also improved the intracellular survival in Nramp1 −/− macrophages. This study indicates that acquisition of Mn(II), in addition to Fe(II), is required for intracellular survival and replication of Salmonella enterica serovar Typhimurium in macrophages in vitro and for virulence in vivo.

scholarly journals Toxicity and Antileishmanial Activity of a New Stable Lipid Suspension of Amphotericin B

2003 ◽  
Vol 47 (12) ◽  
pp. 3774-3779 ◽  
Author(s):  
Malika Larabi ◽  
Vanessa Yardley ◽  
Philippe M. Loiseau ◽  
Martine Appel ◽  
Philippe Legrand ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Leishmania Donovani ◽  
Lethal Dose ◽  
Peritoneal Macrophages ◽  
Lipid Complex ◽  
Complex Formulation ◽  
Cd1 Mice ◽  
New Formulation ◽  
Lipid Formulations

ABSTRACT The aim of the present study was to evaluate the toxicity and the activity of a new lipid complex formulation of amphotericin B (AMB) (LC-AMB; dimyristoyl phosphatidylcholine, dimyristoyl phosphatidylglycerol, and AMB) that can be produced by a simple process. Like other lipid formulations, this new complex reduced both the hemolytic activity of AMB (the concentration causing 50% hemolysis of human erythrocytes, >100 μg/ml) and its toxicity toward murine peritoneal macrophages (50% inhibitory concentration, >100 μg/ml at 24 h). The in vivo toxicity of the new formulation (50% lethal dose,> 200 mg/kg of body weight for CD1 mice) was similar to those of other commercial lipid formulations of AMB. The complex was the most effective formulation against the DD8 strain of Leishmania donovani. It was unable to reverse the resistance of an AMB-resistant L. donovani strain. In vivo LC-AMB was less efficient than AmBisome against L. donovani.

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