scholarly journals Expression of Truncated Internalin A Is Involved in Impaired Internalization of Some Listeria monocytogenes Isolates Carried Asymptomatically by Humans

2003 ◽  
Vol 71 (3) ◽  
pp. 1217-1224 ◽  
Author(s):  
Maïwenn Olier ◽  
Fabrice Pierre ◽  
Sandrine Rousseaux ◽  
Jean-Paul Lemaître ◽  
André Rousset ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Surface Protein ◽  
Human Infection ◽  
Host Cells ◽  
Genetic Lineage ◽  
Chick Embryos ◽  
Asymptomatic Carriage ◽  
High Degree ◽  
Internalin A

ABSTRACT Fourteen human carriage Listeria monocytogenes isolates were compared to sporadic and epidemic-associated human strains in order to ascertain the pathogenic behavior of these unrecognized asymptomatic strains. Experimental infection of 14-day-old chick embryos revealed that the majority of the carriage strains were attenuated for virulence. Of the 10 attenuated carriage strains, 5 were affected in their invasion capacities in vitro. Western blot analysis with antibody directed against InlA, the surface protein implicated in the internalization in host cells, allowed correlation between the ability of the carriage strains to enter Caco-2 cells and InlA expression. Indeed, these five carriage strains produced truncated forms of InlA. Four of the five truncated forms of InlA had an apparent molecular mass of 47 kDa. In order to assess the existence of a genetic lineage, partial sequences of inlA gene of these four strains were compared and revealed that they had a high degree of sequence conservation at the gene (99.86%) and amino acid (100%) levels. Comparison of their nucleotide sequences with that of the corresponding segment of inlA from EGD-e and Scott A strains, taken as epidemic references, showed more divergence. Taken together, these observations suggest the presence of specific traits that characterize L. monocytogenes strains isolated during asymptomatic carriage. Some of these traits could provide some explanations about the determinants that make them unable to cause systemic human infection.

Evaluation of Methods To Assess the Biofilm-Forming Ability of Listeria monocytogenes

2012 ◽  
Vol 75 (8) ◽  
pp. 1411-1417 ◽  
Author(s):  
ANTÓNIO LOURENÇO ◽  
FRANCISCO REGO ◽  
LUISA BRITO ◽  
JOSEPH F. FRANK
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
High Throughput ◽  
Biofilm Formation ◽  
High Throughput Screening ◽  
Screening Methods ◽  
Genetic Lineage ◽  
Production Lines ◽  
Genetic Characteristics

The contamination of ready-to-eat products with Listeria monocytogenes has been related to the presence of biofilms in production lines, as biofilms protect cells from chemical sanitizers. The ability of L. monocytogenes to produce biofilms is often evaluated using in vitro methodologies. This work aims to compare the most frequently used methodologies, including high-throughput screening methods based on microplates (crystal violet and the Calgary Biofilm Device) and methods based on CFU enumeration and microscopy after growth on stainless steel. Thirty isolates with diverse origins and genetic characteristics were evaluated. No (or low) correlations between methods were observed. The only significant correlation was found between the methods using stainless steel. No statistically significant correlation (P > 0.05) was detected among genetic lineage, serovar, and biofilm-forming ability. Because results indicate that biofilm formation is influenced by the surface material, the extrapolation of results from high-throughput methods using microplates to more industrially relevant surfaces should be undertaken with caution.

scholarly journals Invasion of the Brain by Listeria monocytogenes Is Mediated by InlF and Host Cell Vimentin

mBio ◽  
2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Pallab Ghosh ◽  
Elizabeth M. Halvorsen ◽  
Dustin A. Ammendolia ◽  
Nirit Mor-Vaknin ◽  
Mary X. D. O’Riordan ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Host Cell ◽  
Bacterial Pathogen ◽  
Surface Protein ◽  
Host Cells ◽  
Intermediate Filament Protein ◽  
Life Threatening ◽  
Host Cell Surface ◽  
Filament Protein ◽  
The Brain

ABSTRACTListeria monocytogenesis a facultative intracellular bacterial pathogen that is frequently associated with food-borne infection. Of particular concern is the ability ofL. monocytogenesto breach the blood-brain barrier, leading to life-threatening meningitis and encephalitis. The mechanisms used by bacterial pathogens to infect the brain are not fully understood. Here we show thatL. monocytogenesis able to utilize vimentin for invasion of host cells. Vimentin is a type III intermediate filament protein within the cytosol but is also expressed on the host cell surface. We found thatL. monocytogenesinteraction with surface-localized vimentin promoted bacterial uptake. Furthermore, in the absence of vimentin,L. monocytogenescolonization of the brain was severely compromised in mice. TheL. monocytogenesvirulence factor InlF was found to bind vimentin and was necessary for optimal bacterial colonization of the brain. These studies reveal a novel receptor-ligand interaction that enhances infection of the brain byL. monocytogenesand highlights the importance of surface vimentin in host-pathogen interactions.IMPORTANCEListeria monocytogenesis an intracellular bacterial pathogen that is capable of invading numerous host cells during infection.L. monocytogenescan cross the blood-brain barrier, leading to life-threatening meningitis. Here we show that anL. monocytogenessurface protein, InlF, is necessary for optimal colonization of the brain in mice. Furthermore, in the absence of vimentin, a cytosolic intermediate filament protein that is also present on the surface of brain endothelial cells, colonization of the brain was significantly impaired. We further show that InlF binds vimentin to mediate invasion of host cells. This work identifies InlF as a bacterial surface protein with specific relevance for infection of the brain and underscores the significance of host cell surface vimentin interactions in microbial pathogenesis.

scholarly journals Select Listeria monocytogenes Subtypes Commonly Found in Foods Carry Distinct Nonsense Mutations in inlA, Leading to Expression of Truncated and Secreted Internalin A, and Are Associated with a Reduced Invasion Phenotype for Human Intestinal Epithelial Cells

2005 ◽  
Vol 71 (12) ◽  
pp. 8764-8772 ◽  
Author(s):  
K. K. Nightingale ◽  
K. Windham ◽  
K. E. Martin ◽  
M. Yeung ◽  
M. Wiedmann
Keyword(s):  
Listeria Monocytogenes ◽  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Surface Protein ◽  
The United States ◽  
Intestinal Epithelial ◽  
Source Information ◽  
Human Intestinal Epithelial Cells ◽  
Internalin A ◽  
Mutation Type

ABSTRACT The surface protein internalin A (InlA) contributes to the invasion of human intestinal epithelial cells by Listeria monocytogenes. Screening of L. monocytogenes strains isolated from human clinical cases (n = 46), foods (n = 118), and healthy animals (n = 58) in the United States revealed mutations in inlA leading to premature stop codons (PMSCs) in L. monocytogenes ribotypes DUP-1052A and DUP-16635A (PMSC mutation type 1), DUP-1025A and DUP-1031A (PMSC mutation type 2), and DUP-1046B and DUP-1062A (PMSC mutation type 3). While all DUP-1046B, DUP-1062A, DUP-16635A, and DUP-1031A isolates (n = 76) contained inlA PMSCs, ribotypes DUP-1052A and DUP-1025A (n = 72) contained isolates with and without inlA PMSCs. Western immunoblotting showed that all three inlA PMSCs result in the production of truncated and secreted InlA. Searches of the Pathogen Tracker database, which contains subtype and source information for more than 5,000 L. monocytogenes isolates, revealed that the six ribotypes shown to contain isolates with inlA PMSCs were overall more commonly isolated from foods than from human listeriosis cases. L. monocytogenes strains carrying inlA PMSCs also showed significantly (P = 0.0004) reduced invasion of Caco-2 cells compared to isolates with homologous 3′ inlA sequences without PMSCs. Invasion assays with an isogenic PMSC mutant further supported the observation that inlA PMSCs lead to reduced invasion of Caco-2 cells. Our data show that specific L. monocytogenes subtypes which are common among U.S. food isolates but rare among human listeriosis isolates carry inlA mutations that are associated with, and possibly at least partially responsible for, an attenuated invasion phenotype.

scholarly journals Reduced Virulence of HWP1-Deficient Mutants of Candida albicans and Their Interactions with Host Cells

2000 ◽  
Vol 68 (4) ◽  
pp. 1997-2002 ◽  
Author(s):  
Noboru Tsuchimori ◽  
Laura L. Sharkey ◽  
William A. Fonzi ◽  
Samuel W. French ◽  
John E. Edwards ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Cell Injury ◽  
Gene Dosage ◽  
Surface Protein ◽  
Host Cells ◽  
Null Mutant ◽  
Gene Dosage Effect ◽  
Hyphal Development

ABSTRACT The Candida albicans gene HWP1 encodes a surface protein that is required for normal hyphal development in vitro. We used mutants lacking one or both alleles of HWP1to investigate the role of this gene in virulence. Mice infected intravenously with the homozygous hwp1 null mutant, CAL3, survived a median of >14 days, whereas mice infected with a control strain containing two functional alleles of HWP1 survived only 3.5 days. After 1 day of infection, all strains produced similar levels of infection in the kidneys, spleen, and blood. However, after 2 and 3 days, there was a significant decrease in the number of organisms in the kidneys of the mice infected with CAL3. This finding suggests that the hwp1 homozygous null mutant is normal in its ability to initiate infection but deficient in its capacity to maintain infection. CAL3 also germinated minimally in the kidneys. The ability of the heterozygous null mutant to germinate and cause mortality in mice was intermediate to CAL3, suggesting a gene dosage effect. To investigate potential mechanisms for the diminished virulence of CAL3, we examined its interactions with endothelial cells and neutrophils in vitro. CAL3 caused less endothelial cell injury than the heterozygoushwp1 mutant. We conclude that the HWP1 gene product is important for both in vivo hyphal development and pathogenicity of C. albicans. Also, the ability to form filaments may be critical for candidal virulence by enabling the fungus to induce cellular injury and maintain a deep-seated infection.

scholarly journals Detoxification of methylglyoxal by the glyoxalase system is required for glutathione availability and virulence activation in Listeria monocytogenes

2021 ◽  
Vol 17 (8) ◽  
pp. e1009819
Author(s):  
Andrea Anaya-Sanchez ◽  
Ying Feng ◽  
John C. Berude ◽  
Daniel A. Portnoy
Keyword(s):  
Listeria Monocytogenes ◽  
Transcriptional Activation ◽  
Protein Glycation ◽  
Host Cells ◽  
Intracellular Pathogen ◽  
Cell Monolayers ◽  
Food Borne ◽  
Virulence Regulator ◽  
Allosteric Activator

Listeria monocytogenes is a Gram-positive, food-borne pathogen that lives a biphasic lifestyle, cycling between the environment and as a facultative intracellular pathogen of mammals. Upon entry into host cells, L. monocytogenes upregulates expression of glutathione synthase (GshF) and its product, glutathione (GSH), which is an allosteric activator of the master virulence regulator PrfA. Although gshF mutants are highly attenuated for virulence in mice and form very small plaques in host cell monolayers, these virulence defects can be fully rescued by mutations that lock PrfA in its active conformation, referred to as PrfA*. While PrfA activation can be recapitulated in vitro by the addition of reducing agents, the precise biological cue(s) experienced by L. monocytogenes that lead to PrfA activation are not known. Here we performed a genetic screen to identify additional small-plaque mutants that were rescued by PrfA* and identified gloA, which encodes glyoxalase A, a component of a GSH-dependent methylglyoxal (MG) detoxification system. MG is a toxic byproduct of metabolism produced by both the host and pathogen, which if accumulated, causes DNA damage and protein glycation. As a facultative intracellular pathogen, L. monocytogenes must protect itself from MG produced by its own metabolic processes and that of its host. We report that gloA mutants grow normally in broth, are sensitive to exogenous MG and severely attenuated upon IV infection in mice, but are fully rescued for virulence in a PrfA* background. We demonstrate that transcriptional activation of gshF increased upon MG challenge in vitro, and while this resulted in higher levels of GSH for wild-type L. monocytogenes, the glyoxalase mutants had decreased levels of GSH, presumably due to the accumulation of the GSH-MG hemithioacetal adduct. These data suggest that MG acts as a host cue that leads to GSH production and activation of PrfA.

scholarly journals Dual roles of a novel oncolytic viral vector-based SARS-CoV-2 vaccine: preventing COVID-19 and treating tumor progression

2021 ◽  
Author(s):  
Michael A. Caligiuri ◽  
Jianhua Yu ◽  
Yaping Sun ◽  
Wenjuan Dong ◽  
Lei Tian ◽  
...  
Keyword(s):  
Cancer Patients ◽  
Viral Vector ◽  
Protein A ◽  
Surface Protein ◽  
T Cell Response ◽  
Host Cells ◽  
Serious Adverse Events ◽  
S Protein ◽  
Tumor Bearing

The ongoing coronavirus disease 2019 (COVID-19) pandemic is caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Cancer patients are usually immunocompromised and thus are particularly susceptible to SARS-CoV-2 infection resulting in COVID-19. Although many vaccines against COVID-19 are being preclinically or clinically tested or approved, none have yet been specifically developed for cancer patients or reported as having potential dual functions to prevent COVID-19 and treat cancer. Here, we confirmed that COVID-19 patients with cancer have low levels of antibodies against the spike (S) protein, a viral surface protein mediating the entry of SARS-CoV-2 into host cells, compared with COVID-19 patients without cancer. We developed an oncolytic herpes simplex virus-1 vector-based vaccine named oncolytic virus (OV)-spike. OV-spike induced abundant anti-S protein neutralization antibodies in both tumor-free and tumor-bearing mice, which inhibit infection of VSV-SARS-CoV-2 and wild-type (WT) live SARS-CoV-2 as well as the B.1.1.7 variant in vitro. In the tumor-bearing mice, OV-spike also inhibited tumor growth, leading to better survival in multiple preclinical tumor models than the untreated control. Furthermore, OV-spike induced anti-tumor immune response and SARS-CoV-2-specific T cell response without causing serious adverse events. Thus, OV-spike is a promising vaccine candidate for both preventing COVID-19 and enhancing the anti-tumor response.

scholarly journals Paracoccidioides brasiliensis Enolase Is a Surface Protein That Binds Plasminogen and Mediates Interaction of Yeast Forms with Host Cells

2010 ◽  
Vol 78 (9) ◽  
pp. 4040-4050 ◽  
Author(s):  
Sarah Veloso Nogueira ◽  
Fernanda L. Fonseca ◽  
Marcio L. Rodrigues ◽  
Vasanth Mundodi ◽  
Erika A. Abi-Chacra ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Paracoccidioides Brasiliensis ◽  
Surface Protein ◽  
Host Cells ◽  
Yeast Cells ◽  
Soluble Form ◽  
Dimorphic Fungus ◽  
Systemic Disorder ◽  
Fibronectin Binding Protein

ABSTRACT Paracoccidioidomycosis (PCM), caused by the dimorphic fungus Paracoccidioides brasiliensis, is a disseminated, systemic disorder that involves the lungs and other organs. The ability of the pathogen to interact with host components, including extracellular matrix (ECM) proteins, is essential to further colonization, invasion, and growth. Previously, enolase (EC 4.2.1.11) was characterized as a fibronectin binding protein in P. brasiliensis. Interaction of surface-bound enolase with plasminogen has been incriminated in tissue invasion for pathogenesis in several pathogens. In this paper, enolase was expressed in Escherichia coli as a recombinant glutathione S-transferase (GST) fusion protein (recombinant P. brasiliensis enolase [rPbEno]). The P. brasiliensis native enolase (PbEno) was detected at the fungus surface and cytoplasm by immunofluorescence with an anti-rPbEno antibody. Immobilized purified rPbEno bound plasminogen in a specific, concentration-dependent fashion. Both native enolase and rPbEno activated conversion of plasminogen to plasmin through tissue plasminogen activator. The association between PbEno and plasminogen was lysine dependent. In competition experiments, purified rPbEno, in its soluble form, inhibited plasminogen binding to fixed P. brasiliensis, suggesting that this interaction required surface-localized PbEno. Plasminogen-coated P. brasiliensis yeast cells were capable of degrading purified fibronectin, providing in vitro evidence for the generation of active plasmin on the fungus surface. Exposure of epithelial cells and phagocytes to enolase was associated with an increased expression of surface sites of adhesion. In fact, the association of P. brasiliensis with epithelial cells and phagocytes was increased in the presence of rPbEno. The expression of PbEno was upregulated in yeast cells derived from mouse-infected tissues. These data indicate that surface-associated PbEno may contribute to the pathogenesis of P. brasiliensis.

scholarly journals Production of Membrane Vesicles in Listeria monocytogenes Cultured with or without Sub-Inhibitory Concentrations of Antibiotics and Their Innate Immune Responses In Vitro

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 415
Author(s):  
Jung-Hwa Woo ◽  
Shukho Kim ◽  
Taewon Lee ◽  
Je-Chul Lee ◽  
Ji-Hyun Shin
Keyword(s):  
Listeria Monocytogenes ◽  
Inflammatory Responses ◽  
Membrane Vesicle ◽  
Membrane Vesicles ◽  
Host Cells ◽  
Proteinase K ◽  
Tnf Α ◽  
Food Borne Illness ◽  
Proteinase K Treatment

Listeriosis is a food-borne illness caused by Listeria monocytogenes. Ampicillin (AMP) alone or in combination with gentamicin (GEN) is the first-line treatment option. Membrane vesicle (MV) production in L. monocytogenes under antibiotic stress conditions and pathologic roles of these MVs in hosts have not been reported yet. Thus, the aim of this study was to investigate the production of MVs in L. monocytogenes cultured with sub-minimum inhibitory concentrations (MICs) of AMP, GEN, or trimethoprim/sulfamethoxazole (SXT) and determine pathologic effects of these MVs in colon epithelial Caco-2 cells. L. monocytogenes cultured in tryptic soy broth with 1/2 MIC of AMP, GEN, or SXT produced 6.0, 2.9, or 1.5 times more MV particles, respectively, than bacteria cultured without antibiotics. MVs from L. monocytogenes cultured with AMP (MVAMP), GEN (MVGEN), or SXT (MVSXT) were more cytotoxic to Caco-2 cell than MVs obtained from cultivation without antibiotics (MVTSB). MVAMP induced more expression of tumor necrosis factor (TNF)-α gene than MVTSB, MVGEN and MVSXT, whereas MVTSB induced more expression of interleukin (IL)-1β and IL-8 genes than other MVs. Expression of pro-inflammatory cytokine genes by L. monocytogenes MVs was significantly inhibited by proteinase K treatment of MVs. In conclusion, antibiotic stress can trigger the biogenesis of MVs in L. monocytogenes and MVs produced by L. monocytogenes exposed to sub-MIC of AMP can induce strong pro-inflammatory responses by expressing TNF-α gene in host cells, which may contribute to the pathology of listeriosis.

scholarly journals The redox-responsive transcriptional regulator Rex represses fermentative metabolism and is required for Listeria monocytogenes pathogenesis

2021 ◽  
Vol 17 (8) ◽  
pp. e1009379
Author(s):  
Cortney R. Halsey ◽  
Rochelle C. Glover ◽  
Maureen K. Thomason ◽  
Michelle L. Reniere
Keyword(s):  
Listeria Monocytogenes ◽  
Bacterial Infections ◽  
Transcriptional Regulator ◽  
Host Cells ◽  
Bacterial Survival ◽  
Gi Tract ◽  
Fermentative Metabolism ◽  
Peripheral Organs ◽  
Redox Responsive

The Gram-positive bacterium Listeria monocytogenes is the causative agent of the foodborne disease listeriosis, one of the deadliest bacterial infections known. In order to cause disease, L. monocytogenes must properly coordinate its metabolic and virulence programs in response to rapidly changing environments within the host. However, the mechanisms by which L. monocytogenes senses and adapts to the many stressors encountered as it transits through the gastrointestinal (GI) tract and disseminates to peripheral organs are not well understood. In this study, we investigated the role of the redox-responsive transcriptional regulator Rex in L. monocytogenes growth and pathogenesis. Rex is a conserved canonical transcriptional repressor that monitors the intracellular redox state of the cell by sensing the ratio of reduced and oxidized nicotinamide adenine dinucleotides (NADH and NAD+, respectively). Here, we demonstrated that L. monocytogenes Rex represses fermentative metabolism and is therefore required for optimal growth in the presence of oxygen. We also show that in vitro, Rex represses the production of virulence factors required for survival and invasion of the GI tract, as a strain lacking rex was more resistant to acidified bile and invaded host cells better than wt. Consistent with these results, Rex was dispensable for colonizing the GI tract and disseminating to peripheral organs in an oral listeriosis model of infection. However, Rex-dependent regulation was required for colonizing the spleen and liver, and L. monocytogenes lacking the Rex repressor were nearly sterilized from the gallbladder. Taken together, these results demonstrated that Rex functions as a repressor of fermentative metabolism and suggests a role for Rex-dependent regulation in L. monocytogenes pathogenesis. Importantly, the gallbladder is the bacterial reservoir during listeriosis, and our data suggest redox sensing and Rex-dependent regulation are necessary for bacterial survival and replication in this organ.

scholarly journals Evidence that Surface Proteins Sn14 and Sn16 of Sarcocystis neurona Merozoites Are Involved in Infection and Immunity

1998 ◽  
Vol 66 (5) ◽  
pp. 1834-1838 ◽  
Author(s):  
Fang Ting Liang ◽  
David E. Granstrom ◽  
Xiao Min Zhao ◽  
John F. Timoney
Keyword(s):  
Surface Protein ◽  
Neutralization Assay ◽  
Etiologic Agent ◽  
Surface Proteins ◽  
Host Cells ◽  
Inhibitory Effects ◽  
Sarcocystis Neurona ◽  
Equine Protozoal Myeloencephalitis ◽  
Useful Components

ABSTRACT Sarcocystis neurona is the etiologic agent of equine protozoal myeloencephalitis (EPM). Based on an analysis of 25,000 equine serum and cerebrospinal fluid (CSF) samples, including samples from horses with neurologic signs typical of EPM or with histologically or parasitologically confirmed EPM, four major immunoblot band patterns have been identified. Twenty-three serum and CSF samples representing each of the four immunoblot patterns were selected from 220 samples from horses with neurologic signs resembling EPM and examined for inhibitory effects on the infectivity of S. neurona by an in vitro neutralization assay. A high correlation between immunoblot band pattern and neutralizing activity was detected. Two proteins, Sn14 and Sn16 (14 and 16 kDa, respectively), appeared to be important for in vitro infection. A combination of the results of surface protein labeling, immunoprecipitation, Western blotting, and trypsin digestion suggests that these molecules are surface proteins and may be useful components of a vaccine against S. neuronainfection. Although S. neurona is an obligate intracellular parasite, it is potentially a target for specific antibodies which may lyse merozoites via complement or inhibit their attachment and penetration to host cells.

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