31,370 results match your criteria Infection and Immunity[Journal]


PheWAS uncovers a pathological role of coagulation Factor X during infection.

Infect Immun 2019 Feb 19. Epub 2019 Feb 19.

Department of Pathology, Microbiology, & Immunology, Vanderbilt University Medical Center

Coagulation and inflammation are interconnected, suggesting coagulation plays a key role in the inflammatory response to pathogens. A Phenome-Wide Association Study (PheWAS) was used to identify clinical phenotypes of patients with a polymorphism in coagulation Factor X. Patients with this SNP were more likely to be hospitalized with hemostatic and infection-related disorders, suggesting Factor X contributes to the immune response to infection. Read More

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http://dx.doi.org/10.1128/IAI.00031-19DOI Listing
February 2019

subtilisin-like serine protease (SUB1) is crucial for parasite egress from host cells.

Infect Immun 2019 Feb 19. Epub 2019 Feb 19.

Infectious Diseases Division, Department of Internal Medicine, University of Texas Medical Branch, 301 University Boulevard, Galveston, Texas 77555-0435.

Despite the severity and global burden of infection, treatments are less than optimal and there is no effective vaccine. Egress from host cells is a key process to the completion of the parasitic life cycle of apicomplexan parasites. For , subtilisin-like serine proteases (SUB1) is a key mediator of egress. Read More

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http://dx.doi.org/10.1128/IAI.00784-18DOI Listing
February 2019

Dietary chitin particles, "mimetic fungi", ameliorate colitis in TLR2/CD14- and sex- dependent manners.

Infect Immun 2019 Feb 19. Epub 2019 Feb 19.

Florida Atlantic University Charles E. Schmidt College of Medicine and College of Science, Boca Raton, Florida, and Virginia Tech Carilion School of Medicine, Roanoke, Virginia.

Chitin is a natural N-acetyl glucosamine polymer and a major structural component of fungal cell walls. Dietary chitin is mucoadhesive; anti-inflammatory effects of chitin microparticles (CMPs, 1 - 10 μm diameters) have been demonstrated in models of inflammatory bowel disease (IBD). The goals in this study were to assess (i) whether CMPs among various chitin preparations are the most effective against colitis in male and female mice, and (ii) whether host chitin-binding TLR2 and CD14 are required for the anti-inflammatory effect of chitin. Read More

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http://dx.doi.org/10.1128/IAI.00006-19DOI Listing
February 2019

An alternative enzyme protection assay to overcome the drawbacks of gentamicin protection assay for measuring entry and intracellular survival of Staphylococci.

Infect Immun 2019 Feb 19. Epub 2019 Feb 19.

Department of Molecular Cell Biology, Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon 16419, Korea

Precise enumeration of living intracellular bacteria is the key step to estimate invasion potential of pathogens and host immune responses, and understand the mechanism and kinetics of bacterial pathogenesis. Therefore, quantitative assessment of host-pathogen interaction is essential for developing novel antibacterial therapeutics for infectious disease. Gentamicin protection assay (GPA) is the most widely used method for these estimations by counting the colony forming units (CFU) of intracellular living pathogens. Read More

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http://dx.doi.org/10.1128/IAI.00119-19DOI Listing
February 2019

is critical for spirochete population expansion in the skin during early infection.

Infect Immun 2019 Feb 19. Epub 2019 Feb 19.

Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida, 32827 USA.

Lyme disease is caused by the spirochete and is transmitted via the bite of an infected tick. enters the skin, disseminates via the bloodstream, and infects various distal tissues leading to inflammatory sequelae such as Lyme arthritis and Lyme carditis. linear plasmid 36 (lp36) is critical for mammalian infectivity, however, the full complement of lp36-encoded genes that contribute to this process remains unknown. Read More

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http://dx.doi.org/10.1128/IAI.00887-18DOI Listing
February 2019

utilizes both Phospholipase D and Arcanolysin to mediate its uptake into non-phagocytic cells.

Infect Immun 2019 Feb 11. Epub 2019 Feb 11.

Department of Microbiology and Immunology, Louisiana State University Health Sciences Center - Shreveport, 1501 Kings Highway P.O. Box 33932, Shreveport, LA 71130-3932, USA

is an emerging human pathogen that causes pharyngitis and wound infections. A few studies have suggested that is able to induce its uptake into non-phagocytic epithelial cells, but the bacterial factors associated with host-cell invasion and the host-cell processes involved have yet to be studied. We investigated how two virulence factors, arcanolysin and phospholipase D, affect the ability of the bacteria to adhere to and subsequently invade Detroit 562 pharyngeal epithelial cells. Read More

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http://dx.doi.org/10.1128/IAI.00832-18DOI Listing
February 2019

Porcine gastric mucin triggers toxin production of enteropathogenic .

Infect Immun 2019 Feb 11. Epub 2019 Feb 11.

Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764 Oberschleißheim, Germany.

Enteropathogenic cause food-borne infections due to the production of pore- forming enterotoxins in the intestine. Before that, spores have to be ingested, survive the stomach passage and germinate. Thus, before reaching epithelial cells, comes in contact with the intestinal mucus layer. Read More

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http://dx.doi.org/10.1128/IAI.00765-18DOI Listing
February 2019

2-hydroxylation of lipid A contributes to virulence.

Infect Immun 2019 Feb 11. Epub 2019 Feb 11.

Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom

causes a wide range of nosocomial infections. This pathogen is considered a threat to human health due to the increasing isolation of multidrug resistant strains. There is a major gap in knowledge on the infection biology of , and only few virulence factors have been characterized including the lipopolysaccharide. Read More

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http://dx.doi.org/10.1128/IAI.00066-19DOI Listing
February 2019

Virulence traits of serogroup C meningococcus and isogenic mutant, defective in surface-exposed sialic acid, in a murine model of meningitis.

Infect Immun 2019 Feb 4. Epub 2019 Feb 4.

Department of Molecular Medicine and Medical Biotechnology, Federico II University, Naples, Italy

In serogroup C the () gene codes for an UDP--acetylglucosamine 2-epimerase that catalyzes the conversion of UDP--acetyl-α-D-glucosamine into -acetyl-D-mannosamine and UDP in the first step in sialic acid biosynthesis. This enzyme is required for the biosynthesis of the (α2→9)-linked polysialic acid capsule and for lipooligosaccharide (LOS) sialylation. In this study, we have used a reference serogroup C meningococcal strain and an isogenic knockout mutant to investigate the pathogenetic role of surface-exposed sialic acids in a model of meningitis based on intracisternal inoculation of BALB/c mice. Read More

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http://dx.doi.org/10.1128/IAI.00688-18DOI Listing
February 2019

Kinetic and cross-sectional studies on the genesis of hypoargininemia in severe pediatric falciparum malaria.

Infect Immun 2019 Feb 4. Epub 2019 Feb 4.

University of Utah School of Medicine, Division of Infectious Diseases, Department of Medicine, Salt Lake City, Utah, 84132, United States.

Low bioavailability of nitric oxide (NO) and its precursor, arginine, contribute to microvascular pathophysiology of severe falciparum malaria. To better characterize mechanisms underlying hypoargininemia in severe malaria, we measured plasma concentrations of amino acids involved in arginine synthesis in children with uncomplicated (UM; n=61) and cerebral (CM; n=45) falciparum malaria, and in healthy children (HC; n=109). We also administered primed infusions of C-uniform-N-uniform-labeled L-arginine to 8 children with severe malaria (SM; age 4-9 years) and 7 healthy children (HC; age 4-8 years) to measure the metabolic flux of arginine, hypothesizing that arginine flux is increased in SM. Read More

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http://iai.asm.org/lookup/doi/10.1128/IAI.00655-18
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http://dx.doi.org/10.1128/IAI.00655-18DOI Listing
February 2019
4 Reads

The contribution of active iron-uptake to pathogenicity.

Infect Immun 2019 Feb 4. Epub 2019 Feb 4.

Department of Science, Roma Tre University, Rome, Italy

is an important nosocomial pathogen. Mechanisms that allow to cause human infection are still poorly understood. Iron is an essential nutrient for bacterial growth , and the multiplicity of iron-uptake systems in suggests that iron acquisition contributes to the ability of to cause infection. Read More

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http://dx.doi.org/10.1128/IAI.00755-18DOI Listing
February 2019
1 Read

Intracellular degradation of VacA toxin as a determinant of gastric epithelial cell viability.

Infect Immun 2019 Jan 28. Epub 2019 Jan 28.

Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA

VacA is a secreted pore-forming toxin that induces cell vacuolation and contributes to the pathogenesis of gastric cancer and peptic ulcer disease. We observed that purified VacA has relatively little effect on the viability of AGS gastric epithelial cells, but the presence of exogenous weak bases such as ammonium chloride (NHCl) enhances the susceptibility of these cells to VacA-induced vacuolation and cell death. Therefore, we tested the hypothesis that NHCl augments VacA toxicity by altering the intracellular trafficking of VacA or inhibiting intracellular VacA degradation. Read More

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http://dx.doi.org/10.1128/IAI.00783-18DOI Listing
January 2019
1 Read

Interaction of and vaginolysin with the apical versus basolateral face of a 3-dimensional model of vaginal epithelium.

Infect Immun 2019 Jan 28. Epub 2019 Jan 28.

Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, USA

Studies have implicated as an important etiological agent in bacterial vaginosis (BV). It produces a cholesterol-dependent cytolysin, vaginolysin (VLY). In this study, we sought to characterize the interaction between vaginal epithelium, , and VLY using EpiVaginal tissues from MatTek. Read More

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http://dx.doi.org/10.1128/IAI.00646-18DOI Listing
January 2019
2 Reads

biofilm-conditioned medium impairs macrophage-mediated anti-biofilm immune response by upregulating KLF2 expression.

Infect Immun 2019 Jan 28. Epub 2019 Jan 28.

School of Biomedical Sciences, Kent State University, Kent, OH, USA

() infections associated with the formation of biofilm onto medical implants or host tissue play a critical role in the persistence of chronic infections. One critical mechanism of biofilm infection that leads to persistent infection lies in the capacity of biofilms to evade the macrophage-mediated innate immune response. It is now increasingly apparent that microorganisms exploit the negative regulatory mechanisms of pattern recognition receptor (PRR)-mediated inflammatory response to subvert host cell functions by using various virulence factors. Read More

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http://dx.doi.org/10.1128/IAI.00643-18DOI Listing
January 2019
1 Read

Identification of a conserved, orphan G-protein coupled receptor required for efficient pathogen clearance in .

Infect Immun 2019 Jan 28. Epub 2019 Jan 28.

School of Life, Health and Chemical Sciences, The Open University, Milton Keynes MK7 6AA UK

G-protein coupled receptors contribute to host defense across the animal kingdom, transducing many signals involved in both vertebrate and invertebrate immune responses. Whilst it has become well established that the nematode worm triggers innate immune responses following infection with numerous bacterial, fungal and viral pathogens, the mechanisms by which recognises these pathogens have remained somewhat more elusive. G-protein coupled receptors have been implicated in recognising pathogen-associated damage and activating downstream host immune responses. Read More

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http://dx.doi.org/10.1128/IAI.00034-19DOI Listing
January 2019
1 Read

Shiga toxin (Stx) type 1a reduces the toxicity of the more potent Stx2a and .

Infect Immun 2019 Jan 22. Epub 2019 Jan 22.

Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA

Shiga toxin (Stx)-producing (STEC) cause food-borne outbreaks of bloody diarrhea. There are two major types of immunologically distinct Stxs, Stx1a and Stx2a. Stx1a is more cytotoxic to Vero cells than Stx2a, but Stx2a has a lower lethal dose 50% (LD) in mice. Read More

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http://dx.doi.org/10.1128/IAI.00787-18DOI Listing
January 2019
1 Read

Hookworm-derived metabolites suppress pathology in a mouse model of colitis and inhibit secretion of key inflammatory cytokines in primary human leukocytes.

Infect Immun 2019 Jan 22. Epub 2019 Jan 22.

Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD 4878, Australia.

Iatrogenic hookworm therapy shows promise for treating disorders that result from a dysregulated immune system, including inflammatory bowel disease (IBD). Using a murine model of trinitrobenzenesulfonic acid-induced colitis and human peripheral blood mononuclear cells, we demonstrate that low molecular weight metabolites derived from both somatic extracts (LMWM-SE) and excretory-secretory products (LMWM-ESP) of the hookworm, display anti-inflammatory properties. Administration to mice of LMWM-ESP as well as sequentially extracted fractions of LMWM-SE using both methanol (SE-MeOH) and hexane: dichloromethane: acetonitrile (SE-HDA) resulted in significant protection against T cell-mediated immunopathology, clinical signs of colitis and impaired histological colon architecture. Read More

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http://dx.doi.org/10.1128/IAI.00851-18DOI Listing
January 2019
4 Reads
3.731 Impact Factor

Mp1 protein, a novel virulence factor, carries two arachidonic acid-binding domains to suppress inflammatory responses in hosts.

Infect Immun 2019 Jan 22. Epub 2019 Jan 22.

School of Biomedical Sciences, State Key Laboratory of Emerging Infectious Diseases, Department of Microbiology, Research Centre of Infection and Immunity, Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong SAR, China.

() infection causes talaromycosis (previously known as penicilliosis), the second most-deadly opportunistic systematic mycosis in immuno-compromised patients. Different virulence mechanisms in had been proposed and investigated. In the sera of patients with talaromycosis, Mp1 protein (Mp1p), a secretory galactomannoprotein antigen encoding two tandem ligand-binding domains (Mp1p-LBD1 and Mp1p-LBD2), was found to be abundant. Read More

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http://dx.doi.org/10.1128/IAI.00679-18DOI Listing
January 2019
3.731 Impact Factor

Contributions of TolC orthologs to Schu S4 multidrug resistance, modulation of host cell responses, and virulence.

Infect Immun 2019 Jan 22. Epub 2019 Jan 22.

Department of Molecular Genetics and Microbiology, School of Medicine, Stony Brook University, Stony Brook, New York, USA; Center for Infectious Diseases, Stony Brook University, Stony Brook, New York, USA

is a Gram-negative, facultative intracellular pathogen and the causative agent of tularemia. Previous studies in the attenuated Live Vaccine Strain (LVS) identified a role for the outer membrane protein TolC in modulation of host cell responses during infection and virulence in the mouse model of tularemia. TolC is an integral part of efflux pumps that export small molecules and type I secretion systems that export a range of bacterial virulence factors. Read More

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http://dx.doi.org/10.1128/IAI.00823-18DOI Listing
January 2019
1 Read

Redundant and Distinct Roles of Secreted Protein Eap and Cell Wall-Anchored Protein SasG in Biofilm Formation and Pathogenicity of .

Infect Immun 2019 Jan 22. Epub 2019 Jan 22.

Department of Bacteriology, The Jikei University School of Medicine, Tokyo, Japan.

Chronic and fatal infections caused by are sometimes associated with biofilm formation. Secreted proteins and cell wall-anchored proteins (CWAPs) are important for the development of polysaccharide-independent biofilms, but functional relationships between these proteins are unclear. In the current study, we report the roles of the extracellular adherence protein Eap and surface CWAP SasG in MR23, a clinical methicillin-resistant isolate that forms a robust protein-dependent biofilm and accumulates a large amount of Eap in the extracellular matrix. Read More

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http://dx.doi.org/10.1128/IAI.00894-18DOI Listing
January 2019

TLR3-TRIF pathway activation by RNA enhances infection control in mice.

Infect Immun 2019 Jan 22. Epub 2019 Jan 22.

Laboratory of Immunoparasitology "Dr. Mário Endsfeldz Camargo", Department of Immunology, Institute of Biomedical Sciences, Federal University of Uberlândia. Av. Amazonas, 4C01, Campus Umuarama. 38405-320, Uberlândia, Minas Gerais, Brazil

is a protozoan parasite closely related to and has been studied for causing neuromuscular disease in dogs and abortions in cattle. It is recognized as one of the main transmissible causes of reproductive failures in cattle and consequent economic losses to the sector. In that sense, this study aimed to evaluate the role of TLR3-TRIF dependent resistance against infection in mice. Read More

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http://iai.asm.org/lookup/doi/10.1128/IAI.00739-18
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http://dx.doi.org/10.1128/IAI.00739-18DOI Listing
January 2019
4 Reads

Atypical hemolytic are virulent, albeit less than .

Infect Immun 2019 Jan 22. Epub 2019 Jan 22.

Institut Pasteur, National Reference Center and WHO Collaborating Center for Listeria, Paris, France

is considered as a non-pathogenic species. Natural atypical hemolytic have been reported, but have not been characterized in detail. Here we report the genomic and functional characterization of isolates representatives from the two known natural hemolytic clades. Read More

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http://iai.asm.org/lookup/doi/10.1128/IAI.00758-18
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http://dx.doi.org/10.1128/IAI.00758-18DOI Listing
January 2019
3 Reads

The hybrid cluster protein Hcp is required for growth with nitrite and survival with host cells.

Infect Immun 2019 Jan 22. Epub 2019 Jan 22.

Philips Institute for Oral Health Research, Department of Microbiology and Immunology, Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, USA

Although the periodontal pathogen must withstand high levels of nitrosative stress while in oral cavity the mechanisms of nitrosative stress defense are not well understood in this organism. Previously we have shown that the transcriptional regulator HcpR plays a significant role in the defense and here we further defined its regulon. Our study shows that (PG0893), a putative nitric oxide (NO) reductase, is the only gene significantly upregulated in response to nitrite (NO) and this regulation is dependent on HcpR. Read More

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http://dx.doi.org/10.1128/IAI.00572-18DOI Listing
January 2019

A glucuronoxylomannan epitope exhibits serotype-specific accessibility and redistributes towards the capsule surface during Titanisation of the fungal pathogen .

Infect Immun 2019 Jan 22. Epub 2019 Jan 22.

Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK. B15 2TT

Disseminated infections with the fungal species or, less frequently, , are an important cause of mortality in immunocompromised individuals. Central to the virulence of both species is an elaborate polysaccharide capsule that consists predominantly of glucuronoxylomannan (GXM). Due to its abundance, GXM is an ideal target for host antibodies, and several monoclonal antibodies (mAbs) have previously been derived using purified GXM or whole capsular preparations as antigen. Read More

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http://dx.doi.org/10.1128/IAI.00731-18DOI Listing
January 2019

Human intestinal enteroids as a model system of pathogenesis.

Infect Immun 2019 Jan 14. Epub 2019 Jan 14.

Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, USA.

The enteric bacterium and intracellular human pathogen causes hundreds of millions of cases of the diarrheal disease shigellosis per year worldwide. is acquired by ingestion of contaminated food or water; upon reaching the colon, the bacteria invade the colonic epithelial cells, replicate intracellularly, spread to adjacent cells, and provoke an intense inflammatory response. There is no animal model that faithfully recapitulates human disease, thus cultured cells have been used to model pathogenesis. Read More

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http://dx.doi.org/10.1128/IAI.00733-18DOI Listing
January 2019
1 Read

Induction of Inflammatory Responses in Splenocytes by Exosomes Released from Intestinal Epithelial Cells following Infection.

Infect Immun 2019 Jan 14. Epub 2019 Jan 14.

Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America

, a protozoan parasite that infects the gastrointestinal epithelium and other mucosal surfaces in humans and animals, is an important opportunistic pathogen in AIDS patients and one of the most common enteric pathogens affecting young children in developing regions. This parasite is referred to as a "minimally invasive" mucosal pathogen and epithelial cells play a central role in activating and orchestrating host immune responses. We previously demonstrated that infection stimulates host epithelial cells to release exosomes and these released exosomes shuttle several antimicrobial peptides to carry out anti- activity. Read More

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http://iai.asm.org/lookup/doi/10.1128/IAI.00705-18
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http://dx.doi.org/10.1128/IAI.00705-18DOI Listing
January 2019
3 Reads

Moderately-neutralizing epitopes in non-functional regions dominate the antibody response to EBA-140.

Infect Immun 2019 Jan 14. Epub 2019 Jan 14.

Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA

Erythrocyte Binding Antigen-140 plays a role in tight junction formation during parasite invasion of red blood cells and is a potential vaccine candidate for malaria. Individuals in malaria-endemic areas possess Erythrocyte Binding Antigen-140-specific antibodies, and individuals with high antibody titers to this protein have a lower rate of re-infection by parasites. The red cell binding segment of Erythrocyte Binding Antigen-140 is comprised of two Duffy-binding-like domains called F1 and F2 that together create region II. Read More

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http://dx.doi.org/10.1128/IAI.00716-18DOI Listing
January 2019
4 Reads

Artificial selection for pathogenicity mutations in identifies novel factors relevant to chronic infection.

Infect Immun 2019 Jan 14. Epub 2019 Jan 14.

Department of Laboratory Medicine, University of Washington, Seattle, WA

Adaptation of to host microenvironments during chronic infection involves spontaneous mutations, yet changes underlying adaptive phenotypes remain incompletely explored. Here we employed artificial selection and whole genome sequencing to better characterize spontaneous chromosomal mutations that alter two pathogenicity phenotypes relevant to chronic infection in : intracellular invasiveness and intracellular cytotoxicity. We identified 23 genes whose alteration coincided with enhanced virulence, 11 that were previously known and 12 of which (52%) had no previously described role in pathogenicity. Read More

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http://iai.asm.org/lookup/doi/10.1128/IAI.00884-18
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http://dx.doi.org/10.1128/IAI.00884-18DOI Listing
January 2019
5 Reads

Immunological responses to the relapsing fever spirochete in infected Rhesus macaques: implications for pathogenesis and diagnosis.

Infect Immun 2019 Jan 14. Epub 2019 Jan 14.

Department of Pediatrics, National School of Tropical Medicine, and Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas.

The global public health impact of relapsing fever (RF) spirochetosis is significant, as the pathogens exist on five of seven continents. The hallmark sign of infection is episodic fever and the greatest threat is to the unborn. With the goal of better understanding the specificity of B cell responses and the role of immune responses in pathogenicity, we infected Rhesus macaques with (a new world RF spirochete species) by tick bite and monitored the immune responses generated in response to the pathogen. Read More

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http://dx.doi.org/10.1128/IAI.00900-18DOI Listing
January 2019
2 Reads

exploit early activation of myeloid differentiation primary response 88 (MyD88) for growth in the lungs during pneumonic plague.

Infect Immun 2019 Jan 14. Epub 2019 Jan 14.

Department of Veterinary Pathobiology, University of Missouri, 201 Connaway Hall, Columbia, MO, 65211

cause bubonic, pneumonic and septicemic plague. Although no longer responsible for pandemic outbreaks, pneumonic plague continues to be a challenge for medical treatment and has been classified as a reemerging disease in some parts of the world. In the early stage of infection, inflammatory responses are believed to be suppressed by virulence factors in order to prevent clearance, while later the hyper-activation of inflammation contributes to the progression of disease. Read More

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http://dx.doi.org/10.1128/IAI.00757-18DOI Listing
January 2019
1 Read

Evaluating pathogenesis in the human enteroid model.

Infect Immun 2019 Jan 14. Epub 2019 Jan 14.

Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 655 W. Baltimore Street, Baltimore MD 21201

The enteric pathogen, , is one of the leading causes of moderate-to-severe diarrhea and death in young children in developing countries. Transformed cell lines and animal models have been widely used to study pathogenesis. In addition to altered physiology, transformed cell lines are composed of a single cell type that does not sufficiently represent the complex multi-cellular environment of the human colon. Read More

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http://dx.doi.org/10.1128/IAI.00740-18DOI Listing
January 2019

Genetic variation/evolution and differential host responses resulting from in-patient adaptation of .

Infect Immun 2019 Jan 14. Epub 2019 Jan 14.

Centre of Molecular Inflammation Research (CEMIR), Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway

(Mav) complex (MAC) are characterized as non-tuberculosis mycobacteria and are pathogenic mainly in immunocompromised individuals. MAC strains show a wide genetic variability, and there is growing evidence suggesting that genetic differences may contribute to a varied immune response that may impact on the infection outcome. The current study aimed to characterize the genomic changes within Mav isolates collected from single patients over time and test the host immune responses to these clinical isolates. Read More

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http://iai.asm.org/lookup/doi/10.1128/IAI.00323-18
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http://dx.doi.org/10.1128/IAI.00323-18DOI Listing
January 2019
3 Reads

Structural and functional insights into PpgL: a metal-independent β-propeller gluconolactonase that contributes to virulence.

Infect Immun 2019 Jan 14. Epub 2019 Jan 14.

Center of Infectious Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu 610065, China

Biofilm formation is a critical determinant in the pathopoiesis of It could significantly increase bacterial resistance to drugs and host defense. Thus, inhibiting biofilm matrix production could be regarded as a promising attempt to prevent colonization of and the subsequent infection. PpgL, a periplasmic gluconolactonase, has been reported to be involved in QS system regulation. Read More

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http://iai.asm.org/lookup/doi/10.1128/IAI.00847-18
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http://dx.doi.org/10.1128/IAI.00847-18DOI Listing
January 2019
4 Reads

Spotted fever group infection and transmission dynamics in .

Infect Immun 2019 Jan 14. Epub 2019 Jan 14.

Vector-borne Disease Laboratories, Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA

Tick vectors are capable of transmitting several rickettsial species to vertebrate hosts resulting in varying levels of disease. Studies have demonstrated the transmissibility of both rickettsial pathogens and novel species or strains with unknown pathogenicity to vertebrate hosts during tick bloodmeal acquisition; however, the quantitative nature of transmission remains unknown. We tested the hypothesis that if infection severity is a function of rickettsial load delivered during tick transmission, then a more virulent SFG species is transmitted at greater levels during tick feeding. Read More

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http://dx.doi.org/10.1128/IAI.00804-18DOI Listing
January 2019
1 Read

Exploring the Potential Therapeutic Effects of Mepacrine against Enterotoxin in a Mouse Enterotoxemia Model.

Infect Immun 2019 Jan 14. Epub 2019 Jan 14.

California Animal Health and Food Safety Laboratory System, School of Veterinary Medicine, University of California, Davis, San Bernardino, CA

enterotoxin (CPE) is a pore-forming toxin that causes the symptoms of a common bacterial food poisoning and several nonfoodborne human gastrointestinal diseases, including antibiotic-associated diarrhea and sporadic diarrhea. In some cases, CPE-mediated disease can be very severe or fatal due to the involvement of enterotoxemia. Therefore, the development of potential therapeutics against CPE action during enterotoxemia is warranted. Read More

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http://dx.doi.org/10.1128/IAI.00670-18DOI Listing
January 2019
1 Read

Peptide-Based Inhibitors of Fimbrial Biogenesis in .

Infect Immun 2019 Jan 14. Epub 2019 Jan 14.

Department of Molecular Genetics and Microbiology, School of Medicine, Stony Brook University, Stony Brook, New York, USA

Periodontitis is a progressive inflammatory disease that affects roughly half of American adults. Colonization of the oral cavity by the Gram-negative bacterial pathogen is a key event in the initiation and development of periodontal disease. Adhesive surface structures termed fimbriae (pili) mediate interactions of with other bacteria and with host cells throughout the course of disease. Read More

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http://dx.doi.org/10.1128/IAI.00750-18DOI Listing
January 2019

Host-derived metabolites modulate transcription of genes involved in l-lactate utilization during gut colonization.

Infect Immun 2019 Jan 7. Epub 2019 Jan 7.

Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA

During serovar Typhimurium infection, host inflammation alters the metabolic environment of the gut lumen to favor the outgrowth of the pathogen at the expense of the microbiota. Inflammation-driven changes in host cell metabolism lead to the release of l-lactate and molecular oxygen from the tissue into the gut lumen. utilizes lactate as an electron donor in conjunction with oxygen as the terminal electron acceptor to support gut colonization. Read More

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http://dx.doi.org/10.1128/IAI.00773-18DOI Listing
January 2019

VopA is a potent inhibitor of cell migration and apoptosis in the intestinal epithelium of .

Infect Immun 2019 Jan 7. Epub 2019 Jan 7.

Department of Pediatrics, Emory University School of Medicine, Atlanta GA, 30322

Animal models have played a key role in understanding the mechanisms that govern the pathophysiology of intestinal diseases. To expand on the repertoire of organisms available to study enteric diseases, we report on the use of the model to identify a novel function of an effector protein secreted by which is an enteric pathogen found in contaminated seafood. During pathogenesis, secretes effector proteins that usurp the host's innate immune signaling pathways, thus allowing the bacterium to evade detection by the innate immune system. Read More

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http://iai.asm.org/lookup/doi/10.1128/IAI.00669-18
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http://dx.doi.org/10.1128/IAI.00669-18DOI Listing
January 2019
3 Reads

Indole inhibits ToxR regulon expression in .

Infect Immun 2019 Jan 7. Epub 2019 Jan 7.

Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA

Indole is a degradation product of tryptophan that functions as a signaling molecule in many bacteria. This includes where indole was shown to regulate biofilm and type VI secretion in non-toxigenic environmental isolates. Indole is also produced by toxigenic strains in the human intestine, but its significance in the host is unknown. Read More

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http://iai.asm.org/lookup/doi/10.1128/IAI.00776-18
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http://dx.doi.org/10.1128/IAI.00776-18DOI Listing
January 2019
4 Reads

Biochemical and immunological evaluation of recombinant CS6-derived subunit enterotoxigenic vaccine candidates.

Infect Immun 2019 Jan 2. Epub 2019 Jan 2.

Enteric Diseases Department, Naval Medical Research Center, Silver Spring, MD, USA.

CS6, a prevalent surface antigen expressed in nearly 20% of clinical enterotoxigenic (ETEC) isolates, is comprised of two major subunit proteins, CssA and CssB. Using donor strand complementation, we constructed a panel of recombinant proteins of 1-3 subunits, that contained combinations of CssA and/or CssB subunits and a donor strand, a C-terminal extension of sixteen amino acids that was derived from the N-terminus of either CssA or CssB. While the entire panel of recombinant proteins could be obtained as soluble, folded proteins, it was observed that the proteins possessing a heterologous donor strand, derived from the CS6 subunit different from the C-terminal subunit, had the highest degree of physical and thermal stability. Read More

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http://dx.doi.org/10.1128/IAI.00788-18DOI Listing
January 2019

Retention of EsxA in the capsule-like layer of is associated with cytotoxicity and is counteracted by lung surfactant.

Infect Immun 2019 Jan 2. Epub 2019 Jan 2.

Division of Microbiology and Molecular Medicine, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden

, the pathogen that causes tuberculosis, primarily infects macrophages but withstands the host cell's bactericidal effects. EsxA, also called virulence factor 6 kDa early secretory antigenic target (ESAT-6), is involved in phagosomal rupture and cell death. We provide confocal and electron microscopy data showing that grown without detergent retains EsxA on its surface. Read More

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http://dx.doi.org/10.1128/IAI.00803-18DOI Listing
January 2019
1 Read

Characterization of pyrin dephosphorylation and inflammasome activation in macrophages as triggered by the effectors YopE and YopT.

Infect Immun 2019 Jan 2. Epub 2019 Jan 2.

Department of Molecular Genetics and Microbiology, Center for Infectious Diseases, Stony Brook University, Stony Brook, NY.

Pathogenic species deliver Yop effector proteins through a type III secretion system into host cells. Among these effectors, YopE and YopT are Rho-modifying toxins, which function to modulate host cell physiology and evade immune responses. YopE is a GAP and YopT is a protease and they inhibit RhoA by different modes of action. Read More

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http://iai.asm.org/lookup/doi/10.1128/IAI.00822-18
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http://dx.doi.org/10.1128/IAI.00822-18DOI Listing
January 2019
9 Reads

fimbrial protein FimH is involved in the expression of pro-inflammatory cytokines in a Toll-like receptor 4-dependent manner.

Infect Immun 2019 Jan 2. Epub 2019 Jan 2.

Department of Microbiology, Faculty of Pharmacy, Meijo University, Nagoya, Japan.

Type 1 fimbriae are proteinaceous filamentous structures present on bacterial surfaces and are mainly composed of the major fimbrial protein subunit FimA and the adhesive protein FimH, which is located at the tip of the fimbrial shaft. Here, we investigated the involvement of type 1 fimbriae in the expression of pro-inflammatory cytokines in macrophages infected with serovar Typhimurium. The level of interleukin-1 beta (IL-1β) mRNA was lower in macrophages infected with a or mutant strains than in those infected with wild-type Treatment of macrophages with purified recombinant FimH protein, but not FimA, resulted in the activation of the mitogen-activated protein kinase and nuclear factor kappa B signaling pathways, leading to the expression of not only IL-1β but also of other pro-inflammatory cytokines such as IL-6 and tumor necrosis factor alpha. Read More

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http://iai.asm.org/lookup/doi/10.1128/IAI.00881-18
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http://dx.doi.org/10.1128/IAI.00881-18DOI Listing
January 2019
7 Reads

Toll-like receptor 2 prevents neutrophil-driven immunopathology during infection with by curtailing CXCL5 production.

Infect Immun 2018 Dec 17. Epub 2018 Dec 17.

Rutgers-New Jersey Medical School, Newark, NJ

The W-Beijing strain family is globally distributed and is associated with multidrug-resistant tuberculosis (TB) and treatment failure. Therefore, in this study, we examined the contribution of Toll-like receptor (TLR)2 to host resistance against (Mtb) HN878, a clinical isolate belonging to the W-Beijing family. We show that TLR2KO mice infected with Mtb HN878 exhibit increased bacterial burden and are unable to control tissue-damaging, pulmonary neutrophilic inflammation. Read More

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http://dx.doi.org/10.1128/IAI.00760-18DOI Listing
December 2018

The obligate intracellular bacterium targets NLRC5 to modulate the MHC class-I pathway.

Infect Immun 2018 Dec 17. Epub 2018 Dec 17.

Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, Virginia, USA

is an obligate intracellular bacterium that infects mononuclear and endothelial cells to cause the emerging global health threat, scrub typhus. The ability of to survive in monocytes facilitates bacterial dissemination to endothelial cells, which can subsequently lead to several potentially fatal sequelae. As a strict intracellular pathogen that lives in the cytoplasm of host cells, has evolved to counter adaptive immunity. Read More

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http://dx.doi.org/10.1128/IAI.00876-18DOI Listing
December 2018
2 Reads

Immunologic pathways in protective versus maladaptive host responses to attenuated and pathogenic strains of .

Infect Immun 2018 Dec 17. Epub 2018 Dec 17.

Department of Pathobiology and Veterinary Sciences, University of Connecticut, Storrs, Connecticut, USA

Mycoplasmas are small bacterial commensals or pathogens that commonly colonize host mucosal tissues and avoid rapid clearance, in part by stimulating inflammatory, immunopathogenic responses. We previously characterized a wide array of transcriptomic perturbations in avian host tracheal mucosae infected with virulent, immunopathologic ; however, mechanisms delineating these from protective responses, such as those induced upon vaccination, have not been thoroughly explored. Here, host transcriptomic responses to two experimental vaccines were assessed during the first two days of infection. Read More

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http://iai.asm.org/lookup/doi/10.1128/IAI.00613-18
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http://dx.doi.org/10.1128/IAI.00613-18DOI Listing
December 2018
9 Reads

CitAB two-component system-regulated citrate utilization contributes to competitiveness with the gut microbiota.

Infect Immun 2018 Dec 17. Epub 2018 Dec 17.

Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA

Citrate is a ubiquitous compound and can be utilized by many bacterial species, including enteric pathogens, as a carbon and energy source. Genes involved in citrate utilization have been extensively studied in some enteric bacteria, such as , however their role in pathogenesis is still not clear. In this study, we investigated citrate utilization and regulation in , the causative agent of cholera. Read More

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http://dx.doi.org/10.1128/IAI.00746-18DOI Listing
December 2018
2 Reads
3.731 Impact Factor

Specific Chicken Egg Yolk Antibody Improves Protective Response against Infection.

Infect Immun 2018 Dec 17. Epub 2018 Dec 17.

Laboratory of Animal Genetic Engineering and Stem Cell Biology, Department of Advanced Convergence Technology and Science, Jeju National University, Jeju, Republic of Korea

() is a pathogen associated with peritonitis and salpingitis in chickens and other avian species. Novel safety prevention strategies are urgently needed because of widespread multidrug resistance and antigenic diversity. The objective of this study was to produce a specific chicken egg yolk antibody and evaluate its protective response against -infected model in 4-week-old chicks. Read More

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http://dx.doi.org/10.1128/IAI.00619-18DOI Listing
December 2018
1 Read

Mosquito-Bite Induced Controlled Human Malaria Infection with or Generates Immune Responses to Homologous and Heterologous Preerythrocytic and Erythrocytic Antigens.

Infect Immun 2018 Dec 17. Epub 2018 Dec 17.

Malaria Vaccine Branch, U.S. Military Malaria Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, 20910, USA.

Seroepidemiological studies on the prevalence of antibodies to malaria antigens are primarily conducted on individuals from endemic regions. It is, therefore, difficult to accurately correlate the antibody responses to the timing and number of prior malaria infection(s). This study was undertaken to assess the evolution of antibodies to the dominant surface antigens of and following CHMI in malaria-naïve individuals. Read More

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http://iai.asm.org/lookup/doi/10.1128/IAI.00541-18
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http://dx.doi.org/10.1128/IAI.00541-18DOI Listing
December 2018
3 Reads

Lectin activity of the TcdA and TcdB toxins of .

Infect Immun 2018 Dec 10. Epub 2018 Dec 10.

Institute for Glycomics, Griffith University, Gold Coast, QLD 4222, Australia.

is a major cause of hospital-acquired antibiotic-associated diarrhoea. produces two cytotoxins, TcdA and TcdB, both toxins are multi-domain proteins that lead to cytotoxicity through the modification and inactivation of small GTPases of the Rho/Rac family. Previous studies have indicated that host glycans are targets for TcdA and TcdB, with interactions thought to be with both α- and β-linked galactose. Read More

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http://dx.doi.org/10.1128/IAI.00676-18DOI Listing
December 2018
1 Read