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Pathogenic Microbiology Commons

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Full-Text Articles in Pathogenic Microbiology

Virulence Of Group A Streptococci Is Enhanced By Human Complement Inhibitors, David Ermert, Jutamas Shaughnessy, Thorsten Joeris, Jakub Kaplan, Catherine J. Pang, Evelyn A. Kurt-Jones, Peter A. Rice, Sanjay Ram, Anna M. Blom Jul 2015

Virulence Of Group A Streptococci Is Enhanced By Human Complement Inhibitors, David Ermert, Jutamas Shaughnessy, Thorsten Joeris, Jakub Kaplan, Catherine J. Pang, Evelyn A. Kurt-Jones, Peter A. Rice, Sanjay Ram, Anna M. Blom

Open Access Articles

Streptococcus pyogenes, also known as Group A Streptococcus (GAS), is an important human bacterial pathogen that can cause invasive infections. Once it colonizes its exclusively human host, GAS needs to surmount numerous innate immune defense mechanisms, including opsonization by complement and consequent phagocytosis. Several strains of GAS bind to human-specific complement inhibitors, C4b-binding protein (C4BP) and/or Factor H (FH), to curtail complement C3 (a critical opsonin) deposition. This results in diminished activation of phagocytes and clearance of GAS that may lead to the host being unable to limit the infection. Herein we describe the course of GAS infection in ...


Caspase-11 Activation In Response To Bacterial Secretion Systems That Access The Host Cytosol, Cierra N. Casson, Alan M. Copenhaver, Erin E. Zwack, Hieu T. Nguyen, Till Strowig, Bahar Javdan, William P. Bradley, Thomas C. Fung, Richard A. Flavell, Igor E. Brodsky, Sunny Shin Jun 2013

Caspase-11 Activation In Response To Bacterial Secretion Systems That Access The Host Cytosol, Cierra N. Casson, Alan M. Copenhaver, Erin E. Zwack, Hieu T. Nguyen, Till Strowig, Bahar Javdan, William P. Bradley, Thomas C. Fung, Richard A. Flavell, Igor E. Brodsky, Sunny Shin

Department of Microbiology Papers

Inflammasome activation is important for antimicrobial defense because it induces cell death and regulates the secretion of IL-1 family cytokines, which play a critical role in inflammatory responses. The inflammasome activates caspase-1 to process and secrete IL-1β. However, the mechanisms governing IL-1α release are less clear. Recently, a non-canonical inflammasome was described that activates caspase-11 and mediates pyroptosis and release of IL-1α and IL-1β. Caspase-11 activation in response to Gram-negative bacteria requires Toll-like receptor 4 (TLR4) and TIR-domain-containing adaptor-inducing interferon-β (TRIF)-dependent interferon production. Whether additional bacterial signals trigger caspase-11 activation is unknown. Many bacterial pathogens use specialized secretion systems ...


Rapid Pathogen-Induced Apoptosis: A Mechanism Used By Dendritic Cells To Limit Intracellular Replication Of Legionella Pneumophila, Catarina V. Nogueira, Tullia Lindsten, Amanda M. Jamieson, Christopher L. Case, Sunny Shin, Craig B. Thompson, Craig R. Roy Jun 2009

Rapid Pathogen-Induced Apoptosis: A Mechanism Used By Dendritic Cells To Limit Intracellular Replication Of Legionella Pneumophila, Catarina V. Nogueira, Tullia Lindsten, Amanda M. Jamieson, Christopher L. Case, Sunny Shin, Craig B. Thompson, Craig R. Roy

Department of Microbiology Papers

Dendritic cells (DCs) are specialized phagocytes that internalize exogenous antigens and microbes at peripheral sites, and then migrate to lymphatic organs to display foreign peptides to naïve T cells. There are several examples where DCs have been shown to be more efficient at restricting the intracellular replication of pathogens compared to macrophages, a property that could prevent DCs from enhancing pathogen dissemination. To understand DC responses to pathogens, we investigated the mechanisms by which mouse DCs are able to restrict replication of the intracellular pathogen Legionella pneumophila. We show that both DCs and macrophages have the ability to interfere with ...


Type Iv Secretion-Dependent Activation Of Host Map Kinases Induces An Increased Proinflammatory Cytokine Response To Legionella Pneumophila, Sunny Shin, Christopher L. Case, Kristina A. Archer, Catarina V. Nogueira, Koichi S. Kobayashi, Richard A. Flavell, Craig R. Roy, Dario S. Zamboni Nov 2008

Type Iv Secretion-Dependent Activation Of Host Map Kinases Induces An Increased Proinflammatory Cytokine Response To Legionella Pneumophila, Sunny Shin, Christopher L. Case, Kristina A. Archer, Catarina V. Nogueira, Koichi S. Kobayashi, Richard A. Flavell, Craig R. Roy, Dario S. Zamboni

Department of Microbiology Papers

The immune system must discriminate between pathogenic and nonpathogenic microbes in order to initiate an appropriate response. Toll-like receptors (TLRs) detect microbial components common to both pathogenic and nonpathogenic bacteria, whereas Nod-like receptors (NLRs) sense microbial components introduced into the host cytosol by the specialized secretion systems or pore-forming toxins of bacterial pathogens. The host signaling pathways that respond to bacterial secretion systems remain poorly understood. Infection with the pathogen Legionella pneumophila, which utilizes a type IV secretion system (T4SS), induced an increased proinflammatory cytokine response compared to avirulent bacteria in which the T4SS was inactivated. This enhanced response involved ...