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Pathogenic Microbiology Commons

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Articles 1 - 7 of 7

Full-Text Articles in Pathogenic Microbiology

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 ...


Dissection Of A Type I Interferon Pathway In Controlling Bacterial Intracellular Infection In Mice, Juliane Lippmann, Holger Müller, Jan Naujoks, Christoph Tabeling, Sunny Shin, Martin Witzenrath, Katharina Hellwig, Carsten J. Kirschning, Gregory A. Taylor, Winfried Barchet, Stefan Bauer, Norbert Suttorp, Craig A. Roy, Bastian Opitz Nov 2011

Dissection Of A Type I Interferon Pathway In Controlling Bacterial Intracellular Infection In Mice, Juliane Lippmann, Holger Müller, Jan Naujoks, Christoph Tabeling, Sunny Shin, Martin Witzenrath, Katharina Hellwig, Carsten J. Kirschning, Gregory A. Taylor, Winfried Barchet, Stefan Bauer, Norbert Suttorp, Craig A. Roy, Bastian Opitz

Department of Microbiology Papers

Defense mechanisms against intracellular bacterial pathogens are incompletely understood. Our study characterizes a type I IFN-dependent cell-autonomous defense pathway directed against Legionella pneumophila, an intracellular model organism and frequent cause of pneumonia. We show that macrophages infected with L. pneumophila produced IFNβ in a STING- and IRF3- dependent manner. Paracrine type I IFNs stimulated up-regulation of IFN-stimulated genes and a cell-autonomous defense pathway acting on replicating and non-replicating Legionella within their specialized vacuole. Our infection experiments in mice lacking receptors for type I and/or II IFNs show that type I IFNs contribute to expression of IFN-stimulated genes and to ...


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 ...


Thymic Selection Determines Γδ T Cell Effector Fate: Antigen-Naive Cells Make Interleukin-17 And Antigen-Experienced Cells Make Interferon Γ, Kirk D. C Jensen, Xiaoqin Su, Sunny Shin, Luke Li, Sawsan Youssef, Sho Yamasaki, Lawrence Steinman, Takashi Saito, Richard M. Locksley, Mark M. Davis, Nicole Baumgarth, Yueh-Hsiu Chien Jul 2008

Thymic Selection Determines Γδ T Cell Effector Fate: Antigen-Naive Cells Make Interleukin-17 And Antigen-Experienced Cells Make Interferon Γ, Kirk D. C Jensen, Xiaoqin Su, Sunny Shin, Luke Li, Sawsan Youssef, Sho Yamasaki, Lawrence Steinman, Takashi Saito, Richard M. Locksley, Mark M. Davis, Nicole Baumgarth, Yueh-Hsiu Chien

Department of Microbiology Papers

γδ T cells contribute uniquely to host immune competence, but how they do so remain unclear. Here, by analyzing T10/T22-specific γδ T cells in mice with different T10/T22 expression patterns, we find that encountering antigen in the thymus is neither required nor inhibitory for the development of these cells. Instead, ligand recognition determines which of two distinct functional subsets γδ T cells will become. When triggered through the TCR, lymphoid-γδ T cells that encounter ligand during development produce IFNγ, while those that develop in the absence of ligand make IL-17, a major inducer of granulopoiesis during inflammation. Indeed ...


An Autonomous Cdr3Δ Is Sufficient For Γδ T Cell Recognition Of The Nonclassical Mhc-I T10/T22, Erin J. Adams, Pavel Strop, Sunny Shin, Yueh-Hsiu Chien, K. Christopher Garcia Jul 2008

An Autonomous Cdr3Δ Is Sufficient For Γδ T Cell Recognition Of The Nonclassical Mhc-I T10/T22, Erin J. Adams, Pavel Strop, Sunny Shin, Yueh-Hsiu Chien, K. Christopher Garcia

Department of Microbiology Papers

It remains unclear whether γδ T cell receptors (TCRs) detect antigens in a manner similar to antibodies or αβ TCRs. Here we show that reactivity between G8 and KN6 γδ TCRs and the MHC class Ib molecule T22 can be transplanted, with retention of wild-type ligand affinity, after en bloc grafting of G8 and KN6 CDR3δ loops in place onto the CDR3α loop of an αβ TCR. We also find that a shared sequence motif within CDR3δ loops of all T22-reactive γδ TCRs binds T22 in energetically distinct fashions, and that T10d, which binds G8 with weak affinity, is converted ...


Genetic Analysis Of Human Immunodefiency Virus Type I Strains In Kenya: A Comparison Using Phylogenetic Analysis And A Combinatorial Melting Assay, Kenneth E. Robbins, Leondios G. Kostrikis, Teresa M. Brown, Omu Anzala, Sunny Shin, Francis A. Plummer, Marcia L. Kalish Nov 1999

Genetic Analysis Of Human Immunodefiency Virus Type I Strains In Kenya: A Comparison Using Phylogenetic Analysis And A Combinatorial Melting Assay, Kenneth E. Robbins, Leondios G. Kostrikis, Teresa M. Brown, Omu Anzala, Sunny Shin, Francis A. Plummer, Marcia L. Kalish

Department of Microbiology Papers

We surveyed human immunodeficiency virus (HIV) subtype distribution from peripheral blood mononuclear cells (PBMCs) collected in 1995 from 24 HIV-1-infected Kenyan residents (specimens from predominantly male truck drivers and female sex workers near Mombasa and Nairobi). Processed lysates from the PBMC samples were used for env amplification, directly sequenced, and analyzed by phylogenetic analysis. Envelope amplification products were also used for analysis in a polymerase chain reaction (PCR)-based assay, called the combinatorial melting assay (COMA). Results of the two tests were compared for assignment of subtype for this Kenyan cohort. The COMA, a PCR capture technique with colorimetric signal ...