Medical Immunology Commons^™

Role Of The Dna Sensor Sting In Protection From Lethal Infection Following Corneal And Intracerebral Challenge With Herpes Simplex Virus 1, Zachary M. Parker, Aisling A. Murphy, David. A. Leib

Dartmouth Scholarship

STING is a protein in the cytosolic DNA and cyclic dinucleotide sensor pathway that is critical for the initiation of innate responses to infection by various pathogens. Consistent with this, herpes simplex virus 1 (HSV-1) causes invariable and rapid lethality in STING-deficient (STING(-/-)) mice following intravenous (i.v.) infection. In this study, using real-time bioluminescence imaging and virological assays, as expected, we demonstrated that STING(-/-) mice support greater replication and spread in ocular tissues and the nervous system. In contrast, they did not succumb to challenge via the corneal route even with high titers of a virus that was routinely lethal …

The Role Of Glutaminase 1 In Hiv-1 Associated Neurocognitive Disorders And In Brain Development, Yi Wang

Theses & Dissertations

Glutaminase is the enzyme that converts glutamine into glutamate, which serves as a key excitatory neurotransmitter and one of the energy providers for cellular metabolism. Glutamate is essential for proper brain functioning but at excess levels, it is neurotoxic and has a key role in the pathogenesis of various neurodegenerative diseases, including HIV-1 associated neurocognitive disorders (HAND). However, the detailed mechanism of glutamate-mediated neurotoxicity remains unclear. In part I, we identified the regulation of glutaminase 1 (GLS1) in the central nervous system (CNS) of HAND animal models including HIV-Tat transgenic (Tg) mouse and HIVE-SCID mouse, since GLS1 is the dominant …

Application Of Β-Lactamase Reporter Fusions As An Indicator Of Effector Protein Secretion During Infections With The Obligate Intracellular Pathogen Chlamydia Trachomatis , Konrad E. Mueller, Kenneth A. Fields

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Chlamydia spp. utilize multiple secretion systems, including the type III secretion system (T3SS), to deploy host-interactive effector proteins into infected host cells. Elucidation of secreted proteins has traditionally required ectopic expression in a surrogate T3SS followed by immunolocalization of endogenous candidate effectors to confirm secretion by chlamydiae. The ability to transform Chlamydia and achieve stable expression of recombinant gene products has enabled a more direct assessment of secretion. We adapted TEM-1 β-lactamase as a reporter system for assessment of chlamydial protein secretion. We provide evidence that this system facilitates visualization of secretion in the context of infection. Specifically, our findings …

The Right Tool For The Job: Detection Of Soil-Transmitted Helminths In Areas Co-Endemic For Other Helminths, Maria V. Periago, Renata C. Diniz, Simone A. Pinto, Anna Yakovleva, Rodrigo Correa-Oliveira, David J. Diemert, Jeffrey M. Bethony

Microbiology, Immunology, and Tropical Medicine Faculty Publications

Due to the recent increased use of the McMaster (MM) fecal egg counting method for assessing benzimidazole drug efficacy for treating soil-transmitted helminth (STH) infections, the aim of the current study was to determine the operational value of including the MM method alongside the Kato-Katz (KK) fecal thick smear to increase the diagnostic sensitivity when STHs are co-endemic with trematode helminths (e.g., Schistosoma mansoni).

Methods

A cross-sectional study was conducted in school-aged children aged 4-18 years in the northeastern region of the State of Minas Gerais (Brazil), where Necator americanus, Ascaris lumbricoides, Trichuris trichiura, and S …

Intracellular Listeria Monocytogenes Comprises A Minimal But Vital Fraction Of The Intestinal Burden Following Foodborne Infection, Grant S. Jones, Kate M. Bussell, Tanya Myers-Morales, Abigail M. Fieldhouse, Elsa N. Bou Ghanem, Sarah E. F. D'Orazio

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Listeria monocytogenes is a highly adaptive bacterium that replicates as a free-living saprophyte in the environment as well as a facultative intracellular pathogen that causes invasive foodborne infections. The intracellular life cycle of L. monocytogenes is considered to be its primary virulence determinant during mammalian infection; however, the proportion of L. monocytogenes that is intracellular in vivo has not been studied extensively. In this report, we demonstrate that the majority of wild-type (strain EGDe) and mouse-adapted (InlA^m-expressing) L. monocytogenes recovered from the mesenteric lymph nodes (MLN) was extracellular within the first few days after foodborne infection. In addition, …

Mechanisms Of Immunological Tolerance In Central Nervous System Inflammatory Demyelination., Elisabeth R. Mari, Jason N. Moore, Guang-Xian Zhang, A. M. Rostami

Department of Neurology Faculty Papers

Multiple sclerosis is a complex autoimmune disease of the central nervous system that results in a disruption of the balance between pro-inflammatory and anti-inflammatory signals in the immune system. Given that central nervous system inflammation can be suppressed by various immunological tolerance mechanisms, immune tolerance has become a focus of research in the attempt to induce long-lasting immune suppression of pathogenic T cells. Mechanisms underlying this tolerance induction include induction of regulatory T cell populations, anergy and the induction of tolerogenic antigen-presenting cells. The intravenous administration of encephalitogenic peptides has been shown to suppress experimental autoimmune encephalomyelitis and induce tolerance …

Zbtb20 Is A Sequence-Specific Transcriptional Repressor Of Alpha-Fetoprotein Gene, Hai Zhang, Dongmei Cao, Luting Zhou, Ye Zhang, Xiaoqin Guo, Hui Li, Yuxia Chen, Brett T. Spear, Jia-Wei Wu, Zhifang Xie, Weiping J Zhang

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Alpha-fetoprotein (AFP) represents a classical model system to study developmental gene regulation in mammalian cells. We previously reported that liver ZBTB20 is developmentally regulated and plays a central role in AFP postnatal repression. Here we show that ZBTB20 is a sequence-specific transcriptional repressor of AFP. By ELISA-based DNA-protein binding assay and conventional gel shift assay, we successfully identified a ZBTB20-binding site at -104/-86 of mouse AFP gene, flanked by two HNF1 sites and two C/EBP sites in the proximal promoter. Importantly, mutation of the core sequence in this site fully abolished its binding to ZBTB20 in vitro, as well …

B Lymphocytes Are Required During The Early Priming Of Cd4+ T Cells For Clearance Of Pneumocystis Infection In Mice, Michael M. Opata, Melissa L. Hollifield, Frances E. Lund, Troy D. Randall, Robert Dunn, Beth A. Garvy, David J. Feola

Microbiology, Immunology, and Molecular Genetics Faculty Publications

B cells play a critical role in the clearance of Pneumocystis. In addition to production of Pneumocystis-specific Abs, B cells are required during the priming phase for CD4⁺ T cells to expand normally and generate memory. Clearance of Pneumocystis was found to be dependent on Ag specific B cells and on the ability of B cells to secrete Pneumocystis-specific Ab, as mice with B cells defective in these functions or with a restricted BCR were unable to control Pneumocystis infection. Because Pneumocystis-specific antiserum was only able to partially protect B cell–deficient mice from infection, we …

Selective Involvement Of The Checkpoint Regulator Vista In Suppression Of B-Cell, But Not T-Cell, Responsiveness By Monocytic Myeloid-Derived Suppressor Cells From Mice Infected With An Immunodeficiency-Causing Retrovirus, Kathy A. Green, Li Wang, Randolph J. Noelle, William R. Green

Dartmouth Scholarship

Inhibition of T-cell responses in tumor microenvironments by myeloid-derived suppressor cells (MDSCs) is widely accepted. We demonstrated augmentation of monocytic MDSCs whose suppression of not only T-cell, but also B-cell, responsiveness paralleled the immunodeficiency during LP-BM5 retrovirus infection. MDSCs inhibited T cells by inducible nitric oxide synthase (iNOS)/nitric oxide (NO), but uniquely, inhibition of B cells was ~50% dependent each on iNOS/NO and the MDSC-expressed negative-checkpoint regulator VISTA. Blockade with a combination of iNOS/NO and VISTA caused additive or synergistic abrogation of MDSC-mediated suppression of B-cell responsiveness.

Ceramides Promote Apoptosis For Virus-Infected Lymphoma Cells Through Induction Of Ceramide Synthases And Viral Lytic Gene Expression, Lu Dai, Jimena Trillo-Tinoco, Aiping Bai, Yihan Chen, Jacek Bielawski, Luis Del Valle, Charles D. Smith, Augusto C. Ochoa, Zhiqiang Qin, Chris Parsons

School of Medicine Faculty Publications

Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent for several human cancers including primary effusion lymphoma (PEL), a rapidly progressive malignancy arising preferentially in immunocompromised patients. With conventional chemotherapy, PEL continues to portend high mortality, dictating the development of novel therapeutic strategies. Sphingosine kinase 2 (SphK2) represents a key gatekeeper for sphingolipid metabolism, responsible for conversion of ceramides to sphingosine-1-phosphate (S1P). We have previously demonstrated that targeting SphK2 using a novel selective inhibitor, ABC294640, leads to intracellular accumulation of ceramides and induces apoptosis for KSHV-infected PEL cells, while suppressing tumor progression in vivo. In the current study, we sought to …

Bacterially-Based Immune Challenges And Trauma Elicit Terminal Investment In Male Aedes Aegypti, Molly K. Schumacher

Theses and Dissertations

Investment in life history traits such as immune function and reproduction is constrained by finite available resources. A cost-of-immunity trade-off may occur in response to infection when resources are diverted away from reproductive effort and into an immune response. Alternatively, an infected individual may enhance reproductive effort to maximize terminal reproductive success in response to the survival threat inherent to infection (terminal investment). We measured male Aedes aegypti reproductive behavior following inoculations with: living bacteria; killed bacteria as an immune elicitor; and a sham control. Mating competitiveness relative to naïve males was also determined through a binary mate choice experiment …

Levels Of 8-Oxodg Predict Hepatobiliary Pathology In Opisthorchis Viverrini Endemic Settings In Thailand., Prasert Saichua, Anna Yakovleva, Christine Kamamia, Amar R. Jariwala, Paul J. Brindley, Jeffrey M. Bethony, + 8 More

Microbiology, Immunology, and Tropical Medicine Faculty Publications

Opisthorchis viverrini is distinct among helminth infections as it drives a chronic inflammatory response in the intrahepatic bile duct that progresses from advanced periductal fibrosis (APF) to cholangiocarcinoma (CCA). Extensive research shows that oxidative stress (OS) plays a critical role in the transition from chronic O. viverrini infection to CCA. OS also results in the excision of a modified DNA lesion (8-oxodG) into urine, the levels of which can be detected by immunoassay. Herein, we measured concentrations of urine 8-oxodG by immunoassay from the following four groups in the Khon Kaen Cancer Cohort study: (1) O. viverrini negative individuals, (2) …

Ganoderma Lucidum Reduces Obesity In Mice By Modulating The Composition Of The Gut Microbiota, Chih-Jung Chang, Chuan-Sheng Lin, Chia-Chen Lu, Jan Martel, Yun-Fei Ko, David M. Ojcius, Shun-Fu Tseng, Tsung-Ru Wu, Yi-Yuan Margaret Chen, John Ding-E. Young, Hsin-Chih Lai

All Dugoni School of Dentistry Faculty Articles

Obesity is associated with low-grade chronic inflammation and intestinal dysbiosis. Ganoderma lucidum is a medicinal mushroom used in traditional Chinese medicine with putative anti-diabetic effects. Here, we show that a water extract of Ganoderma lucidum mycelium (WEGL) reduces body weight, inflammation and insulin resistance in mice fed a high-fat diet (HFD). Our data indicate that WEGL not only reverses HFD-induced gut dysbiosis—as indicated by the decreased Firmicutes-to-Bacteroidetes ratios and endotoxin-bearing Proteobacteria levels—but also maintains intestinal barrier integrity and reduces metabolic endotoxemia. The anti-obesity and microbiota-modulating effects are transmissible via horizontal faeces transfer from WEGL-treated mice to HFD-fed mice. We further …

Vitamin D As An Adjunctive Therapy In Asthma. Part 1: A Review Of Potential Mechanisms, Conor Kerley, Basil Elnazir, John Faul, Liam Cormican

Articles

Vitamin D deficiency (VDD) is highly prevalent worldwide. The classical role for vitamin D is to regulate calcium absorption form the gastrointestinal tract and influence bone health. Recently vitamin D receptors and vitamin D metabolic enzymes have been discovered in numerous sites systemically supporting diverse extra-skeletal roles of vitamin D, for example in asthmatic disease. Further, VDD and asthma share several common risk factors including high latitude, winter season, industrialization, poor diet, obesity, and dark skin pigmentation. Vitamin D has been demonstrated to possess potent immunomodulatory effects, including effects on T cells and B cells as well as increasing production …

Vitamin D As An Adjunctive Therapy In Asthma. Part 2: A Review Of Human Studies, Conor Kerley, Basil Elnazir, John Faul, Liam Cormican

Articles

Vitamin D deficiency (VDD) is highly prevalent worldwide, with adverse effects on bone health but also potentially other unfavorable consequences. VDD and asthma-incidence/severity share many common risk factors, including winter season, industrialization, poor diet, obesity, dark skin pigmentation, and high latitude. Multiple anatomical areas relevant to asthma contain both the enzyme responsible for producing activated vitamin D and the vitamin D receptor suggesting that activated vitamin D (1,25- dihydroxyvitamin D) may have important local effects at these sites. Emerging evidence suggests that VDD is associated with increased airway hyperresponsiveness, decreased pulmonary function, worse asthma control, and possibly decreased response to …

Regulation Of Phosphatidylinositol 4-Kinase Iii Alpha Complex Formation In B Cells And Its Role In Autoantibody Production, Michaela M. Sangillo Ms

All Student Scholarship

The plasma membrane protein Efr3b, the Tetratricopeptide domain repeat 7 (Ttc7), and the kinase phosphatidylinositol 4-kinase III alpha (PI4KIIIa) are found to form a complex a the plasma membrane. This complex is thought to play a role regulating the PI4P pools at the plasma membrane, which is imperative to membrane identity and vesicle transport.

Use Of Immunotherapy In The Treatment Of Peanut Allergies In The Pediatric Population, Bethany Rauscher

Senior Honors Theses

Peanut allergies are a serious issue that must be monitored and treated effectively to avoid severe adverse effects and death. In the last decade, their incidence has increased significantly, due to indeterminate factors. Because people typically do not outgrow peanut allergies and the effects of exposure can be life-threatening, it is important that a cure or management method is developed and refined. Recent research regarding treatment for peanut allergies has focused on the use of immunotherapy, a process aimed at desensitizing children's immune systems so that they do not reject foods that contain peanuts. Some studies utilizing immunotherapy have provided …

Nonreplicating, Cyst-Defective Type Ii Toxoplasma Gondii Vaccine Strains Stimulate Protective Immunity Against Acute And Chronic Infection, Barbara Andrea Fox, David J. Bzik

Dartmouth Scholarship

Live attenuated vaccine strains, such as type I nonreplicating uracil auxotroph mutants, are highly effective in eliciting lifelong immunity to virulent acute infection by Toxoplasma gondii. However, it is currently unknown whether vaccine-elicited immunity can provide protection against acute infection and also prevent chronic infection. To address this problem, we developed nonreverting, nonreplicating, live attenuated uracil auxotroph vaccine strains in the type II Δku80 genetic background by targeting the deletion of the orotidine 5′-monophosphate decarboxylase (OMPDC) and uridine phosphorylase (UP) genes. Deletion of OMPDC induced a severe uracil auxotrophy with loss of replication, loss of …

A Cohort Study Investigating Autoantibody Levels During And After Infection With Influenza A Virus, Michelle Collins

All NMU Master's Theses

Antinuclear autoantibodies (ANAs) are present in all individuals. In those with autoimmune diseases they are routinely present in elevated levels. Although the nature and development of autoimmune diseases are not fully understood there are many hypotheses as to possible causes of an autoimmune disorder. One possible cause is viral infections. The scope of this thesis study was to examine if autoantibodies levels in individuals without autoimmune disorders increase during or after infection with influenza A virus. Blood was collected from volunteers (n=11) at time intervals of 0, 7, 42 and 63 days, respectively. Antibody levels were measured using ELISA assays …

Reverse Genetics Of Mononegavirales: How They Work, New Vaccines, And New Cancer Therapeutics., Christian K Pfaller, Roberto Cattaneo, Matthias J. Schnell

Department of Microbiology and Immunology Faculty Papers

The order Mononegavirales includes five families: Bornaviridae, Filoviridae, Nyamaviridae, Paramyxoviridae, and Rhabdoviridae. The genome of these viruses is one molecule of negative-sense single strand RNA coding for five to ten genes in a conserved order. The RNA is not infectious until packaged by the nucleocapsid protein and transcribed by the polymerase and co-factors. Reverse genetics approaches have answered fundamental questions about the biology of Mononegavirales. The lack of icosahedral symmetry and modular organization in the genome of these viruses has facilitated engineering of viruses expressing fluorescent proteins, and these fluorescent proteins have provided important insights about the molecular and cellular …

Killer Cell Activation By A Novel Multifunctional Protein: An Immuno/Gene Therapy For Cancer, Ashlee Tietje

All Dissertations

One of the characteristics of advanced tumors is the evasion of the immune system. There are multiple methods that tumor cells employ to achieve this including reducing the expression of activating ligands on the cell surface and a shift in the tumor microenvironment toward pro-tumor cytokines. The purpose of this research is to develop a novel bifunctional fusion protein that will target these two deficiencies in the tumor microenvironment and activate killer cells that are already present. The proposed protein combines the extracellular domain of a ligand for the killer cell activating receptor NKG2D and Interleukin-12 (IL-12). It is hypothesized …

Immune Reconstitution But Persistent Activation After 48 Weeks Of Antiretroviral Therapy In Youth With Pre-Therapy Cd4 >350 In Atn 061., Bret J. Rudy, Bill G. Kapogiannis, Carol Worrell, Kathleen E. Squires, James Bethel, Su Li, Craig M. Wilson, Allison Agwu, Patricia Emmanuel, Georgine Price, Stephanie Hudey, Maureen M. Goodenow, John W. Sleasman

Department of Medicine Faculty Papers

BACKGROUND: Measures of immune outcomes in youth who initiate combination antiretroviral therapy (cART) early in HIV infection are limited.

DESIGN: Adolescent Trials Network 061 examined changes over 48 weeks of cART in T-cell subsets and markers of T-cell and macrophage activation in subjects with pre-therapy CD4 > 350 cells/mm. All subjects had optimal viral suppression from weeks 24 through 48.

METHODS: Subjects (n = 48) initiated cART with tenofovir/emtricitabine plus ritonavir-boosted atazanavir. Data were collected at baseline and weeks 12, 24, and 48. Trends were compared to uninfected controls.

RESULTS: Significant increases over 48 weeks were noted in all CD4 populations, …

Site-Specific Immunomodulator: A Novel Treatment For Crohn's Disease, Brian Bressler, Kevin P. Bethel, Ralf Kleef, Sophie L. Reynolds, Simon Sutcliffe, David W. Mullins, Hal Gunn

Dartmouth Scholarship

We investigated the mechanism of action, safety, and efficacy of the Site-Specific Immunomodulator (SSI) QBECO, a novel immunotherapy for Crohn’s disease (CD). Using human monocytic THP-1 cells, we demonstrate that SSI QBECO (derived from the common colon bacteria E. coli) activates macrophages to an M1 phenotype (associated with enhanced capacity to eliminate bacteria and activate innate immune responses). We assessed SSI QBECO in a compassionate use protocol of ten adult patients with active CD. Patients with moderate to severe clinical symptoms receiving conventional CD treatments and/or complementary therapies were included, except patients receiving anti-TNF medications. SSI QBECO was self-administered subcutaneously …

A Microrna Profile Associated With Opisthorchis Viverrini-Induced Cholangiocarcinoma In Tissue And Plasma., Jordan Plieskatt, Gabriel Rinaldi, Yanjun Feng, Jin Peng, Samantha Easley, Xinying Jia, Jeremy Potriquet, Chawalit Pairojkul, Vajarabhongsa Bhudhisawasdi, Banchob Sripa, Paul J Brindley, Jeffrey Bethony, Jason Mulvenna

Microbiology, Immunology, and Tropical Medicine Faculty Publications

Background

Intrahepatic cholangiocarcinoma (ICC) is a highly aggressive tumor of the bile duct, and a significant public health problem in East Asia, where it is associated with infection by the parasiteOpisthorchis viverrini. ICC is often detected at an advanced stage and with a poor prognosis, making a biomarker for early detection a priority.

Methods

We have comprehensively profiled miRNA expression levels in ICC tumor tissue using small RNA-Seq and validated these profiles using quantitative PCR on matched plasma samples.

Results

Distinct miRNA profiles were associated with increasing histological differentiation of ICC tumor tissue. We also observed that histologically …

Early Inflammatory Mediator Gene Expression In Two Models Of Traumatic Brain Injury: Ex Vivo Cortical Slice In Mice And In Vivo Cortical Impact In Piglets, David J. Graber, Beth A. Costine, William F. Hickey

Dartmouth Scholarship

Background: The immunological response during the first 24 hours after traumatic brain injury (TBI) may be a critical therapeutic interval for limiting the secondary neuronal damage that is influenced by enhanced inflammatory mediator expression.

Methods: To gain further insight of the early injury response, we examined the expression of several inflammatory genes by real-time qPCR as a function of time or distance from injury in two distinct mammalian models: an ex vivo mouse cortical slice injury system and an in vivo piglet model of brain injury.

Opisthorchiasis: An Overlooked Danger, Ludmila M. Ogorodova, Olga S. Fedorova, Banchob Sripa, Viatcheslav A. Mordvinov, Aleksei V. Katokhin, Paul J. Brindley, The Topic Consortium

Microbiology, Immunology, and Tropical Medicine Faculty Publications

No abstract provided.

Opisthorchiasis: An Overlooked Danger., Ludmila M Ogorodova, Olga S Fedorova, Banchob Sripa, Viatcheslav A Mordvinov, Aleksei V Katokhin, Jennifer Keiser, Peter Odermatt, Paul J. Brindley, Oleg A Mayboroda, Thirumalaisamy P Velavan, Maxim B Freidin, Alexey E Sazonov, Irina V Saltykova, Mariya Y Pakharukova, Yulia V Kovshirina, Kostas Kaloulis, Olga Y Krylova, Maria Yazdanbakhsh

Microbiology, Immunology, and Tropical Medicine Faculty Publications

No abstract provided.

C-Anca Positive Necrotizing Crescentic Glomerulonephritis With Linear Immunoglobulin Staining, Akshita Mehta

GW Research Days 2015

Necrotizing crescentic glomerulonephritis is found in anti-glomerular basement membrane (GBM) disease (Type 1), immune complex (Type 2) deposition and anti-neutrophil cytoplasmic (ANCA)-related disease (Type 3).

ANCA positive glomerulonephritis is typically characterized on renal biopsy as pauci-immune, with mild or absent glomerular staining for immunoglobulin, or complement staining by immunofluorescence.

Rare cases of concomitant p-ANCA plus linear immunofluorescence pattern staining have been discussed, however none with prior association with c-ANCA.

We report a case of systemic c-ANCA pulmonary-renal syndrome with anti-GBM-disease-typical linear staining on renal biopsy immunofluorescence.

Apparent Role For Borrelia Burgdorferi Luxs During Mammalian Infection, William K. Arnold, Christina R. Savage, Alyssa D. Antonicello, Brian Stevenson

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The Lyme disease spirochete, Borrelia burgdorferi, controls protein expression patterns during its tick-mammal infection cycle. Earlier studies demonstrated that B. burgdorferi synthesizes 4,5-dihydroxy-2,3-pentanedione (autoinducer-2 [AI-2]) and responds to AI-2 by measurably changing production of several infection-associated proteins. luxS mutants, which are unable to produce AI-2, exhibit altered production of several proteins. B. burgdorferi cannot utilize the other product of LuxS, homocysteine, indicating that phenotypes of luxS mutants are not due to the absence of that molecule. Although a previous study found that a luxS mutant was capable of infecting mice, a critical caveat to those results is that bacterial …

Aggregatibacter Actinomycetemcomitans Cytolethal Distending Toxin Activates The Nlrp3 Inflammasome In Human Macrophages Leading To The Release Of Pro-Inflammatory Cytokines, Bruce J. Shenker, David M. Ojcius, Lisa P. Walker, Ali Zekavat, Monika Damek Scuron, Kathleen Boesze-Battaglia

All Dugoni School of Dentistry Faculty Articles

The cytolethal distending toxin (Cdt) is produced from a number of bacteria capable of causing infection and inflammatory disease. Our previous studies with Actinobacillus actinomycetemcomitans Cdt demonstrate not only that the active toxin subunit functions as a phosphatidylinositol-3,4,5-triphosphate (PIP3) phosphatase but also that macrophages exposed to the toxin were stimulated to produce proinflammatory cytokines. We now demonstrate that the Cdt-induced proinflammatory response involves the activation of the NLRP3 inflammasome. Specific inhibitors and short hairpin RNA (shRNA) were employed to demonstrate requirements for NLRP3 and ASC as well as caspase-1. Furthermore, Cdt-mediated inflammasome activation is dependent upon upstream signals, including reactive …