Spotlight
Minireview
MinireviewUnraveling the Role of MicroRNAs in Mycobacterium tuberculosis Infection and Disease: Advances and PitfallsTuberculosis (TB) is an infectious disease of extremely high epidemiological burden worldwide that is easily acquired through the inhalation of infected respiratory droplets. The complex pathogenesis of this infection spans from subjects never developing this disease despite intense exposure, to others in which immune containment fails catastrophically and severe or disseminated forms of disease ensue.
Molecular Pathogenesis
Molecular PathogenesisThe Staphylococcus aureus Cystine Transporters TcyABC and TcyP Facilitate Nutrient Sulfur Acquisition during InfectionStaphylococcus aureus is a significant human pathogen due to its capacity to cause a multitude of diseases. As such, S. aureus efficiently pillages vital nutrients from the host; however, the molecular mechanisms that support sulfur acquisition during infection have not been established. One of the...
Molecular Pathogenesis | SpotlightThe Manganese-Responsive Transcriptional Regulator MumR Protects Acinetobacter baumannii from Oxidative StressAcinetobacter baumannii is an emerging opportunistic pathogen that primarily infects critically ill patients in nosocomial settings. Because of its rapid acquisition of antibiotic resistance, infections caused by A. baumannii have become extremely difficult to treat, underlying the importance of...
Molecular PathogenesisMechanical Stimuli Affect Escherichia coli Heat-Stable Enterotoxin-Cyclic GMP Signaling in a Human Enteroid Intestine-Chip ModelModeling host-pathogen interactions with human intestinal epithelia using enteroid monolayers on permeable supports (such as Transwells) represents an alternative to animal studies or use of colon cancer-derived cell lines. However, the static monolayer model does not expose epithelial cells to mechanical forces normally present in the intestine, including luminal flow and serosal blood flow (shear force) or peristaltic forces.
...
Molecular PathogenesisRegulation of OmpA Translation and Shigella dysenteriae Virulence by an RNA ThermometerRNA thermometers are cis-acting riboregulators that mediate the posttranscriptional regulation of gene expression in response to environmental temperature. Such regulation is conferred by temperature-responsive structural changes within the RNA thermometer that directly result in differential ribosomal binding to the regulated transcript. The significance of RNA thermometers in controlling bacterial physiology and pathogenesis...
Molecular PathogenesisThe Invasion Plasmid Antigen J (IpaJ) from Salmonella Inhibits NF-κB Activation by Suppressing IκBα UbiquitinationSalmonella enterica serovar Pullorum is the pathogen of pullorum disease, which leads to severe economic losses in many developing countries. In contrast to the strong inflammatory response induced by Salmonella enterica serovar Typhimurium and...
Molecular Pathogenesis | SpotlightTwin-Arginine Translocation System Is Involved in Citrobacter rodentium Fitness in the Intestinal TractThe twin-arginine translocation (Tat) system is involved in not only a wide array of cellular processes but also pathogenesis in many bacterial pathogens; thus, this system is expected to become a novel therapeutic target to treat infections. To the best of our knowledge, involvement of the Tat system has not been reported in the gut infection caused by Citrobacter rodentium...
Molecular PathogenesisVibrio cholerae OmpR Represses the ToxR Regulon in Response to Membrane Intercalating Agents That Are Prevalent in the Human Gastrointestinal TractMultidrug efflux systems belonging to the resistance-nodulation-division (RND) superfamily are ubiquitous in Gram-negative bacteria. RND efflux systems are often associated with multiple antimicrobial resistance and also contribute to the expression of diverse bacterial phenotypes including virulence, as documented in the intestinal pathogen Vibrio cholerae, the...
Molecular PathogenesisVibrio cholerae Virulence Activator ToxR Regulates Manganese Transport and Resistance to Reactive Oxygen SpeciesLike many other pathogens, Vibrio cholerae, the causative agent of cholera, can modulate its gene expression to combat stresses encountered in both aquatic and host environments, including stress posed by reactive oxygen species (ROS). We previously reported that the virulence activator AphB in V. cholerae...
Cellular Microbiology: Pathogen-Host Cell Molecular Interactions
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsBiogenesis of the Spacious Coxiella-Containing Vacuole Depends on Host Transcription Factors TFEB and TFE3Coxiella burnetii is an obligate intracellular bacterial pathogen that replicates inside the lysosome-derived Coxiella-containing vacuole (CCV). To establish this unique niche, C. burnetii requires the Dot/Icm type IV secretion system (T4SS) to translocate a cohort of effector proteins into...
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsCaspase-4 Mediates Restriction of Burkholderia pseudomallei in Human Alveolar Epithelial CellsMelioidosis is an infectious disease with a high mortality rate responsible for community-acquired sepsis in Southeast Asia and Northern Australia. The causative agent of this disease is Burkholderia pseudomallei, a Gram-negative bacterium that resides in soil and contaminated natural water. After entering into host cells, the bacteria escape into the cytoplasm, which...
Bacterial Infections
Bacterial InfectionsRedundant and Cooperative Roles for Yersinia pestis Yop Effectors in the Inhibition of Human Neutrophil Exocytic Responses Revealed by Gain-of-Function ApproachYersinia pestis causes a rapid, lethal disease referred to as plague. Y. pestis actively inhibits the innate immune system to generate a noninflammatory environment during early stages of infection to promote colonization. The ability of...
Host Response and Inflammation
Host Response and InflammationImmunosuppression in Cows following Intramammary Infusion of Mycoplasma bovisMycoplasma bovis is a destructive pathogen that causes large economic losses in rearing cattle for beef and dairy worldwide. M. bovis causes suppression of and evades the host immune response; however, the mechanisms of host immune function involved in...
Host Response and InflammationSurvival of Streptococcus suis in Porcine Blood Is Limited by the Antibody- and Complement-Dependent Oxidative Burst Response of GranulocytesBacteremia is a hallmark of invasive Streptococcus suis infections of pigs, often leading to septicemia, meningitis, or arthritis. An important defense mechanism of neutrophils is the generation of reactive oxygen species (ROS). In this study, we report high levels of ROS production by blood granulocytes after intravenous infection of a pig with high levels of...
Host Response and InflammationWhipworm Infection Promotes Bacterial Invasion, Intestinal Microbiota Imbalance, and Cellular ImmunomodulationInfections with Trichuris trichiura are among the most common causes of intestinal parasitism in children worldwide, and the diagnosis is based on microscopic egg identification in the chronic phase of the infection. During parasitism, the adult worm of the trichurid nematode maintains its anterior region inserted in the intestinal mucosa, which causes serious damage...
Host Response and InflammationIn Vivo Imaging of the Buccal Mucosa Shows Loss of the Endothelial Glycocalyx and Perivascular Hemorrhages in Pediatric Plasmodium falciparum MalariaSevere malaria is mostly caused by Plasmodium falciparum, resulting in considerable, systemic inflammation and pronounced endothelial activation. The endothelium forms an interface between blood and tissue, and vasculopathy has previously been linked with malaria severity. We studied the extent to which the endothelial glycocalyx that normally maintains endothelial...
Host Response and InflammationPD-1 Expression on NK Cells in Malaria-Exposed Individuals Is Associated with Diminished Natural Cytotoxicity and Enhanced Antibody-Dependent Cellular CytotoxicityNatural killer (NK) cells are key effector cells of innate resistance capable of destroying tumors and virus-infected cells through cytotoxicity and rapid cytokine production. The control of NK cell responses is complex and only partially understood. PD-1 is an inhibitory receptor that regulates T cell function, but a role for PD-1 in regulating NK cell function is only beginning to emerge.
Host Response and InflammationProfiles of Local and Systemic Inflammation in the Outcome of Treatment of Human Cutaneous Leishmaniasis Caused by Leishmania (Viannia)The immune mechanisms that contribute to the efficacy of treatment of cutaneous leishmaniasis (CL) are not fully understood. The aim of this study was to define immune correlates of the outcome of treatment of CL caused by Leishmania (Viannia) species during standard of care treatment with pentavalent antimonials.
Host Response and InflammationB Cell Compartmentalization in Blood and Cerebrospinal Fluid of HIV-Infected Ugandans with Cryptococcal MeningitisActivated B cells modulate infection by differentiating into pathogen-specific antibody-producing effector plasmablasts/plasma cells, memory cells, and immune regulatory B cells. In this context, the B cell phenotypes that infiltrate the central nervous system during human immunodeficiency virus (HIV) and cryptococcal meningitis coinfection are ill defined.
Host Response and InflammationInflammatory Monocytes and Neutrophils Regulate Streptococcus suis-Induced Systemic Inflammation and Disease but Are Not Critical for the Development of Central Nervous System Disease in a Mouse Model of InfectionStreptococcus suis is an important porcine bacterial pathogen and zoonotic agent responsible for sudden death, septic shock, and meningitis. These pathologies are a consequence of elevated bacterial replication leading to exacerbated and uncontrolled inflammation, a hallmark of the S. suis systemic...
Host Response and InflammationDifference in Strain Pathogenicity of Septicemic Yersinia pestis Infection in a TLR2−/− Mouse ModelYersinia pestis is the causative agent of bubonic, pneumonic, and septicemic plague. We demonstrate that Toll-like receptor 2-deficient (TLR2−/−) mice are resistant to septicemic infection by the KIM5 strain of Y. pestis but not to infection by the CO92 Δpgm strain. This...
Host Response and InflammationElevated Levels of Interleukin-27 in Early Life Compromise Protective Immunity in a Mouse Model of Gram-Negative Neonatal SepsisNeonates are at increased risk for bacterial sepsis. We established that the immune-suppressive cytokine interleukin-27 (IL-27) is elevated in neonatal mice. Similarly, human cord blood-derived macrophages express IL-27 genes and secrete more cytokine than macrophages from adults. In the present work, we hypothesized that increased levels of IL-27 predispose neonatal mice to more severe infection during Gram-negative sepsis. Serum IL-27...
Host Response and InflammationProprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) Is Not Induced in Artificial Human Inflammation and Is Not Correlated with Inflammatory ResponseLipoproteins, as well as proprotein convertase subtilisin/kexin type 9 (PCSK9), have been shown to play a key role in the innate immune response. However, knowledge about the role and kinetics of PCSK9 in human inflammation is currently insufficient. This study aimed to investigate the interaction between inflammation and lipid metabolism, including the possible role of PCSK9. A single-blinded, placebo-controlled cross-over study using...
Fungal and Parasitic Infections
Fungal and Parasitic InfectionsPathways That Synthesize Phosphatidylethanolamine Impact Candida albicans Hyphal Length and Cell Wall Composition through Transcriptional and Posttranscriptional Mechanisms...Candida albicans is a leading cause of systemic bloodstream infections, and synthesis of the phospholipid phosphatidylethanolamine (PE) is required for virulence. The psd1Δ/Δ psd2Δ/Δ mutant, which cannot synthesize PE by the cytidine diphosphate diacylglycerol (CDP-DAG) pathway, is avirulent in the mouse model of systemic candidiasis.
Fungal and Parasitic InfectionsInterleukin-4 Signaling Plays a Major Role in Urogenital Schistosomiasis-Associated Bladder PathogenesisInterleukin-4 (IL-4) is crucial in many helminth infections, but its role in urogenital schistosomiasis, infection with Schistosoma haematobium worms, remains poorly understood due to a historical lack of animal models. The bladder pathology of urogenital schistosomiasis is caused by immune responses to eggs deposited in the bladder wall. A range of pathology occurs,...
Fungal and Parasitic InfectionsContribution of Laccase Expression to Immune Response against Cryptococcus gattii InfectionCryptococcosis is an infectious disease caused by two fungal species, Cryptococcus neoformans and Cryptococcus gattii. While C. neoformans affects mainly immunocompromised patients,...
Microbial Immunity and Vaccines
Microbial Immunity and VaccinesVaccine-Specific Immune Responses against Mycobacterium ulcerans Infection in a Low-Dose Murine Challenge ModelThe neglected tropical disease Buruli ulcer (BU) is an infection of subcutaneous tissue with Mycobacterium ulcerans. There is no effective vaccine. Here, we assessed an experimental prime-boost vaccine in a low-dose murine tail infection model. We used the enoyl reductase (ER) domain of the M. ulcerans...
Microbial Immunity and Vaccines | SpotlightMajor Histocompatibility Complex Class II-Restricted, CD4+ T Cell-Dependent and -Independent Mechanisms Are Required for Vaccine-Induced Protective Immunity against Coxiella burnetiiTo understand the role of major histocompatibility complex class I (MHC-I) and MHC-II in vaccine-mediated protection against Coxiella burnetii, we evaluated the protective efficacy of a formalin-inactivated C. burnetii Nine Mile phase I vaccine (PIV) in β2-microglobulin-deficient (B2m KO...
Microbial Immunity and Vaccines | SpotlightClostridioides difficile Infection Induces an Inferior IgG Response to That Induced by Immunization and Is Associated with a Lack of T Follicular Helper Cell and Memory B Cell ExpansionThe intracellularly active bacterial toxin TcdB is a major Clostridioides difficile virulence factor that contributes to inflammation and tissue damage during disease. Immunization with an inactive TcdB fragment prevents C. difficile infection (CDI)-associated pathology. The protective immune...
Host-Associated Microbial Communities
Host-Associated Microbial CommunitiesEvasion of Innate Lymphoid Cell-Regulated Gamma Interferon Responses by Chlamydia muridarum To Achieve Long-Lasting Colonization in Mouse ColonRevealing the mechanisms by which bacteria establish long-lasting colonization in the gastrointestinal tract is an area of intensive investigation. The obligate intracellular bacterium Chlamydia is known to colonize mouse colon for long periods. A colonization-deficient mutant strain of this intracellular bacterium is able to regain long-lasting colonization in gamma interferon (IFN-γ) knockout mice following intracolon...
Host-Associated Microbial CommunitiesThe Cryptic Plasmid Improves Chlamydia Fitness in Different Regions of the Gastrointestinal TractThe cryptic plasmid is important for chlamydial colonization in the gastrointestinal tract. We used a combination of intragastric, intrajejunal, and intracolon inoculations to reveal the impact of the plasmid on chlamydial colonization in distinct regions of gastrointestinal tract. Following an intragastric inoculation, the plasmid significantly improved chlamydial colonization. At the tissue level, plasmid-positive Chlamydia...
Masthead
NEW! ASM Open Data Policy
Current Issue
About IAI
Infection and Immunity® (IAI) reports key discoveries that help microbiologists, immunologists, epidemiologists, pathologists, and clinicians to gain new insights into the underlying mechanisms of host-pathogen interactions and develop novel strategies to prevent or treat infectious diseases.