innate immunity
Editor's Pick Research Article | Host-Microbe BiologySimian Immunodeficiency Virus Infection of Rhesus Macaques Results in Delayed Zika Virus ClearanceImmunocompromised individuals often become symptomatic with infections which are normally fairly asymptomatic in healthy individuals. The particular mechanisms that underlie susceptibility to coinfections in human immunodeficiency virus (HIV)-infected individuals are multifaceted. ZIKV and other flaviviruses are sensitive to neutralizing antibodies, whose production can be limited in HIV-infected individuals but are also sensitive to...
Research Article | Host-Microbe BiologyIRG1 and Inducible Nitric Oxide Synthase Act Redundantly with Other Interferon-Gamma-Induced Factors To Restrict Intracellular Replication of Legionella pneumophilaLegionella pneumophila is one example among many species of pathogenic bacteria that replicate within mammalian macrophages during infection. The immune signaling factor interferon gamma (IFN-γ) blocks L. pneumophila replication in macrophages and is an essential component of the immune response to...
Research Article | Host-Microbe BiologyBacterial Pathogens Hijack the Innate Immune Response by Activation of the Reverse Transsulfuration PathwayMacrophages are professional immune cells that ingest and kill microbes. In this study, we show that different pathogenic bacteria induce the expression of cystathionine γ-lyase (CTH) in macrophages. This enzyme is involved in a metabolic pathway called the reverse transsulfuration pathway, which leads to the production of numerous metabolites, including cystathionine. Phagocytized bacteria use cystathionine to better survive in...
Research Article | Applied and Environmental ScienceThe Ancestral N-Terminal Domain of Big Defensins Drives Bacterially Triggered Assembly into Antimicrobial Nanonetsβ-Defensins are host defense peptides controlling infections in species ranging from humans to invertebrates. However, the antimicrobial activity of most human β-defensins is impaired at physiological salt concentrations. We explored the properties of big defensins, the β-defensin ancestors, which have been conserved in a number of marine organisms, mainly mollusks. By focusing on a big defensin from oyster (Cg-BigDef1), we...
Research Article | Host-Microbe BiologyInterferon-Induced Protein 44 Interacts with Cellular FK506-Binding Protein 5, Negatively Regulates Host Antiviral Responses, and Supports Virus ReplicationInnate immune responses mediated by IFN and inflammatory cytokines are critical for controlling virus replication. Nevertheless, exacerbated innate immune responses could be detrimental for the host and feedback mechanisms are needed to maintain the cellular homeostasis. In this work, we describe a completely novel function for IFI44 in negatively modulating the innate immune responses induced after viral infections. We show that...
Editor's Pick Research Article | Host-Microbe BiologyStable Occupancy of the Crimean-Congo Hemorrhagic Fever Virus-Encoded Deubiquitinase Blocks Viral InfectionCrimean-Congo hemorrhagic fever virus is an important human pathogen with a wide global distribution for which no therapeutic interventions are available. CCHFV encodes a cysteine protease belonging to the ovarian tumor (OTU) family which is involved in host immune suppression. Here we demonstrate that artificially prolonged binding of the OTU to a substrate inhibits virus infection. This provides novel insights into CCHFV OTU function...
Research Article | Host-Microbe BiologyCharge-Mediated Pyrin Oligomerization Nucleates Antiviral IFI16 Sensing of Herpesvirus DNAThe ability of mammalian cells to detect the genomes of nuclear-replicating viruses via cellular DNA sensors is fundamental to innate immunity. Recently, mounting evidence is supporting the universal role of polymerization in these host defense factors as a signal amplification strategy. Yet, what has remained unclear are the intrinsic properties that govern their immune signal transmission. Here, we uncover the biochemical basis for...
Research Article | Host-Microbe BiologyToxoplasma gondii Parasitophorous Vacuole Membrane-Associated Dense Granule Proteins Orchestrate Chronic Infection and GRA12 Underpins Resistance to Host Gamma InterferonToxoplasma gondii cysts reactivate during immune deficiency and cause fatal encephalitis. Parasite molecules that coordinate the development of acute and chronic infection are poorly characterized. Here, we show that many intravacuolar network membrane and parasitophorous vacuole membrane-associated dense granule (GRA) proteins orchestrate the development of chronic...
Research Article | Host-Microbe BiologyIntravital Imaging Reveals Divergent Cytokine and Cellular Immune Responses to Candida albicans and Candida parapsilosisIn modern medicine, physicians are frequently forced to balance immune suppression against immune stimulation to treat patients such as those undergoing transplants and chemotherapy. More-targeted therapies designed to preserve immunity and prevent opportunistic fungal infection in these patients could be informed by an understanding of how fungi interact with professional and nonprofessional immune cells in mucosal candidiasis. In this...
Research Article | Host-Microbe BiologySerum Amyloid P Component Binds Fungal Surface Amyloid and Decreases Human Macrophage Phagocytosis and Secretion of Inflammatory CytokinesMacrophages are a key part of our innate immune system and are responsible for recognizing invading microbes, ingesting them, and sending appropriate signals to other immune cells. We have found that human macrophages can recognize invading yeast pathogens that have a specific molecular pattern of proteins on their surfaces: these proteins have structures similar to the structures of amyloid aggregates in neurodegenerative diseases like...