is a human-restricted bacteria that is a normal nasopharyngeal resident, yet it can also disseminate, causing invasive meningococcal disease. Meningococci are highly adapted to life in humans, with human-specific virulence factors contributing to bacterial adhesion, nutrient acquisition and immune evasion. While these factors have been explored in isolation, their relative contribution during infection has not been considered due to their absence in small animal models and their expression by different human cell types not readily combined in either or systems.
View Article and Find Full Text PDFThe type IV secretion system (-T4SS) of exploits specific cellular carcinoembryonic antigen-related cell adhesion molecules (CEACAMs), such as CEACAM1, -3, -5, and -6, as cellular receptors for CagA translocation into human gastric epithelial cells. We studied the interaction of with human CEACAM1, CEACAM3, and CEACAM6 receptors (hCEACAMs) expressed on myeloid cells from CEACAM-humanized mice. Human and CEACAM-humanized mouse polymorphonuclear neutrophils (PMNs) allowed a specific HopQ-dependent interaction strongly enhancing CagA translocation.
View Article and Find Full Text PDFDysbiosis of the gut microbiome, including elevated abundance of putative leading bacterial triggers such as in inflammatory bowel disease (IBD) patients, is of great interest. To date, most studies in IBD patients are focused on clinical isolates, overlooking their relative abundances and turnover over time. Metagenomics-based studies, on the other hand, are less focused on strain-level investigations.
View Article and Find Full Text PDFThe gonococcal Opa proteins are an antigenically variable family of surface adhesins that bind human carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1), CEACAM3, CEACAM5, and/or CEACAM6, cell surface glycoproteins that are differentially expressed on a broad spectrum of human cells and tissues. While they are presumed to be important for infection, the significance of various Opa-CEACAM-mediated cellular interactions in the context of the genital tract has remained unclear. Here, we observed that CEACAM1 and CEACAM5 are differentially expressed on epithelia lining the upper and lower portions of the human female genital tract, respectively.
View Article and Find Full Text PDFListeria monocytogenes is a common foodborne bacterial pathogen that contaminates plant and animal consumable products. The persistent nature of L. monocytogenes is associated with millions of dollars in food recalls annually.
View Article and Find Full Text PDFHost recognition of pathogen-associated molecular patterns (PAMPs) initiates an innate immune response that is critical for pathogen elimination and engagement of adaptive immunity. Here we show that mammalian cells can detect and respond to the bacterial-derived monosaccharide heptose-1,7-bisphosphate (HBP). A metabolic intermediate in lipopolysaccharide biosynthesis, HBP is highly conserved in Gram-negative bacteria, yet absent from eukaryotic cells.
View Article and Find Full Text PDFObjective: To evaluate if systemic murine malarial infection enhances HIV susceptibility through parasite-induced mucosal immune alterations at sites of HIV sexual exposure.
Background: Malaria and HIV have a high degree of geographical overlap and interact substantially within coinfected individuals. We used a murine model to test the hypothesis that malaria might also enhance HIV susceptibility at mucosal sites of HIV sexual exposure.
The bacterial pathogen Listeria monocytogenes causes serious food-borne illnesses in pregnant women and the immunocompromised. L. monocytogenes promotes its internalization into host epithelial cells and then uses an F-actin-dependent motility process to spread from infected cells to surrounding healthy cells.
View Article and Find Full Text PDFAdherent-invasive Escherichia coli (AIEC) is a pathogen isolated from the ileum of patients with Crohn disease. IFNγ is a key mediator of immunity, which regulates inflammatory responses to microbial infections. Previously, we showed enterohemorrhagic E.
View Article and Find Full Text PDFCarcinoembryonic antigen-related cell adhesion molecule 1 (CC1) is a cell adhesion molecule within the Ig superfamily. The Tyr-phosphorylated isoform of CC1 (CC1-L) plays an important metabolic role in the regulation of hepatic insulin clearance. In this report, we show that CC1-deficient (Cc1(-/-)) mice are prone to hepatic steatosis, as revealed by significantly elevated hepatic triglyceride and both total and esterified cholesterol levels compared with age-matched wild-type controls.
View Article and Find Full Text PDFThe CEACAM1 cell adhesion molecule is a member of the carcinoembryonic antigen family. In the mouse, four distinct isoforms are generated by alternative splicing. These encode either two or four immunoglobulin domains linked through a transmembrane domain to a cytoplasmic domain that encompasses either a short 10-amino acid tail or a longer one of 73 amino acids.
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