Browsing by Author "Bruns, Heather A."

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Host cell invasion by Staphylococcus aureus stimulates the shedding of microvesicles
    (Elsevier B.V., 2013-03-22) DeWalt, Robin I.; Petkovich, Daniel A.; Zahrt, Ashley N.; Bruns, Heather A.; McDowell, Susan A.; Department of Medicine, IU School of Medicine
    During severe sepsis, microvesicles that are positive for tissue factor (TF) are at increased levels within blood and in pulmonary lavage. These microvesicles potentially disperse TF, the major initiator of the coagulation cascade, throughout multiple organ systems, initiating fibrin deposition and resultant ischemia. The source of these microvesicles has remained incompletely defined. Although TF+ microvesicles are shed from cells that express nascent TF transcript in response to injury, recent findings revealed that circulating, full-length TF protein is detectable prior to these nascent transcripts. This finding suggested that the protein is released from constitutive sources as an acute response. We examined whether Staphylococcus aureus, the Gram-positive bacteria that is emerging as one of the most common etiologic agents in sepsis, is capable of stimulating the release of TF+ microvesicles from a pulmonary cell line that constitutively expresses TF protein. We found that host cell invasion stimulated an acute release of TF+ microvesicles and that these microvesicles mediated the transfer of the protein to TF-negative endothelial cells. We also found that transfer was inhibited by cholesterol-lowering simvastatin. Taken together, our findings reveal that S. aureus pathogenesis extends to the acute release of TF+ microvesicles and that inhibiting dispersal by this mechanism may provide a therapeutic target.
  • Thumbnail Image
    Item
    Th17 cells demonstrate stable cytokine production in a proallergic environment
    (The American Association of Immunologists, 2014-09-15) Glosson-Byers, Nicole L.; Sehra, Sarita; Stritesky, Gretta L.; Yu, Qing; Awe, Olufolakemi; Pham, Duy; Bruns, Heather A.; Kaplan, Mark H.; Department of Pediatrics, IU School of Medicine
    Th17 cells are critical for the clearance of extracellular bacteria and fungi, but also contribute to the pathology of autoimmune diseases and allergic inflammation. After exposure to an appropriate cytokine environment, Th17 cells can acquire a Th1-like phenotype, but less is known about their ability to adopt Th2 and Th9 effector programs. To explore this in more detail, we used an IL-17F lineage tracer mouse strain that allows tracking of cells that formerly expressed IL-17F. In vitro-derived Th17 cells adopted signature cytokine and transcription factor expression when cultured under Th1-, Th2-, or Th9-polarizing conditions. In contrast, using two models of allergic airway disease, Th17 cells from the lungs of diseased mice did not adopt Th1, Th2, or Th9 effector programs, but remained stable IL-17 secretors. Although in vitro-derived Th17 cells expressed IL-4Rα, those induced in vivo during allergic airway disease did not, possibly rendering them unresponsive to IL-4-induced signals. However, in vitro-derived, Ag-specific Th17 cells transferred in vivo to OVA and aluminum hydroxide-sensitized mice also maintained IL-17 secretion and did not produce alternative cytokines upon subsequent OVA challenge. Thus, although Th17 cells can adopt new phenotypes in response to some inflammatory environments, our data suggest that in allergic inflammation, Th17 cells are comparatively stable and retain the potential to produce IL-17. This might reflect a cytokine environment that promotes Th17 stability, and allow a broader immune response at tissue barriers that are susceptible to allergic inflammation.
  • Thumbnail Image
    Item
    The ImmunoSkills Guide: Competencies for undergraduate immunology curricula
    (Public Library of Science, 2024-11-11) Pandey, Sumali; Elliott, Samantha L.; Liepkalns, Justine; Taylor, Rebekah T.; Vanniasinkam, Thiru; Kleinschmit, Adam J.; Justement, Louis B.; Lal, Archana; Condry, Danielle; Bruns, Heather A.; Paustian, Timothy; Mixter, Philip F.; Sparks-Thissen, Rebecca L.; Sletten, Sarah; Wisenden, Brian D.; Microbiology and Immunology, School of Medicine
    Immune literacy garnered significant attention in recent years due to the threat posed by emerging infectious diseases. The pace of immunological discoveries and their relevance to society are substantial yet coordinated educational efforts have been rare. This motivated us to create a task force of educators to reflect on pedagogical approaches to teaching immunology and to draft, develop, and evaluate key competencies for undergraduate immunology education. The research questions addressed include: 1) Which competencies are considered important by educators? 2) Are the illustrative skills clear, accurate and well aligned with the core competencies listed in the Vision and Change report?; 3) What are the concerns of immunology educators about competencies and skills? We collected data on the draft competencies using surveys, focus groups, and interviews. The iterative revision phase followed the community review phase before finalizing the framework. Here, we report a hierarchical learning framework, with six core competencies, twenty illustrative skills, and companion immunology-specific example learning outcomes. Predominant themes from interviews and focus groups, which informed revisions of this framework are shared. With the growing need for immunology education across the sciences, the ImmunoSkills Guide and accompanying discussion can be used as a resource for educators, administrators and policymakers.