Intravital Microscopy of Borrelia burgdorferi: Delineation of Dissemination Kinetics and Persistence Within Murine Skin
Full text release has been delayed at the author’s request until August 7, 2013.
Degree: Doctor of Philosophy in Biomedical Science (Ph.D.), University of Toledo Health Science Campus, College of Medicine, 2012.
Lyme disease is caused by Borrelia burgdorferi, a tick-transmitted, spirochetal, bacterium which remains at the skin inoculation site of the mammalian host for approximately 48 hours before disseminating and initiating disease. Possessing many surface agonists, B. burgdorferi predictably elicits prompt clearance by phagocytes in vitro. However, efficient immunoevasion occurs in vivo yielding an ID50 of less than or equal to 50 organisms. As current in vitro models appear inadequate for delineating natural B. burgdorferi pathogenesis and evasion behaviors, the objective of this work was to devise a confocal microscopy-based approach allowing in vivo assessment of host-pathogen interactions critical to disease progression. Here, the development of a novel method for visualizing and collecting 4-D data depicting the behavior of fluorescent B. burgdorferi and immune cells within the skin of transgenic mice is reported. Rigorous evaluation of the model is also discussed as well as its initial application in addressing key questions regarding Lyme disease progression. Using the model, it was found that early post-inoculation many B. burgdorferi at the injection site appear to fragment and die. However, surviving bacteria preferentially disseminate through dermal tissues exhibiting varying patterns of motility and moving at rates 40- to 100-times faster than resident and migratory immune cells. These host cells respond to the microbial infection through motility behaviors characteristic of their cell type and studies to delineate the kinetics of this phenomenon are described. Finally, weeks after initial inoculation, B. burgdorferi can still be found actively moving within the dermis despite a strong host antibody response specific for the bacterium. These findings suggest that B. burgdorferi motility may be critical for pathogenesis and evasion behaviors at all stages in infection. This conclusion is contrary to the current paradigm for Lyme disease progression, which emphasizes hematogenous spread and eventual residence of immotile bacteria in immunoprotected niches. Expansion of the imaging model designed in conjunction with this research is anticipated to allow true delineation of host-B. burgdorferi interactions vital for Lyme disease progression and may subsequently reveal key targets for preventative and curative therapies.
Immunology; Microbiology Keywords host-pathogen interactions; Borrelia burgdorferi;
Committee / Advisors:
R. Mark Wooten, Ph.D (Committee Chair)
Robert Blumenthal, PhD (Committee Member)
Andrea Nestor Kalinoski, PhD (Committee Member)
Akira Takashima, MD, PhD (Committee Member)
M.A. Julie Westerink, MD (Committee Member)
Document number: mco1340104556
Permalink: http://rave.ohiolink.edu/etdc/view?acc_ ... 1340104556
Topics with information and discussion about published studies related to Lyme disease and other tick-borne diseases.
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