The invasion and attachment of Borrelia burgdorferi to eukaryotic cells : a dissertation /
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| Format: | Thesis Book |
| Language: | English |
| Published: |
[College Station, Tex.] :
[Texas A&M University System Health Science Center],
[2011]
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| Subjects: |
| Abstract: | ABSTRACT: Borrelia burgdorferi, the etiologic agent of Lyme disease, is the most widespread tick-borne infection in North America and Europe. During late-stage experimental infection in mice, B. burgdorferi effectively "hide" from the host immune response and persist in unknown immunoprivileged niches. One possible explanation for this observation may involve the ability of B. burgdorferi to invade host cells where they would be protected from antibody-mediated killing. In the this study, we demonstrate that B. burgdorferi invade murine immortalized fibroblast cells, as well as primary human fibroblasts and endothelial cells. Subsequent cell infectivity analyses with B. burgdorferi indicated that a portion of B. burgdorferi were protected from gentamicin killing due to their ability to invade cultured cells. Long-term co-cultured B. burgdorferi with primary human fibroblast cells further supported the possibility of intracellular protection. Furthermore, comparison of mouse fibroblast cells positive and negative for the [beta]₁ integrin subunit showed that cells without [beta]₁ subunits had a significantly decreased invasion, indicating that [beta]₁ subunits are required for optimal borrelial invasion. However, [beta]₁-dependent invasion did not require either the [alpha]₅[beta]₁ integrin or the borrelial fibronectin-binding protein BBK₃₂. The internalization of B. burgdorferi could be inhibited by cytochalasin D and PP₂, suggesting that the invasion of B. burgdorferi involves the reorganization of actin filaments and signaling through the Src family kinases (SFK), respectively. We also showed that B. burgdorferi interacts with the collagen specific integrin heterodimer, [alpha]₁[beta]₂ directly or indirectly in a [alpha]-I domain independent manner. Neither the borrelial [beta]₃-integrin ligand P66 nor the fibronectin-binding protein BBK₃₂ are involved in the [alpha]₁[beta]₁ integrin interactions. Preliminary results with immunoblot overlays and immunoprecipitation assays suggest that a putative B. burgdorferi protein of around 50 kDa binds to [alpha]₁[beta]₁ integrins. Subsequent studies will focus on further characterization of the B. burgdorferi-[alpha]₁[beta]₁ interaction and the identification of the borrelial [alpha]₁[beta]₁ integrin-binding protein(s). Taken together, these results, both in regard to borrelial invasion and attachment, define new interactions between B. burgdorferi and eukarytoic cells taht may be key to both optimal infectivity and persistence as they relate to borrelial pathogenesis. |
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| Item Description: | Vita. "Major Subject: Medical Sciences". "Submitted to the Office of Graduate Studies of Texas A&M Health Science Center in partial fulfillment of the requirements for the degree of Doctor of Philosophy May 2011." Approved as to style and content by: Jon T. Skare, Vernon L. Tesh, James Samuel, Kayla J. Bayless |
| Physical Description: | xi, 134 leaves : illustrations (some color) ; 28 cm. |
| Bibliography: | Includes bibliographical references (leaves 114-133). |