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Date of Award
Doctor of Philosophy (PhD)
Wilmore C. Webley
Michele M. Klingbeil
John M. Lopes
Immunology and Infectious Disease | Microbiology
Chlamydia trachomatis is the leading cause of bacterial sexually transmitted disease worldwide and while antibiotic treatment is effective in eliminating the pathogen, up to 70% of all infections are asymptomatic. Despite sustained efforts over the past 2 decades, an effective chlamydial vaccine remains elusive, due in large part to the lack of an effective delivery system. We explored the use of gas vesicles derived from Halobacterium salinarium as a potential display and delivery vehicle for chlamydial antigens of vaccine interest. Various size gene fragments coding for the major outer membrane protein (MOMP), outer membrane complex B (OmcB), polymorphic outer membrane protein D (PompD) and polymorphic outer membrane protein B (Pomp B) were integrated into and expressed as part of the gas vesicle protein C (gvpC) on the surface of these stable structures. The gas vesicle purifications are free of any viable Halobacterium cells and constitute a pure preparation of gas vesicles. The presence of the recombinant proteins was confirmed by Western blots probed using anti-gvpC and anti-Chlamydia antibodies as well as sera from Chlamydia trachomatis and Chlamydia pneumoniae -positive patients. Tissue culture evaluation revealed stability and a time-dependent degradation of recombinant gas vesicles (r-Gv) in human and animal cell lines. In vitro assessment using human foreskin fibroblasts (HFF) confirmed Toll-like receptor (TLR) 4 and 5 engagement by wild type and r-Gv, leading to MyD88 activation, TNF-α, IL-6 and IL-12 production. Successful construction of a polymorphic outer membrane protein E/F (Pomp E/F) fusion linked to a chloramphenicol resistance cassette was successful displayed on the surface of gas vesicles. The Pomp E/F fusion was detected by anti- Chlamydia antibodies and resulted in a shift in the GvpC band detected via Western blot. The data suggest that r-GV could be an effective, naturally adjuvanting, time-release antigen delivery system for immunologically relevant Chlamydia vaccine antigens, which are readily recognized by human immune sera.
Childs, Tawanna Sabrina, "Validation Of A Novel Vaccine Delivery System for Chlamydia Trachomatis Using Recombinant Gas Vesicles Derived From Halobacterium Salinarium" (2013). Doctoral Dissertations 1896 - February 2014. 493.