Author ORCID Identifier


Defense Date


Document Type


Degree Name

Doctor of Philosophy


Microbiology & Immunology

First Advisor

Dr. Richard Marconi

Second Advisor

Dr. Jason Carlyon

Third Advisor

Dr. Lisa Shock

Fourth Advisor

Dr. Huiping Zhou

Fifth Advisor

Dr. Chunhao Li

Sixth Advisor

Dr. John Ryan


Lyme disease (LD) is a tick-transmitted infection caused by Borreliella burgdorferi in North America and several closely related species in Europe and Asia (collectively referred to as the LD spirochetes). All LD spirochetes encode a relatively uncharacterized family of lipoproteins designated as protein family 12 (PF12). In Borreliella burgdorferi type strain B31 PF12 consists of ORFs BBK01, BBG01, BBJ08, BBH37 and BB0844. BB0844 is divergent from other PF12 members and is not considered in this study. Henceforth, we designate the PF12 proteins as Family 12 lipoprotein (Ftl) A (BBK01), FtlB (BBG01), FtlC (BBH37), and FtlD (BBJ08). In this report, the potential utility of the Ftl proteins in diagnostic assay and vaccine development was assessed. Immunoblot analyses using Ftl paralog-specific antisera detected proteins consistent in size with FtlA, FtlB, and FtlC in most LD isolates. In contrast, FtlD was detected in a smaller subset of isolates. Triton X-114 extraction and phase partitioning revealed that the Ftl proteins localize to the outer membrane. BlueNative-PAGE analysis showed that the Ftl antigens form oligomeric structures. ELISA analyses of client-owned, B. burgdorferi Ab positive dogs (n=50) and horses (n=90) detected Ab that bound to one or more of the Ftl proteins in most serum samples. Ab to the Ftl antigens remained elevated out to 497 days post-infection in experimentally infected laboratory dogs. Bactericidal assays using anti-FtlA and FtlB antisera generated in rats revealed potent complement-dependent antibody-mediated killing. The bactericidal epitopes were localized within the N-terminal domain of the Ftl proteins. Knowledge of the expression profiles of surface proteins during infection in mammals is required for fully understanding the interactions between pathogen and host and for the rational design of vaccines and diagnostic assays.


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Available for download on Thursday, June 13, 2222