Genetic basis for persistence of Borrelia burgdorferi

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ABSTRACT The genetic factors required to establish a persistent infection in vertebrate hosts is one of the least understood aspects of an infection with Borrelia burgdorferi. Multiple triggers for establishment of persistence have been proposed. However, the lack of sensitive serologic and molecular assays has substantially impeded work examining the biology of persistent spirochetes and their direct role in Post-Treatment Lyme Disease Syndrome (PTLDS). We have developed two assays that overcome these major limitations and can facilitate studies of persistent infections. The TBDCapSeq, a next generation capture sequencing assay, has a sensitivity superior to quantitative PCR and enables B. burgdorferi genome assembly in host tissue samples. The TBD-Serochip, a peptide array that can identify antibody responses to 170,000 linear peptides per assay, provides unprecedented glimpses into B cell responses to the major antigens of B. burgdorferi. In this proposal these assays will be employed in three Specific Aims that will examine molecular and genetic footprints of a persistent B. burgdorferi infection. In Specific Aim 1, we will perform a comprehensive serologic analysis of sera and cerebrospinal fluid from a well characterized PTLDS patient cohort. We will identify all major immunoreactive epitopes in both specimen types. These data will be differentiated with serology data from other non-PTLDS Lyme disease cohorts to implicate potential specific biomarkers of PTLDS. In Specific Aim 2, we will employ the TBDCapSeq to identify molecular footprints of B. burgdorferi in the PTLDS patient cohort. The combination of superior sensitivity of TBDCapSeq coupled with high sequencing depth will provide the most robust molecular analysis of the link between B. burgdorferi and PTLDS. In Specific Aim 3, we will establish an animal model for three distinct genotypes of B. burgdorferi in C3H/HeN, BALB/c and Peromyscus leucopus mice. The capacity of each B. burgdorferi genotype for establishing persistence with and without antibiotic treatment will be assessed and the TBDCapSeq will be used to identify genetic features unique to persistent spirochetes. Along with genomic analysis, we will perform the first transcriptome investigation of persistent spirochetes. Combined, these Aims will provide insight into the immune response of patients with PTLDS and identify mechanistic triggers of spirochete persistence.