T-Cell Epitope Mapping of the Borrelia garinii Outer Surface Protein A in Lyme Neuroborreliosis

We studied the T-cell reactivity to overlapping peptides of B. garinii OspA, in order to locate possible immunodominant T-cell epitopes in neuroborreliosis. Cells from cerebrospinal fluid (CSF) and blood from 39 patients with neuroborreliosis and 31 controls were stimulated with 31 overlapping peptides, and interferon-γ secreting cells were detected by ELISPOT. The peptides OspA₁₇₋₃₆, OspA₄₉₋₆₈, OspA₁₀₅₋₁₂₄, OspA₁₃₇₋₁₅₆, OspA₁₉₃₋₂₁₂ and OspA₂₃₃₋₂₅₂ showed the highest frequency of positive responses, being positive in CSF from 38% to 50% of patients with neuroborreliosis. These peptides also elicited higher responses in CSF compared with controls (P = 0.004). CSF cells more often showed positive responses to these peptides than blood cells (P = 0.001), in line with a compartmentalization to the central nervous system. Thus, a set of potential T-cell epitopes were identified in CSF cells from patients with neuroborreliosis. Further studies may reveal whether these epitopes can be used diagnostically and studies involving HLA interactions may show their possible pathogenetic importance.