Cerebrospinal fluid-infiltrating CD4⁺ T cells recognize Borrelia burgdorferi lysine-enriched protein domains and central nervous system autoantigens in early lyme encephalitis

Neurological manifestations of Lyme disease are usually accompanied by inflammatory changes in the cerebrospinal fluid (CSF) and the recruitment of activated T cells into the CSF compartment. In order to characterize the phenotype and identify target antigens of CSF-inflltrating T cells in early neuroborreliosis with central nervous system (CNS) involvement, we combined T-cell cloning, functional testing of T-cell responses with positional scanning synthetic combinatorial peptide libraries, and biometric data analysis. We demonstrate that CD4⁺ gamma interferon-producing T cells specifically responding to Borrelia burgdorferi lysate were present in the CSF of a patient with acute Lyme encephalitis. Some T-cell clones recognized previously uncharacterized B. burgdoiferi epitopes which show a specific enrichment for lysine, such as the heat shock-induced chaperone HSP90. Degenerate T-cell recognition that included T-cell responses to borreliaspecific and CNS-specific autoantigens derived from the myelin protein 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNPase) could be demonstrated for one representative clone. Our results show that spirochetal antigen-specific and Thl-polarized CD4⁺ lymphocytes infiltrate the CSF during monophasic CNS symptoms of Lyme disease and demonstrate that cross-recognition of CNS antigens by B. burgdorferi-specific T cells is not restricted to chronic and treatment-resistant manifestations.