DOMINANT RECOGNITION OF A BORRELIA-BURGDORFERI OUTER SURFACE PROTEIN-A PEPTIDE BY T-HELPER CELLS IN PATIENTS WITH TREATMENT-RESISTANT LYME ARTHRITIS

In an earlier study,we found that T-cell lines (TCL) from five patient s with treatment-resistant Lyme arthritis preferentially recognized Bo rrelia burgdorferi outer surface protein A (OspA), but TCL from four p atients with treatment-responsive arthritis only rarely recognized thi s protein, Dominant T-cell recognition of an arthritogenic OspA epitop e is one way in which the immune response against OspA might be involv ed in the pathogenesis of treatment-resistant Lyme arthritis. In an ef fort to test this hypothesis, we mapped the epitopes of 31 OspA-specif ic TCL and five T-cell clones derived from the synovial fluid or perip heral blood samples of three patients with treatment-resistant Lyme ar thritis, Although each patient's TCL recognized a broad array of OspA peptides with different individual patterns, two regions of OspA were dominantly recognized. Each patient's TCL dominantly recognized a C-te rminal epitope of OspA, ranging from amino acids (aa) 214 to 233 in on e patient to 244 to 263 in another, and the TCL of all three patients dominantly recognized an epitope between aa 84 and 113, These dominant regions were confirmed by clonal analysis in one patient. Thus, the r egion of OspA between aa 84 and 113 was the dominant T-cell epitope sh ared by these three patients with treatment-resistant Lyme arthritis, If the T-cell response to OspA is involved in the pathogenesis of trea tment-resistant Lyme arthritis, an epitope contained within aa 84 to 1 13 is a potentially arthritogenic epitope.