PREFERENTIAL USAGE OF T-CELL ANTIGEN RECEPTOR-V REGION GENE SEGMENT V-BETA-5.1 BY BORRELIA-BURGDORFERI ANTIGEN-REACTIVE T-CELL CLONES ISOLATED FROM A PATIENT WITH LYME-DISEASE

Forty-three CD3+4+8- TCRalphabeta+ Borrelia burgdorferi-reactive T cel l clones isolated from the peripheral blood of a single patient with c linically active chronic Lyme arthritis were characterized. The spiroc hetal Ag recognized by 16 of these T cell clones was determined by rea ctivity with a panel of recombinant spirochetal Ag, which included the OspA, OspB, flagellin, Hsp60 and Hsp70 proteins. All three T cell clo nes reactive with heat shock proteins recognized a non-cross-reactive epitope unique to the spirochetal Ag. Analysis of the TCR V regions re vealed preferential usage of Vbeta5.1; 5 of 15 T cell clones that reco gnized an unidentified spirochetal Ag utilized this Vbeta gene segment . Most of the T cell clones recognized a given spirochetal Ag exclusiv ely within the context of one HLA class II allele. However, two T cell clones, which recognized an unidentified Ag in the spirochetal lysate within the context of different HLA class II alleles, were both TCR V beta5.1+, although each displayed a distinct alpha-chain. Moreover, in vitro incubation of this patient's PBMC with B. burgdorferi Ag result ed in a specific increase in the percentage of T cells expressing TCR Vbeta5.1. These results indicate that B. burgdorferi has a Vbeta-selec tive factor influencing the cellular immune response in a patient with clinically active Lyme disease.