| Abstract: | We have examined the T cell receptor (TcR) expression of clones specific for epitopes of mycobacterial 65-kDa heat-shock protein (hsp65) in the context of two different HLA molecules, and used this system as a model to assess the selection of T cells responsive to this antigen in vivo. DR3-restricted clones were raised from both the synovial fluid (SF) and peripheral blood (PB) of a patient with reactive arthritis in three separate cloning events. Five of five SF-derived clones tested expressed either Vβ5.2 or a closely related β chain, Vβ5.6.The α chains expressed by Vβ5.2+ and Vβ5.6+ clones were from different families, Vα2.4 and Vα23.2, respectively. Nine of ten clones derived from two cloning procedures on PB taken 3 years later also expressed either Vβ5.2 or Vβ5.6. This suggests that the TcR repertoire for recognizing this major histocompatibility complex/peptide complex is relatively restricted and favors the use of Vβ5. Conservation of the β chain third complementarity-determining region (CDR3) sequence was not evident, however. Sequencing α and β chains of representative Vβ5.2+ and Vβ5.6+ PB-derived clones revealed TcR which were identical to those utilized by the SF-derived clones, showing that the repertoire for recognition of this antigen is stable over time. Similar studies of TcR expression were carried out on hsp65-specific, DP4-restricted clones derived from the SF of a patient with rheumatoid arthritis by two independent cloning procedures. There was conservation of a chain usage, since all clones expressed a member of the Vαl family, but again CDR3 sequence conservation was not apparent, β chain usage was not restricted since different clones expressed Vβ6.7, Vβ22.3 and Vβ12. Subtle differences in epitope specificity were detected for two clones with differing TcR. Once more, T cell clones with identical α and β TcR chains were obtained from the separate cloning procedures, suggesting oligoclonalty of T cells with this defined specificity in the patient's SF. |
