['To determine the structure of T cell receptors (TCR) used by Sm-B-reactive human T cell clones, to map T cell epitopes on the Sm-B autoantigen, and to determine the HLA restriction element used in the recognition of Sm-B by T cells.', 'Sm-B-reactive T cell clones were generated from patients with connective tissue disease by using either a recombinant fusion protein or synthetic peptides. The TCR structure was defined with the use of polymerase chain reaction and DNA sequencing. Synthetic peptides were used to map T cell epitopes on Sm-B. HLA restriction element usage was defined by using monoclonal antibody blocking.', 'Usage of the TCR third complementarity-determining region (CDR3) was highly restricted among Sm-B autoantigen-specific human T cell clones. Only amino acids 48-96 of the Sm-B2 autoantigen were recognized by T cells, and this occurred in the context of HLA-DR.'] Is t cell receptor beta-chain third complementarity-determining region gene usage highly restricted among Sm-B autoantigen-specific human T cell clones derived from patients with connective tissue disease?