Characterization of monoclonal antibodies specific for the Vβ3 family of the human T cell receptor generated using soluble TCR β-chain

A soluble, recombinant form of the human T cell receptor (TCR) β-chain containing the Vβ3.1 sequence has been constructed, expressed in Chinese hamster ovary cells, amplified by dihydrofolate reductase selection, and purified in quantities appropriate for the generation of monoclonal antibodies (mAb). The Vβ3 sequence was chosen because of its reported elevated usage in the synovial T cells of rheumatoid arthritis patients but the approach described should be applicable to other known human Vβ gene sequences. By this method, two mAb were prepared which reacted with up to 10% of normal, live peripheral blood T cells but with reactivity varying greatly among individual donors. Both mAb specifically bound to a murine T cell line transfected with a human TCR Vβ3.1 and immunoprecipated a protein of the expected molecular weight for the TCR β-chain. Both antibodies were mitogenic for T cells and analysis of peripheral blood lymphocyte cultures stimulated with the mAb suggested that both were specific for the Vβ3.1 subfamily and not Dβ or Jβ. Clones expressing Vβ3, which were derived from mAb-stimulated peripheral blood lymphocytes of a single individual, preferentially (8/13), but not exclusively, utilized the Jβ2.7 gene segment. The Vβ3.1 usage showed no preference for the CD8+ or CD4+ subpopulations of normal peripheral blood T cells.