We examine the rules governing Ti beta variable (V) gene segment usage in the formation of T cell antigen-MHC receptors in diverse regulatory and effector T lymphoid subpopulations. To this end, a single Ti beta V gene family and its products were analyzed. A monoclonal antibody, termed anti-Ti3A, which was shown to be reactive with an epitope encoded by members of the REX cell line Ti beta V gene family, and which was expressed on 2% of human T lymphocytes was used in selection of clones from unprimed peripheral T lymphocytes. Both T4+, as well as T8+ T cell clones with inducer, suppressor, and/or cytotoxic function were defined. Southern analysis, isoelectric focusing and two-dimensional peptide mapping indicated that individual members of the REX V gene family were linked to different Ti beta diversity and/or joining and constant region segments. Moreover, the Ti alpha chains of such clones were distinct. These results imply that Ti beta V gene usage is not restricted to any functionally or phenotypically defined T cell subsets, and there is presumably little, if any, restriction on the mechanisms that generate combinational, junctional or chain association-mediated diversity.

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