We have detected rearrangement and expression of a gene encoding a T-cell antigen receptor alpha chain in the keyhole limpet hemocyanin (KLH)-specific, inducible suppressor-T-cell (Ts) hybridoma 34S-281 (BW5147 lymphoma-C57BL/6Ts) by using alpha-chain cDNA clones isolated from this Ts hybridoma. The cDNA clones have a restriction length polymorphism in the constant region that identifies them as being of C57BL/6 origin. The cDNA sequence has an ATG start codon for an open reading frame including variable, joining, and constant gene segments. Furthermore, the Ts alpha-chain gene transcripts were detected on membrane-bound polysomes by RNA blot analysis using a variable-region fragment from one of the alpha-chain cDNA clones as probe, suggesting that they are actively translated in the Ts hybridoma. As the beta-chain gene is deleted in all Ts hybridomas analyzed, and since a disulfide-linked dimer is detectable by two-dimensional NaDodSO4/PAGE of lysates of surface-radioiodinated Ts, we suggest that Ts antigen receptors are either alpha-chain homodimers or heterodimers composed of the alpha chain in association with an undefined chain.