cDNA cloning of functional T cell receptor γ/δ chains expressed in human peripheral blood lymphocytes

We have identified in earlier studies two V_δ rearrangements corresponding to a 4.5‐kb Eco RI fragment detected with a V_δ1 probe and to a 7‐kb Eco RI band detected with a V_δ2 probe. These rearrangements have been found in two human T cell clones, F6C7 and G6, displaying surface phenotypes unfrequent in human peripheral blood, namely Ti_γA⁺ BB3^‐ (F6C7) and Ti_γA^‐ BB3⁺ (G6). Herein, we report the sequences of the functional transcripts encoded by these rearranged genes and show that the 4.5‐and the 7‐kb Eco RI fragments correspond to V1/D3/J_δ3 and to V2/D3/J_δ3 recombinations, respectively. In addition, we have sequenced the V2/D3/J1/C_δ transcripts expressed in two clones, AB12 and VTC, which have a Ti_γA⁺ BB3⁺ surface phenotype corresponding to that of most γ/δ peripheral lymphocytes. Analyses of the δ transcripts expressed by these four cells further strengthen the hypothesis that anti‐BB3 and anti‐δ‐TCS‐1 monoclonal antibodies recognize a V_δ2‐ and a V1/(D)/J_δ1‐encoded epitope, respectively. Sequence of the γ transcripts expressed by AB12 and F6C7 cells shows that they encode a V9/JP/C_γ1 chain. Finally, we confirm that non‐combinatorial diversity in the γ and δ proteins is generated by both junctional flexibility and N‐region addition without any somatic mutation.