Human peripheral blood lymphocytes bearing T cell receptor γ/δ. Expression of CD8 differentiation antigen correlates with the expression of the 55-kD, Cγ2-encoded γ chain

We analyzed the CD3-associated molecules present on peripheral blood-derived TCR-γ/δ⁺ clones that express CD8 surface antigens. Clones was derived by limiting dilution from CD3⁺ WT31^- FACS-purified populations derived from several donors. Eight of > 300 TCR-γ/δ⁺ clones analyzed expressed CD8 and reacted with δ-TCS-1 mAb. Cell numbers suitable for more detailed analyses could be obtained from four clones, including one derived from thymus. Analysis of CD3-associated TCR molecules immunoprecipitated by anti-Leu-4 (anti-CD3) mAb under conditions that preserve the CD3/TCR association (1% digitonin) showed a predominant 55-60-kD molecule both under reducing and nonreducing conditions. On the other hand, the δ-TCS-1-reactive molecules immunoprecipitated from 25 CD3⁺ δ-TCS-1⁺ CD8^- clones, in all instances, displayed a 40-44-kD mol mass. In two-dimensional PAGE, TCR-γ molecules precipitated from δ-TCS-1⁺ CD8⁺ clones appeared more acidic than those of BB3⁺ or δ-TCS-1⁺ CD8⁺ clones. Southern analysis confirmed that this type of non-disulphide-linked TCR-γ/δ is also coded for by the Cγ2 gene segment.