Isolation of cDNA clones encoding the 20K non-glycosylated polypeptide chain of the human T-cell receptor/T3 complex

Abstract

The antigen receptor on human T lymphocytes consists of two variable immunoglobulin-like glycoproteins, α and β, which occur in association with three invariable T3 membrane proteins1-3. In humans two of these proteins, T3-γ and T3-δ, are glycoproteins of relative molecular mass (Mr) 25,000 (25K) and 20,000 (20K), respectively, while the third, T3-ε, is a 20K non-glycosylated protein4-6. On the surface of murine T cells, a non-glycosylated protein dimer composed of 17K subunits (T3-ζ) is found associated with the T-cell receptor α and β chains and the three T3-like polypeptide chains7,8. It is generally accepted that major histocompatibility complex-restricted antigen recognition is a function of the α-β heterodimer. This has led to the postulation that the proteins of the T3 complex are involved in the signal transduction that immediately follows antigen recognition via the antigen receptor9. Events believed to be involved in early T-cell activation, such as rapid increases in phosphatidylinositol turnover and free intracellular calcium9,10, can be triggered by antibodies directed against either the T3 complex or the clonotypic receptor. We have previously reported our findings on the cloning of the complementary DNA and genomic structure encoding both the human and murine 20K glycoprotein, T3-δ (refs 11-13). We now present our results on the cloning of the cDNA encoding the human 20K non-glycosylated chain, T3-ε. © 1986 Nature Publishing Group.