Regions of the T cell receptor α and β chains that are responsible for interactions with CD3

Abstract

The T cell antigen receptor consists of the Ti α/β heterodimer which recognizes antigen, and the associated CD3 chains, thought to be involved in signal transduction. To understand the nature of the interaction between Ti and CD3, chimeric molecules which included the COOH-terminal segments of Ti α or β linked to the extracellular segment of CD8, were transfected into a mutant T cell deficient in Tiβ chain expression and cell surface CD3. Both chimeric chains were required to express the chimeric Ti and to restore CD3 surface expression. CD8/Ti and CD3 cointernalized and coimmunoprecipitated. Stimulation of the chimeric receptor induced transmembrane signaling events and cell activation. These results demonstrate that the Ti α and β COOH termini containing the transmembrane domains are sufficient for structural and functional coupling of Ti to CD3.