T cell antigen receptor (TcR) of T helper clone has been expressed on a T cell hybridoma line by transfecting the chimeric cDNAs of TcR cDNAs were replaced with glycosyl phosphatidylinositol (GPI) anchorage signal sequences of Thy-1.1 antigen. The positive transfectants were reactive with clonotypic antibodies in FACS analysis. Heterodimeric TcR cleaved by phosphatidylinositol-specific phospholipase C (PIPLC) was purified through affinity column conjugated with 3D3 clonotypic antibody. This approach to purify TcR preserved the determinants for clonotypic antibodies and the purified TcR might be equivalent to TcR expressed on T helper clone.