Surface Expression of Alternative Forms of the Tcr/cd3 Complex

T-cell antigen receptor (TCR) heterodimers of both the αβ and γδ types are expressed at the surface of T cells only in association with a complex of invariant chains called CD3. The requirement for individual CD3 components to achieve TCR surface expression was examined by cotransfection of a non-T-cell line with TCR α and β, as well as CD3 δ, ε, γ, and ζ, cDNAs. Both transient and stable transfectants expressing TCR and CD3 epitopes at the cell surface were generated. By transfection of TCR and CD3 components in different combinations, the TCR chains, as well as the CD3 ε and ζ chains, were each shown to be essential for reconstituting surface expression. On the other hand, CD3 δ and γ chains could be used alternatively, providing evidence for two different types of TCR/CD3 complexes.