The T cell receptor/CD3 complex is composed of at least two autonomous transduction modules

Recent studies have demonstrated that the CD3-ζ subunit of the T
cell antigen receptor (TCR) complex is involved in signal
transduction. However, the function of the remaining invariant
subunits, CD3-γ, -δ, and , is still poorly understood. To examine
their role in TCR function, we have constructed TCR/CD3 complexes
devoid of functional ζ subunit and showed that they are still able
to trigger the production of interleukin-2 in response to antigen
or superantigen. These data, together with previous results,
indicate that the TCR/CD3 complex is composed of at least two
parallel transducing units, made of the γδ and ζ chains,
respectively, Furthermore, the analysis of partially truncated ζ
chains has led us to individualize a functional domain that may
have constituted the building block of most of the transducing
subunits associated with antigen receptors and some Fc receptors.