Differential expression of T-cell CD3-zeta chains in patients with cervical dysplasia before and after treatment

This study addresses whether CD3-zeta suppression associated with cervical intraepithelial neoplasia (CIN) I, II, and III is mediated by a circulating factor and if this suppression is reversed following treatment. Serum was isolated from patients with CIN before and after curative therapy. Jurkat T cells were incubated with patient-derived sera for 4 days, and CD3-zeta expression was analyzed by western immunoblot. Sera from control female volunteers did not suppress CD3-zeta expression of Jurkat cells, while sera from women with CIN I, II, and III suppressed 58.9%, 75.3%, and 80.5%, respectively. Suppression observed in women with CIN I was significantly different from that observed with CIN II and III. Posttreatment zeta suppression was noted to be reversed in women with CIN II and III although the decreased suppression in CIN III patients was not statistically significant. Our study demonstrates that in vivo suppression of zeta chains in patients with CIN can be the result of a circulating factor. In vitro zeta expression increased in patients with CIN II and III after treatment, although the increase was only statistically significant in patients with CIN II.

The pre-T cell receptor (TCR) complex is functionally coupled to the TCR-zeta subunit.

The pre-T cell receptor (TCR) complex regulates early T cell development and consists of a heterodimer of the TCR-beta subunit in association with the pre-TCR-alpha chain. Notably, in contrast to alpha/beta-expressing T cells, several studies suggested that the TCR-zeta chain is not stably associated with this pre-TCR complex. To examine the proximal signaling processes mediated by the pre-TCR complex and the role of the TCR-zeta chain in these processes, we stimulated pre-TCR-expressing cells and analyzed the interactions of the TCR/CD3 invariant chains with the Syk/ZAP-70 family of protein tyrosine kinases. Stimulation of the pre-TCR complex led to the tyrosine phosphorylation of the CD3 epsilon and TCR-zeta chains, as well as the phosphorylation and association of ZAP-70 and Syk with phosphorylated CD3 epsilon and TCR-zeta. These results demonstrate that the pre-TCR complex is functionally coupled to the TCR-zeta subunit and to the ZAP-70 and Syk protein tyrosine kinases.

Expression and function of a variant T cell receptor complex lacking CD3-gamma.

A T cell line termed DIL2 has been derived from an infant with a polyclonal T cell receptor (TCR)/CD3 cell surface expression defect. Indirect immunofluorescence showed that the expression of certain TCR/CD3 epitopes (like those detected by WT31 and BMA031 monoclonals) was strongly reduced (around five-fold) on DIL2, whereas other epitopes (like those detected by SP34 and Leu4) were only around two-fold lower than in normal T cell lines. Specific immunoprecipitates of surface-radioiodinated DIL2 cells contained TCR-alpha, TCR-beta, CD3-delta, CD3-epsilon and TCR-zeta chains, but lacked CD3-gamma. This structural TCR/CD3 variant was, however, capable of transducing certain activation signals, since normal proliferation and a low but significant calcium flux was observed in DIL2 cells after engagement with specific antibodies. Our data suggest that a functional TCR/CD3 complex can be expressed on the surface of T cells in the absence of CD3-gamma.