A GAMMA-DELTA T-CELL SPECIFIC SURFACE-RECEPTOR (WC1) SIGNALING G0 G1 CELL-CYCLE ARREST/

Three monoclonal antibodies (mAb; SC-6, SC-12, and SC-29) reactive wit h the gamma delta T cell-restricted antigen WC1 were obtained immunizi ng mice with an ovine interleukin (IL)-2-dependent gamma delta T cell line. These mAb strongly inhibited DNA synthesis in IL-2-dependent gam ma delta T cell lines with cell cycle arrest in G0/G1 phase, but did n ot induce apoptosis. The mAb-induced growth arrest was reversible, eit her by removing the mAb or by co-culture with mitogen or anti-CD3 in t he presence of IL-2. In contrast, addition of phorbol ester, ionomycin and IL-2 had no effect on the mAb-induced growth arrest. The observat ions define a biologically important role for the cell surface molecul e WC1 in the regulation of gamma delta T cell proliferation and also p rovide a suitable system to study the relevant signal transduction eve nts.