A MOLECULAR COMPLEX, DETECTED BY MONOCLONAL ANTIBODIES ON THE SURFACE OF NORMAL T CELLS AND LYMPHOBLASTIC LEUKEMIA CELLS, REGULATES IL-2 PRODUCTION AND CELL PROLIFERATION11This work was supported in part by grant PO1-CA-20194 from National Cancer Institute, DHEW, AI-18321-01 from National Institute of Health and by the Gar Reichman Foundation.