CTLA4 and neoplasm: To know if decreased CTLA-4 levels would affect anti-tumor properties of 19-28z+ T cells, we conducted similar experiments in which approximately 50% of the 19-28z+ T cells expressed the anti-CTLA-4 shRNA (Fig 4B), comparably to the shRNA transduced 19z1-CD80+ T cells (Fig 4A).