Chimeric receptors bearing CD3ζ overcome the NK resistance of leukemic cells. The results shown for 3 cell lines, 380, RS4;11, and 697, are expressed as the mean (± SD; n = 4) percentage of leukemic cell recovery after 24 hours of culture at a 1:1 E/T ratio relative to cultures without NK cells, as measured by flow cytometry. NK cells expressing anti-CD19-ζ receptors were more cytotoxic than NK cells expressing anti-CD19-DAP10 receptors, anti-CD19 receptors without signaling capacity (anti-CD19-trunc), or NK cells transduced with GFP control vector (P < .001).