Detection of ZAP-70 in ZAP-70⁻ CLL following transduction with Ad-ZAP-70 or Ad-ZAP-70-KA³⁶⁹. Dot plots depicting the log fluorescence of blood lymphocytes stained with Alexa-488–conjugated anti–ZAP-70 (x-axis) and PE-conjugated anti-CD19 (y-axis). The horizontal line depicts the threshold fluorescence exceeded by CD19⁺ CLL B cells, whereas the vertical line indicates the threshold fluorescence exceeded by cells scored as ZAP-70⁺, using a defined gating strategy, as described.¹¹  The number provided in the top right-hand corner of each panel provides the percentage of the CD19⁺ CLL B cells with fluorescence exceeding the ZAP-70 threshold. CLL cell samples that have more than 20% ZAP-70⁺ cells are scored as being ZAP-70⁺. (A) ZAP-70⁺ CLL cell sample. (B) a ZAP-70⁻ CLL cell sample transduced with a control adenovirus vector. (C) The same CLL sample as in panel B transduced with Ad-ZAP-70. (D) The same CLL sample as in panel B transduced with Ad-ZAP-70-KA³⁶⁹.