Increases in phosphorylated p72^Syk induced by anti-μ in ZAP-70⁻ CLL transduced with Ad-ZAP-70 or Ad-ZAP-70-KA³⁶⁹. (A) Comparison of CBA assay with immunoblot analysis to detect phosphorylated p72^Syk. Phosphorylated p72^Syk was determined by immunoblot analysis and CBA assay for ZAP-70⁻ CLL transduced with Ad-ZAP-70 or Ad-ZAP-70-KA³⁶⁹. The band intensity for the anti-μ–stimulated CLL samples transfected with wild-type ZAP-70 was similar to that noted for the anti-μ–stimulated samples transfected with ZAP-70-KA³⁶⁹, providing a ratio of signal intensity that was similar to that using the CBA assay. The immunoblot results are a representative one of 3 experiments. (B,C) Percentage increase in phosphorylated p72^Syk induced by treatment with anti-μ, as indicated on the y-axis of each panel. Each symbol represents the percentage increase in phosphorylated protein detected in an individual CLL cell sample. The lines connect the percentage increase in detected phosphorylated protein of anti-μ–treated CLL cell samples transduced with Ad-lacZ (“Control” in each panel) versus that measured in the same CLL cells that had been transduced with Ad-ZAP-70 (B) or Ad-ZAP-70-KA³⁶⁹ (C). The mean anti-μ–induced increase in each phosphoprotein detected in the Ad-ZAP-70– or Ad-ZAP-70-KA³⁶⁹–transduced CLL cells was significantly greater than that noted for the same phosphoprotein in the Ad-lacZ–transduced CLL cells following treatment with anti-μ (P < .05), which was not significantly different from that of anti-μ–treated mock-transfected CLL cells.