Transduction of ZAP-negative CLL B cells with Ad-ZAP70 enhanced p72^Syk, BLNK, and PLCγ phosphorylation and calcium mobilization. (A, B) Intracellular ZAP-70 in ZAP-70^– CLL B cells following transduction with a control adenovirus vector (–) or Ad-ZAP70 (+) by immunoblot analysis and flow cytometry. (C) IgM-induced phosphorylation of p72^Syk, BLNK and PLCγ in ZAP-70^– CLL B cells following transduction with a control adenovirus vector (light gray bars) or Ad-ZAP70 (dark gray bars). The bar size corresponds to the percent increase in phosphorylated proteins after anti-μ stimulation by CBA assay. *P < .01 between the cells transduced with a control adenovirus vector versus Ad-ZAP70. (D) IgM-induced calcium mobilization in ZAP-70^– CLL B cells following transduction with a control adenovirus vector (–) or Ad-ZAP70 (+). The relative mean fluorescence intensity in intracellular calcium is plotted as a function of time: arrow A indicates IgM stimulation; arrow B, ionomycin stimulation. (E) IgM ligation–induced calcium fluorescence intensity increase in ZAP-70^– CLL B cells following transduction with a control adenovirus vector (–) or Ad-ZAP70 (+). The bar size corresponds to the increase of fluorescence intensity value after anti-μ stimulation. + indicates CLL B cells transduced with Ad-ZAP70; –, CLL B cells transduced with control adenovirus vector. Error bars indicate mean ± SD.