IgM-induced p72^Syk, BLNK, and PLCγ phosphorylation and calcium mobilization in CLL B cells with or without ZAP-70. (A) IgM-induced phosphorylation of p72^Syk (Syk), BLNK, and PLCγ in CLL B cells with or without ZAP-70. The bar size corresponds to the percent increase in phosphorylated proteins after anti-μ stimulation by CBA assay. (B) IgM-induced calcium mobilization in CLL B cells with or without ZAP-70. The relative mean fluorescence intensity in intracellular calcium is plotted as a function of time: arrow A indicates IgM stimulation; arrow B, ionomycin stimulation. (C) IgM-induced calcium fluorescence intensity increase in CLL B cells with or without ZAP-70. The bar size corresponds to the increase of fluorescence intensity value after anti-μ stimulation. + indicates CLL B cells with ZAP-70 expression; –, CLL B cells without ZAP-70 expression. The horizontal line drawn among the samples of each group represents the median increase in signal intensity for that group.