Effect of soluble Jagged1 ligand on B-CLL cell survival. Freshly isolated B-CLL cells were cultured for 48 hours in complete medium with 10 μg/mL (100 μL/well) immobilized soluble Jagged1 ligand or IgG-Fc as control (n = 4) as described in “Soluble Jagged1 ligand immobilization and B-CLL cell stimulation.” (A) Cell viability was evaluated by trypan blue exclusion. Data for each patient are expressed as mean plus or minus SD of 4 determinations. **P less than .01, Jagged1-treated cells vs IgG-Fc–treated cells for each patient, according to the Student t test. (B) Hes1 protein expression was analyzed in 25 μg whole-cell lysates by Western blot, and protein loading was assessed by reprobing the blots with an anti–β-actin mAb. Densitometry was performed, and the density of the bands expressed as arbitrary units is reported for each patient. Densitometry units (U) were calculated relative to β-actin for each lane. Results from all 4 patients examined are shown.