Chronic lymphocytic leukemia B cells contain anomalous Lyn tyrosine kinase, a putative contribution to defective apoptosis
J. Clin. Invest. Antonella Contri, et al. 115:369 doi:10.1172/JCI22094 [Go to this article.]

Figure 4
Kinase activity of Lyn in normal and CLL B cells before and after IgM ligation. (A) Analysis of Lyn activity in unstimulated B cells. Normal cells refer to tonsil (T), total peripheral blood B cells (P_T), naive peripheral blood B lymphocytes (P_N), and memory peripheral blood B lymphocytes (P_M). Normal and leukemic B cells from CLL patients were lysed and Lyn was immunoprecipitated. The immunocomplexes were then analyzed for both the in vitro kinase activity tested toward the Src-specific peptide substrate cdc2(6–20) and anti-Lyn immunostaining. The data are representative of experiments performed with 3 different tonsils, 5 peripheral blood samples, and 40 B-CLL samples. (B) Analysis of Lyn activity in B cells after IgM ligation. B lymphocytes were isolated from 1 healthy donor and 2 CLL patients, 1 (CLL no. 29) expressing high levels and 1 (CLL no. 18) expressing low levels of IgM, as indicated by flow cytometry analysis (upper panels). B cells were incubated with anti-human IgM (20 μg/ml) at 37–C for the indicated times and the kinase activity of anti-Lyn immunoprecipitates was detected as described in A (lower panels). The data are representative of 3 separate experiments.