Analysis of iNOS protein expression in B-CLL cells by flow cytometry. B-CLL cells from eight different patients and A549 cells (positive control for iNOS expression) were permeabilized with the Cytoperm kit and labeled with either the monoclonal anti-iNOS (clone 54) or unrelated IgG1 MoAb as an isotype-matched control, then incubated in the presence of a fluoresceinated goat F(ab′)2 anti-mouse Ig antibody. Fixed cells were analyzed by flow cytometry with a FACScan instrument, using the lysis II and Procyt softwares. Gray line, control labeling with IgG1; black line, labeling with anti-iNOS. The statistical significance was P < .001, according to the Kolmogorov-Smirnov test and the data are representative of a total of 13 different B-CLL cell samples tested.
