Modulation of CD25 expression in normal lymphocytes by DSP30.

B-lymphocytes from tonsils of patients with nonmalignant diseases (A), or normal T cells from peripheral blood (B) were isolated by density gradient centrifugation and immunomagnetic enrichment as described in the text. Cells were incubated with DSP30 for 48 hours, followed by staining with fluorochrome-labeled, monoclonal anti-CD25 antibodies or isotype control antibodies. Cellular fluorescence was analyzed by flow cytometry. Histograms show fluorescence intensities of the anti-CD25 antibody (shaded), overlayed with that of an isotype control (solid line). Shown are representative experiments; 2 additional experiments gave similar results. (C) Unseparated peripheral blood cells from a patient with B-CLL were incubated for 48 hours in the presence or in the absence of DSP30. Cells were then stained for flow cytometric analysis with FITC-conjugated anti-CD25 antibodies and PE-labeled antibodies to CD3 or CD19.