c-Rel modulates CD23 expression. Transient transfection of pt1-LCL^tet cells with a c-Rel expression plasmid (outlined peak) and an empty vector (shaded peak) as the negative control (A) or siRNAs for c-Rel (outlined peak) and a scrambled control sequence (shaded peak) (C). Cell surface expression of CD23 was analyzed by flow cytometry. Total cell lysate from the corresponding overexpression (B) or siRNA transfections, with the CD23^lo and CD23^hi siRNA^Rel subpopulations cell sorted (D), were further examined for c-Rel expression by Western blot analysis, with actin as a loading control. Results are representative of 3 independent experiments.