Analysis of expression of P-selectin on HUVEC by flow cytometry.

HUVEC were cultured with either medium, IL-4, or IL-13 and were stimulated for up to 48 hours. (A) Representative histogram demonstrating P-selectin expression in medium- and cytokine-treated HUVEC (shaded histogram P-selectin, open histogram mouse control immunoglobulin). (B) Time course of P-selectin expression expressed as specific median fluorescence with the mouse control immunoglobulin values subtracted. In this experiment, the low levels of P-selectin in the medium-stimulated cells declined in culture. Expression in cytokine-stimulated cells was near maximal at 24 hours and was maintained for at least 48 hours (data shown from 1 experiment representative of 2). (C) Dose response of P-selectin expression. HUVEC were stimulated for 48 hours in increasing concentrations of IL-4 or IL-13 (data shown from 1 experiment representative of 2). (D) IL-4 and IL-13 induce a significant increase in expression of both P-selectin and VCAM-1 after 48 hours in culture. Data are expressed as specific median fluorescence, n = 7; *P < .05.