Analysis of VCAM-1 (A) and ICAM-1 (B) expression on cultured human TECs by flow cytometry. Pretreatment of the TECs with rIL-4 overnight (1,000 U/mL) consistently increased the constitutive expression of VCAM-1, but had no effect on the level of ICAM-1 expression. The results of staining with an isotype-matched control antibody is shown in both panels for comparison (CTRL).