Transcellular TEM requires intact ICAM-1. (A) ICAM-1GFP iHUVECs were incubated with penatratin-ICAM-1 peptide or control penetratin peptide (100 μg/mL, 2 hours). PMN accumulation and the route of TEM were assessed at 1 dyne/cm² as described in Figure 1D legend. (B) Initial location of PMN adhesion and TEM at 1 dyne/cm² were assessed for iHUVECs, GFP iHUVECs, ICAM-1GFP iHUVECs, and tailless ICAM-1GFP iHUVECs. (C) PMN accumulation and TEM were assessed for the 4-hour TNF-α-stimulated endothelial monolayers after preincubation of PMNs with function-blocking mAb to LFA-1 (TS 1/22) or Mac-1 (mAb 44), or both. A second mAb to Mac-1 (LPM19c, data not shown) gave similar results. ^*P < .05.