REN and PECAM-1–transfected REN cells are phenotypically similar to ECs and support cytokine-stimulated, ICAM-1–dependent PMN transmigration.

(A) Confluent REN and RHP monolayers plated on transwells stained with anti–PECAM-1 antibody (mAb4G6). RHP monolayers were treated for 24 hours with IL-1β or vehicle exactly as performed in TEM experiments. (B) PMN transmigration through confluent REN and RHP monolayers treated for 24 hours with vehicle or 10 U/mL IL-1β (luminal). (C) PMN transmigration though IL-1β–stimulated REN and RHP monolayers. Monolayers and PMNs were exposed to either isotype-matched anti–MHC-1 or anti–ICAM-1 mAbs (100 μg/mL) 20 minutes prior to and during transmigration. Identical results were obtained using BSA (100 μg/mL) for nonblocking conditions (not shown). Transmigration rates are expressed as the proportion of PMNs migrating through the transwell filter compared with the total number of PMNs added (500 000). In these representative experiments, data represent the mean ± SEM from a minimum of 3 transwells for each condition. (*Significantly different from “unblocked” controls, P < .05.)