FIG. 2.
VLA-4 and CD11/CD18 integrins mediate the transendothelial migration of T lymphocytes. T lymphocytes (5 × 105 cells/cm2) were resuspended in medium containing 10 μg of MAb to VLA-4 per ml and/or 40 μg of MAb to CD18 per ml (A), 40 μg of the isotype-matched control MAb MOPC21 per ml (B), or an equivalent volume of phosphate-buffered saline (No MAb). The T lymphocytes were then added for 4 h to HUVEC that had either been left unstimulated (Unstim) or previously activated with IL-1β or B. burgdorferi (Bb) for 24 h. The total height of each bar represents the percentage of added T cells that became associated with the cultures. The lower (patterned) portion of each bar depicts the percentage of cells that migrated beneath the endothelium; the upper (unfilled) portion denotes the percentage that was adherent to the apical surface. Bars represent the means ± standard deviations of three to four replicate samples. For A, data shown are representative of two separate experiments. Asterisks denote significant reductions in migration compared to control assays performed in the absence of MAb: *, P < 0.01; **, P < 0.001.