Comparison of the adhesion of T cells to bEndI1/2.1 or bEndI1.1 re-expressing ICAM-1 or its mutants. A representative experiment directly comparing the adhesion of SJLB.PLP3 to unstimulated and TNF-α-stimulated bEndI1/2.1 (A) or bEndI1.1 (B) with their adhesion to the respective daughter cell lines retransduced with wild-type (wt) ICAM-1 or the ICAM-1 mutants M1, M2, M3, M4, or M5 is shown. Adhesion assays were performed with the use of 16-well Nunc glass chamber slides and analyzed by video-associated light microscopy (NIH Image software; National Institutes of Health, Bethesda, MD) counting for 5 predefined fields per well bound cells on the endothelial surface. Neither deletion of the cytoplasmic tail (M1 and M5) of ICAM-1 nor mutations of tyrosines to phenylalanines (M2, M3, M4) lead to a statistically significantly different adhesion of T cells when compared with adhesion to wild-type ICAM-1. Bars represent mean ± SD (n = 5). Significant differences were only observed for the parental cells versus wt ICAM-1 and each mutant and are marked as follows: ^**P < .01, very significant; ^***P < .001, extremely significant. These results were reproduced twice.