FIGURE 4.

LFA-1/ICAM-1 stimulated T-cells are unresponsive to TGF-β. a, PBL T-cells purified from healthy volunteers were pre-treated with or without control IgG, or LFA-1 blocking antibody (α-LFA-1) for 30 min. These cells were stimulated with or without ICAM-1 for 6 h and then incubated with anti-CD3/CD28 (α-CD3/28) for an additional 24 h in the presence or absence of TGF-β. Conditioned medium was collected, and IL-2 secretion was measured by ELISA. b, PBL T-cells pre-treated with or without control IgG, or LFA-1 blocking antibody (α-LFA-1) were stimulated via LFA-1/ICAM-1 for 6 h or un-stimulated and then treated with or without 5 ng/ml TGF-β before lysis. Cell lysates (20 μg each) were Western blotted and probed with anti-pSMAD2 or anti-SMAD2. Relative densitometric analysis of the individual pSMAD2 protein band is presented. Data are representative of three independent experiments (mean ± S.E.). *, p < 0.05; NS, not significant.