Regulation of cell surface expression of the integrin 6/β1 in Th1 and Tc1 cells. (A) Cord blood–derived type 1 (solid lines) or type 2 (dotted lines) polarized cell lines were cultured in a medium supplemented with IL-2 and stimulated with IL-12 (left panels) or IFN- (right panels) as described in Materials and Methods. At different times after stimulation with the cytokines, the cells were harvested, washed, and stained for surface expression of the integrin 6/β1. The mean fluorescence intensity measured for untreated Th2 cells was given the arbitrary value of 1 and all other values were expressed as fold increase over this value. Surface expression of the integrin 6/β1 was analyzed on CD4⁺ Th1 and Th2 cells (upper panels), and CD8⁺ Tc1 and Tc2 cells (lower panels). One representative experiment of 3 performed is shown. (B) Th1 cells were generated by the action of either IL-12 or IL-12 + IFN-. Cells were stained with FITC-conjugated anti-CD49f MoAb (thick lines) or with an isotype matched control (thin lines) and cell surface expression of integrin 6/β1 was analyzed by FACS. One representative experiment of 5 is shown. (C) ET 3.22 Th1 clone (upper panel) and E 4.1 Th2 clone (lower panel) were cultured in a medium supplemented with IL-2 and either left untreated (n.t.) or stimulated with IL-12 for 24 hours. Cells were stained with FITC-conjugated anti-CD49f MoAb (black lines) or with an isotype-matched control (grey lines). One experiment of 3 performed is shown.