Characterization of a transgenic mouse expressing T-bet under the human CD2 promoter. (A) Western blot of T-bet expression by CD4⁺ T cells from either WT BALB/c (WT) or T-bet CD2-transgenic (TG) mice (also on the BALB/c background) activated with anti-CD3 and anti-CD28 antibodies under different polarizing conditions. (B-D) Cytokine profiles measured by enzyme-linked immunosorbent assay (ELISA) secreted by CD4⁺ T cells activated under different polarizing conditions. (B) IFN-γ production during primary stimulation from WT (□) and TG (▪) T cells. (C) IFN-γ production during secondary stimulation from WT and TG T cells. (D) IL-4 production during secondary stimulation from WT and TG T cells. (E-F) Interaction of WT and TG CD4⁺ T cells with immobilized P-selectin (left columns) and E-selectin (right columns) under conditions of laminar shear stress as indicated. Cells were by stimulated with plate-bound CD3 and CD28 antibodies in the presence of appropriate skewing cytokines. (E) CD4⁺ Th1-cell interactions. (F) Th2-cell interactions. All data are expressed as mean ± SEM.