Fig. 3.
IL-2 secretion and Akt phosphorylation are particularly costimulation-dependent in 5C.C7 T cells. (A) The dependence of IL-2 secretion (Fig. 5) on costimulation in 5C.C7/I-Ek-GFP transfected A20 versus DO11.10/A20 interactions in the presence of the indicated concentrations of agonist peptide is shown. Blockade of ICAM-1 and B7–1/B7–2 with 10 μg/ml antibody is indicated. IL-2 secretion was normalized (the value for 10 μM agonist peptide = 100%). Two to five independent experiments were performed, and averages plus standard deviations are given. *, a significant (P < 0.05) difference between buffer only and anti-B7. (B) Akt S473 phosphorylation after 30 min of T cell/APC interactions (Fig. 8B) is shown similar to A. In C, correlation coefficients (R2 values) of normalized Akt phosphorylation against central TCR accumulation and IL-2 data as determined by linear regression (similar to Fig. 6) are listed.