Figure 2. TGF-β bioassay in co-culture.

Mouse CD4 T cells were stimulated with plate-bound anti-CD3/CD28 for 2 days, and rested for 1 day. The pre-activated CD4 T cells were recovered, and the indicated numbers of T cells were added to 293T-caga-Luc-CD32-CD86 cells with 0.5 µg/ml anti-CD3 antibody. Recombinant human TGF-β was also added as a standard. After 16 hr of culture, the reporter cells were lysed and the luciferase activity was measured. Error bars represent mean ± S.D. of duplicates.