Secretion of TGF-β by AND T cells. Purified T cells from AND
TCR+ mice were activated as in Fig. 1. At 72 h,
supernatants were collected and assayed for the presence of TGF-β by
ELISA (A) or bioassay (B).
(A) TGF-β production by AND TCR transgenic T cells
stimulated with TCR alone (open bars), TCR/CTLA-4 (solid bars),
TCR/CD28 (shaded bars), and TCR/CD28/CTLA4 (hatched bars).
(B) For the bioassay, a 1:1 dilution of supernatant was
added to the cell line Mv1Lu, and the proliferation of these cells was
determined at 20 h. T cell activation supernatants were heated at
80°C for 2 min to activate latent TGF-β. Shown is inhibition of
proliferation of Mv1Lu cells 20 h after addition of treated
supernatants.