Figure 4.

Effect of anti-TGF-β antibodies on HeLa vector control cell inhibition of IL-2-mediated allogeneic PBL proliferation. (a) At the initiation of the assay, recombinant TGF-β was added at 8 ng/ml (+) or 80 ng/ml (+ +) to PBL cocultured with a CD80-expressing HeLa cell clone lacking the inhibitory phenotype (clone 2) and IL-2. Anti-TGF-β mAb was added as indicated at 1 or 20 µg/ml (+ +) upon initiation of the cultures and again 24 h later. (b) Anti-TGF-β mAb was added at 1 µg/ml (+) or 20 µg/ml (+ +), upon initiation of the cultures and again 24 hr later, to PBL incubated with HeLa vector control cells. Assays were conducted in the absence (open bars) or presence (closed bars) of exogenous IL-2 and were incubated for a total of 5 days. Tritiated thymidine was added at 0·5 µCi/well for the final 18 hr of coculture. Data are representative of two independent experiments. Error bars represent the standard deviation of ³H-thymidine incorporation in triplicate cultures.