The simultaneous addition of 1,000 ng/ml cyclosporine and neutralizing anti-TGF-β antibodies to mBECs in C-SFM caused a concentration-dependent increase in [3H]-thymidine incorporation after 48 hours, compared to mBECs treated with 1,000 ng/ml cyclosporine and control nonimmune immunoglobulin. This result further confirms that inhibition of BEC growth, in vitro, is mediated via TGF-β. The results shown are representative of two separate experiments (*, P < 0.002; **, P < 0.0003).