Figure 4.

T cell costimulatory effect of wild-type and mutants of B7-H1 and B7-DC. (a) Purified T cells from B6 mice were stimulated with immobilized wild-type or mutants of B7-H1 and B7-DC Ig fusion proteins at 5 μg/ml in the presence anti-CD3 mAb at indicated concentrations. Human Ig was used as negative control. The proliferation of T cells was determined by incorporation of 1 μCi/well of ³H-TdR during the last 12 h of the 3-d culture. Data depict one representative experiment of three. (b) For analysis of IFN-γ secretion, purified T cells were cultured in the presence of precoated anti-CD3 (1 μg/ml) and 5 μg/ml of immobilized Ig fusion proteins and control human Ig. Supernatants were collected after 48 and 72 h culture and assayed for IFN-γ using ELISA. Data depict one representative experiment of three.