Costimulation of T-cell proliferation by B7-H2Ig.

(A) Purified T cells were cultured in the presence of immobilized anti-CD3 mAb at indicated doses (horizontal axis) and immobilized B7-H2Ig (open circle) or control Ig (closed circle) at 5 μg/mL; cpm indicates counts per minute. (B) Purified T cells were cultured with indicated doses of B7-H2Ig (open circle) or control Ig (closed circle) in the presence of immobilized anti-CD3 mAb at 20 ng/mL.