Fig. 3.

T-cell inhibition by blast cells. a CTL activity of CD8-sorted T cells expanded for 2 weeks against blast cells from six patients with AML. Before the CTL assay, blast cells were pre-incubated for 1 h with or without 500 ng/ml Ultrapure LPS, anti-B7-H1 mAb or isotype control. Data represent the mean and SD of experiments performed in quadruplicate. *indicates significant differences with LPS (Student’s t test). E:T effector:target ratio. b CTL activity of CD8-sorted T cells expanded for 2 weeks against blast cells from one patient with AML collected upon diagnosis and upon first relapse. Target cells were pre-incubated for 1 h with anti-B7-H1 or isotype control before the CTL assay. Data represent the mean and SD of experiments performed in quadruplicate