The effect of mCTLA4-Ig on the secondary immune response to factor VIII.

All mice initially received 3 intravenous injections of 0.2 μg factor VIII at 2-week intervals. (A) Control mice (○) were then injected with factor VIII an additional 3 times, and blood samples were obtained for assay. (B, C) The other mice (•) were injected intraperitoneally with 250 μg mCTLA4-Ig the day before and the day after the fourth factor VIII injection (as indicated by the arrow). This was followed by 2 more injections of only factor VIII at 3-week intervals. The number of factor VIII injections prior to the blood sample tested for antifactor VIII is indicated on the horizontal axis.