Representative competitive repopulation assay between STAT5ab^−/− and wild-type BM grafts.

Total BM cells were collected from either STAT5ab^−/− or wild-type mice and mixed at 1:1 donor equivalent ratios. The BM cell mixes were then injected into lethally irradiated recipient mice (1100 rads). (A) Primary transplanted mice from experiment no. 1 were bled from the retroorbital venous plexus 6 months after transplantation and analyzed for the relative ratio of the 2 donor grafts. Hemoglobin electrophoresis of packed red blood cells on cellulose acetate gels was used to analyze the donor engraftment. The Hb_s and Hb_d patterns of control mice that did not receive transplants are shown on the right. The number above each lane is the individual mouse identification number. Identical experiment no. 2 and experiment no. 3 are not shown. (B) Primary transplanted mice were killed at 6 months, and the BM cells were injected into lethally irradiated (1100 rads) secondary recipient mice. Secondary transplanted mice were analyzed 4 months after transplantation for the relative ratio of the 2 donor grafts. The number above each lane represents the primary donor mouse from which each mouse was derived.