Figure 4.
Figure 4. Rescue of early transplantation defect by wild-type hematopoiesis. (A) Deletion of SCL in mixed chimeras. Donor cells (MxSCL+/loxP or MxSCL-/loxP) mixed with wild-type competitor cells (SCL+/+) in a ratio of 80:20 were transplanted into lethally irradiated wild-type primary recipients. Reconstituted primary recipients were then treated with poly(I:C) to generate donor SCL-heterozygous (MxSCL+/Δ) or -deleted (MxSCL-/Δ) hematopoiesis in the presence of wild-type hematopoiesis and stroma. Bone marrow cells from these recipients were transplanted into secondary recipients 6 days after poly(I:C). The percentage of donor-derived myeloid (Mac-1) and B (B220) cells was measured in secondary recipients 4 and 16 weeks after transplantation. Each bar represents the mean and SD of 3 to 5 recipients. The dashed line indicates the expected donor contribution (80%). *P < .05. (B) Deletion of SCL in chimeras. Donor cells (MxSCL+/loxP or MxSCL-/loxP) were transplanted into lethally irradiated wild-type primary recipients. Reconstituted primary recipients were then treated with poly(I:C) to generate SCL-heterozygous (MxSCL+/Δ) or -deleted (MxSCL-/Δ) hematopoiesis in the presence of wild-type stroma. The SCL-heterozygous and SCL-deleted bone marrow cells were then mixed with SCL-wild-type cells in a ratio of 90:10 for assay by competitive repopulation. Competitor cells had also been serially transplanted so that their repopulating potential would be similar to the donor cells. The percentage of donor-derived myeloid (Mac-1) and B (B220) cells was measured in secondary recipients 4 and 16 weeks after transplantation. Each bar represents the mean and SD of 3 to 5 recipients. *P < .05. (C) Reciprocal transplantations to assess the ability stroma in SCL-deleted mice to support short-term repopulating cells. Donor cells (SCL-wild-type) were transplanted into lethally irradiated MxSCL+/loxP (n = 4) or MxSCL-/loxP (n = 4) mice. Reconstituted primary recipients were then treated with poly(I:C) to generate SCL-wild-type hematopoiesis within a SCL-heterozygous (MxSCL+/Δ) or -deleted (MxSCL-/Δ) stroma. The SCL-wild-type hematopoietic cells were then assayed by competitive repopulation in a ratio of 80:20 with SCL-wild-type competitor cells. Unlike the donor cells, the competitor cells had not been serially transplanted and thus provided greater than the expected repopulation (20%) in the secondary recipients. The percentage of donor-derived myeloid (Mac-1) and B (B220) cells was measured in secondary recipients 4 and 16 weeks after transplantation. Each bar represents the mean and SD of at least 3 recipients.

Rescue of early transplantation defect by wild-type hematopoiesis. (A) Deletion of SCL in mixed chimeras. Donor cells (MxSCL+/loxP or MxSCL-/loxP) mixed with wild-type competitor cells (SCL+/+) in a ratio of 80:20 were transplanted into lethally irradiated wild-type primary recipients. Reconstituted primary recipients were then treated with poly(I:C) to generate donor SCL-heterozygous (MxSCL+/Δ) or -deleted (MxSCL-/Δ) hematopoiesis in the presence of wild-type hematopoiesis and stroma. Bone marrow cells from these recipients were transplanted into secondary recipients 6 days after poly(I:C). The percentage of donor-derived myeloid (Mac-1) and B (B220) cells was measured in secondary recipients 4 and 16 weeks after transplantation. Each bar represents the mean and SD of 3 to 5 recipients. The dashed line indicates the expected donor contribution (80%). *P < .05. (B) Deletion of SCL in chimeras. Donor cells (MxSCL+/loxP or MxSCL-/loxP) were transplanted into lethally irradiated wild-type primary recipients. Reconstituted primary recipients were then treated with poly(I:C) to generate SCL-heterozygous (MxSCL+/Δ) or -deleted (MxSCL-/Δ) hematopoiesis in the presence of wild-type stroma. The SCL-heterozygous and SCL-deleted bone marrow cells were then mixed with SCL-wild-type cells in a ratio of 90:10 for assay by competitive repopulation. Competitor cells had also been serially transplanted so that their repopulating potential would be similar to the donor cells. The percentage of donor-derived myeloid (Mac-1) and B (B220) cells was measured in secondary recipients 4 and 16 weeks after transplantation. Each bar represents the mean and SD of 3 to 5 recipients. *P < .05. (C) Reciprocal transplantations to assess the ability stroma in SCL-deleted mice to support short-term repopulating cells. Donor cells (SCL-wild-type) were transplanted into lethally irradiated MxSCL+/loxP (n = 4) or MxSCL-/loxP (n = 4) mice. Reconstituted primary recipients were then treated with poly(I:C) to generate SCL-wild-type hematopoiesis within a SCL-heterozygous (MxSCL+/Δ) or -deleted (MxSCL-/Δ) stroma. The SCL-wild-type hematopoietic cells were then assayed by competitive repopulation in a ratio of 80:20 with SCL-wild-type competitor cells. Unlike the donor cells, the competitor cells had not been serially transplanted and thus provided greater than the expected repopulation (20%) in the secondary recipients. The percentage of donor-derived myeloid (Mac-1) and B (B220) cells was measured in secondary recipients 4 and 16 weeks after transplantation. Each bar represents the mean and SD of at least 3 recipients.

Close Modal
This Feature Is Available To Subscribers Only

or Create an Account

Close Modal
Close Modal