Murine Bone Marrow Transplant and Tumor Models

Recipient mice were irradiated with two split doses of 1,000 cGy from a ¹³⁷Cs source (IBL 437 C; CIS Bio International, Bangnols sur Ceze, France) with a 5-h interval. BM cells isolated from the femur and tibia of gender-matched donors were depleted of T cells by MACS and 5 × 10⁶ T cell-depleted BM (TCD-BM) cells were transferred i.v. into recipients 5 h after the second irradiation as previously described^{57 (link),58 (link)}. EL4 cells were purchased from ATCC (TIB-39; Rockville, MD, USA), and transduced to express H60, H60 and Luciferase, or H60 and Thy1.1 (H60⁺EL4) or transduced with empty vector^{32 (link)}. Original and transduced EL4 cells were periodically checked for expression of CD3 and the relevant antigens by flow cytometry. H60-positive or negative EL4 tumor cells were injected s.c. (5 × 10⁵) or i.v. (1 × 10⁶) into BMT recipients at 6 weeks after BMT. C1498 (B6 acute myeloid leukemia cells) were purchased from ATCC (TIB-49) and transduced to express Thy1.1 alone or together with H60 as described above. Original and transduced C1498 cells were periodically checked for expression of the relevant antigens by flow cytometry. H60-positive or -negative C1498 leukemic cells were injected i.v. (5 × 10⁵) into BMT recipients at 6 weeks after BMT. Both original and transduced EL4 and C1498 cell lines have been periodically tested to exclude mycoplasma contamination by PCR.