Myeloablative effectiveness of the irradiation protocol before BMT. These are light micrographs of bone marrow cytospin preparations. Mouse bone marrow was isolated and layered onto discontinuous Percoll (Sigma-Aldrich) gradient of 82%/65%/55%. Neutrophils were recovered at the 82%/65% interface, and cytospin preparations were subsequently prepared and stained using the Wright-Giemsa method. The left panel shows mouse bone marrow neutrophils 1 week after irradiation without BMT rescue, and the right panel shows mouse bone marrow neutrophils from a healthy control mouse. These micrographs demonstrate the effectiveness of our radiation protocol in depleting the recipient's immune system in preparation for donor BMT. Original magnification, × 40.