Marrow transplantation measured by uptake of Fe59 by spleen

Abstract

Transplantation of isologous (syngeneic) bone marrow into lethally X-irradiated mice has been quantified in terms of the degree to which the spleen incorporates Fe⁵⁹. Spleen uptake of Fe⁵⁹ is linear with bone marrow cell dose and reflects the erythropoietic integrity of the transplanted cells. Parameters of the assay were investigated including X-ray exposure to the recipient, time of assay, Fe⁵⁹ uptake time and plasma clearance of the isotope. The following protocol was adopted: (C₃H x C₅₇BL) F₁ male mice are a) exposed to 850 r of X rays, b) injected with bone marrow 24 hr later, c) given Fe⁵⁹ 8 days later, and d) killed 6 hr after isotope injection to obtain spleens for Fe⁵⁹ analysis. The assay was used to determine radiosensitivity of the erythropoietic compartment of marrow and to determine integrity of marrow cells after short-term culture as a means of studying in vitro recovery from radiation damage. Results showed that the in vitro radiation exposure required to reduce the surviving cells to 37% (D₃₇) was 75 r. Studies of normal cells in short-term culture showed that cell integrity could be maintained for at least 6 hr in Tyrode's solution with calf serum at 22 C but that integrity was reduced after 6 hr at 37 C in all media tested.