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.