Regeneration of Bone Marrow Cells and Thymus induced by 19S Alpha-2 Globulin in Irradiated Mice

Abstract

THE 19S alpha-2 globulin isolated by us from the alpha-2 globulin fraction of human serum (obtained from Mann Res. Lab., New York) by the procedure of Schonenberger et al.¹ and identified by electrophoresis on poly aery lamide gel² and ultracentrifugation was found to stimulate the regeneration of bone marrow cells in X-irradiated mice (C57Bl/6). A sample (0.5 mg) of the 19S alpha-2 globulin injected intraperitoneally into 33–35 day old mice within an hour of exposure to 170 r. produced a significant speeding up in the incorporation of ³H-thymidine into bone marrow cells, as compared with that in irradiated animals injected with saline (Fig. 1). Seven days after irradiation 19S alpha-2 globulin-injected animals showed an actual overshoot in number of cells of femoral and tibial bone marrow (55 × 10⁶/mouse), as compared with unirradiated controls (42 × 10⁶/mouse) and irradiated but saline-injected controls (41 × 10⁶/mouse), respectively. The total DNA content of bone marrow cells at this stage showed a similar picture, the femoral and tibial bone marrow cells of mice injected with 19S alpha-2 globulin containing 527 µg of DNA, while the irradiated (saline-injected) controls contained 410 µg and the non-irradiated controls contained 414 µg of DNA.