Ikuo Kashiwakura, Mikinori Kuwabara, Osamu Inanami, Miho Murakami, Yukitoshi Hayase, Tsuneo A. Takahashi, Yoshinari Takagi
Radiation Research 153 (2), 144-152, (1 February 2000) https://doi.org/10.1667/0033-7587(2000)153[0144:RSOMCF]2.0.CO;2
Kashiwakura, I., Kuwabara, M., Inanami, O., Murakami, M., Hayase, Y., Takahashi, T.A. and Takagi Y. Radiation Sensitivity of Megakaryocyte Colony-Forming Cells in Human Placental and Umbilical Cord Blood.
The in vitro radiation sensitivity of CFU-Meg isolated from human placental and umbilical cord blood was evaluated in plasma clot cultures stimulated by recombinant human cytokines, including thrombopoietin, the FLT3 ligand (FLT3LG), interleukin-3, interleukin-11 and stem cell factor. The CD34 cells were irradiated with X rays at a dose rate of 73 cGy/min. The megakaryocyte colonies were identified by using an FITC-conjugated antibody to glycoprotein IIbIIIa and were classified into two groups based on colony size: large colonies (immature CFU-Meg) and small colonies (mature CFU-Meg). Treatment with thrombopoietin alone or in combination with FLT3LG and/or interleukin-11 gave exponential radiation survival curves (D0 for immature CFU-Meg = 56–77 cGy, D0 for mature CFU-Meg = 86 cGy–1.12 Gy), while marked shoulders were observed on the survival curves for colonies supported by the combination of thrombopoietin, interleukin-3 and stem cell factor (D0 for immature CFU-Meg = 89–98 cGy; D0 for mature CFU-Meg = 1.25–1.31 Gy). Our results showed that the immature CFU-Meg were more radiosensitive than the mature CFU-Meg and that the combination of cytokines, including thrombopoietin, interleukin-3 and stem cell factor, affected the radiation sensitivity of CFU-Meg to the same extent as with thrombopoietin alone or in combination with FLT3LG and/or interleukin-11.