Enhancement of haemopoietic colony-formation in irradiated mice by the serum from carbon-treated mice.

*森 和博 ,瀬 戸 昭,伊 藤洋平:京 都大学医学部微生物学教室,京 都市左京区吉田近 衛町,〒606 **中 村清一:大 阪府立公衆衛生研究所 ,大 阪市東成区中道,〒537 一 Effect of sera from carbon-treated and/or irradiated mice on the colony-formation in the X-irradiated recipient mice was studied with respect to 'colony-enhancing factor(s)' and the effect of 'RES-blockade' on these factor(s). Treatment of irradiated mice with serum from carbon-injected and irradiated mice resulted in the significant increase of CFUs in the spleen. Sera from the mice treated with carbon particles alone also had the favorable effect. There were no apparent differences among the spleens of variously treated mice in their weights. The sera were effective only when they were given before the irradiation of the recipient mice. These results suggest that there are some humoral factor(s) in the serum of carbon-treated and/or irradiated mice. And these factor(s) seem to enhance spleen colony-formation mainly by changing the physiological condition of the spleen by the time of the irradiation rather than by affecting colony-forming cells directly.