In vivo production and hematopoietic activity of interleukin 3 (IL-3) in mice

在移植物抗宿主病(GVH-D)小鼠的血清中发现了高水平的IL-3。IL-3水平随着GVH-D的加重而升高。用14天胎鼠肝细胞的红系集落形成法和依赖于IL-3的FDC-P2细胞摄取~3H-TdR的方法检测了这一因子的水平。用FDC-P2细胞的方法检测到了这种抑制活性，而不是用红系集落形成技术检测到的。然而，用红系集落形成技术检测到GVH-D的抑制活性。这一活性的特异性或生理作用尚不清楚。通过内毒素无应答的C3H/HeJ小鼠的实验，排除了血清的造血活性可能是由于内毒素诱导的因素所致。在患GVH-D时，GVH-D小鼠的血清活性与对照组小鼠一样高。在GVH-D小鼠的骨髓、脾和淋巴结细胞的液体培养上清液中观察到IL-3的产生。在注射多环GVH-D小鼠血清的小鼠中，证实了IL-3的体内效应，其中血清促红细胞生成素水平降低到无法检测到的范围。注射后3d，小鼠脾CFU-C和CFU-Mix显著升高，血清中IL-3刺激小鼠造血祖细胞增殖和分化。因此，它在体内和体外的造血中都发挥着重要的作用。

We have demonstrated a high level of interleukin 3(IL-3) in the serum of mice with graft-versus-host disease(GVH-D).The level of IL-3 rised as the GVH-D became severer.The level of this factor was measured by the method of either erythroid colony-formation from 14 day-fetal mouse liver cells or^3H-TdR uptake in FDC-P2 cells which are IL-3 dependent cell line.The inhibitory activity was detected in the serum by the method using FDC-P2 cells but not erythroid colony-forming technique.However,the specificity or physiological role of this activity was obscure.The possibility that the hematopoietic activity of the serum might be due to a factor induced by endotoxin was excluded by the experiments with endotoxin non-responder C3H/Hej mice,in which the activity was elevated as much as the control mice when suffering from GVH-D.The production of IL-3 was observed in liquid culture media from bone marrow,spleen and lymph node cells in GVH-D mice.The in vivo effect of IL-3 was confirmed in mice injected with the serum from polycytemic GVH-D mice, in which serum erythropoietin level was reduced into undetectable range.Total numbers of BFU-E,CFU-C and CFU-Mix were remarkably increased in spleens of the mice 3 days after the injection.IL-3 in the serum stimulated the proliferation and differentiation of the hematopoietic progenitors in mice. Consequently,it plays and important role in hematopoiseis in vivo as well as in vitro.