Pritchard L L, Goodman J W
Exp Hematol. 1978 Feb;6(2):161-71.
We have used the spleen colony assay and the 24-h uptake of 59Fe by hemopoietic tissues to study certain quantitative aspects of the interaction of parent-strain thymocytes and marrow cells transplanted into lethally irradiated F1 hybrid mice. The data show that thymocytes augment bone marrow growth at least partly by increasing the proportion of stem cells from parental marrow that from colonies in the hybrid animal. This increase in spleen colony number is a linear function of the number of thymocytes injected within certain dose ranges. At higher thymocytes doses, a plateau is reached where further increase in the number of thymocytes injected does not result in an increase in the number of spleen colonies; this plateau occurs at just that level of response given by the same marrow dose when transplanted into isogeneic (parent-strain) recipients. Experiments in which 59Fe uptake up red blood cells and spleen was used to measure marrow growth yielded similar results, except that the plateau in uptake occurred at a much lower level than that measured for the same marrow dose in isogeneic recipients. This apparent discrepancy in results obtained from the two different assays may best be explained by the recent observation that thymocytes shift the differentiation pattern of marrow stem cells away from erythropoiesis and toward granulopoiesis. The absolute thymocyte dose seems to be more important than the thymocyte: marrow-cell ratio in determining the degree of augmentation observed.
我们运用脾集落测定法以及造血组织对59Fe的24小时摄取量，来研究移植到致死剂量照射的F1杂种小鼠体内的亲代品系胸腺细胞与骨髓细胞相互作用的某些定量方面。数据表明，胸腺细胞至少部分地通过增加亲代骨髓干细胞在杂种动物中形成集落的比例来促进骨髓生长。在特定剂量范围内，脾集落数量的增加是注入胸腺细胞数量的线性函数。在更高的胸腺细胞剂量下，会达到一个平台期，此时注入的胸腺细胞数量进一步增加并不会导致脾集落数量增加；这个平台期恰好出现在相同骨髓剂量移植到同基因（亲代品系）受体时所给出的反应水平上。利用红细胞和脾脏对59Fe的摄取量来测量骨髓生长的实验得出了类似的结果，只是摄取量的平台期出现在比同基因受体中相同骨髓剂量所测得的水平低得多的水平上。从这两种不同测定方法获得的结果中出现的这种明显差异，可能最好由最近的观察结果来解释，即胸腺细胞会使骨髓干细胞的分化模式从红细胞生成转向粒细胞生成。在确定所观察到的增强程度时，绝对胸腺细胞剂量似乎比胸腺细胞与骨髓细胞的比例更为重要。
