Harel L, Chatelain G, Golde A
J Cell Physiol. 1984 Apr;119(1):101-6. doi: 10.1002/jcp.1041190117.
We recently fractionated, from the culture medium of 3T3 cells, a thermolabile inhibitory diffusible factor (IDFN) with a molecular weight of about 40,000 daltons, which decreased nucleic acids synthesis of stimulated target 3T3 cells. In the present publication the inhibitory activities of IDFN (produced by 3T3 cells) and IDFT (produced by RSV-transformed 3T3 [3T3 SRA/H] cells) on 3T3 and 3T3 SRA/H cells have been compared. The inhibitory activity of IDFN decreased (by a mean of 57%) when it was tested on transformed instead of 3T3 cells. On the other hand, IDFT was able to decrease 14C-inosine incorporation in target 3T3 cells. However, the inhibitory activity of IDFT decreased (by mean 50%) when tested on 3T3 SRA/H instead of 3T3 cells. Therefore, transformed cells produced an inhibitory factor but were less sensitive than 3T3 cells to its inhibitory activity. The inhibitory activity of IDFT on 3T3 SRA/H cells was only 20% of the inhibitory activity of IDFN on 3T3 cells. This appreciable difference is of particular interest, since it could explain the release of density-dependent inhibition of growth (DDI) in transformed 3T3 SRA/H cells. Furthermore, it provides more evidence for the hypothesis that, in 3T3 cells, DDI of growth is due to the release of an inhibitory molecule into the medium, and that IDFN is in fact, the inhibitory molecule involved in this phenomenon.
我们最近从3T3细胞的培养基中分离出一种分子量约为40,000道尔顿的热不稳定抑制性扩散因子（IDFN），它可降低受刺激的靶3T3细胞的核酸合成。在本出版物中，已比较了IDFN（由3T3细胞产生）和IDFT（由劳斯肉瘤病毒转化的3T3 [3T3 SRA/H]细胞产生）对3T3和3T3 SRA/H细胞的抑制活性。当在转化细胞而非3T3细胞上进行测试时，IDFN的抑制活性降低（平均降低57%）。另一方面，IDFT能够降低靶3T3细胞中14C - 肌苷的掺入。然而，当在3T3 SRA/H细胞而非3T3细胞上进行测试时，IDFT的抑制活性降低（平均降低50%）。因此，转化细胞产生了一种抑制因子，但比3T3细胞对其抑制活性的敏感性更低。IDFT对3T3 SRA/H细胞的抑制活性仅为IDFN对3T3细胞抑制活性的20%。这一显著差异特别值得关注，因为它可以解释转化的3T3 SRA/H细胞中生长密度依赖性抑制（DDI）的解除。此外，它为以下假设提供了更多证据：在3T3细胞中，生长的DDI是由于一种抑制性分子释放到培养基中，并且IDFN实际上就是参与这一现象的抑制性分子。
