PROLIFERATIVE ACTIVITY OF THE LYMPHATIC TISSUES OF RATS AS STUDIED WITH TRITIUM-LABELED THYMIDINE.
PROLIFERATIVE ACTIVITY OF THE LYMPHATIC TISSUES OF RATS AS STUDIED WITH TRITIUM-LABELED THYMIDINE.
复制标题
DOI：
10.1084/jem.120.3.389
复制
发表时间：
1964-09-01
期刊：
影响因子：
--
通讯作者：
VANSLAGER LM
中科院分区：
文献类型：
--
作者：
CRADDOCK CG;NAKAI GS;FUKUTA H;VANSLAGER LM
细胞动力学数据，采用定量H3Tdr给药后连续处死的正常大鼠淋巴组织中的H3DNA。在胸腺和外周淋巴组织之间观察到初始标记和标记丢失模式的显著差异。这些数据与胸腺中快速细胞更新的其他迹象是一致的。胸腺中每个大淋巴细胞祖细胞的DNA对H3Tdr的初始摄取有抑制作用，这显然是因为胸腺中小淋巴细胞对含胸苷物质的反馈。由于手术应激或全身X射线导致胸腺小细胞耗竭，导致大胸腺细胞DNA摄取H3Tdr显著增加。这一发现与Sugino等人（33，34）的先前发现一致，表明胸腺嘧啶核苷酸从小胸腺淋巴细胞转移到前体细胞，可能与胸腺细胞之间DNA标记的明显转移有关，也可能无关。后者的证据包括胸腺增殖细胞群中DNA标记的曲线稀释和胸腺中大细胞中DNA标记稀释率与小细胞中H3DNA之间的关系。胸腺和淋巴结中祖细胞中的DNA标记进入小细胞群后，这些分裂细胞中颗粒的后续稀释遵循与整个淋巴结放射性损失相同的斜率。在分裂的淋巴结细胞群中存在一些H3DNA标记的长保留。这表明分裂细胞和小细胞群作为一个整体的放射性损失是相同的。无论大小细胞的百分比是否在实验中改变，这种模式都是普遍存在的。这些发现可以用小淋巴细胞和大淋巴细胞之间的DNA核标记互换来解释。这可以通过某些过程发生，如吞噬作用或胞饮作用，或通过小淋巴细胞转化为大的分裂细胞。数据最符合后一种可能性。所有或任何这些机制将导致大细胞和小细胞之间的DNA标记的平衡。这一发现阻止了基于DNA标记动力学的淋巴细胞的有限寿命的分配。然而，似乎至少有两种不同类型的淋巴细胞。一种是“胸腺型”淋巴细胞，存在于胸腺皮质、骨髓和淋巴滤泡的生发中心。另一种在广泛的外周淋巴组织中大量存在，显示出DNA标记的非常长的保留，并且被认为是其他人描述的再循环的“免疫定向”细胞。这些细胞似乎不进入胸腺皮质。
Cytokinetic data are presented, employing quantitation of H3DNA in the lymphatic tissues of normal rats serially sacrificed after H3Tdr administration. A marked difference in the patterns of initial labeling and label loss was observed between the thymus and peripheral lymphatic tissue. The data are compatible with other indications of rapid cell renewal in the thymus. There is suppression of initial uptake of H3Tdr into the DNA of each large lymphocytic progenitor cell in the thymus, apparently because of a feedback of thymidine containing material from small lymphocytes in the thymus. Depletion of the thymus of small cells, as by operative stress or whole body x-ray, leads to a marked increase in the uptake of H3Tdr into the DNA of large thymocytes. This finding, which is in agreement with the previous findings of Sugino et al. (33, 34) suggesting transfer of thymine nucleotides from small thymus lymphocytes to precursor cells, may or may not be related to the apparent transfer of DNA label between thymic cells. The evidence for the latter consists of the curvilinear dilution of the DNA label in the thymus proliferating cell population and the relationship between the rate of DNA label dilution in large cells and the H3DNA in the small cells in the thymus. After the DNA label in progenitor cells in the thymus and lymph nodes has entered the small cell population, the subsequent dilution of grains in these dividing cells follows the same slope as the loss of radioactivity from the entire lymph node. There is a long retention of some H3DNA label in the dividing lymph node cell population. This suggests that the loss of radioactivity from the dividing cells and from the small cell population as a whole occurs equally. This pattern prevails regardless of whether the percentage of large and small cells is altered experimentally. These findings can be explained by an interchange of the DNA nuclear label between small lymphocytes and large lymphocytes. This could occur by some process such as phagocytosis or pinocytosis, or by transformation of the small lymphocyte into a large, dividing cell. The data fit best with the latter possibility. All or any of these mechanisms would lead to an equilibration of the DNA label between large and small cells. This finding prevents the assignment of a finite life span to lymphocytes on the basis of DNA labeling kinetics. Nevertheless, there appear to be at least two different types of lymphocytes. One, the "thymus-type" lymphocyte, is found in the thymus cortex, bone marrow and germinal centers of lymphoid follicles. The other type, found abundantly in the widespread peripheral lymphatic tissue, shows a very prolonged retention of DNA label and is believed to be the recirculating, "immunologically committed" cells described by others. These cells do not appear to enter the thymus cortex.