T cell ontogeny: extrathymic and intrathymic development of embryonic lymphohemopoietic stem cells.
T cell ontogeny: extrathymic and intrathymic development of embryonic lymphohemopoietic stem cells.
复制标题
T 细胞个体发育：胚胎淋巴造血干细胞的胸腺外和胸腺内发育。
DOI：
10.1007/bf02935522
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发表时间：
1987
影响因子：
4.4
通讯作者：
Globerson,A
中科院分区：
文献类型：
--
作者：
Eren,R;Auerbach,R;Globerson,A
The appearance of different T lymphocyte subsets in the fetal thymus (FT) has attracted considerable attention [1] and attempts have been made to delineate their developmental patterns [2, 3]. Furthermore, recent studies have shown that the early molecular processes leading to expression of the T cell antigen receptor genes occur in the FT [4, 5]. On the other hand, the primary source and nature of lymphohemopoietic stem cells that give rise to different T cell subsets have not yet been clearly elucidated. Efforts have concentrated in the past on determining whether thymocytes develop from intrathymic [6, 7] or from extrathymic [8, 9] stem cells. In this respect, the possibility that various T cell subsets may actually be derived from more than one distinct origin has been raised [10, 11] but not critically established. The bulk of evidence conforms to the idea that lymphoid differentiation of the thymus is primarily dependent on an inflow of precursor cells from an extrinsic origin. Yet, it is not clear whether the first T cells that emerge in the embryo originate from extraembryonic (ie, yolk sac) or intraembryonic (ie, fetal liver) cells that colonize the thymus. Furthermore, it has yet to be determined whether the stem cells of the fetal liver derive from the yolk sac or whether these two compartments of embryonic hemopoietic stem cells are independent of each other. Moreover, other sites of potential lymphopoiesis, such as the embryonic omenturn and the placenta are only now beginning to be identified.Early experiments utilizing chromosome markers and histological techniques in combination with parabiosis and transplantation procedures in chick embryos suggested that the primary source of stem cells is the yolk sac [8]. On the other hand, studies using the quail-chick chimera system in which quail embryos were grafted onto chick yolk sacs indicated that the hemopoietic stem cells which colonized embryonic hemopoietic organs were from intraembryonic origin [12]. Studies on the developmental origin of lym-
