Spangrude G J, Scollay R
Walter and Eliza Hall Institute for Medical Research, Royal Melbourne Hospital, Parkville, Victoria, Australia.
J Immunol. 1990 Dec 1;145(11):3661-8.
To define cell populations which participate in the very early stages of T cell development in the mouse thymus, we enriched hematopoietic stem cells from mouse bone marrow and injected them into thymic lobes of irradiated Ly-5 congenic recipients. The progeny of the stem cells were identified and their phenotypes were determined by two-color flow cytometry for the expression of various cell surface differentiation Ag during the course of their subsequent intrathymic development. The majority of the differentiation which occurred in the first 10 days after intrathymic cell transfer was myeloid in nature; hence, this study demonstrates that the irradiated thymus is not strictly selective for T cell development. Further, the maximum rate of T cell development was observed after intrathymic injection of 200 stem cells. Donor-derived cells which did not express Ag characteristic of the myeloid lineage could be detected and their phenotypes could be determined by flow cytometry as early as 7 days after intrathymic injection. At this time, the cells were still very similar phenotypically to the bone marrow hematopoietic stem cells. Exceptions to this were the expression of stem cell Ag 2 and a decrease in the level of MHC class I Ag expression. After 9 days, the donor-derived cells expressed high levels of the Thy-1 Ag and proceeded to change in cell surface phenotype as differentiation continued. These cell phenotypes are described for the time frame ending 18 days after injection, when most donor-derived cells were phenotypically small CD4+ CD8+ (double-positive) thymocytes.
为了确定参与小鼠胸腺T细胞发育早期阶段的细胞群体，我们从小鼠骨髓中富集造血干细胞，并将其注入经照射的Ly-5同基因受体的胸腺叶中。通过双色流式细胞术鉴定干细胞的后代，并在其随后的胸腺内发育过程中，确定各种细胞表面分化抗原的表达情况，以此来确定它们的表型。胸腺内细胞移植后的前10天内发生的大多数分化本质上是髓系的；因此，本研究表明，经照射的胸腺对T细胞发育并非严格具有选择性。此外，胸腺内注射200个干细胞后观察到T细胞发育的最大速率。早在胸腺内注射后7天，就可以通过流式细胞术检测到不表达髓系谱系特征性抗原的供体来源细胞，并确定其表型。此时，这些细胞在表型上仍与骨髓造血干细胞非常相似。例外情况是干细胞抗原2的表达以及MHC I类抗原表达水平的降低。9天后，供体来源的细胞高水平表达Thy-1抗原，并随着分化的继续在细胞表面表型上发生变化。这些细胞表型是针对注射后18天结束的时间段进行描述的，此时大多数供体来源的细胞在表型上是小的CD4+CD8+（双阳性）胸腺细胞。
