DeLuca D, Bluestone J A, Shultz L D, Sharrow S O, Tatsumi Y
Department of Microbiology and Immunology, University of Arizona, Tucson 85721.
J Immunol Methods. 1995 Jan 13;178(1):13-29. doi: 10.1016/0022-1759(94)00236-p.
Fetal thymus organ culture (FTOC) has become widely used to investigate the impact of immunomodulators on T cell development. However, these studies have given variable results among different laboratories. In this study, we have found that fetal tissue age and mouse strain differences can affect the development of T cell phenotypes in this system. T cell development in FTOC occurred in two 'waves', defined as peaks of cell recovery. The first wave consisted initially of CD4-CD8- double negative (DN) cells and CD4-CD8+ single positive (SP) T cells expressing gamma delta T cell receptor (TCR). CD4+CD8+ double positive (DP) cells expressing low levels of alpha beta TCR were produced soon thereafter; and these cells dominated the cultures for the balance of the first wave. Prolonged FTOC resulted in the production of another wave of T cells which were relatively enriched for CD4 or CD8 SP cells expressing high levels of alpha beta TCR, as well as DN cells and CD4-CD8+ SP T cells expressing high levels of gamma delta TCR. As defined by cell number and differentiation of alpha beta TCR SP cells, development was delayed in FTOC using fetal thymus tissue from younger fetuses relative to that observed when older fetal thymus tissue was used. The degree of development of T cells in FTOC was also strain dependent. Organ cultures derived from 14 gestation days (gd) C.B-17 scid/scid fetal thymus did not generate TCR-bearing mature SP cells, but they did produce TCR-negative CD4 and CD8 SP cells likely to be precursors of DP thymocytes. Such cultures made from 18 gd tissue did not produce SP cells. Negative selection in FTOC was also evaluated. Mtv-specific V beta 3 cells were deleted in FTOC of C3H/HeN tissue. Deletion occurred only in late FTOC, suggesting a late encounter between the Mtv deleting elements and susceptible T cells during ontogeny. These results show that while FTOC recapitulates normal thymic development by a variety of criteria, results can be influenced by the length of culture, as well as by the age and strain of fetal thymus tissue utilized.
胎儿胸腺器官培养（FTOC）已被广泛用于研究免疫调节剂对T细胞发育的影响。然而，不同实验室的这些研究结果存在差异。在本研究中，我们发现胎儿组织年龄和小鼠品系差异会影响该系统中T细胞表型的发育。FTOC中的T细胞发育以细胞恢复的峰值定义为两个“波”。第一波最初由表达γδT细胞受体（TCR）的CD4-CD8-双阴性（DN）细胞和CD4-CD8+单阳性（SP）T细胞组成。此后不久产生表达低水平αβTCR的CD4+CD8+双阳性（DP）细胞；这些细胞在第一波的剩余时间里主导了培养物。延长FTOC培养时间会产生另一波T细胞，这些T细胞相对富含表达高水平αβTCR的CD4或CD8 SP细胞，以及表达高水平γδTCR的DN细胞和CD4-CD8+ SP T细胞。根据αβTCR SP细胞的数量和分化情况定义，与使用较老胎儿胸腺组织时相比，使用较年轻胎儿胸腺组织进行FTOC培养时，发育会延迟。FTOC中T细胞的发育程度也取决于品系。源自妊娠14天（gd）的C.B-17 scid/scid胎儿胸腺的器官培养物不会产生带有TCR的成熟SP细胞，但它们确实会产生可能是DP胸腺细胞前体的TCR阴性CD4和CD8 SP细胞。由18 gd组织制成的此类培养物不会产生SP细胞。还评估了FTOC中的阴性选择。在C3H/HeN组织的FTOC中，Mtv特异性Vβ3细胞被删除。删除仅发生在FTOC培养后期，这表明在个体发育过程中，Mtv删除元件与易感T细胞之间的相遇较晚。这些结果表明，虽然FTOC在多种标准下概括了正常胸腺发育，但结果可能会受到培养时间长度以及所用胎儿胸腺组织的年龄和品系的影响。
