在胸腺，不成熟的CD4 + 8 +胸腺细胞表达随机重排的T细胞受体的α-和B链的基因进行积极和消极的选择根据自己的能力，认识到self-peptide/major胸腺表达的组织相容性复合体（MHC）分子的事件基质细胞。在体内的胸腺基质细胞在胸腺内选择的作用分析是难以在胸腺微环境的稳态成人胸腺细胞的复杂性，以及缺乏适当的定位策略来操纵基因的表达，尤其是胸腺基质车厢。我们已经证明胸腺微环境，可以在体外很容易操纵，通过使用reaggregate胸腺器官培养，这让准备从定义的基质和淋巴样细胞的三维胸腺叶。虽然在体外系统支持T细胞发育的某些方面，reaggregate胸腺器官培养仍然是唯一在体外系统能够支持高效的MHCⅠ类，我和II介导的胸腺细胞的选择事件，等等，可作为一种有效的工具来研究使用的正面和负面的选择在胸腺细胞和分子调控。
Formal Correction: Erratum: Preparation of 2-dGuo-Treated Thymus Organ Cultures
Posted by JoVE Editors on 04/01/2012. Citeable Link.
A correction was made to: Preparation of 2-dGuo-Treated Thymus Organ Cultures. A revised abstract was republished due to a publisher error. The abstract was corrected to:
In the thymus, interactions between developing T-cell precursors and stromal cells that include cortical and medullary epithelial cells are known to play a key role in the development of a functionally competent T-cell pool. However, the complexity of T-cell development in the thymus in vivo can limit analysis of individual cellular components and particular stages of development. In vitro culture systems provide a readily accessible means to study multiple complex cellular processes. Thymus organ culture systems represent a widely used approach to study intrathymic development of T-cells under defined conditions in vitro. Here we describe a system in which mouse embryonic thymus lobes can be depleted of endogenous haemopoeitic elements by prior organ culture in 2-deoxyguanosine, a compound that is selectively toxic to haemopoeitic cells. As well as providing a readily accessible source of thymic stromal cells to investigate the role of thymic microenvironments in the development and selection of T-cells, this technique also underpins further experimental approaches that include the reconstitution of alymphoid thymus lobes in vitro with defined haemopoietic elements, the transplantation of alymphoid thymuses into recipient mice, and the formation of reaggregate thymus organ cultures. (This article is based on work first reported Methods in Molecular Biology 2007, Vol. 380 pages 185-196).
In the thymus, immature CD4+8+ thymocytes expressing randomly rearranged T-cell receptor α- and b-chain genes undergo positive and negative selection events based on their ability to recognize self-peptide/major histocompatibility complex (MHC) molecules expressed by thymic stromal cells. In vivo analysis of the role of thymic stromal cells during intrathymic selection is made difficult by the cellular complexity of the thymic microenvironment in the steady-state adult thymus, and by the lack of appropriate targeting strategies to manipulate gene expression in particular thymic stromal compartments. We have shown that the thymic microenvironment can be readily manipulated in vitro through the use of reaggregate thymus organ cultures, which allow the preparation of three-dimensional thymus lobes from defined stromal and lymphoid cells. Although other in vitro systems support some aspects of T-cell development, reaggregate thymus organ culture remains the only in vitro system able to support efficient MHC class I and II-mediated thymocyte selection events, and so can be used as an effective tool to study the cellular and molecular regulation of positive and negative selection in the thymus.