When grafted <i>in vivo</i> a population of fetal thymic epithelial cells, marked by the monoclonal antibodies MTS20 and MTS24, can generate all major thymic epithelial cell subtypes. Furthermore, the resultant thymic organoid can recruit T cell precursors and support their differentiation into mature CD4<sup>+</sup> and CD8<sup>+</sup> T cells. The work presented here evaluates the potential of MTS20<sup>+</sup> thymic epithelial progenitor cells to form the basis of a thymus equivalent <i>in vitro</i>. To assess the ability of the MTS20<sup>+</sup> thymic epithelial progenitor cell (TEPC) population to support T cell differentiation <i>in vitro</i>, improvements were made to the established reaggregate fetal thymic organ culture (RFTOC) method that permitted the reliable generation and culture of TEPC-based RFTOC (TEPOC). Subsequent analysis demonstrated that both MTS20<sup>+</sup> and MTS20<sup>+</sup> fetal thymic epithelial cells were able to support the differentiation of αβ and γδ T cells and also supported the differentiation of several other haematopoietic populations including dendritic cells and thymic macrophages. However, while immunofluorescence analysis showed that MTS20<sup>+</sup> cells were able to differentiate <i>in vitro</i> to generate all major thymic epithelial cell populations, only limited differentiation was observed in MTS20<sup>+ </sup>cell-based cultures. Strikingly, the TEPOCs were able to form organised epithelial structures <i>in vitro</i>, characterised by clearly distinguished adjacent medullary and cortical areas. No evidence of organisation was seen in MTS20<sup>+</sup> cell-based cultures. Together, these data establish that MTS20<sup>+</sup> but not MTS20<sup>+</sup> thymic epithelial cells can generate functional <i>in vitro</i> thymus-equivalents that recapitulate the epithelial and haematopoietic landscape of the wild-type thymus. Furthermore, the unique organisational ability inherent within the TEPOCs may be useful as an <i>in vitro</i> model of the processes governing thymus organisation.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:661850 |
| Date | January 2007 |
| Creators | Sheridan, Julie Marie |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/14412 |
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