http://repub.eur.nl/res/aut/34950/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/34917/ 2012-01-01T00:00:00Z In wild-type mice, T-cell receptor (TCR) γδ+cells differentiate along a CD4 CD8 double-negative (DN) pathway whereas TCRαΒ+cells differentiate along the double-positive (DP) pathway. In the human postnatal thymus (PNT), DN, DP and single-positive (SP) TCRγδ+populations are present. Here, the precursor-progeny relationship of the various PNT TCRγδ+populations was studied and the role of the DP TCRγδ+population during T-cell differentiation was elucidated. We demonstrate that human TCRγδ+cells differentiate along two pathways downstream from an immature CD1+DN TCRγδ+precursor: a Notch-independent DN pathway generating mature DN and CD8αα SP TCRγδ+cells, and a Notch-dependent, highly proliferative DP pathway generating immature CD4 SP and subsequently DP TCRγδ+populations. DP TCRγδ+cells are actively rearranging the TCRα locus, and differentiate to TCR DP cells, to CD8αΒ SP TCRγδ+cells and to TCRαΒ+cells. Finally, we show that the γδ+subset of T-cell acute lymphoblastic leukemias (T-ALL) consists mainly of CD4 SP or DP phenotypes carrying significantly more activating Notch mutations than DN T-ALL. The latter suggests that activating Notch mutations in TCRγδ+thymocytes induce proliferation and differentiation along the DP pathway in vivo. http://repub.eur.nl/res/pub/26699/ 2011-07-01T00:00:00Z This study tested the hypothesis that Vγ3 TCR-bearing T cells are influenced by LCs. Vγ3 T cells and LCs are located in the epidermis of mice. Vγ3 T cells represent the main T cell population in the skin epithelium and play a crucial role in maintaining the skin integrity, whereas LCs are professional APCs. Although Vγ3 T cells and LCs form an interdigitating network in the epidermis, not much is known about their reciprocal influence and/or interdependence. We used two different LC-deficient mouse models, in which LCs are constitutively or inducibly depleted, to investigate the role of LCs in maturation, homeostasis, and function of Vγ3 T cells. We show that Vγ3 T cell numbers are unaltered by LC deficiency, and Vγ3 T cells isolated from LC-deficient mice are phenotypically and upon in vitro stimulation, functionally indistinguishable from Vγ3 T cells isolated from WT mice based on their cytotoxic potential and cytokine production. Additionally, in vivo skinwounding experiments show no major difference in response of Vγ3 T cells to wounding in the absence or presence of LCs. These observations indicate that Vγ3 T cells develop and function independently of LCs. http://repub.eur.nl/res/pub/25448/ 2009-06-01T00:00:00Z Human embryonic stem cells (hESC) are pluripotent stem cells. A major challenge in the field of hESC is the establishment of specific differentiation protocols that drives hESC down a particular lineage fate. So far, attempts to generate T cells from hESC in vitro were unsuccessful. In this study, we show that T cells can be generated in vitro from hESC-derived hematopoietic precursor cells present in hematopoietic zones (HZs). These zones are morphologically similar to blood islands during embryonic development, and are formed when hESC are cultured on OP9 stromal cells. Upon subsequent transfer of these HZs on OP9 cells expressing high levels of Delta-like 1 and in the presence of growth factors, cells expand and differentiate to T cells. Furthermore, we show that T cells derive exclusively from a CD34highCD43lowpopulation, further substantiating the notion that hESC-derived CD34highCD43lowcells are formed in HZs and are the only population containing multipotent hematopoietic precursor cells. Differentiation to T cells sequentially passes through the physiological intermediates: CD34+CD7+T/NK committed, CD7+CD4+CD8-immature single positive, CD4+CD8+double positive, and finally CD3+CD1-CD27+mature T cell stages. TCRαβ+and TCRγδ+T cells are generated. Mature T cells are polyclonal, proliferate, and secrete cytokines in response to mitogens. This protocol for the de novo generation of T cells from hESC could be clinically and scientifically relevant. Copyright