Abstract
BackgroundT cell development occurs within the highly specialized thymus. Cytotoxic CD8 T cells are critical in adaptive immunity by targeting virally infected or tumor cells. In this study, we addressed whether functional CD8 T cells can be generated fully in vitro using human umbilical cord blood (UCB) hematopoietic stem cells (HSCs) in coculture with OP9-DL1 cells.ResultsHSC/OP9-DL1 cocultures supported the differentiation of CD8 T cells, which were TCR/CD3hi CD27hi CD1aneg and thus phenotypically resembled mature functional CD8 single positive thymocytes. These in vitro-generated T cells also appeared to be conventional CD8 cells, as they expressed high levels of Eomes and low levels of Plzf, albeit not identical to ex vivo UCB CD8 T cells. Consistent with the phenotypic and molecular characterization, upon TCR-stimulation, in vitro-generated CD8 T cells proliferated, expressed activation markers (MHC-II, CD25, CD38), secreted IFN-γ and expressed Granzyme B, a cytotoxic T-cell effector molecule.ConclusionTaken together, the ability to direct human hematopoietic stem cell or T-progenitor cells towards a mature functional phenotype raises the possibility of establishing cell-based treatments for T-immunodeficiencies by rapidly restoring CD8 effector function, thereby mitigating the risks associated with opportunistic infections.
Highlights
T cell development occurs within the highly specialized thymus
While we have demonstrated that specific populations of T-progenitor cells generated in vitro can reconstitute the thymus of immunodeficient mice and generate CD8 single positive (SP) T cells in vivo [8], it was not clear whether functional maturation of mature CD8 T cells could take place entirely in vitro starting from umbilical cord blood (UCB) hematopoietic stem cells (HSCs) in OP9-DL1 cell cocultures
Phenotypic characterization of human CD8 SP T-cells derived from HSCs cultured with OP9-DL1 cells We have previously reported the ability to generate CD4 + CD8+ T-lineage cells as well as CD4 and CD8 single positive (SP) cells from human cord blood-derived CD34+ CD38-/low HSC/OP9-DL1 cocultures [7], the maturational, molecular and functional status of these CD8 SP T-cells were not assessed
Summary
T cell development occurs within the highly specialized thymus. Cytotoxic CD8 T cells are critical in adaptive immunity by targeting virally infected or tumor cells. Results: HSC/OP9-DL1 cocultures supported the differentiation of CD8 T cells, which were TCR/CD3hi CD27hi CD1aneg and phenotypically resembled mature functional CD8 single positive thymocytes. These in vitrogenerated T cells appeared to be conventional CD8 cells, as they expressed high levels of Eomes and low levels of Plzf, albeit not identical to ex vivo UCB CD8 T cells. CD7 is one of the earliest markers to be expressed during human T cell ontogeny, followed by the upregulation of CD1a, which marks T cell commitment Following this stage, human thymocytes progress to a CD4 immature single positive (CD4ISP) stage, at which point CD4 is expressed in the absence of CD8. Following successful TCRa rearrangement, TCRab expressing DP thymocytes undergo positive and negative selection events, which result in the production of CD4+ CD8- and CD4- CD8+
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
