Stem cell-like plasticity of naive and distinct memory CD8+ T cell subsets

Most models regarding the 'clonal' origin of CD8(+) T cell effector and memory subset diversification suggest that during the first contact of a naive T cell with the priming antigen-presenting cell major decisions for subsequent differentiation are made. Data using novel single-cell T cell tracking technologies demonstrate that a single naive CD8(+) T cell can give rise to virtually all different subtypes of effector and memory T cells, and direct major determinants of subset diversification to the time period beyond the first cell division. Thereby, some 'stem cell-like' characteristics typical for naive T cells are probably still maintained within distinct subsets of memory T cells. These observations have direct consequences for clinical applications like adoptive T cell therapy. (C) 2009 Elsevier Ltd. All rights reserved.