Caractérisation des lymphocytes T CD8+ générés en conditions inflammatoires stériles

Most memory CD8 T cell subsets that have been defined are generated during viral infection. The aim of this work was to characterize a memory cell subset generated in sterile inflammatory conditions, i.e. in the absence of pathogen-derived signals. Those memory cells are characterized by their surface expression level of CD44/CD122, which are intermediate between those of naïve and pathogen-induced memory CD8 T cells. The memory cells from the sterile inflammation-induced subset also express intermediate levels of several other memory traits, including functional (IFN-g secretion capacity) and molecular (T-bet and Eomes) features. They correspond to an early differentiation stage and can further differentiate in conventional central memory T cells. This work made it possible to characterize the various properties of the cells memories generated in a sterile inflammatory context and especially the implication of these cells in skin inflammatory diseases like allergic contact dermatisLa plupart des sous-populations des lymphocytes T CD8 mémoires sont définies suite à une infection virale. Le but de ce travail fut de caractériser une sous-population des cellules mémoires générées en conditions inflammatoires stériles, c'est-à-dire en l'absence des signaux délivrés par des pathogènes. Ces cellules mémoires expriment des niveaux intermédiaires pour CD44 et CD122, compris entre les cellules naïves et les cellules mémoires induites par des pathogènes. Elles expriment également des niveaux intermédiaires de plusieurs autres propriétés fonctionnelles (production de l'IFN-g) et moléculaires (T-bet et Eomes) des cellules mémoires classiques. Elles correspondent à une étape précoce de différenciation et peuvent se différencier en mémoire centrale. Ce travail a permis de caractériser les cellules mémoires générées dans un contexte inflammatoire stérile et surtout l'implication de ces cellules dans les maladies inflammatoires de la peau comme la dermatite allergique de contac

TLR2 engagement on memory CD8 + T cells improves their cytokine-mediated proliferation and IFN-γ secretion in the absence of Ag

International audienc

Characterization of a CD44/CD122int memory CD8 T cell subset generated under sterile inflammatory conditions.

International audienceMost memory CD8 T cell subsets that have been hitherto defined are generated in response to infectious pathogens. In this study, we have characterized the CD8 T cells that survive priming conditions, devoid of pathogen-derived danger signals. In both a TCR-transgenic model and a model of contact hypersensitivity, we show that the priming of naive CD8 T cells under sterile inflammatory conditions generates memory. The corresponding memory CD8 T cells can be identified by their intermediate expression levels of CD44 and CD122. We also show that CD44/122(int) memory CD8 T cells spontaneously develop in wild type mice and that they display intermediate levels of several other memory traits including functional (IFN-gamma secretion capacity, CCL5 messenger stores), phenotypic, and molecular (T-bet and eomesodermin expression levels) features. We finally show that they correspond to an early differentiation stage and can further differentiate in CD44/122(high) memory T cells. Altogether, our results identify a new memory CD8 T cell subset that is generated under sterile inflammatory conditions and involved in the recall contact hypersensitivity reactions that are responsible for allergic contact dermatitis