The cellular microenvironment regulates CX3CR1 expression on CD8 T cells and the maintenance of CX3CR1 CD8 T cells.

Expression levels of the chemokine receptor CX3CR1 serve as high-resolution marker delineating functionally distinct antigen-experienced T-cell states. The factors that influence CX3CR1 expression in T cells are, however, incompletely understood. Here, we show that in vitro priming of naïve CD8 T cells failed to robustly induce CX3CR1, which highlights the shortcomings of in vitro priming settings in recapitulating in vivo T-cell differentiation.