Tissue-resident memory T cells (TRM cells) persist long term at epithelial barrier surfaces and are essential in anti-pathogen responses at these sites. In Nature, Kupper and colleagues demonstrate that mouse TRM cells in the skin are characterized by high expression of the fatty-acid-binding proteins FABP4 and FABP5. This expression is critical for the maintenance but not the ingress of skin TRM cells, as Fabp4−/−Fabp5−/− mice have a much lower abundance of these cells and are vulnerable to experimental infection with vaccinia virus. Consistent with their high expression of FABP4 and FABP5, skin TRM cells show enhanced uptake and metabolism of free fatty acids. Finally, human psoriatic lesions also contain TRM cells that express FABP4 and FABP5. Not only do these data reveal an essential and cell-type-specific mechanism for the maintenance of TRM cells but they also offer a possible means of targeting this population.

Nature (20 February 2017) doi:10.1038/nature21379