T Cells Make the Skin Home

The concept that skin is an immune organ with resident T cells has gained considerable traction in the past decade. These researchers show that a localized vaccinia virus (VACV) skin infection generates long-lived, nonrecirculating CD8⁺ T_RM cells that reside within the entire skin.

Using a VACV infection model, Jiang and colleagues introduced ovalbumin (OVA) into the skin of mice infused with CD8⁺ T cells that recognize OVA peptide. These cells gave rise to both circulating central memory T cells (T_CM) and skin-resident effector memory T cells (T_RM). By linking through parabiosis the circulation of the “vaccinated” mice to the unexposed mice, the researchers found that T_CM efficiently populated both sets of mice, whereas the T_RM cells stayed…