Contact allergens induce CD8⁺ T cell-derived interleukin 10 that appears dispensable for regulation of contact hypersensitivity

Interleukin 10 (IL-10) has been implied in the regulation of allergic contact dermatitis. Using transcriptional reporter mice we analyzed cellular sources of IL-10 during contact hypersensitivity (CHS) and identified IL-10 expressing CD8⁺ T cells in the skin that are antigen-specific, display PD-1, an effector memory phenotype, and IL-10 expression comparable to that of CD4⁺ T cells. However, in mice with a selective IL-10 deficiency in CD8⁺ T cells CHS responses were comparable to that of controls, even in the absence of CD4⁺ cells, suggesting that CD8⁺ T cell-derived IL-10 does not contribute significantly to the resolution of CHS responses.