Local Inflammatory Cues Regulate Differentiation and Persistence of CD8⁺ Tissue-Resident Memory T Cells

Highlights

• IFN-β and IL-12 are produced in the intestinal tissue during local infection

• IFN-β and IL-12 regulate differentiation of CD8⁺ Trm populations

• Cytokine signaling in CD8⁺ T cells is required for persistence in the tissue

• Intestinal monocytes/macrophages produce cytokines that drive Trm differentiation

Summary

Many pathogens initiate infection at mucosal surfaces, and tissue-resident memory T (Trm) cells play an important role in protective immunity, yet the tissue-specific signals that regulate Trm differentiation are poorly defined. During Yersinia infection, CD8⁺ T cell recruitment to areas of inflammation within the intestine is required for differentiation of the CD103⁻CD69⁺ Trm subset. Intestinal proinflammatory microenvironments have elevated interferon (IFN)-β and interleukin-12 (IL-12), which regulated Trm markers, including CD103. Type I interferon-receptor- or IL-12-receptor-deficient T cells functioned similarly to wild-type (WT) cells during infection; however, the inability of T cells to respond to inflammation resulted in defective differentiation of CD103⁻CD69⁺ Trm cells and reduced Trm persistence. Intestinal macrophages were the main producers of IFN-β and IL-12 during infection, and deletion of CCR2⁺ IL-12-producing cells reduced the size of the CD103⁻ Trm population. These data indicate that intestinal inflammation drives phenotypic diversity and abundance of Trm cells for optimal tissue-specific immunity.