Adipose tissue T_M cells

Immunity 47, 1154–1168 (2017)

Memory T cells (T_M cells) are present in the white adipose tissue (WAT). In Immunity, Belkaid and colleagues show that the WAT reservoir of T_M cells provides potent and rapid protective immune responses. In the mesenteric adipose tissue (mAT), CD8⁺ T cells with a CD44^–CD62L^–CD69⁺ phenotype are non-circulating, tissue-resident cells (T_RM cells), while CD4⁺ T_M cells are non-resident. T_RM cells accumulate and persist in the mAT after acute or persistent infection with mucosal pathogens and reactivate quickly after re-infection. Transplantation of WAT from previously infected mice transfers protection against lethal infection with Yersinia pseudotuberculosis. At homeostasis, T_M cells in the mAT are more metabolically active and more proliferative than are T_M cells in the spleen or lamina propria of the small intestine, while during recall responses, they upregulate genes encoding antimicrobial molecules at the expense of lipid metabolism.