Table 1.

Markers of tissue‐resident memory T cells

Marker	Up/down	Function	Site	Notes	Mouse	Reference	Human	Reference
CCR9	↑	migration	SI>LI		√	[18]
α4β7	↑	migration	SI, LI?	early upregulation, decreased in memory phase	√	[levels that from 21, 22]
CXCR3		migration	SI? LI		√	[24]
CD103	↑	binds to E‐cadherin	SI, LI	necessary for cell accumulation but not retention	√	[22]	√	[25]
CD69	↑	inhibits S1pr1	SI, LI	dispensable for Trm retention in mouse intestine	√	[26]	√	[25]
CD49a	↑	binds to collagen IV	skin	not studied in intestine	√	[27]	√	[28]
S1pr1	↓	cell egress	SI, LI?	regulated by KLF2	√	[29]
S1pr5	↓	cell egress	skin	not studied in intestine	√	[30]
CCR7	↓	LN homing	skin	not studied in intestine	√	[31]
Transcription factors
Hobit	↑	inhibits cell egress	SI, LI?	in humans, it can be expressed by circulating memory cells and liver resident NK cells	√	[32]	√	[33, 34]
Blimp1	↑	inhibits cell egress	SI, LI?	early upregulation, lower level in Trm	√	[32]
Runx3	↑	promotes residency	SI, LI?		√	[35]
Bhlhe40	↑	promotes Trm mitochondrial fitness and epigenetic programming	Lung and tumor		√	[36]
Junb/Fosl2	↑	not well studied	SI, LI?		√	[37]
Klf2	↓	promotes cell egress	SI, LI?		√	[29]