Table 1.

Subsets of memory CD8 T cell pool and their characteristics.

Subset	Phenotype	Location	Function	Transcription Factors (TFs)
TCM	CD62Lhi, CCR7hi, CD127hi CD27hi, CX3CR1lo, KLRG1lo	Circulation, Primarily in LN and SLO	++ Ag-dependent expansion +/- Cytotoxicity	Eomes, FOXO1, Bcl6, Id3, TCF1
TEM	CD62Llo, CCR7lo, CD127hi/lo CD27hi/lo, CX3CR1hi/lo KLRG1hi/lo	Circulation, primarily in blood and occasionally NLT	+/- Ag-dependent expansion ++ Cytotoxicity	T-bet, Blimp1, Zeb2, Id2
TRM	CD69hi depending on NLT: CD103hi CD49ahi, CXCR3hi, CXCR6hi	Primarily NLTs, also found in draining LN	+ Proliferation ++ Sense and alarm function	Hobit, Blimp1, Runx3

+/- means a great fraction of the cells in the subset is endowed with the function while a noticeable population within the subset is not.