Table 1.

Characteristics of innate T cells.

TCR	Human: Vα24-Jα18	Human: Vα7.2-Jα33	Human: Vδ1, Vδ3, Vγ9vδ2
	Mouse: Vαl4-Jα18	Mouse: Vαl9-Jα33	Mouse: VγlVδ6.3, Vγ5Vδ1, Vγ6Vδ1
Ligand	Glycolipids, phospholipids	Vitamin B2 metabolites, transitory neo-antigens	Phosphoantigens, phycoerythrin, glycolipids
Frequency	Low (0.01–1% of T cells)	1–20% of T cells	2–10% of T cells
Location	Blood, mucosal site, and liver	Blood, gut, lung, liver	Blood, mucosal sites
Maturation	Thymus	Secondary lymphoid tissue	Thymus
Present at birth	Yes	Yes	Yes
HSCT	Yes	?	Poor

?, information not known.