Table 1.

Features of universal donor cells.

Cell type	Size of the TCR repertoire	Polymorphism of restricting element	TCR cross-pairing potential *	Difficulties of ex vivo expansion	Risk of off-tumor on target recognition	Reported or expected risk of GVHD	Universality score (lowest is best)	Intrinsic immune activity	References
αβ-TCR T cells
VST	++	+++	++	–	–	–	7	Anti-viral	(11, 12)
iNKT	+	+	+	–	+	–	4	Anti-tumoral, pro-inflammatory, protect from GVHD	(13–16)
dNKT	+++	+	+++	++	++	+	12	Immune suppressive	(7, 17, 18)
CD1a-restricted	+++	+	+++	+	++	+	11	Unknown	(19–21)
CD1b GEM	+	+	++	+	++	+	8	Unknown	(22, 23)
CD1b LDN5-like	+	+	++	+	++	+	8	Unknown	(22, 23)
CD1b-restricted	++	+	+++	+	++	+	10	Unknown	(19–21)
CD1c-restricted	+++	+	+++	+	++	+	11	Unknown	(19–21)
MAIT	+	+	+++	+++	++	+	11	Unknown
γδ-TCR T cells
Vγ9Vδ2	–	+	–	–	+	–	2	Anti-tumoral, pro-inflammatory, APC	(24–27)
Vδ1	+++	Unknown (non-HLA)	–	–	+	–	4	Anti-tumoral, pro-inflammatory	(28)

Table summarizing the different features restricting the use of a T cell subset as universal donor cells. The amplitude of each restricting feature is depicted as none/extremely low (–), low (+), intermediate (++) and high (+++). The addition of each (+) is reported in the “Universality score” column, which represents the universal potential of each T cell subset, with a lower score corresponding to higher universality.

^*Upon introduction of a transgenic TCR.

TCR, T cell receptor; VST, virus-specific T cell; MAIT, mucosal-associated invariant T cell; GEM, germline-encoded mycolyl lipid-reactive; dNKT, diverse natural killer T cells; iNKT, invariant natural killer T cells; HLA, human leukocyte antigen; GVHD, graft-versus-host disease; APC, antigen-presenting cell.