Table 1.

Comparison of human conventional and unconventional T cells.

	Conventional		Unconventional
	CD4+ (Th) cell	CD8+ (Tc) cell	γδT cell	iNKT cell	MAIT cell
TCR chain repertoire	αβ (Diverse)		γδ (Limited)	Invariant αβ (Limited)
Antigen	Peptides	Peptides	Phosphoantigens	Glycolipids	Microbial metabolites
Restriction	MHC II	MHC I	Butyrophylin-dependent	CD1	MR1
CD4+	+	−	+ (rare)	+*	+ (rare)
CD8+	−	+	+ (minor)	+*	+ (major)
DN	−	−	+ (major)	+*	+ (minor)
CD161+	+/++ (Th17)	+	+++	+++	++++
Initial response	7–10 days		Hours-days

^*Reports are contradictory about the relative proportion of these subsets^229–231

DN, double negative; Tc, cytotoxic T; Th, T helper; TCR, T cell receptor.