Table 1.

Comparison of two types of CD4 T cells and NKT cells

		CD4 T		NKT
		E-CD4 T	T-CD4 T
Selecting cell type		Epithelial cells	Thymocytes	Thymocytes
Selecting element		MHC class II	MHC class II	CD1
Antigen		Peptides	?	Glycolipids
TCR repertoire		Diverse	Diversea	Limited
NK1.1 expression		No	Nob	Yes
Preformed IL-4 mRNA		No	Yesc	Yes
Stat6 requirement to express IL-4		Yes	Nod	No
PKCθ requirement to express IL-4		Yes	No	Yese
Developmental requirement	SAP	No	↓	↓
	Fyn	No	↓	↓
	PKCθ	No	↓	↓
	T-bet	No	NS	↓
	IL-15Rα	No	NS	↓
	Ly108	No	NS	NS

↓, reduced; NS, not significant

References for a, b, c, d, and e are Choi et al. (2005), Li et al. (2005), Li et al. (2007), Patel et al. (2005), and Stanic et al. (2004), respectively.