TABLE 1.

The effect of AHR ligands on different cell types.

Sources	Ligands	Targeted cells	Function
Exogenous substances	TCDD	Treg	Treg generation
		ES cell	Inhibition of ES cell differentiation
	10-CI-BBQ	CD4+ Nrp1+ Foxp3– RORγt+ cell	Attenuation of cell formation
	FICZ	Th17, Treg	Th17 generation; Foxp3 expression
Dietary	Glucosinolate	ILCs	Expansion of RORγt+ ILCs
	I3C	ILCs, IELs	Formation of lymphoid follicles, IL-22 production
	DIM	ILCs, IELs	Maintenance of IELs;
	ICZ	Th22, iNKTs	Epithelial cell proliferation
	LTr-1	γδT cells	Surveillance of microbial load;
Endogenous metabolites	Kyn	Treg, DC	Treg differentiation; Tolerogenic DC generation
	ITE	DC	Induction of tolerogenic DC
	KA	Cancer cell, Macrophage	IL-6 production
Microbiome	IPA	Intestinal epithelial cell	Activation of IL-10 signaling
	IAld	Astrocyte	Regulation of IFN-I signaling in astrocytes

TCDD: 2,3,7,8-tetracholrodibenzo-p-dioxin; 10-CI-BBQ: 10-chloro-7H-benzimidazo [2,1-a] benzo [de] iso-quinolin-7-one; FICZ:6-formylindolo[3,2-b]carbazole; I3C: indole-3-carbinol; DIM: 3,3′-di-indoly-methane; ICZ: indole [3,4-b] carbazole; LTr-1: [2-(indol-3-ylmethy)-indol-3-yl] indol-3-ylmethane; Kyn: kynurenine; ITE: 2-(1′H-indole, 3′carbonyl) thiazole-4-carboxylic acid methyl ester; KA: Kynurenic acid; IPA: indole-3-propionic IAId: indole-3-aldehyde; ES: embryonic stem; ILCs: innate lymphoid cells; IELs: intraepithelial lymphocytes; DC: dendritic cells.