Role of mucosal dendritic cells in inflammatory bowel disease

Table 1 Anatomic compartments of GALT

Compartment			Gut segment
Inductive/effector sites	Structure	Abbreviation	Small intestine		Large intestine3
			Upper1	Lower2
Effector	Lamina propria	LP	+++	+++	+++
	Intraepithelial lymphocytes	IEL	+++	+++	+++
Inductive	Peyer’s patch	PP	+	+++	-
	Intestinal lymph follicle	iLF	+	+++	-
	Intestinal lymph aggregate	iLA	+	++	++
	Mesenteric lymph node	MLN	-	-	-

¹Distribution of the described structures in the upper small intestine (duodenum and jejunum);

²Distribution of the described structures in the upper small intestine (ileum);

³Distribution of the described structures in the upper small intestine (ileum). “+++”: Very frequent; “++”: Frequent; “+”: Randomly; “-“: Not present.

Table 2 Mucosal DCs and their proposed function

DC1		Intestinal compartment2					Comment3	Ref.
Lineage	Phenotype	MLN	siLP	cLP	PP	iLF
cDC	CD4-CD8-	+++	+++	+++	+++	+++	Express CD103 or CX3CR1.	12-14, 47, 86, 99
	CD11b+CD11c+						Mediate intestinal antigen acquisition.
							Involved in the RA dependent Treg conversation.
							Permitting homing of conventional T cells to intestinal tissues by inducing CCR9 and α4β7.
	CD4+CD8-CD11b+CD11c+	+++	-	-	++	+	Prime CD4 T cell responses.	8, 28
	CD4-CD8+CD11b-CD11c+	++	-	-	++	++	Prime CD8 T cell responses.	8, 28
pDC	B220+PDCA1+CD11c+	+	+/-	+/-	+	+	Produce type I interferons	10

cDC: Conventional DC; pDC: Plasmacytoid DC; MLN: Mesenteric lymph node; PP: Peyer´s patch; cLP: colonic lamina propria; siLP: small intestinal lamina propria; iLF: intestinal lymph follicle.

¹DC lineage;

²Phenotype of the described DC lineage;

³Distribution of the described DC lineage in distinct intestinal compartments.