Table 3.

Main studies about the effects of periodontal pathogens on the intestinal immune barrier.

Periodontal pathogens	Objects of study	effector	Target cells	receptor	Related signals	Related function
F. nucleatum	Primary Human NK Cells	Fap2	Nature killer cells	TIGIT		The inhibition of cytotoxicity (115)
	Patients		myeloid-derived immune cells			The augmentation of myeloid-derived immune cells (117)
	CRC cell lines, C57BL mice		CRC cells	TLR4	TLR4/Myd88/NF-κB/miR21	The proliferation of CRC cells (118)
	Human colon cancer cells HCT116, DLD1, SW480, and HT29	FadA	CRC cells	E-cadherin	E-cadherin/β-catenin	The proliferation of CRC cells (119)
			Tumor associated macrophages	TLR4	TLR4/IL-6/p-STAT3/c-MYC	macrophage M2 polarization (120)
	U937 cells	AI-2	macrophage	TNSF9	TNFSF9/IL-1β	macrophage M1 polarization (121)
	Clinical samples, mice, intestinal epithelial cells		epithelial cells	NOD2	NOD2/CARD3/IL-17F/NF-κB	Inflammation (123)
	HT29 cells, C57BL/6 mice	OMV	epithelial cells	TLR4	TLR4/ERK/CREB/NF-κB	Inflammation (124)
	Jurkat cells	Fap2, RadD	T, mononuclear and polymorphonuclear cells		NF-κB, ICE	The induction of apoptosis (138)
P. gingivalis	C57BL/6 mice		B, T cells	DNMT3b, BTLA		Inflammation (126)
	DBA/1J mice		Th17 cells			Inflammation (24)
	Human specimen, C57BL/6J mice		myeloid-derived immune cells			The augmentation of myeloid-derived immune cells (137)
			hematopoietic cells	NLRP3		colorectal tumor growth (137)
	C57BL/6 mice		macrophage			macrophage M1 polarization (139)
P. nigrescens	C57BL/6 mice		macrophage			increased the M1/M2 macrophage ratio (139)