Table.

Prominent innate-like lymphocytes present in the intestine

Cell type	Locations & frequencies	TCR	Recognized antigen	Activating cytokines	Cytokines produced	Functions in intestinal immunity
γδ	-Blood (1–10% of T cells in humans) -Gut (25–60% of T cells in humans) -Thymus, Spleen	Vγ9δ2 (humans) Vδ1 Vδ2 Vγ4δ5	-HMB-PP (Vγ9δ2) -MICA, CD1c, lipohexapeptides (Vδ1) -ULBP4 (Vδ2) -EPCR (Vγ4δ5)	IL-1β IL-23	IFN-γ TNF-α IL-17 IL-4	-Lysis of infected/stressed cells -Cytokine/chemokine production -B cell help -Priming of αβ T cells -DC maturation -Regulation of stromal cell function
MAIT	-Blood (1–10% of T cells in humans, ~0.1% in mice) -Gut (LP, PP) -Liver (~30% of T cells in humans) -Lungs	-Vα7.2-Jα33/12/20, Vβ2/13.2 (humans) -Vα19-Jα33, Vβ6/8 (mice)	-Vitamin B metabolites	IL-12 IL-18	IFN-γ TNF-α IL-17	-Anti-bacterial immunity -Cytokine production -Lysis of infected cells
iNKT	-Blood (0.1–0.2% in humans) -Liver (<1% of T cells in humans, ~10–20 % in mice) -Gut, Lung, Spleen, Bone Marrow, Thymus	Vα24-Jα18, Vβ11 (humans) Vα14-Jα18, Vβ2/7/8.2 (mice)	-Endogenous and bacterial-derived glycolipids -α-galactosyl ceramide -β-galactosyl ceramide	IL-12 IL-18 IL-23 IL-1β IL-7 IL-25	Th1 (IFN-γ, TNF-α) Th2 (IL-1, IL-4, IL-13) Th17 (IL-17, IL22)	-Recognition of endogenous lipid antigens upregulated by DC upon TLR activation -Enhance priming of antigen-specific B and T cell responses -Cytokine production
ILC3	-Gut (LP, PP)	N/A	N/A	IL-7 IL-15 SCF (cKit) IL-23 IL-1β	IL-17 IL-22	-Stimulation of antimicrobial peptide RegIIIγ from epithelial cells by ILC-derived IL-22 -Regulating gut CD4 T cell resposnes -Maintenance of epithelial barrier function -Promoting formation of Peyer’s patches and lymph nodes during embryogenesis (LTi)