TABLE 1.

T_H17-associated cytokine production by non-T_H17 cells and effects at the mucosa

Cytokine	Producers	Receptor	Effects
IL-17A	rTH17, Tregs, CD8+ T cell, γδ T cell, TFH, NKT cell, ILC, neutrophil, Paneth cell, macrophage	IL-17RA/IL-17RC	Neutrophil recruitment [71, 72] Antimicrobial peptide production (e.g., S100A8, S100A9 [73]) Cytokine and chemokine production (e.g., G-CSF, IL-6, CXCL1 [74, 75]) Inhibits TH1 polarization [7]
IL-17F	γδ T cell	IL-17RA/IL-17RC	Neutrophil recruitment [76] Cytokine and chemokine production (e.g., G-CSF, IL-6, CXCL1 [74, 75]) Lymphocyte and macrophage recruitment [18] Mucus hyperplasia in the lung [18]
IL-21	CD8+ T cell, TFH, NKT cell, neutrophil	IL-21R/γc	Cell proliferation, especially NK cells [22] Enhances TH17 responses [27] B cell class-switching [77] Regulatory B cell function [78]
IL-22	rTH17, CD8+ T cell,γδ T cell, NKT cell, ILC, neutrophil, macrophage	IL-22RA1/IL-10R2	Antimicrobial peptide production (e.g., S100A8, S100A9, Reg3γ [73, 79]) Epithelial cell proliferation/transformation [43] Enhances mucosal barrier function [79] Inhibits epithelial apoptosis [46]
IL-26	ILCs	IL-20R1/IL-10R2	Cytokine production (e.g., IL-8, IL-10 [55, 56]) Decreased epithelial proliferation [56]

Reg3γ, Regenerating islet-derived protein 3 γ.