Table 1. Functions of PRRs in initiating innate immune response in mouse testicular cells.

Cell types	PRRs	Ligands	Signaling	Immune molecules	Ref.
Sertoli cells	TLR2	LipoproteinDAMPs	NF-κBMAPKs	TNF-α, IL-1β, IL-6, MCP-1	27,99,103
	TLR3	Poly(I:C)	IRF3/NF-κB	TNF-α, IL-6, IFN-α, IFN-β	81,104
	TLR4	LPSDAMPs	NF-κB, MAPKs, IRF3	TNF-α, IL-1β, IL-6, MCP-1, IFN-α, IFN-β	27,99,103
	TLR5	Flagellin	NF-κB, MAPKs	TNF-α, IL-1, IL-6, MCP-1	103
	TLR6	Peptidoglycan	NF-κB, MAPKs	TNF-α, IL-1, IL-6	103
Leydig cells	TLR3	Poly(I:C)	IRF3NF-κB	TNF-α, IL-6, IFN-α, IFN-βAntiviral proteins	82
	TLR4	LPS	NF-κBIRF3	TNF-α, IL-1β, IL-6IFN-α, IFN-β	82
	RIG-I	Poly(I:C)	IRF3NF-κB	IFN-β, TNF-α, IL-6Antiviral proteins	109
	MDA5	Poly(I:C)	IRF3NF-κB	IFN-β, TNF-α, IL-6Antiviral proteins	109
SpermatogniaSpermatocytes	TLR3	poly(I:C)	IRF3NF-κB	IFN-α, IFN-β, TNF-α, IL-6Antiviral proteins	105
Spermatids	TLR11	ProfillinUPEC	NF-κB, MAPKsIRF3	TNF-α, IL-6, MCP-1IL-12, IFN-β, IFN-γ	106
	MDA5	Poly(I:C)	IRF3	IFN-β, TNF-α, IL-6Antiviral proteins	109

Abbreviations: DAMP, damage-associated molecular pattern; IFN, interferon; IRF, interferon regulatory factor; LPS, lipopolysaccharide; MDA5, melanoma differentiation-associated protein 5; PRR, pattern recognition receptor; RIG-I, retinoic acid-inducible gene I; TLR, Toll-like receptor.