Objective: Mumps virus (MuV) infection frequently causes oophoritis and is associated with female infertility.Mechanisms behind ovarian innate immune responses to MuV infection are largely unknown.This study aimed to investigate pattern recognition receptor-initiated innate immune responses to MuV infection in mouse ovarian cells.Methods: Real-time qRT-PCR and ELISA were mainly used to detect the expression of proinflammatory cytokines and chemokines at mRNA and protein levels.Western blotting and immunohistochemistry were used to analyze the distribution and activation of NF-B and interferon regulatory factor 3.Results: We found that MuV infection induced the expression of proinflammatory cytokines TNF-α and IL-1 β, chemokines MCP-1 and IP-10, as well as type 1 interferons IFN-α and IFN-β in the ovarian cells.MuV-induced proinflammatory cytokine and chemokine expression was significantly reduced in TLR2/cells.However, MuV-induced IFN-α and IFN-β expression was dramatically decreased by knockdown of retinoic acid-inducible gene I signaling.Moreover, we demonstrated that MuV infection inhibited the expression of key steroidogenic enzymes,including P450 aromatase, β-HSD, P450scc, in the ovarian cells.Conclusion: This study indicated that Toll-like receptor 2 and retinoic acid-inducible gene I cooperatively mediated MuV-induced innate immune responses in mouse ovarian cells.Data provide novel insights into the mechanisms underlying the ovarian innate immune responses to MuV infection.