Identification of Cells Eliminating and Harboring Mumps Viruses in the Male Reproductive System

A large spectrum of viruses can infect the male reproductive system (MRS). Although the MRS adopts the local antiviral defense, it has also been considered as a potential viral reservoir. We hypothesize that tissue-specific cells may eliminate invading viruses and harbor viral replication in the MRS. We herein aimed to identify viral eliminators and potential reservoirs in the MRS using mumps virus (MuV) and mouse models. Primary cells, mainly consisting of epithelial cells, stromal cells, and macrophages, were isolated from the epididymis, seminal vesicle, and prostate of mice. MuV infection and replication were analyzed by determining MuV nucleoprotein (MuV-NP) in the primary cells. We demonstrated that a subset of resident macrophages efficiently took up and eliminated MuV, which should be involved in the antiviral defense in the MRS. However, a small subset of epithelial and stromal cells in these organs harbored MuV replication, and these cells could be viral reservoirs. Furthermore, interferon-β (IFN-β) inhibited MuV replication in MuV-replicating cells, suggesting that IFN-β administration may limit viral reservoirs. The results of the present study provide novel insights into the antiviral defense and viral reservoirs in the MRS, which can aid in the development of preventive and therapeutic approaches for viral infection of the MRS.