Interferon epsilon as a novel anti-viral agent in the testis [human]

The testis is susceptible to viral infections, which can impair fertility. Spermatogenic cells were thought to lack anti-viral defences, including interferon (IFN) or IFN-stimulated gene (ISG) expression. Challenging this dogma, we discovered that interferon-epsilon (IFNɛ), a type-I IFN first identified in female reproductive epithelia, is constitutively expressed by spermatogenic cells and macrophages in mouse and human testes. Moreover, mice lacking IFNɛ are more susceptible to viral epididymo-orchitis. The mechanisms of IFNɛ-mediated anti-viral protection in the testis were examined in this study.