Oral Presentation ESA-SRB-APEG-NZSE 2022

A novel role for Interferon-epsilon in protecting the male reproductive tract against Zika virus infection (#209)

Rukmali Wijayarathna 1 2 , Eveline de Geus 2 3 , Rosemary Genovese 1 , Michelle Tate 2 3 , Paul Hertzog 2 3 , Mark Hedger 1 2
  1. Centre For Reproductive Health, Hudson Institute of Medical Research, Melbourne, Victoria, Australia
  2. Dept. of Molecular and Translational Sciences, School of Clinical Sciences, Monash University, Melbourne, Victoria, Australia
  3. Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Melbourne, Victoria, Australia

Viruses, including HIV, mumps, Zika and SARS, frequently infect the testis and disrupt fertility. This has been attributed to an inability of spermatogenic cells to produce interferons (IFN) or IFN-induced proteins, required for viral resistance. Challenging this dogma, we discovered that interferon-epsilon (IFNe), a type-I IFN first identified in female reproductive epithelia, is constitutively expressed by meiotic and post-meiotic spermatogenic cells and testicular macrophages in mice and humans. We aimed to investigate the anti-viral role of IFNe in the testis, using an established mouse model of Zika virus infection and a human Sertoli cell-line (HSerc, ScienCellTM). Adult wildtype mice (WT), Ifne-/- mice lacking IFNe, and Ifnar1-/- mice lacking the IFNAR1 receptor subunit required for IFN-signalling, received a single intraperitoneal injection of Zika virus (PRVABC59, 5x105 pfu in saline). Controls received saline only. Reproductive organs were collected 7 days post-infection (peak illness). Infected WT mice lacked histological evidence of orchitis or epididymitis, but infected Ifne-/- and Ifnar1-/- mice displayed testicular hyperaemia, oedema, and immune cell infiltrates. The epididymis of infected Ifne-/- and Ifnar1-/- mice displayed immune cell infiltrates, epithelial damage, luminal obstruction and fibrosis. Expression of critical Leydig cell (Cyp11a1, Cyp17a1) and spermatid genes (Tnp1) was also reduced in infected Ifne-/- and Ifnar1-/- mice. The HSerc cell-line was infected with 5 or 10 MOI Zika virus, and treated with 100IU recombinant human IFNe either 12h before or 1h after infection. qPCR for viral RNA and plaque assays for infectious virus performed 24h post-infection showed that IFNe pre-treatment reduced the viral load by ~98%. Post-infection IFNe treatment reduced viral RNA by ~70% and infectious virus by 97%. These data indicate that IFNe plays a key role in protecting the testis against Zika virus, shifting the existing paradigm of testicular anti-viral defences, and identifying IFNe as a potential therapeutic for testicular viral infections.