Interferon ɛ restricts Zika virus infection in the female reproductive tract.

Interferon ɛ (IFNɛ) is a unique type I IFN that has been implicated in host defense against sexually transmitted infections. Zika virus (ZIKV), an emerging pathogen, can infect the female reproductive tract (FRT) and cause devastating diseases, particularly in pregnant women. How IFNɛ contributes to protection against ZIKV infection in vivo is unknown. In this study, we show that IFNɛ plays a critical role in host protection against vaginal ZIKV infection in mice. We found that IFNɛ was expressed not only by epithelial cells in the FRT but also by immune and stromal cells at baseline or after exposure to viruses or specific Toll-like receptor (TLR) agonists. IFNɛ-deficient mice exhibited abnormalities in the epithelial border and underlying tissue in the cervicovaginal tract, and these defects were associated with increased susceptibility to vaginal but not subcutaneous ZIKV infection. IFNɛ deficiency resulted in an increase in magnitude, duration, and depth of ZIKV infection in the FRT. Critically, intravaginal administration of recombinant IFNɛ protected Ifnɛ-/- mice and highly susceptible Ifnar1-/- mice against vaginal ZIKV infection, indicating that IFNɛ was sufficient to provide protection even in the absence of signals from other type I IFNs and in an IFNAR1-independent manner. Our findings reveal a potentially critical role for IFNɛ in mediating protection against the transmission of ZIKV in the context of sexual contact.

Interferon ε restricts Zika virus infection in the female reproductive tract.

Interferon ε (IFNε) is a unique type I IFN that has been implicated in host defense against sexually transmitted infections (STIs). Zika virus (ZIKV), an emerging pathogen, can infect the female reproductive tract (FRT) and cause devastating diseases, particularly in pregnant women. How IFNε contributes to protection against ZIKV infection in vivo is unknown. Here, we show that IFNε plays a critical role in host protection against vaginal ZIKV infection in mice. We found that IFNε was expressed not only by epithelial cells in the FRT, but also by certain immune and other cells at baseline or after exposure to viruses or specific TLR agonists. IFNε-deficient mice exhibited abnormalities in the epithelial border and underlying tissue in the cervicovaginal tract, and these defects were associated with increased susceptibility to vaginal, but not subcutaneous ZIKV infection. IFNε-deficiency resulted in an increase in magnitude, duration, and depth of ZIKV infection in the FRT. Critically, intravaginal administration of recombinant IFNε protected Ifnε-/- mice and highly susceptible Ifnar1-/- mice against vaginal ZIKV infection, indicating that IFNε was sufficient to provide protection even in the absence of signals from other type I IFNs and in an IFNAR1-independent manner. Our findings reveal a potentially critical role for IFNε in mediating protection against transmission of ZIKV in the context of sexual contact.

Depot medroxyprogesterone acetate administration increases cervical CCR5+CD4+ T cells and induces immunosuppressive milieu at the cervicovaginal mucosa.

OBJECTIVES: Depot medroxyprogesterone acetate (Depo-Provera) is the most commonly used injectable hormone contraceptive in Sub-Saharan Africa where HIV incidence is high. We determined the impact of Depo-Provera on cervical immune cells and mediators in healthy women. METHODS: In this longitudinal study, vaginal, endocervical, and rectal swabs were collected at baseline (visit 1), 1 month (visit 2), and 3 months (visit 3) after Depo-Provera injection. Cervical cells were collected by cytobrush and immune markers on cervical CD4 T cells were analyzed by multicolor flow cytometry at three different visits. The levels of immune mediators in cytobrush supernatants as well as vaginal, cervical, and rectal secretions from swabs were analyzed by multiplex assays and ELISA. RESULTS: Compared with baseline levels, we found a significant increase in the frequency of cervical CCR5CD4 T cells and a significant decrease in the frequency of cervical central memory CD4 T cells. Depo-Provera treatment had little effect on expression of immune mediators in rectal mucosa but significantly suppressed numerous immune mediators at cervicovaginal mucosa. Levels of MCP-1, G-CSF, IL-6, IL-10, GM-CSF, and IP-10 were significantly decreased in both vaginal and cervical secretions after Depo-Provera injection. In cervical samples collected by cytobrush, we found reduced levels of 22 of 25 immune mediators after Depo-Provera injection. Changes in immune mediators differed between vaginal and cervical mucosa, demonstrating compartment-specific responses. CONCLUSION: Depo-Provera altered immune profiles of cervical CD4 T cells and suppressed host immune response at cervicovaginal mucosa, suggesting its likely effect on transmission of sexually transmitted infections including HIV.