ABSTRACT
We report here that sex hormones modulate susceptibility to a sexually transmitted viral agent, herpes simplex virus type 2 (HSV-2), in a mouse model. Ovariectomized mice were administered either saline (control), estradiol (E2), progesterone (P4), or a combination of both estradiol and progesterone (E+P) and infected intravaginally with HSV-2. With an inoculation dose of 105 PFU, the saline- and P4-treated mice were found to be highly susceptible to genital HSV-2 infection. Both groups had extensive pathology and high viral titers in vaginal secretions, and 100% of mice succumbed by day 4 postinfection. E2-treated mice were protected from HSV-2 infection at the same dose and did not display any vaginal pathology or viral shedding. There was a slow progression of genital pathology in the combination hormone-treated group, along with prolonged viral shedding; 80% of animals succumbed by day 13. With lower inoculation doses of 103 and 102 PFU, 50 and 100%, respectively, of the combination hormone-treated mice survived. Localization of HSV-2 infection showed extensive infection in the vaginal epithelium of P4- and saline-treated animals within 24 h of inoculation. E2-treated animals were clear of infection, while the E+P-treated group had focal infection at 24 h that had progressed extensively by day 3. Infection was accompanied by persistent inflammation and infiltration of neutrophils in the P4-treated group. An analysis of the genes in the vaginal tissue showed that inflammation in the P4-treated group correlated with local induction of chemokines and chemokine receptors that were absent in the E2-treated mice and in uninfected P4-treated mice. The results show that sex hormones regulate initiation of infection and immune responses to genital HSV-2 infection.
Susceptibility of Human Female Primary Genital Epithelial Cells to Herpes Simplex Virus, Type-2 and the Effect of TLR3 Ligand and Sex Hormones on Infection1
