Candida causes an estimated half-billion cases of vulvovaginal candidiasis (VVC) every year. VVC is most commonly caused by Candida albicans , which, in this setting, triggers nonprotective neutrophil infiltration, aggressive local inflammation, and symptomatic disease. Despite its prevalence, little is known about the molecular mechanisms underpinning the immunopathology of this fungal infection. In this study, we describe the molecular determinant of VVC immunopathology and a potentially straightforward way to prevent disease. In response to zinc limitation, C. albicans releases a trace mineral binding molecule called Pra1 (pH-regulated antigen). Here, we show that the PRA1 gene is strongly up-regulated during vaginal infections and that its expression positively correlated with proinflammatory cytokine concentrations in women. Genetic deletion of PRA1 prevented vaginal inflammation in mice, and application of a zinc solution down-regulated expression of the gene and also blocked immunopathology. We also show that treatment of women suffering from recurrent VVC with a zinc gel prevented reinfections. We have therefore identified a key mediator of symptomatic VVC, giving us an opportunity to develop a range of preventative measures for combatting this disease.

Despite a high incidence of VVC, we still have a poor understanding of this female-specific disease whose negative impact on women’s quality of life has become a public health issue. It is not yet possible to determine by genotype or laboratory phenotype if a given Candida albicans strain is more or less likely to cause VVC.

Antimicrobial peptides represent a promising alternative to traditional drugs in relation to cost, toxicity, and, primarily, the growing problem of drug resistance. Here, we report on the activity against HSV-1 and HSV-2 of a previously described wide-spectrum synthetic decapeptide, Killer Peptide (KP). As determined by plaque reduction assays, treatment with KP at 100 μg/mL resulted in a reduction in the viral yield titer of 3.5 Logs for HSV-1 and 4.1 Logs for HSV-2. Further evaluation of KP antiviral activity focused on the early stages of the virus replicative cycle, including the determination of the residual infectivity of viral suspensions treated with KP. A direct effect of the peptide on viral particles impairing virus absorption and penetration was shown. The toxicity profile proved to be extremely good, with a selectivity index of 29.6 for HSV-1 and 156 for HSV-2. KP was also active against acyclovir (ACV)-resistant HSV isolates, while HSV subcultures in the presence of sub-inhibitory doses of KP did not lead to the emergence of resistant strains. Finally, the antiviral action of KP proved to be synergistic with that of ACV. Overall, these results demonstrate that KP could represent an interesting addition/alternative to acyclovir for antiviral treatment.

Little is known about the complex events driving host–pathogen and pathogen–pathogen interplay in polymicrobial infections. Using an in vitro model of a reconstituted vaginal epithelium (RVE) employing the A-431 cell line supplemented with synthetic vaginal fluid (SVF), we studied the consequences of single versus dual infections with Candida albicans and/or Herpes Simplex Virus-2 (HSV-2). Our data show (a) a relevant, SVF-enhanced expression of the differentiation marker cytokeratin 5/6 in the RVE; (b) the ability of Candida albicans to enhance HSV-2 in the dual infection model, with the virus titer almost doubling in the presence of SVF; (c) RVE damage (>20%), mostly attributable to Candida albicans and related to oxidative stress whether SVF is present; (d) the dysregulation of mucin-1, the production of which is enhanced (from 13 to 21 ng/mL) or impaired (from 21 to 10 ng/mL) in response to either SVF or infection, respectively; and (e) a partial-to-negligible cytokine response from the RVE, depending upon SVF presence. In conclusion, using an in vitro RVE model upgraded through the addition of synthetic vaginal fluid, we provide details on epithelial cell–pathogen–pathogen interaction, contributing to a better comprehension of the pathogenesis of polymicrobial infections at a mucosal level.

Antimicrobial peptides represent a promising alternative to traditional drugs in relation to cost, toxicity and, primarily, the growing problem of drug resistance. Here we report on the activity against HSV-1 and HSV-2 of a previously described wide-spectrum synthetic decapeptide, Killer Peptide (KP). As determined by plaque reduction assays, treatment with KP at 100 μg/mL resulted in a reduction in the viral yield titer of 3.5 Logs for HSV-1 and 4.1 Logs for HSV-2. Further evaluation of KP antiviral activity focused on the early stages of virus replicative cycle, including the determination of the residual infectivity of viral suspensions treated with KP. A direct effect of the peptide on viral particles, impairing virus absorption and penetration, was shown. The toxicity profile proved to be extremely good with a selectivity index of 29.6 for HSV-1 and 156 for HSV-2. KP was also active against an acyclovir (ACV)-resistant HSV-1 strain, while HSV-1 subcultures in the presence of sub-inhibitory doses of KP did not lead to the emergence of resistant strains. Finally, the antiviral action of KP proved to be synergistic with that of ACV. Overall, these results demonstrate that KP could represent an interesting addition/alternative to acyclovir for antiviral treatment.