In vitro and in vivo adherence of Candida albicans to mucosal surfaces

In continuation of a previous study, chitin soluble extract (CSE) and anti-Candida albicans antibodies were found to inhibit the in vitro adherence of C. albicans to human vaginal epithelial cells by 60-70%. Pretreatment of epithelial cells with chitin, CSE or N-acetyl-glucosamine (NAG) decreased the percentage of adherence, while pretreatment of yeasts had no such effect, indicating that chitin or its derivatives may be involved in mediating the adherence of C. albicans. In vivo attachment of C. albicans to epithelial cells was studied in an experimental murine vaginitis created by inoculating mice intravaginally with yeasts at the oestrus stage. Attachment of the yeasts to exfoliated vaginal epithelial cells was followed microscopically, and the course of infection was assessed histopathologically in tissue sections at various times post-yeast inoculation. The infection rate at 24-h post-yeast inoculation was approximately 50%. Attempts were made to block in vivo attachment and prevent infection by pretreating 208 mice with either CSE, NAG, mannan or phosphate-buffered saline (PBS) prior to inoculation with yeasts. The infection rate among mice pretreated with mannan or PBS was 41.6% and 43.8%, respectively. Among CSE- or NAG-pretreated animals, the rate ranged from 0-9%. Treatment of mice with CSE or NAG after inoculation of the yeasts did not prevent infection. The data from the in vivo experiments reveal that pretreatment of animals with chitin derivatives blocks attachment of yeasts to the vaginal mucosal surfaces and leads to the prevention of vaginal infection in an experimental model.