Candida albicans is a common human opportunistic pathogen, and a causative agent of denture-induced stomatitis. The mechanism of its colonization of the oral cavity is unclear. Objective: Investigate the interaction of C. albicans with human plasma fibronectin, comparing yeast grown in liquid media versus yeast obtained from biofilm. Methods: C. albicans ATCC 44505 grown fresh culture media or grown in artificially created biofilm, was used throughout this study. 96-well microtiter plates were coated with fibronectin or with a 120 kDa fragment of fibronectin for 4 h at room temperature. The plates were washed with PBS, incubated with 100 µl of liquid-cultured or biofilm-isolated yeast cells (10⁶ cells/ml) for 2 h, and the wells were washed with PBS to remove the non-adherent yeasts. Adherent yeast cells were quantified by XTT assay. For competition experiments, fibronectin-coated wells were incubated with clarified whole human saliva or with saliva depleted of gelatin-binding component. Results: 85 ± 2% of biofilm versus 76 ± 2% of liquid-cultured C. albicans cells adhered to fibronectin (n = 6, P < 0.01). In wells coated with the 120 kDa fragment of fibronectin, the biofilm cells also adhered in greater numbers than the liquid-cultured cells (64 ± 2% versus 24 ± 2%, n = 6, P < 0.001). Pretreatment of fibronectin-coated wells with saliva inhibited adherence of both types of cells. When fibronectin-coated plates were pretreated with gelatin-binding component-depleted saliva, adhesion of liquid-cultured cells was inhibited by 12%, whereas biofilm cells showed 66% inhibition. Conclusion: Growth conditions affect C. albicans interaction with fibronectin. The biofilm cells appeared to have different binding sites for fibronectin than the liquid-cultured cells, which might be a factor in pathogenesis of C. albicans in the oral cavity.

Supported by DE05494 and UT College of Dentistry Alumni Endowment Fund.