COMPARATIVE ADHERENCE OF CANDIDA ALBICANS AND CANDIDA DUBLINIENSIS TO HUMAN BUCCAL EPITHELIAL CELLS AND EXTRACELLULAR MATRIX PROTEINS

Abstract

Candida albicans and Candida dubliniensis are very closely related pathogenic yeast species. Despite their close relationship, the former is a far more successful coloniser and pathogen of humans. The purpose of the current study was to investigate if the disparity in the virulence of the two species could be attributed to differences in their ability to adhere to human buccal epithelial cells (BECs) and/or extracellular matrix proteins. When grown overnight at 30?C in Yeast Extract Peptone Dextrose (YEPD), genotype 1 C. dubliniensis isolates were found to be significantly more adherent to human BECs than C. albicans or C. dubliniensis genotypes 2-4 (P < 0.001). However, when the yeast cells were grown at 37?C, no significant difference between the adhesion of C. dubliniensis genotype 1 and C. albicans to human BECs was observed, and C. dubliniensis genotype 1 and C. albicans adhered to BECs in significantly greater numbers than the other C. dubliniensis genotypes (P < 0.001). Using surface plasmon resonance analysis, C. dubliniensis isolates were found to adhere in significantly greater numbers than C. albicans to type I and IV collagen, fibronectin, laminin, vitronectin and proline-rich peptides. These data suggest that C. albicans is not more adherent to epithelial cells or matrix proteins than C. dubliniensis and therefore other factors must contribute to the greater levels of virulence exhibited by C. albicans.