Adhesion ofCandida albicansmutant strains to host tissue

Abstract

Adhesion of Candida albicans to host cells is believed to represent a fungal virulence factor and a significant step in the development of candidiasis. As C. albicans strains may differ in their in vitro adhesion ability we initiated a study to investigate whether mutant strains differ in this respect from their parent wild-type. We assessed the in vitro adhesion of C. albicans CBS562 and two mutants obtained by mutagenesis with N'-nitrosoguanidine: a histidine auxotroph, SAG5, derived from CBS562, and a respiratory-deficient strain (a petite mutant), SAR1, derived from SAG5. The adhesion was tested in vitro using two target cell systems: (1) exfoliated human buccal epithelial cells (BEC); and (2) human keratinocyte tissue line cells (HaCaT cells). Adhesion to BEC was evaluated microscopically and that to HaCaT cells by a direct ELISA technique. The results indicated a 54% reduction in adhesion to BEC for SAG5 and 30% for SAR1 as compared to the wild-type, and a 25% reduction in adhesion to HaCaT cells for SAG5 and 20% for SAR1. To verify whether the prototrophy restores the adhesion ability, we complemented the his-negative auxotroph by transforming the strain with the HIS4 gene. Then we assayed the adhesion to BEC of the complemented his-negative mutant in comparison to that of the wild-type, the his-negative mutant (SAG5) and the plasmid-cured transformant. The adhesion values of the complemented his-negative strain were similar to those of the wild-type, whereas the values of the plasmid-cured strain were similar to those of SAG5.

Candida albicans Uses the Surface Protein Gpm1 to Attach to Human Endothelial Cells and to Keratinocytes via the Adhesive Protein Vitronectin

“…In addition to Gpm1 candida also uses Als3 and Ssa1 for interaction with human endothelial cells [47], [48], [49]. Thus candida apparently uses a combination of fungal adhesions proteins that aid in attachment, and in combination with acquired and endogenous proteases aid in destruction of endothelial barriers [50], [51], [52]. Gpm1, also mannose and phospholipomannan moieties, central fungal cell wall components contribute to fungal attachment to human keratinocytes [33], [53], [54].…”