Role of the Inducible Adhesin CpAls7 in Binding of Candida parapsilosis to the Extracellular Matrix under Fluid Shear.

The yeast is an increasingly common cause of systemic fungal infections among immunocompromised individuals, including premature infants. Adhesion to host surfaces is an important step in pathogenesis, but this process has not been extensively studied in this organism. A microfluidics assay was developed to test the ability of to adhere to immobilized host extracellular matrix proteins under physiological fluid shear conditions. Growth in mammalian tissue culture medium at 37°C for 3 to 6 h led to the induction of an adhesive phenotype at shear forces of 1 to 5 dynes/cm in some isolates of Glutamic acid, proline, and calcium appeared to be the minimally necessary requirements for increased adhesion in these assays. To determine whether genes homologous to the gene family of were important for the adhesive phenotype, the expression levels of 5 homologous genes were quantified by using quantitative PCR (qPCR) under conditions leading to increased adhesion. () and showed increased expression levels compared to those in control yeast. The extent of adhesion was variable among different isolates, and linear regression identified the expression of but not as having a strong positive correlation with adhesion. A homozygous deletion strain was deficient in adhesion, whereas the expression of in resulted in increased adhesion. Together, these data provide strong evidence that CpAls7 aids in the adherence of to the extracellular matrix under shear forces and support its previously reported role in virulence.