Interaction of Host Proteins with Cell Surface Molecules of the Pathogenic Yeast Trichosporon asahii.

Trichosporon asahii is an invasive pathogenic yeast that infects immunocompromised hosts. Several virulence factors contribute to the fungal infection; however, the factors that contribute to the occurrence of T. asahii infections remain unclear. Since adhesins are typical virulence factors reported for pathogenic fungi, we looked for host proteins that interact with the T. asahii cell surface. T. asahii and Candida albicans were used for screening using a pull-down assay with fetal bovine serum. Serum albumin and elongation factor 2 were identified as the yeast-binding serum proteins. Additionally, we investigated the interactions of the cell surface-associated molecules (CSM) of T. asahii with vitronectin (VTN), fibronectin, fetuin-A, and alpha-1antitrypsin (AAT). The surface plasmon resonance (SPR) method was used to examine the interaction between CSM and human proteins. On the other hand, the pull-down assay was used to examine the interaction between human proteins and the T. asahii cell surface. Serum albumin, AAT, and VTN were found to interact with T. asahii in both SPR and pull-down assays. This study identified several proteins that interact with T. asahii, suggesting that these proteins play a role in infection mechanisms.