Candida albicans biofilm extracellular vesicles deliver candidalysin to epithelial cell membranes and induce host cell responses.

Extracellular vesicles (EVs) are heterogeneous particles encapsulated with a phospholipid bilayer membrane. EVs have evolved diverse biological functions, serving mainly as prominent mediators and regulators of cell-cell communication. This study investigated whether candidalysin, a key virulence factor in Candida albicans infections, is present within EVs derived from C. albicans biofilms and retains activity by inducing host immune responses. We found that biofilm EVs contain candidalysin and can permeabilize planar lipid bilayer membranes in a dose-dependent manner. However, biofilm EVs were unable to damage oral epithelial cells (OECs) but were able to induce cytokine responses. Notably, EVs obtained from biofilms cultured for 24 h and 48 h exhibited differences in cargo composition and their ability to activate OECs. This study highlights the potential of biofilm EVs as a toxin delivery system during C. albicans infection and identifies temporal differences in the ability of EVs to activate epithelial cells.