FIG. 2.

Schematic diagram illustrating the contribution of the various virulence attributes to C. albicans pathogenicity. C. albicans commonly colonizes the epithelial surface (stage 1) and causes superficial infections (stage 2), but under conditions when the host is compromised, the fungus establishes deep-seated infections (stage 3) by penetrating further into the epithelial tissue. Occasionally, C. albicans causes disseminated infections (stage 4), which allow the fungus to colonize and infect other host tissues and can be fatal. This infective process involves numerous virulence attributes including adhesins, hydrolytic enzyme production (Sap proteins, phospholipases, and lipases), hypha formation, and phenotypic switching. Sap2 (and possibly other Sap proteins) is known to degrade many human proteins, including mucin, extracellular matrix proteins, numerous immune system molecules, endothelial cell proteins, and coagulation and clotting factors. Therefore, the action of Sap proteins could be involved in all four stages of infection and probably greatly enhances the pathogenic ability of C. albicans. Modified from reference 160 with permission.