Candida proteinases and candidosis.

Infections caused by the opportunistic yeast pathogen, Candida albicans, are becoming increasingly important. Superficial Candida infections, particularly those of the mouth and vagina, are very common; for example, candidal vaginitis plaques millions of women worldwide, often proving refractory to treatment. Systemic candidosis is much rarer, but it is an important hazard of modern medical procedures such as transplant surgery, i.v. hyperalimentation, and immunosuppressive therapy. One significant virulence factor of C. albicans is its ability to secrete extracellular acid proteinase. This attribute is shared by C. tropicalis and C. parapsilosis, but not by other less pathogenic Candida species. The enzymes produced by these yeasts are all carboxyl proteinases capable of degrading secretory IgA, the major immunoglobulin of mucous membranes. Some have keratino- or collagenolytic activity. Two secretory proteinases of C. albicans have been purified and characterized; their properties are reviewed. Possible applications of this work to the treatment and diagnosis of candidosis are discussed.