Related Experiment Videos
Human immunodeficiency virus type 1 gp160 and gp41 binding to Candida albicans selectively enhances candidal
A Gruber1, E Lukasser-Vogl, M Borg-von Zepelin
1Institut für Hygiene, University of Innsbruck, Austria.
Insights
Human immunodeficiency virus (HIV)-1 envelope proteins, gp160 and gp41, can increase Candida albicans virulence by elevating proteinase activity and reducing phagocytosis. This interaction may enhance candidal virulence in HIV-1-positive individuals.
Area of Science:
- Mycology
- Virology
- Immunology
Background:
- Human immunodeficiency virus (HIV)-1 envelope proteins gp160 and gp41 are known to bind to Candida albicans.
- The impact of this interaction on the virulence of Candida albicans in vitro remains largely unexplored.
Purpose of the Study:
- To investigate whether the binding of HIV-1 envelope proteins gp160 and gp41 to Candida albicans affects its virulence factors in vitro.
- To assess the influence of HIV-1 envelope proteins on Candida albicans growth, phospholipase activity, aspartate proteinase secretion, and susceptibility to phagocytosis.
Main Methods:
- Candida albicans yeast cells were treated with purified HIV-1 envelope proteins (gp160, gp120, gp41).
- Growth and phospholipase activity were measured.
- Aspartate proteinase activity (free and cell-bound) was assessed.
- Proteinase activity in culture supernatants was quantified.
- Phagocytosis assays were performed using polymorphonuclear leukocytes (PMNs) and serum.
Main Results:
- Treatment with HIV-1 gp160 or gp120 did not significantly alter Candida albicans growth or phospholipase activity.
- HIV-1 gp160 treatment significantly increased both free and cell-bound aspartate proteinase levels in Candida albicans.
- Culture supernatants from Candida albicans treated with gp160 or gp41 exhibited markedly increased proteinase activity.
- Candida albicans cells treated with gp160 or gp41 were phagocytosed less effectively by PMNs compared to cells treated with gp120 or serum alone.
Conclusions:
- The interaction between HIV-1 gp160 and Candida albicans can enhance fungal virulence by increasing aspartate proteinase activity.
- HIV-1 gp160 and gp41 may contribute to increased Candida albicans virulence in HIV-1-positive patients by modulating proteinase secretion and immune evasion.
- These findings highlight a potential mechanism by which HIV-1 infection could exacerbate candidal infections.
Abstract:
Previously, it has been shown that human immunodeficiency virus (HIV)-1 envelope proteins gp160 and gp41 bind to Candida albicans. Whether this interaction affects candidal virulence in vitro was investigated. HIV-1 gp160 or gp120 treatment of C. albicans significantly altered neither growth nor phospholipase activity of the fungus. However, treatment of C. albicans with gp160, but not with gp120, led to an elevation of free and cell-bound aspartate proteinase. In addition, culture supernatants obtained from C. albicans treated with gp160 or gp41, but not with gp120, showed a strong increase in proteinase activity. Finally, C. albicans viable yeast cells treated with gp160 or gp41 and serum were phagocytosed by polymorphonuclear leukocytes to a lesser extent than was C. albicans treated with gp120 and serum or serum alone. These findings suggest that the interaction between HIV-1 gp160 and C. albicans may promote the virulence of C. albicans in HIV-1-positive patients.