Purpose: Alpha1,3 glucan is a major cell wall component of Aspergillus fumigatus. It is also found in several human pathogenic yeasts where its role in virulence has been repeatedly demonstrated. Methods: Recent studies have shown that this polysaccharide has multiple functions in A. fumigatus 1- It composes the cement of the wall and plays an essential role in cell wall organisation. 2. It displays immunoprotective and "œvaccine" properties in several models of experimental murine aspergillosis. 3. It is an adhesin: (i) in static and aerial conditions in vitro in a Petri dish or in vivo in human aspergilloma, A. fumigatus develops a network of highly agglutinated hyphae glued together by an extracellular matrix composed of polysaccharides including alpha1,3 glucan. Results: In contrast, in vivo in murine invasive aspergillosis, the hyphae that grow separately, are also embedded by an extracellular matrix exempt of alpha1,3 glucan. (ii) the first step of conidial germination in A. fumigatus is swelling and agglutination of conidia together. This step is correlated with the apparition of alpha1,3 glucan at the surface of the conidia. The binding of alpah1,3 glucan to the cell wall of the next conidia is currently studied. Conclusions: Three alpha1,3 glucan synthase genes are responsible for the synthesis of this polysaccharide in A. fumigatus. The triple mutant has been undertaken.
Full conference title:
4th Advances Against Aspergillosis
- AAA 4th (2010)