Aspergillus galactosaminogalactan mediates adherence to host constituents and conceals hyphal β-glucan from the immune system
Related Experiment Video
Updated: May 8, 2026

Isolation and Purification of Fungal β-Glucan as an Immunotherapy Strategy for Glioblastoma
Published on: June 2, 2023
Fabrice N Gravelat1, Anne Beauvais, Hong Liu
1Departments of Microbiology and Immunology, Medicine, McGill University, Montréal, Québec, Canada.
Abstract:
Aspergillus fumigatus is the most common cause of invasive mold disease in humans. The mechanisms underlying the adherence of this mold to host cells and macromolecules have remained elusive. Using mutants with different adhesive properties and comparative transcriptomics, we discovered that the gene uge3, encoding a fungal epimerase, is required for adherence through mediating the synthesis of galactosaminogalactan. Galactosaminogalactan functions as the dominant adhesin of A. fumigatus and mediates adherence to plastic, fibronectin, and epithelial cells. In addition, galactosaminogalactan suppresses host inflammatory responses in vitro and in vivo, in part through masking cell wall β-glucans from recognition by dectin-1. Finally, galactosaminogalactan is essential for full virulence in two murine models of invasive aspergillosis. Collectively these data establish a role for galactosaminogalactan as a pivotal bifunctional virulence factor in the pathogenesis of invasive aspergillosis.
Insights
Aspergillus fumigatus uses galactosaminogalactan, synthesized by the uge3 gene, as its main adhesin. This molecule aids fungal adherence and suppresses immune responses, crucial for invasive aspergillosis.
Area of Science:
- Medical Mycology
- Molecular Biology
- Immunology
Background:
- Aspergillus fumigatus is a leading cause of invasive mold disease.
- Mechanisms of fungal adherence to host cells are not fully understood.
Purpose of the Study:
- Identify fungal factors mediating adherence of Aspergillus fumigatus.
- Characterize the role of galactosaminogalactan in fungal pathogenesis.
Main Methods:
- Utilized mutant strains with altered adhesive properties.
- Performed comparative transcriptomics to identify key genes.
- Investigated galactosaminogalactan's function in vitro and in vivo.
Main Results:
- The gene uge3 is essential for galactosaminogalactan synthesis and fungal adherence.
- Galactosaminogalactan acts as a major adhesin, binding to various surfaces and host cells.
- Galactosaminogalactan inhibits host inflammatory responses by masking β-glucans.
- Galactosaminogalactan is critical for virulence in murine models of invasive aspergillosis.
Conclusions:
- Galactosaminogalactan is a key adhesin and virulence factor for Aspergillus fumigatus.
- The uge3 gene product is vital for galactosaminogalactan-mediated pathogenesis.
- Galactosaminogalactan's dual role in adherence and immune suppression highlights its importance in invasive aspergillosis.
Related Concept Videos
Proteoglycans
Glycocalyx and its Functions
Components of...
Cell Adhesion in Plants
Pectins are complex heteropolymers mainly composed of negatively-charged α-D-glucopyranosyl uronic acid and some neutral glycosyl residues such as α-L-rhamnopyranose, α-L-arabinofuranose, and...
Laminins are the Adhesive Proteins of Basal Lamina
In humans, the five forms of alpha chains are LAMA 1, LAMA 2, LAMA 3, LAMA 4, and LAMA 5. The four forms of beta chains are LAMB 1, LAMB 2, LAMB 3, and LAMB 4. The three forms of gamma...
Glycosaminoglycans
GAGS are found in the extracellular matrix of vertebrates, invertebrates, and bacteria. Due to their polar nature they attract water, and serve as excellent lubricants or shock absorbers in an animal body.
Hyaluronic...
Oligosaccharide Assembly
Multiple sugar molecules that may or may...
