Galactosaminogalactan (commonly abbreviated as GAG or GG), is an exopolysaccharide composed of galactose and N-acetylgalactosamine (GalNAc).
Galactosaminogalactan is typically extracted by ethanol precipitation from liquid culture or by alkaline treatment from the cell wall.
In Aspergillus fumigatus, a causative agent of aspergillosis, galactosaminogalactan is required for adherence to host tissue, to mask PAMPs like β-1,3-glucans and to mediate virulence in several animal models.
[4] While its role in pathogenesis is still being defined, galactosaminogalactan has been found in histological sections of lungs of patients with aspergillosis.
[5] Besides its role in fungal virulence, certain fractions of laboratory purified galactosaminogalactan has been shown to induce neutrophil apoptosis[6] and reduce inflammation.