Galactosaminogalactan

rdf:langString Galactosaminogalactan

rdf:langString Galactosaminogalactan (commonly abbreviated as GAG or GG), is an exopolysaccharide composed of galactose and N-acetylgalactosamine (GalNAc). It is commonly found in the biofilm and cell wall of various fungal species. Although the sugar residues are arranged in no particular/discrete order, and thus a heteroglycan, the residues are all linked by α-1,4 glycosidic bonds. Galactosaminogalactan is typically extracted by ethanol precipitation from liquid culture or by alkaline treatment from the cell wall. Once extracted, galactosaminogalactan becomes highly insoluble. 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. While its role in pathogenesis is still being defined, galactosaminogalactan has been found in histological sections of lungs of patients with aspergillosis. Besides its role in fungal virulence, certain fractions of laboratory purified galactosaminogalactan has been shown to induce neutrophil apoptosis and reduce inflammation.