Galactosaminogalactan of Aspergillus fumigatus, a bioactive fungal polymer

Galactosaminogalactan (GAG) is an extracellular polysaccharide produced by the mycelium of the opportunistic human fungal pathogen Aspergillus fumigatus. GAG is the first polysaccharide described as a virulence factor in medical mycology. This review presents our current knowledge of the structural organization and biosynthesis of this polymer. The function of this molecule as an adhesin that also masks Aspergillus PAMPs and the impact of GAG on the modulation of the host immune response by inducing neutropenia and blocking the IL-1 signaling pathway also will be emphasised.