Galactosaminogalactan, a New Immunosuppressive Polysaccharide of <em>Aspergillus fumigatus</em> FontaineThierry DelangleAurélie SimenelCatherine CoddevilleBernadette J. van VlietSandra KooykYvette van BozzaSilvia MorettiSilvia SchwarzFlavio TrichotColine AebiMarkus DelepierreMuriel ElbimCarole RomaniLuigina LatgéJean-Paul 2011 <div><p>A new polysaccharide secreted by the human opportunistic fungal pathogen <em>Aspergillus fumigatus</em> has been characterized. Carbohydrate analysis using specific chemical degradations, mass spectrometry, <sup>1</sup>H and <sup>13</sup>C nuclear magnetic resonance showed that this polysaccharide is a linear heterogeneous galactosaminogalactan composed of α1-4 linked galactose and α1-4 linked N-acetylgalactosamine residues where both monosacharides are randomly distributed and where the percentage of galactose per chain varied from 15 to 60%. This polysaccharide is antigenic and is recognized by a majority of the human population irrespectively of the occurrence of an <em>Aspergillus</em> infection. GalNAc oligosaccharides are an essential epitope of the galactosaminogalactan that explains the universal antibody reaction due to cross reactivity with other antigenic molecules containing GalNAc stretches such as the N-glycans of <em>Campylobacter jejuni</em>. The galactosaminogalactan has no protective effect during <em>Aspergillus</em> infections. Most importantly, the polysaccharide promotes fungal development in immunocompetent mice due to its immunosuppressive activity associated with disminished neutrophil infiltrates.</p> </div>