Chemical and immunological characterization of the extracellular galactomannan of Aspergillus fumigatus.
The galactomannan (GM) produced extracellularly by Aspergillus fumigatus has been purified by a double sequential hydrazine-nitrous acid treatment of the ethanol precipitate of the culture filtrate. Nuclear magnetic resonance and gas-liquid chromatography-mass spectrometry analysis have been performed on intact GM, acid-hydrolyzed GM, and oligomers resulting from the acetolysis of the acid-hydrolyzed GM. Results show that A. fumigatus GM is composed of a linear mannan core with an alpha-(1-2)-linked mannotetraose repeating unit attached via alpha-(1-6) linkage. Side chains composed of an average of 4 to 5 beta-(1-5)-galactofuranose units are linked to C-6 and C-3 positions of alpha-(1-2)-linked mannose units of the mannan. The immunoreactivity of GM and HCl-hydrolyzed GM was studied by use of human sera from aspergillosis patients and an antigalactofuran monoclonal antibody. The alpha-(1-2) (1-6)-mannan core is not antigenic. The immunogenic galactofuran is found amongst several exocellular glycoproteins. According to a direct enzyme-linked immunosorbent assay with GM as the detector antigen, only 26% of the serum samples from aspergilloma patients (all positive by immunodiffusion assays) give optical density values superior to a cutoff estimated as the mean +/- 3 standard deviations of values obtained with control sera.
Unité de Mycologie, Institut Pasteur, Paris, France.
J P
JP
Latgé
H
H
Kobayashi
J P
JP
Debeaupuis
M
M
Diaquin
J
J
Sarfati
J M
JM
Wieruszeski
E
E
Parra
J P
JP
Bouchara
B
B
Fournet
D000908:Antibodies, Fungal / Q000097:blood; D000946:Antigens, Fungal / Q000737:chemistry* / Q000276:immunology; D001228:Aspergillosis / Q000276:immunology; D001232:Aspergillus fumigatus / Q000737:chemistry* / Q000276:immunology; D002240:Carbohydrate Sequence; D002849:Chromatography, Gas; D004797:Enzyme-Linked Immunosorbent Assay; D005690:Galactose / Q000031:analogs & derivatives; D006801:Humans; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D008351:Mannans / Q000737:chemistry* / Q000276:immunology; D008969:Molecular Sequence Data
D000908:Antibodies, Fungal; D000946:Antigens, Fungal; D008351:Mannans; C012990:galactomannan; D005690:Galactose