Reinvestigation of fine epitope specificity of EB-A2 antibody used in the immune detection of galactomannan of Aspergillus fumigatus: molecular basis of false-positive signals

NE Nifantiev, VB Krylov, DA Argunov

Author address: 

Laboratory of Glycoconjugate Chemistry, N.D. Zelinsky Institute of Organic Chemistry, RAS, Moscow, Russia

Abstract: 

Purpose: To assess fine carbohydrate specificity of EB-A2 antibody used in A. fumigatus galactomannan detection under Enzyme-Linked Immunosorbent Assay conditions and determine the molecular basis of false-positive signals measured in the presence of polysaccharides of Bifidobacteria and other components of common human microflora (see f.ex. M.A.S.H. Mennink-Kersten et al., J. Clin. Microbiol., 43 (2005) 3925–3931).

Methods: The thematic array built up of synthetic oligosaccharide ligands (GlycoArray) of distinct structure representing different fragments of A. fumigatus galactomannan chains (they were described in: Latgé et al., Infect. Immun., 62 (1994) 5424-5433; Shibata et al., Glycobiology, 25 (2015) 74–87) was used to assess the epitope specificity of antibody EB-A2 used in galactomannan immune detection.

Results: Obtained results shown that the antibody EB-A2 recognizes smaller galactomannan fragments than reported previously for antibody EB-A2 (Latgé et al., Infect. Immun., 60 (1992) 2237-2245). This forms the basis of false detection of polysaccharides with oligogalactofuranosyl fragments connected not only through (1→5)-linkages but also through altered (1→5)- and (1→6)-linkages which are produced by Bifidobacteria and other components of common human microflora.

Conclusion: The detection of galactomannan of A. fumigatus can be improved by using antibody which recognizes selectively the oligomers of galactofuranosyl units which are larger than disaccharide and are connected through (1→5)-linkages only. This study was supported by RSF grant 14-23-00199 (NEN).

2018

Full conference title: 

The 8th Advances Against Aspergillus, Lisbon Conference Center, Lisbon, Portugal
    • AAA 8th (2018)