Cloning, production, characterization and IgE cross-reactivity of different manganese superoxide dismutases in individuals sensitized to Aspergillus fumigatus

Background: Manganese superoxide dismutase (MnSOD) from Aspergillus fumigatus has been demonstrated to be an allergen showing a high degree of homology with phylogenetically distant MnSODs. We describe cloning, production and characterization of MnSODs from different species. Methods: MnSODs were cloned by PCR, expressed as inclusion body protein in Escherichia coli, purified by Ni2+-chelate affinity chromatography and characterized. Results: The MnSODs from A. fumigatus, man, yeast, Drosophila melanogaster and E. coli show about 50% identity and 70% similarity on the primary structure. All proteins were produced at a high level in E. coli and refolded to achieve enzymatic activity. The proteins were able to bind IgE from sera of individuals sensitized to the A. fumigatus MnSOD. Conclusions: MnSOD represents a novel pan-allergen restricted to individuals sensitized to A. fumigatus.