
<ArticleTitle>Identification of a <prot>Hevea brasiliensis latex manganese superoxide dismutase</prot> (<prot>Hev b 10</prot>) as a cross-reactive allergen.</ArticleTitle>
<AbstractText>BACKGROUND: Cross-reactive allergens play an increasingly important role in latex allergy in complicating both the diagnosis and time course of allergic symptoms. <prot>Manganese superoxide dismutase</prot> (<prot>MnSOD</prot>), a ubiquitous protein of prokaryotic and eukaryotic organisms, was described as a cross-reactive allergen in Aspergillus fumigatus. Little information is available on the importance of this pan-allergen in Hevea brasiliensis latex. The aim of this study was to clone and express <prot>MnSOD</prot> from H. brasiliensis latex, and to obtain the soluble and immunologically active recombinant allergen for diagnosis of latex allergy and to investigate possible cross-reactivities with the structurally related A. fumigatus and human <prot>MnSOD</prot>s. METHODS: A complementary DNA coding for <prot>Hevea latex MnSOD</prot> was amplified by PCR. The recombinant protein was produced in Escherichia coli with an N-terminal hexahistidyl tag. Enzymatic activity of the recombinant protein was determined using an enzyme assay for SODs. <prot>IgE</prot> immunoblotting and IgE inhibition assays were performed to characterize the recombinant allergen and its cross-reactivity. RESULTS: A <prot>Hevea latex MnSOD</prot> consisting of 206 amino acid residues was cloned and expressed in E. coli. The allergen was designated <prot>Hev b 10</prot>. The recombinant protein was enzymatically active, indicating the correct folding of the protein. In immunoblots, latex- as well as A. fumigatus-allergic patients revealed IgE binding to recombinant (r)<prot>Hev b 10</prot>. Cross-reactivity to Asp f 6, the <prot>MnSOD</prot> from A. fumigatus, and human <prot>MnSOD</prot> was determined by inhibition of <prot>IgE</prot> binding to these <prot>MnSOD</prot>s by rHev b 10. CONCLUSIONS: <prot>Hev b 10</prot> is a new cross-reactive allergen of H. brasiliensis which belongs to the 'latex-mold' group of latex allergens. Furthermore, it is a candidate for primary sensitization in patients allergic to the pan-allergen <prot>MnSOD</prot>.</AbstractText>
