Monoclonal antibodies against the newly identified allergen β-enolase from common carp (Cyprinus carpio)

β-enolase is a heat-labile fish allergen identified in different fish species. In this study, β-enolase gene was cloned from common carp muscle tissue and the target protein was expressed as a fusion with maltose binding protein (MBP-Eno) in E. coli. Recombinant MBP-Eno was reactive with blood serum specimens of fish-allergic patients, confirming that β-enolase is a newly identified allergen of common carp. Two monoclonal antibodies (MAbs) against recombinant β-enolase were generated that showed cross-reactivity with β-enolases of other organisms. Both antibodies recognized β-enolases from other fish species extracts, while MAb 6E4 showed a broad reactivity with pork, chicken, yeast, and E. coli samples. Epitope mapping using MBP-Eno variants revealed that β-enolase region comprising amino acids 623-698 presumably includes MAb 6E4 epitope. The generated broadly reactive MAb 6E4 directed against a conserved epitope of β-enolases may represent a valuable tool for the characterization of allergen extracts and fish allergy diagnostics.