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A mutant of the major melon allergen, Cuc m 2, with reduced IgE binding capacity is a good candidate for specific immunotherapy

Tordesillas, Leticia, Gamboa, Pedro, Sanz, Maria L., Palacín, Arantxa, Gómez-Casado, Cristina, Cuesta-Herranz, Javier, Pacios, Luis F., Salcedo, Gabriel, Díaz-Perales, Araceli
Molecular immunology 2011 v.49 no.3 pp. 504-511
Escherichia coli, T-lymphocytes, alanine, allergenicity, allergens, anaphylaxis, binding capacity, chromatography, cross reaction, cytokines, epitopes, immunoglobulin E, immunotherapy, melons, mutants, pollen
Hypoallergenic mutants with reduced IgE-binding capacity but which show a similar T-cell response to the corresponding natural allergen are ideal tools for immunotherapy, for preventing a possible anaphylactic shock. An IgE conformational epitope has been identified in Cuc m 2, the major allergen and profilin from melon. Since this epitope is highly conserved in most pollen profilins, it may contribute to an explanation of cross-reactivity between pollen and food profilins. Mutants (Mut 1 and Mut 2) were generated by changing specific residues of the Cuc m 2 epitope to alanine, produced in Escherichia coli, and purified by chromatographic methods. Mut 1 showed a slight reduction in IgE binding but an allergenic activity that was similar to recombinant Cuc m 2, as measured by basophil activation test (BAT) and skin prick test (SPT). By contrast, Mut 2 displayed a substantial reduction in IgE-binding capacity (57%) and positive responses, as determined by BAT (33%) and SPT (50%), when compared to those of rCuc m 2. However, the T-cell proliferation and cytokine production induced by Mut 2 and rCuc m 2 were similar. Thus, this mutant represent potential candidate for immunotherapy of profilin allergies.