A mutant of the major melon allergen, Cuc m 2, with reduced IgE binding capacity is a good candidate for specific immunotherapy.
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.
Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Madrid, Spain.
Leticia
L
Tordesillas
Pedro
P
Gamboa
Maria L
ML
Sanz
Arantxa
A
Palacín
Cristina
C
Gómez-Casado
Javier
J
Cuesta-Herranz
Luis F
LF
Pacios
Gabriel
G
Salcedo
Araceli
A
Díaz-Perales
D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D052179:Antigens, Plant / Q000737:chemistry / Q000276:immunology*; D002478:Cells, Cultured; D017124:Conserved Sequence; D019662:Cucurbitaceae / Q000737:chemistry / Q000276:immunology*; D000939:Epitopes / Q000276:immunology; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology*; D007167:Immunotherapy; D008297:Male; D008969:Molecular Sequence Data; D051304:Profilins / Q000737:chemistry / Q000276:immunology*; D016415:Sequence Alignment; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology; D055815:Young Adult
D052179:Antigens, Plant; C507132:Cuc m 2 allergen, Cucumis melo; D000939:Epitopes; D051304:Profilins; D007073:Immunoglobulin E