The alpha and beta subchain of Amb a 1, the major ragweed-pollen allergen show divergent reactivity at the IgE and T-cell level

Divergent immunological properties of Amb a 1α (aa 181-396) and Amb a 1β (aa 26-180) were revealed. Amb a 1β contained important IgE epitopes, whereas Amb a 1α showed low IgE binding. When compared to natural Amb a 1, all recombinant variants possessed >100-fold reduced IgE-mediated mediator release activity. At the T-cell level recombinant and natural Amb a 1 stimulated comparable T-cell responses and the T-cell reactivity was largely directed to the C-terminal part. The results demonstrated that recombinant Amb a 1α behaves as hypoallergen with reduced IgE binding but preservation of the major T-cell reactivity. In addition, recombinant Amb a 1α can be easily purified to homogeneity in large quantity and therefore represents an ideal candidate for specific immunotherapy.