Identification of Profilin as a Novel Pollen Allergen; IgE Autoreactivity in Sensitized Individuals

TLDR

Structural similarity of conserved proteins may maintain IgE antibody titers in type I allergy. A cDNA encoding a birch pollen allergen, isolated with IgE from an allergic individual, revealed significant homology to profilins. The recombinant birch profilin bound IgE from allergic individuals, cross‑reacted with human profilin, and triggered histamine release from basophils of profilin‑allergic subjects but not from those sensitized to other plant allergens.

Abstract

A complementary DNA encoding a pollen allergen from white birch ( Betula verrucosa ) that was isolated from a pollen complementary DNA library with serum immunoglobulin E from a birch pollen-allergic individual revealed significant sequence homology to profilins. The recombinant protein showed high affinity to poly-L-proline. Immunoglobulin E antibodies from allergic individuals bound to natural and recombinant birch profilin and also to human profilin. In addition, birch and human profilin induced histamine release from blood basophils of profilin-allergic individuals, but not of individuals sensitized to other plant allergens. The structural similarity of conserved proteins might therefore be responsible for maintaining immunoglobulin E antibody titers in type I allergy.