N-terminal hevein-like domains (4.3 kDa) but not 31 kDa endochitinases are responsible for IgE-mediated in vitro and in vivo reactions in latex-fruit syndrome

Immunological characterization and engineering of the major latex allergen, hevein (Hev b 6.02)

Piia Karisola tutki luonnonkumiallergiaa välittömän (tyyppi I) allergian mallina. Hän keskittyi työssään luonnonkumiallergian pääallergeeniin, heveiiniin (Hev b 6.02), jota vastaan 70 %:lla luonnonkumiallergisista potilaista on IgE-luokan vasta-aineita. Vuorovaikutus näiden vasta-aineiden ja heveiinin välillä aiheuttaa erilaisia kliinisiä oireita, kuten ihottuma, allergista nuhaa, nokkosrokkoa ja jopa anafylaksiaa. Joskus nämä IgE-luokan vasta-aineet tunnistavat ”vahingossa” samankaltaisia valkuaisaineita eri kasveista. Noin puolet luonnonkumiallergiaa sairastavista potilaista saakin oireita syötyään trooppisia hedelmiä, jota kutsutaan luonnonkumi-hedelmä -oireyhtymäksi.Karisolan väitöskirj…

The Major Conformational IgE-binding Epitopes of Hevein (Hev b6.02) Are Identified by a Novel Chimera-based Allergen Epitope Mapping Strategy

A novel approach to localize and reconstruct conformational IgE-binding epitope regions of hevein (Hev b6.02), a major natural rubber latex allergen, is described. An antimicrobial protein (AMP) from the amaranth Amaranthus caudatus was used as an immunologically non-IgE-binding adaptor molecule to which terminal or central parts of hevein were fused. Hevein and AMP share a structurally identical core region but have different N-terminal and C-terminal regions. Only 1 of 16 hevein-allergic patients showed weak IgE binding to purified native or recombinant AMP. Chimeric AMP with the hevein N terminus was recognized by IgE from 14 (88%) patients, and chimeric AMP with the hevein C terminus wa…

Construction of hevein (Hev b 6.02) with reduced allergenicity for immunotherapy of latex allergy by comutation of six amino acid residues on the conformational IgE epitopes.

Abstract Recently we have established that IgE Abs bind to conformational epitopes in the N- and C-terminal regions of the major natural rubber latex allergen, hevein (Hev b 6.02). To identify the critical amino acid residues that interact with IgE, the hevein sequence was scanned by using site-specific mutations. Twenty-nine hevein mutants were designed and produced by a baculovirus expression system in insect cells and tested by IgE inhibition-ELISA using sera from 26 latex allergic patients. Six potential IgE-interacting residues of hevein (Arg5, Lys10, Glu29, Tyr30, His35, and Gln38) were identified and characterized further in detail. Based on these six residues, two triple mutants (HΔ…

Isolated hevein-like domains, but not 31-kd endochitinases, are responsible for IgE-mediated in vitro and in vivo reactions in latex-fruit syndrome.

Background Individuals with natural rubber latex allergy often have immediate reactions to plant-derived foods and fresh fruits, such as avocado and banana. IgE of these patients has been shown to bind endochitinases containing an N-terminal hevein-like domain (HLD). However, evidence on 31-kd endochitinase-induced reactions in vivo is lacking. Objective We sought to assess the clinical significance of 31-kd endochitinases and isolated HLDs in latex-fruit syndrome. Methods The 31-kd endochitinases and corresponding HLDs were purified or produced from avocado, banana, latex, and wheat germ. Skin prick test reactivities against purified proteins were examined in 15 patients with natural rubbe…