BACKGROUND: Patients allergic to natural rubber latex (NRL) frequently exhibit immediate hypersensitivity reactions to banana, but the molecular basis of these putative cross-reactions is unknown. OBJECTIVE: We wanted to examine whether proteins resembling hevein, a major NRL allergen, exist in banana and whether coexisting allergy to NRL and banana can be explained by IgE cross-reactivity to these proteins. METHODS: Allergens in banana cross-reacting with hevein were identified by IgE immunoblot inhibition. The cross-reacting proteins were purified by reversed-phase chromatography and characterized by amino acid sequencing. Allergen cross-reactivity was further assessed by IgE ELISA, IgE ELISA inhibition, and skin prick testing. RESULTS: In immunoblotting, 9 of 15 sera from patients allergic to NRL with IgE to hevein showed IgE binding to 32- and 33-kd banana proteins. These 2 protein bands were also targets to IgG from a hevein-immunized rabbit. IgE binding to both 32- and 33-kd protein bands was totally inhibited by hevein (10 ng/mL) in all 5 sera from patients allergic to NRL sera studied. N-terminal sequencing of the purified 32- and 33-kd proteins revealed 80% identity to the N-terminus of hevein. An internal peptide (19 amino acids) of the 33-kd protein gave over 90% identity to endochitinases of several plants. In ELISA all 15 sera from patients allergic to NRL had IgE to the purified 32-kd banana protein. In ELISA inhibition hevein (10 ng/mL) inhibited approximately 50% of IgE binding to the solid-phase 32-kd banana protein in a pool of sera from patients allergic to NRL. CONCLUSION: These results suggest that the commonly occurring hypersensitivity to banana in patients allergic to NRL could be explained by cross-reacting IgE antibodies binding to epitopes in hevein and in a hevein-like domain of a previously undescribed endochitinase in banana.
BACKGROUND:Patientsallergic to natural rubber latex (NRL) frequently exhibit immediate hypersensitivity reactions to banana, but the molecular basis of these putative cross-reactions is unknown. OBJECTIVE: We wanted to examine whether proteins resembling hevein, a major NRL allergen, exist in banana and whether coexisting allergy to NRL and banana can be explained by IgE cross-reactivity to these proteins. METHODS: Allergens in banana cross-reacting with hevein were identified by IgE immunoblot inhibition. The cross-reacting proteins were purified by reversed-phase chromatography and characterized by amino acid sequencing. Allergen cross-reactivity was further assessed by IgE ELISA, IgE ELISA inhibition, and skin prick testing. RESULTS: In immunoblotting, 9 of 15 sera from patientsallergic to NRL with IgE to hevein showed IgE binding to 32- and 33-kd banana proteins. These 2 protein bands were also targets to IgG from a hevein-immunized rabbit. IgE binding to both 32- and 33-kd protein bands was totally inhibited by hevein (10 ng/mL) in all 5 sera from patientsallergic to NRL sera studied. N-terminal sequencing of the purified 32- and 33-kd proteins revealed 80% identity to the N-terminus of hevein. An internal peptide (19 amino acids) of the 33-kd protein gave over 90% identity to endochitinases of several plants. In ELISA all 15 sera from patientsallergic to NRL had IgE to the purified 32-kd banana protein. In ELISA inhibition hevein (10 ng/mL) inhibited approximately 50% of IgE binding to the solid-phase 32-kd banana protein in a pool of sera from patientsallergic to NRL. CONCLUSION: These results suggest that the commonly occurring hypersensitivity to banana in patientsallergic to NRL could be explained by cross-reacting IgE antibodies binding to epitopes in hevein and in a hevein-like domain of a previously undescribed endochitinase in banana.
Authors: Margitta Worm; Uta Jappe; Jörg Kleine-Tebbe; Christiane Schäfer; Imke Reese; Joachim Saloga; Regina Treudler; Torsten Zuberbier; Anja Waßmann; Thomas Fuchs; Sabine Dölle; Martin Raithel; Barbara Ballmer-Weber; Bodo Niggemann; Thomas Werfel Journal: Allergo J Int Date: 2014