Hexamerin-2 Protein of Locust as a Novel Allergen in Occupational Allergy

BACKGROUND: Occupational exposure to locusts induces a high prevalence of allergic sensitization. However, knowledge on occupational locust allergens remains unclear. OBJECTIVE: This study aimed to identify the allergens from locusts causing occupational allergies. METHODS: We conducted a survey of 57 persons exposed to locusts using questionnaires and immunological tests for occupational allergies in long-term locust laboratories. The major allergen was identified by immunoblotting and analysed by mass spectrometry. The allergenicity of the allergen was assessed by sIgE detection, immunoblotting and ELISA inhibition assays. RESULTS: The survey indicated that the frequency of locust occupational allergies was 40.4% among subjects exposed to locust. The symptoms in most males were allergic rhinitis, while females showed higher prevalence of atopic dermatitis. Occupational exposure increased the allergy risk. The recombinant hexamerin-2 protein possesses high allergenicity in the allergic exposure group. Hexamerin-2 protein can inhibit IgE reactivity with locust protein extracts by approximately 60%. The potential for cross-reactivity with cockroaches was indicated by sequence alignment of hexamerin-2 protein and allergens of cockroaches. CONCLUSION: The hexamerin-2 protein of locusts as an important allergen was identified. Therefore, occupational exposure is an important risk factor for locust allergy.