Abstract
Background: Locusts as model systems are widely used in many
biological laboratories worldwide. Occupational exposure to locusts
induces a high prevalence of allergic sensitization. However, knowledge
on occupational locust allergens remains unclear. This study aimed to
identify a novel allergen from locusts that causes occupational
allergies.
Methods: We conducted a
20-year retrospective survey of 94
persons using questionnaires and
a
cross-sectional
survey of 57 persons using questionnaires and immunological tests for
occupational allergies in long-term locust laboratories. We identified
the major allergens by immunoblotting and analysed them by LC-MS/MS. The
allergenicity of the major allergen proteins was assessed by specific
IgE (sIgE) detection, immunoblotting and ELISA inhibition assays.
Results: The retrospective survey indicated that the frequency
of occupational allergies was relatively low (13.8%), while the
cross-sectional survey showed a higher frequency (40.4%). The symptoms
in most allergic males were allergic rhinitis and asthma, while females
showed higher prevalence of atopic dermatitis. Occupational exposure for
2-3 h per day or continuing one and half years obviously increased the
allergy risk. We identified the
hexamerin-2 protein as a major allergen in locusts. Purified hexamerin-2
protein achieved approximately 60% serum IgE reactivity with locust
protein extract. The potential for cross-reactivity with
cockroaches was indicated by
sequence alignment of the hexamerin-2 protein and allergens of
cockroaches.
Conclusion: Occupational exposure is an important risk factor
for locust allergy. The hexamerin-2 protein of locusts as a major
allergen in occupational allergy was identified for the first time.