Identification of important allergenic proteins in extracts of the granary weevil (Sitophilus granarius)

This paper describes the identification of important allergens from the granary weevil (Sitophilus granarius) (Sg). Sera from Danish bakers whose skin prick tests were positive to extracts of Sg were screened for IgE against Sg extracts. We found that 54% (n = 66) had elevated levels of IgE (RAST classes 1-3, by luminescent immunoassay) against whole-body extracts of Sg. The specificity of patient IgE was investigated in an inhibition-dot immunoblotting assay. IgE binding was inhibited in all sera but two, thus indicating that the patients' IgE was indeed specific for the Sg extract. In crossed immunoelectrophoresis, 23 different proteins were identified. All RAST-positive sera were investigated in crossed radioimmuno-electrophoresis. At least 11 proteins in the Sg extract were capable of binding IgE. All individual sera reacted with at least four different proteins. The two most prominent allergens bound IgE from 88% and 100%, respectively, of the patients. These two are considered to be the most important allergens from Sg, and will be useful as markers in environmental immunochemical assays to detect allergens in samples from bakeries, grain stores, etc.