Rice proteins recognized by immunoglobulin E antibodies of patients with food allergies

Results We have demonstrated that boiling decrease solubility and IgE reactivity of PBS-extracted rice and wheat proteins, but in SDS-extracts this reactivity was only slightly affected. The sera of patients highly positive on the IgE immunoblot, positive in basophil activation and skin prick test with boiled rice components were used for characterizing the IgE-binding proteins separated by 1-D or 2-D electrophoresis. Employing mass spectrometry, we identified 22 rice SDS soluble proteins. Six of them were new potential rice allergens: glutelin C precursor, granulebound starch synthase 1 protein, disulfide isomerase-like 1-1 protein, hypothetical protein OsI_13867, putative acid phosphatase precursor 1, and a protein encoded by locus Os02g0453600. These proteins retaining IgE-binding capacity also after thermal processing potentially represent important allergens in rice-containing foodstuffs. All of the identified rice proteins differed from known wheat allergens, except proteins belonging to the á amylase/trypsin-inhibitor family.