Shrimp is a causative food that elicits food-dependent
exercise-induced anaphylaxis (FDEIA). In this study, we sought to identify
IgE-binding
allergens in patients with shrimp-FDEIA. Sera were obtained from eight patients with shrimp-FDEIA and two healthy control subjects.
Proteins were extracted from four shrimp species by homogenization in
Tris buffer. Immunoblot analysis revealed that
IgE from patient sera bound strongly to a 70-kDa and a 43-kDa
protein in a preparation of Tris-soluble extracts from Litopenaeus vannamei. Mass spectrometry identified the 70-kDa and 43-kDa
proteins as a P75 homologue and
fructose 1,6-bisphosphate aldolase (FBPA), respectively. To confirm that the putative shrimp
allergens were specifically recognized by serum
IgE from shrimp-FDEIA patients, the two
proteins were purified by
ammonium sulfate precipitation followed by reversed-phase HPLC and/or
anion-exchange hydrophobic interaction chromatography and then subjected to immunoblot analysis. Purified P75 homologue and FBPA were positively bound by serum
IgE from one and three, respectively, of the eight patients with shrimp-FDEIA, but not by sera from control subjects. Thus, P75 homologue and FBPA are identified as
IgE-binding
allergens for shrimp-FDEIA. These findings could be useful for the development of diagnostic tools and desensitization
therapy for shrimp-FDEIA patients.