SPECIFIC HUMORAL IMMUNE-RESPONSES IN 12 CASES OF FOOD SENSITIZATION TO SESAME SEED

Background Hypersensitivity to sesame seeds is becoming increasingly f requent, probably owing to the larger use of this compound in internat ional food. Objectives This study investigated serum responses of 12 s esame sensitized patients (seven with food allergy, five with food sen sitization), to a sesame protein extract, and attempted at identifying sesame major antigens. Methods Sesame protein extracts were prepared from black, white and brown sesame seeds. Electrophoretic analysis sho wed similar protein patterns in the three extracts, and proper preserv ation of the proteins integrity. The brown sesame extract was used to set-up an ELISA assay and measure serum levels of antisesame IgG, IgA, IgM and IgE in 12 samples fi om sesame-sensitized individuals and six controls. It also allowed to perform western blot analyses in order t o investigate the molecular weight of sesame proteins recognized by Ig G, IgA and IgE. Results Nineteen protein bands were observed upon poly acrylamide gel electrophoresis of the sesame protein extracts. Using t his whole extract in ELISA, significant antisesame IgG, IgA and IgE-re sponses were observed in the serum of sensitized individuals, differen t from the lower signals obtained with control samples. Western blot a nalysis demonstrated highly polymorphic IgG and IgA responses and a mo re restricted IgE response pattern, suggesting that two proteins, resp ectively, 14kDa and 25kDa are mostly involved in sesame IgE-dependent hypersensitivity, the 25kDa band presenting several characteristics of a major allergen. Conclusions This study reports novel information on the possible involvement of a 25kDa sesame protein in IgE-dependent h ypersensitivity to sesame seeds.