[The involvement of rice protein 16KD in cross-allergenicity between antigens in rice, wheat, corn, Japanese millet, Italian millet].

Cross-reactivity between rice, wheat, corn, Japanese millet and Italian millet in Poaceae family were studied by absorption test, radioallergosorbent test (RAST), and RAST inhibition assay. In absorption test using Phadebas RAST discs, more than 50% absorption of IgE antibodies was observed between rice, wheat and corn. There were significant correlations of RAST values for cereal grains including rice, wheat, corn, Japanese millet and Italian millet. RAST inhibition assay between every combinations of these cereals showed dose-dependent decrease in IgE-binding. These data indicated cross-reactivity with IgE antibodies between the five cereals in Poaceae family. RAST values for RP16KD significantly correlated with those for Italian millet as well as rice but not with those for corn and wheat. There was a trend of positive correlation between RAST values for RP16KD and Japanese millet. In RAST inhibition assay using sera with positive RAST for these five cereal grains and RP16KD, RP16KD inhibited IgE-binding to these all cereal discs in dose-dependent manner. Similarly, all of five cereal grain extracts showed an effective diminution in IgE-binding to RP16KD disc. These results indicated possible participation of IgE-binding structure on RP16KD in cross-reactivity between these cereal grains in Poaceae family.