Cross-reactivity between major IgE core epitopes on Cry j 2 allergen of Japanese cedar pollen and relevant sequences on Cha o 2 allergen of Japanese cypress pollen

Cry j 2 and Cha o 2 are major allergens in Japanese cedar (Cryptomeria japonica; CJ) and Japanese cypress (Chamaecyparis obtusa; CO) pollen, respectively. Here, we assessed the epitopes related to the cross-reactivity between Cry j 2 and Cha o 2 using in vitro analyses. Peptides were synthesized based on Cry j 2 sequential epitopes and relevant Cha o 2 amino acid sequences. Four representative monoclonal antibodies (mAbs) against Cry j 2 were used according to their epitope recognitions. Serum samples were collected from 31 patients with CJ pollinosis. To investigate cross-reactivity between Cry j 2 and Cha o 2, ELISA and inhibition ELISA were performed with mAbs and sera from patients with CJ pollinosis. Two of four mAbs had reactivity to both Cry j 2 and Cha o 2. Of these two mAbs, one mAb (T27) recognized the amino acid sequence 169KVVNGRTV176 on Cha o 2. This is related to the core epitope 169KWVNGREI176 on Cry j 2, which is an important IgE epitope. In addition, we found that these correlative sequences and purified allergens showed cross-reactivity between Cry j 2 and Cha o 2 in IgE of CJ patients. We demonstrated the importance of 169KVVNGRTV176 in Cha o 2 for cross-reactivity with the Cry j 2 epitope 169KWVNGREI176, which plays an important role in allergenicity in CJ pollinosis. Our results are useful for the development of safer and more efficient therapeutic strategies for the treatment of CJ and CO pollen allergies.