Common antigenicity between Japanese cedar (Cryptomeria japonica) pollen and Japanese cypress (Chamaecyparis obtusa) pollen, II. Determination of the cross‐reacting T‐cell epitope of Cry j 1 and Cha o 1 in mice

We have previously detected common antigenicity between Cry j 1 and Cha o 1 in B10.S mice. B10.S mice immunized with Cry j 1- or Cha o 1-generated T cells and antibodies reactive to both allergens. In the present study, we investigated the cross-reacting and Cry j 1-specific T-cell epitopes in B10.S mice. Lymph node cells from B10. S mice immunized with Cry j 1 recognized Cry j 1 p111-130, p211-230, and p310-330 as well as Cha o 1 p209-228. The existence of the cross-reacting T-cell epitope in Cry j 1 and Cha o 1 was confirmed by the response of newly established p211-230-specific and Cha o 1 p209-228-specific T-cell lines. The minimum peptide sequence (p213-224) of the cross-reacting T-cell epitope was identical in Cry j 1 and Cha o 1. These findings clearly demonstrate that common antigenicity at the T-cell level between Japanese cedar and cypress pollen allergens was caused by the existence of an identitical-cell epitope in Cry j 1 and Cha o 1.