Development of\nHypoallergenic Derivatives of Cra a\n1 with B Cell Epitope Deletion and T Cell Epitope Retention

Tropomyosin was reported as an important allergen in Crassostrea angulata and designated as Cra a 1. The\nlocalization of the T cell epitopes and the reduction of the immunoreactivity\nof Cra a 1 are still lacking. In this study, four T cell epitopes\nwere identified by using wild-type Cra a 1 (wtCra a 1)-immunized mouse\nsplenocytes cultured with synthetic peptides. The immunoreactivity\nwas maintained after chemical denaturation treatment, indicating that\nthe linear epitope is an immunodominant epitope of wtCra a 1. Furthermore,\nthe hypoallergenic derivative (mCra a 1) was developed by the deletion\nof linear B cell epitopes and retention of T cell epitopes. mCra a\n1 could stimulate CD4<sup>+</sup>T cell proliferation and upregulate\ninterleukin-10 secretion. Overall, basophil activation by mCra a 1\nwas low, but its ability to induce T cell proliferation was retained,\nsuggesting that mCra a 1 may serve as a viable candidate for treating\noyster allergy.