Development of a rice-based peptide vaccine for Japanese cedar and cypress pollen allergies.

Peptide immunotherapy using dominant T-cell epitopes is a safe treatment alternative to conventional subcutaneous injection of natural crude allergen extract, which is sometimes accompanied by anaphylactic shock. For Japanese cedar pollinosis (JCP), hybrid peptides composed of six to seven major T-cell epitopes (7Crp peptide) from the causative allergens Cry j 1 and Cry j 2 have been developed on the basis of different human leukemia antigen class II restrictions, because of the diversity of patients' genetic backgrounds. However, other dominant T-cell epitopes that are produced in some patients are not covered by these peptides. To develop a more universal peptide vaccine for JCP, we generated transgenic rice seeds containing seven new T-cell epitopes (Crp3) in addition to the T-cell epitopes used in the 7Crp peptide. Next, we co-expressed unique T-cell epitopes (6Chao) from the Japanese cypress pollen allergens Cha o 1 and Cha o 2 in transgenic rice seeds, with 7Crp and Crp3. These transgenic rice seeds, containing many highly homologous T-cell epitopes derived from cedar and cypress allergens, are expected to be applicable to a wide range of patients suffering from these pollen allergies.