Identification of an hla-peptide complex contributing to japanese cedar pollinosis

We investigated the association between Japanese cedar pollinosis and HLA-class II alleles by HLA-DNA typing using a PCR-SSOP method and found that the frequency of HLA-DP5 (DPA 1*02022 and DPB 1*0501) was significantly increased in the patients. To investigate whether the HLA-DP5 was merely a genetic marker or rather involved in the pathogenesis of the disease, Japanese cedar pollen antigen (CPAg)-specific T cell lines were established from three patients who possessed HLA-DR4-DR53-DQ4-DP5 (DRB1 *0405-DRB4*01 -DQA1*0302-DQB1*0401 -DPA1*02022-DPB l *0501) haplotype. By using these CPAg-specific T cell lines and 88 synthesized overlapping peptides spanning the entire length of two major cedar pollen allergens, Cry j 1 and Cry j 2, two peptides recognized by DR53-restricted T cells and one peptide recognized by DPS-restricted T cells were identified. DPS-restricted T cell lines as well as DR53-restricted T cell lines produced Th2-type cytokines. Therefore, HLA-DP5 may be directly involved in the pathogenesis, by helping the IgE Ab production to CPAg.