Lymphocyte proliferation induced by high-affinity peptides for HLA-B*51:01 in Behçet's uveitis

Several proteins have been proposed as candidate auto-antigens in the pathogenesis of Behçet's disease (BD). In this study, we aimed to confirm the cellular responses to candidate peptide autoantigens with high affinity for the HLA-B*51:01 molecule using computerized binding predictions and molecular dynamics simulations. We identified two new candidate peptides (HSP65PD, derived from heat shock protein-65, and B51PD, derived from HLA-B*51:01) with high-affinity to the HLA-B*51:01 binding pocket using the Immune Epitope Database for Major Histocompatibility Complex-I Binding Prediction and molecular dynamics simulations. The peptide-induced proliferation of lymphocytes from patients with BD, sarcoidosis, Vogt-Koyanagi-Harada disease (VKH) with panuveitis, systemic scleroderma (SSc) without uveitis, and healthy controls (HC) was investigated using the bromodeoxyuridine assay. The proliferative response of leukocytes to HSP65PD was significantly higher in BD (SI 1.92 ± 0.65) than that in sarcoidosis (SI 1.38 ± 0.46), VKH (SI 1.40 ± 0.33), SSc (SI 1.32 ± 0.31), and HC (SI 1.27 ± 0.28) (P = 0.0004, P = 0.0007, P < 0.0001, P < 0.0001, respectively, Mann-Whitney's U-test). The proliferative response of leukocytes to B51PD was also higher in BD than that in sarcoidosis, VKH, SSc without uveitis, and HC, whereas no significant differences were observed among the five groups in response to a control peptide derived from topoisomerase 1. A significantly higher response to HPS65PD and B51PD was observed in the HLA-B*51:01-positive patients with BD than in the HLA-B*51:01-negative patients. In conclusion, two peptides that had high affinity to HLA-B*51:01 in computerized binding prediction showed significantly higher response in HLA-B*51:01-positive patients with BD, indicating the usefulness of computerized simulations for identifying autoreactive peptides to HLAs.