Abstract
Purpose::
It is possible that retinal protein components exposed in a process of destructive endogenous uveoretinitis might result in additional targets of immune cells to extend ocular inflammation. In this study, we first comprehensively identified the retinal proteins recognized by autoantibodies induced in experimental autoimmune uveoretinitis (EAU), and examined the antigenicity of detected proteins by using sera of patients with endogenous uveitis.
Methods::
EAU was induced in C57BL/6 mice by inoculation with interphotoreceptor retinoid binding protein peptide 1-20 (IRBP-p) emulsified in complete Freund’s adjuvant (CFA). As the control, mice inoculated with CFA only were prepared. Six weeks after immunization, the sera were collected and tested for the content of autoantibodies against normal murine retinal proteins by two-dimensional electrophoresis-Western blotting (2DE-WB). Reacted retinal protein spots on 2DE-WB were compared between EAU and the control, and EAU specific spots were identified by mass spectrometry. In addition, 1DE-WB and/or enzyme-linked immunosorbent assay (ELISA) were performed using the identified proteins and sera from mice with EAU or from patients with Behcet’s disease (BD, n=36), Vogt-Koyanagi-Harada disease (VKH, n=16), and sarcoidosis (n=17).
Results::
Besides IRBP, four candidates of autoantigens in EAU were detected by 2D-WB, in which three proteins were confirmed their autoantigenicity in EAU by 1DE-WB and ELISA. Positive rate of autoantibody for each protein was as follows; EsteD (EAU:70%, control:0%), BB-CK (EAU:40%, control:0%) and ßAct (EAU:40%, control:0%). Autoantibody production against EsteD and BB-CK were also confirmed in human endogenous uveitis with statistical significance compared to healthy control; anti-EsteD antibody was positive in 25% of BD and 25% of VKH patients, and anti-BB-CK antibody was positive in 25% of VKH and 38.4% of sarcoidosis patients.
Conclusions::
Since autoantibodies to EsteD and BB-CK were produced in mice inducing EAU and in patients with endogenous uveitis, it is conceivable that these antigens could play a role of autoantigen to progress ocular inflammation.
Keywords: uveitis-clinical/animal model • proteomics • autoimmune disease