Inter- and intramolecular epitope spreading in equine recurrent uveitis.
OBJECTIVE
To test the hypothesis that inter- and intramolecular spreading to S-antigen (S-Ag) and interphotoreceptor retinoid binding protein (IRBP)-derived epitopes occurs in a spontaneous model of recurrent uveitis in the horse.


METHODS
The immune response of eight horses with equine recurrent uveitis (ERU) was compared with that of five control horses with healthy eyes. Lymphocytes derived from peripheral blood (PBLs) were tested every 8 weeks for their reactivity against S-Ag and various S-Ag and IRBP-derived peptides for 12 to 39 months (median, 22 months). During uveitic episodes, additional blood samples were analyzed.


RESULTS
Intermolecular epitope spreading was detectable in all ERU cases during the study. Intramolecular spreading occurred in seven (of eight) horses with ERU. Fourteen relapses were analyzed during the observation period. Ten uveitic episodes were accompanied by neoreactivity to S-Ag or IRBP-derived peptides during the relapse. Shifts in the immune response profile were also detectable without any clinical signs of inflammation. Eye-healthy control horses were negative at all time points in the in vitro proliferation assays.


CONCLUSIONS
Inter- and intramolecular spreading was detectable in a spontaneous model of recurrent uveitis. The shifts in immunoreactivity could account for the remitting-relapsing character of the disease.
Deeg
Cornelia A
CA
Institute for Animal Physiology, Ludwig-Maximilians-University, Munich, Germany. deeg@tiph.vetmed.uni-muenchen.de
Amann
Barbara
B
Raith
Albert J
AJ
Kaspers
Bernd
B
D000818:Animals; D019393:Arrestin / Q000276:immunology*; D001323:Autoantibodies / Q000276:immunology; D001324:Autoantigens / Q000276:immunology*; D000939:Epitopes / Q000276:immunology*; D006734:Horse Diseases / Q000276:immunology*; D006736:Horses; D008213:Lymphocyte Activation / Q000502:physiology; D023421:Models, Animal; D015864:Panuveitis / Q000276:immunology / Q000662:veterinary*; D010446:Peptide Fragments / Q000276:immunology; D012008:Recurrence; D012177:Retinol-Binding Proteins / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology; D014606:Uveitis, Anterior / Q000276:immunology / Q000662:veterinary*
D019393:Arrestin; D001323:Autoantibodies; D001324:Autoantigens; D000939:Epitopes; D010446:Peptide Fragments; D012177:Retinol-Binding Proteins