/ Positive T-Cells in hIRBP Peptide Induced Eau

Abstract

Abstract: : Purpose: The model of hIRBP (human Interphoreceptor Retinoid Binding Protein) peptide (aa 161-180) induced murine EAU (experimental Autoimmun-uveitis) represents a chronic disease and is used as a model for ocular (BD) Behçet’s disease. We studied the infiltration of TCRγ/δ+ T-cells into the eye during interferon-alpha (IFN-α) treatment in this model. Methods: B10.RIII mice (n=24) were immunized subcutaneously (sc) with 100µg of the hIRBP derived peptide aa 161-180. IFN-α dosage was applied according to our scheme in patients. Twelve animals received daily sc. injected IFN-α (day 1-3: 3x10³IU, day 4-10 (18): 6x10³ IU). Twelve control mice received no IFN-α. Histological and immunohistochemical analyses of the eyes were carried out on animals sacrificed at day 10 and 18 post-immunization (n=6 for each treatment and time point). Results: Histology at day 10 disclosed 4 of 6 control mice to have severe EAU (grading >3) compared to only 2 of 6 IFN-α treated mice. At day 18 there was histologically little difference between control and IFN-α treated mice. TCRγ/δ+ T-cells infiltrating the retina were detectable in control eyes, a significantly lower amount in IFN-α treated animals. Conclusion: TCRγ/δ⁺ T-cells have been identified for the first time in the murine EAU model. It has been shown that IFN-α seems to regulate the amount of these T-cells. Interestingly in BD also increased levels of TCRγ/δ⁺ T-cells are reduced under by IFN-a treatment. It has to be investigated whether these T-cells are antigen specific or exhibit regulatory functions.

Keywords: immunohistochemistry • inflammation • immunomodulation/immunoregulation