Experimental Autoimmune Uveitis Induced by Murine Retinoid–Binding Protein 3 (RBP–3) 1–16

Abstract

Abstract: : Purpose: Experimental autoimmune uveitis (EAU) can be induced in rodents following immunisation with retinal proteins or peptides derived from them. Peptide 1–20 of human retinoid–binding protein 3 (hRBP–3 1–20) (previously IRBP) is immunogenic and pathogenic in C57Bl/6 mice (H–2^b), but has some experimental disadvantages. hRBP–3 1–20 is insoluble in water and its sequence at position 17 (valine) differs from that of murine RBP–3 (mRBP–3) (isoleucine). A new peptide has been synthesised, mRBP–3 1–16, that overcomes these problems. Altered peptide ligands (APLs) of mRBP–3 1–16 have also been generated. Methods: Disease induction following immunisation with mRBP–3 1–16 vs. hRBP–3 1–20 was studied by histological analysis. The phenotype of T cells from mice immunised with either peptide was compared, along with the phenotype of mRBP–3 1–16–reactive T cell clones. The in vitro characteristics of mRBP–3 1–16–reactive T cells and the mRBP–3 1–16–reactive T cell clones in response to activation with the mRBP–3 1–16 APLs were also analysed. Results: mRBP–3 1–16 induces EAU in C57Bl/6 mice with severity and kinetics comparable to that following immunisation with hRBP–3 1–20. T cells taken from mice immunised with mRBP–3 1–16 have a Th1 phenotype, and proliferate in response to reactivation with either mRBP–3 1–16, hRBP–3 1–20 or mRBP–3 1–16 APLs. mRBP–3 1–16–reactive T cell clones show a range of proliferation levels and cytokine production upon stimulation with the above peptides. APLs elicit at least three distinct patterns of reactivity when tested with the T cell clones. Conclusions: mRBP–3 1–16 can immunise and cause EAU. The studies using T cell clones and APLs demonstrate that the immune response to mRBP–3 1–16 is drawn from a diverse population of antigen–specific T cells.

Keywords: autoimmune disease • inflammation • microglia