Autoreactive Cd8 T Cells in the B10riii Mouse Recognize the Antigenic Epitope Spanning Amino Acid 168 to 177 of Interphotoreceptor Retinoid-Binding Protein (irbp)

Abstract

Purpose: : We previously demonstrated that a significant proportion of interphotoreceptor retinoid-binding protein (IRBP)-specific uveitogenic T cells in the C57BL/6 mouse and Lewis rat express CD8. The aims of this study were to determine whether some of the IRBP-specific T cells in the B10RIII mouse also express CD8 and whether CD8 and CD4 IRBP-specific T cells in the B10RIII mouse recognize a different or the same antigenic epitope.

Methods: : B10RIII mice were immunized with the uveitogenic peptide, IRBP161-180, then the in vivo primed T cells were separated and stimulated with the immunizing peptide after labeling with CFSE, and the antigen-specific response of CD8 T cells was demonstrated by FACS analysis and proliferation assay. Using multimers of recombinant H-2D^r molecules, we also showed that the binding of the H-2D^r fusion protein to IRBP161-180-expanded CD8 T cells was dependent on the peptide complexed with the recombinant molecules.

Results: : Autoreactive CD8 T cells were abundant in B10RIII mice immunized with the uveitogenic peptide IRBP161-180. The use of a panel of truncated peptides showed that the truncated 10-mer peptide, IRBP168-177, retained the ability to bind to, and stimulate, IRBP161-180-specific CD8 T cells after complexing with a dimeric MHC class I (H-2D^r) molecule. Finally, adoptive transfer of IRBP161-180-specific T cells stimulated with IRBP168-177 consistently induced mild, but significant, EAU in naïve B10RIII mice.

Conclusions: : Autoreactive CD8⁺ T cells can be readily demonstrated among the activated autoreactive T cells in the B10RIII mouse. Sequence 168 to 177 of the IRBP molecule contains an antigenic epitope for the CD8⁺ autoreactive T cell.

Keywords: autoimmune disease • inflammation • uveitis-clinical/animal model