Suppression of spontaneous uveoretinitis development by non-immunopathogenic peptide immunization

Area of Science:

• Immunology
• Ophthalmology
• Autoimmune Diseases

Background:

• Transgenic (TG) nude mice, developed by grafting fetal rat thymus into BALB/c nude mice, spontaneously develop autoimmune diseases, including uveoretinitis.
• Interphotoreceptor retinoid-binding protein (IRBP) is implicated in ocular autoimmune conditions.

Purpose of the Study:

• To investigate the role of specific IRBP peptide fragments in the induction and regulation of uveoretinitis in TG nude mice.
• To characterize the T cell responses elicited by these IRBP peptides.

Main Methods:

• TG nude mice were immunized with IRBP-derived peptides (P518-529 and P1182-1194).
• T cell lines specific for these peptides were established and characterized (CD4+, Vbeta usage).
• Cytokine production profiles (IL-2, IFN-gamma, IL-4, IL-10) of T cells were analyzed.
• Adoptive transfer of peptide-specific T cells into naive mice was performed.

Main Results:

• Immunization with P518-529 induced uveoretinitis and Th1-type T cells (producing IL-2, IFN-gamma).
• Immunization with P1182-1194 inhibited uveoretinitis and induced Th2-type T cells (producing IL-4, IL-10).
• Adoptive transfer of P518-529-specific T cells caused uveoretinitis, while P1182-1194-specific T cells did not.

Conclusions:

• The IRBP peptide P518-529 is both immunogenic and uveitogenic, inducing Th1 responses that drive autoimmune uveoretinitis.
• The IRBP peptide P1182-1194 is immunogenic but not uveitogenic, inducing Th2 responses that suppress uveoretinitis.
• Specific IRBP peptide fragments differentially modulate autoimmune responses via distinct T helper cell subsets.