Background/Purpose: Type II collagen (CII) has been suggested as a possible autoantigen in RA, since autoimmunity to CII is commonly detected in patients with RA. Also a RA-like disease, collagen-induced arthritis (CIA) can be induced in rodents expressing H-2Aq and H-2Ar MHC class II haplotypes after immunization with heterologous CII. Autoreactive T cells in both RA and CIA recognize the same immunodominant CII epitope 259-273, which binds both CIA-associated mouse H-2Aq and human RA-associated HLA-DRB1 MHC class II molecules. CII-reactive T cells from RA patients predominantly recognize the immunodominant CII 259-273 epitope when it is glycosylated at positions 264 and 270. Glycosylation of the lysine side chain at position 264 is of particular importance for CIA development as well as for tolerance induction to CII. It has been previously shown in our laboratory that administration of soluble MHC class II molecules in complex with the glycosylated CII peptide 259-273 (GalOK264/Aq) can prevent CIA development and ameliorate chronic relapsing disease, which can be relevant for patients with RA. However, the exact mechanism of tolerance induction by GalOK264/Aq complexes remains to be elucidated. 

Methods: We established Vb12-transgenic mouse model, which have galactosylated CII epitope specific T cells and the corresponding clonotypic antibody to track them unambiguously. By immune-phenotyping of galactosylated CII epitope specific T cells we investigated the role of CII-reactive T cells in tolerance induced by vaccination with GalOK264/Aq complexes.

Vb12-tg mice were immunized with rat CII emulsified in CFA. 100 mg of GalOK264/Aq complexes or PBS were injected intravenously day 3 post-immunization. Day 10 post-immunization T cells from draining (inguinal) lymph nodes were either directly analyzed by FACS or restimulated in vitro with galactosylated CII peptide and the numbers of cytokine-expressing T cells were determined by FACS or ELISPOT and cytokine concentrations in cell culture supernatants were evaluated by ELISA.

Results: Injection of Vβ12 transgenic mice with GalOK264/Aq complexes leads to reduction in number of the galactosylated CII-specific T cells. Also the proportion of T cells expressing CD69, an early activation marker, within galactosylated CII specific T cell population, was reduced in vaccinated mice compared to PBS controls. Further phenotypic analysis of galactosylated CII-specific T cells revealed that vaccination with GalOK264/Aq of Vβ12 transgenic mice leads to an increased expression of the co-inhibitory molecules such as PD-1 and LAG3.

Furthermore, administration of Aq/gal-K264 complexes significantly attenuates Th1 and Th17 responses in galactosylated CII specific T cells both in and Vβ12-transgenic- and B6NQ mice.

Conclusion: Thus, vaccination with GalOK264/Aq complexes skews the CII specific T cell responses from activation and differentiation into effector cells toward antigen specific immune tolerance phenotype.

 

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/t-cell-tolerance-induction-by-the-glycosylated-type-ii-collagen-peptide-based-vaccination-in-murine-arthritis/