A new humanized TCR transgenic mouse model to study citrullinated tenascin C reactive T cells relevant to rheumatoid arthritis

Schuelein, M.; Afonso, M.; Sijbranda, M.; Pulgarin, D. V.; Dubnovitsky, A.; Hansson, M.; Rethi, B.; Wermeling, F.; Winkler, A.; Klareskog, L.; Espinosa, A.; Malmstrom, V.; Raposo, B.

doi:10.64898/2026.02.12.705563

bioRxiv · 10.64898/2026.02.12.705563

A new humanized TCR transgenic mouse model to study citrullinated tenascin C reactive T cells relevant to rheumatoid arthritis

Schuelein, M.·Afonso, M.·Sijbranda, M.·Pulgarin, D. V.·Dubnovitsky, A.·Hansson, M.·Rethi, B.·Wermeling, F.·Winkler, A.·Klareskog, L.·Espinosa, A.·Malmstrom, V.·Raposo, B.

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Abstract

ObjectivesAutoreactive T cells recognizing citrullinated antigens, although rare and difficult to study, are implicated in rheumatoid arthritis (RA). To allow functional studies and manipulation of such T cells, we have generated and characterized transgenic mice expressing a TCR cloned from an RA patient and reactive with a prominent target, citrullinated tenascin C (citTNC). MethodsA humanized TCR transgenic (hTCR-tg) mouse recognizing the citrullinated TNC22 (citTNC22) antigen in an HLA-DRB1*04:01 (HLA-DR4) restricted manner was developed by genetically engineering a chimeric TCR expressing murine constant domains and human V(D)J sequences. hTCR-tg mice were immune phenotyped in murine H-2b and humanized HLA-DR4 backgrounds using full spectrum flow cytometry, cytokine ELISAs and fluorospot assays at steady-state and after antigen challenge. Additionally, we investigated the presence of antibodies to citTNC and arthritis following citTNC protein immunization. ResultsThymic selection of hTCR T cells differed between the two MHC-II alleles, with a normal CD4+ T cell development observed solely under HLA-DR4 restriction. The chimeric hTCR maintained its citTNC22 specificity in vitro and ex vivo, without cross-reactivity to native TNC22 or other citrullinated autoantigens. hTCR-tg CD4+ T cells responded to antigen challenge in vivo and provided support to IgG class-switch and antigen-specific antibody production. Moreover, protein immunized hTCR-tg mice developed arthritis after periarticular challenge with citTNC. ConclusionshTCR-tg mice expressing an RA patient-derived autoreactive TCR develop functional antigen-specific and HLA-restricted CD4+ T cells. The combination of humanized HLA-DR4 and TNC22 mice will be a valuable tool in the development of antigen-specific therapies translatable to human disease.

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Schuelein, M., Afonso, M., Sijbranda, M., Pulgarin, D. V., Dubnovitsky, A., Hansson, M., Rethi, B., Wermeling, F., Winkler, A., Klareskog, L., Espinosa, A., Malmstrom, V., Raposo, B.. 2026-02-14. A new humanized TCR transgenic mouse model to study citrullinated tenascin C reactive T cells relevant to rheumatoid arthritis. https://doi.org/10.64898/2026.02.12.705563

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