Germline T cell receptor exchange results in physiological T cell development and function

• Published in: Nature communications 2023-02, Vol.14 (1), p.528-19, Article 528
• Main Authors: Rollins, Meagan R., Raynor, Jackson F., Miller, Ebony A., Butler, Jonah Z., Spartz, Ellen J., Lahr, Walker S., You, Yun, Burrack, Adam L., Moriarity, Branden S., Webber, Beau R., Stromnes, Ingunn M.
• Format: Article
• Language: English
• Subjects: 631/250/1619/554; 631/250/2152/1566/1618; 631/61/338; 64; 64/60; 692/4028/67/1059/2325; Affinity; Animals; Antigens; Autoantigens; Avidity; Cell culture; Cell Differentiation; Clonal selection; Gene dosage; Humanities and Social Sciences; Immunological tolerance; Lymphocytes; Lymphocytes T; Major histocompatibility complex; Mice; Mice, Transgenic; multidisciplinary; Physiology; Positive selection; Receptors; Receptors, Antigen, T-Cell - genetics; Science; Science (multidisciplinary); Sensitivity enhancement; T cell receptors; Thymocytes; Transgenic mice
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-36180-1

T cell receptor (TCR) transgenic mice represent an invaluable tool to study antigen-specific immune responses. In the pre-existing models, a monoclonal TCR is driven by a non-physiologic promoter and randomly integrated into the genome. Here, we create a highly efficient methodology to develop T cell receptor exchange (TRex) mice, in which TCRs, specific to the self/tumor antigen mesothelin ( Msln ), are integrated into the Trac locus, with concomitant Msln disruption to circumvent T cell tolerance. We show that high affinity TRex thymocytes undergo all sequential stages of maturation, express the exogenous TCR at DN4, require MHC class I for positive selection and undergo negative selection only when both Msln alleles are present. By comparison of TCRs with the same specificity but varying affinity, we show that Trac targeting improves functional sensitivity of a lower affinity TCR and confers resistance to T cell functional loss. By generating P14 TRex mice with the same specificity as the widely used LCMV-P14 TCR transgenic mouse, we demonstrate increased avidity of Trac -targeted TCRs over transgenic TCRs, while preserving physiologic T cell development. Together, our results support that the TRex methodology is an advanced tool to study physiological antigen-specific T cell behavior. The currently available transgenic T cell receptor (TCR) models represent high affinity antigen-TCR interactions. Authors here present an alternative approach to target an exogenous TCR into the physiological Trac locus in the germline of mice, which uncovers that the natural genomic context for TCRs can enhance the antigen sensitivity of lower affinity TCRs and enables the physiologic range of antigen-TCR interaction and a gene dosage dependent mechanism of central tolerance.