Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, USA.
Center for Immunology, University of Minnesota, Minneapolis, MN, USA.
Nat Commun. 2023 Feb 1;14(1):528. 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.
T 细胞受体 (TCR) 转基因小鼠是研究抗原特异性免疫反应的宝贵工具。在现有的模型中，单克隆 TCR 由非生理启动子驱动并随机整合到基因组中。在这里，我们创建了一种高效的方法来开发 T 细胞受体交换 (TRex) 小鼠，其中针对自身/肿瘤抗原间皮素 (Msln) 的 TCR 整合到 Trac 基因座中，同时破坏 Msln 以避免 T 细胞耐受。我们表明，高亲和力的 TRex 胸腺细胞经历了所有连续的成熟阶段，在 DN4 表达外源性 TCR，需要 MHC Ⅰ类分子进行阳性选择，只有当两个 Msln 等位基因都存在时才会经历阴性选择。通过比较具有相同特异性但亲和力不同的 TCR，我们表明 Trac 靶向提高了较低亲和力 TCR 的功能敏感性，并赋予对 T 细胞功能丧失的抗性。通过生成与广泛使用的 LCMV-P14 TCR 转基因小鼠具有相同特异性的 P14 TRex 小鼠，我们证明了 Trac 靶向的 TCR 比转基因 TCR 具有更高的亲和力，同时保持了生理 T 细胞的发育。总之，我们的结果支持 TRex 方法是研究生理抗原特异性 T 细胞行为的先进工具。
