The T-cell receptor (TCR) is a crucial molecule in cellular immunity. The single-chain T-cell receptor (scTCR) is a potential format in TCR therapeutics because it eliminates the possibility of αβ-TCR mispairing. However, its poor stability and solubility impede the in vitro study and manufacturing of therapeutic applications. In this study, some conserved structural motifs are identified in variable domains regardless of germlines and species. Theoretical analysis helps to identify those unfavored factors and leads to a general strategy for stabilizing scTCRs by substituting residues at exact IMGT positions with beneficial propensities on the consensus sequence of germlines. Several representative scTCRs are displayed to achieve stability optimization and retain comparable binding affinities with the corresponding αβ-TCRs in the range of μM to pM. These results demonstrate that our strategies for scTCR engineering are capable of providing the affinity-enhanced and specificity-retained format, which are of great value in facilitating the development of TCR-related therapeutics.

中文翻译：

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基于结构的稳定单链 T 细胞受体以增强亲和力的合理通用策略

T 细胞受体 (TCR) 是细胞免疫中的关键分子。单链 T 细胞受体 (scTCR) 是 TCR 治疗中的一种潜在形式，因为它消除了 αβ-TCR 错配的可能性。然而，其稳定性和溶解度差阻碍了治疗应用的体外研究和制造。在这项研究中，无论种系和物种如何，在可变域中鉴定了一些保守的结构基序。理论分析有助于识别那些不利因素，并通过用种系共有序列上的有益倾向替换精确 IMGT 位置上的残基，得出稳定 scTCR 的一般策略。显示了几种代表性的 scTCR，以实现稳定性优化，并在 μM 至 pM 范围内与相应的 αβ-TCR 保持相当的结合亲和力。这些结果表明，我们的 scTCR 工程策略能够提供亲和力增强和特异性保留的形式，这对于促进 TCR 相关疗法的开发具有重要价值。