Adoptive cell transfer between genetically identical hosts relies on the use of a congenic marker to distinguish the donor cells from the host cells. CD45, a glycoprotein expressed by all hematopoietic cells, is one of the main congenic markers used because its two isoforms, CD45.1 and CD45.2, can be discriminated by flow cytometry. As a consequence, C57BL/6J (B6; CD45.2) and B6.SJL-Ptprc^a Pepc^b/BoyJ (B6.SJL; CD45.1) mice are widely used in adoptive cell transfer experiments, under the presumption that they differ only at the CD45 (Ptprc) locus. However, recent studies have identified genetic variations between these congenic strains and have notably highlighted a differential expression of cathepsin E (CTSE). The B6.SJL mouse presents a number of functional differences in hematopoietic stem cell engraftment potential and immune cell numbers compared with the B6 mouse. In this study, we showed that B6 and B6.SJL mice also differ in their CD8⁺ T cell compartment and CD8⁺ T cell responses to viral infection. We identified Ctse as the most differentially expressed gene between CD8⁺ T cells of B6 and B6.SJL and demonstrated that the differences reported between these two mouse strains are not due to CTSE. Finally, using CRISPR–Cas9 genome editing, we generated a CD45.1-expressing B6 mouse by inserting one nucleotide mutation (A904G) leading to an amino acid change (K302E) in the Ptprc gene of the B6 mouse. We showed that this new B6-Ptprc^{em(K302E)Jmar}/J mouse resolves the experimental biases reported between the B6 and B6.SJL mouse lines and should thus represent the new gold standard for adoptive cell transfer experiments in B6.

遗传相同的宿主之间的过继细胞转移依赖于使用同源标记来区分供体细胞和宿主细胞。CD45 是一种由所有造血细胞表达的糖蛋白，是使用的主要同源标记之一，因为它的两种亚型 CD45.1 和 CD45.2 可以通过流式细胞术区分。因此，C57BL/6J (B6; CD45.2) 和 B6.SJL- Ptprc ^a Pepc ^b /BoyJ (B6.SJL; CD45.1) 小鼠广泛用于过继细胞转移实验，假设它们不同仅在 CD45 ( Ptprc)位点。然而，最近的研究已经确定了这些同源菌株之间的遗传变异，并特别强调了组织蛋白酶 E (CTSE) 的差异表达。与 B6 小鼠相比，B6.SJL 小鼠在造血干细胞植入潜力和免疫细胞数量方面存在许多功能差异。在这项研究中，我们发现 B6 和 B6.SJL 小鼠的 CD8 ⁺ T 细胞区室和 CD8 ⁺ T 细胞对病毒感染的反应也存在差异。我们确定Ctse是 B6 和 B6.SJL 的 CD8 ⁺ T 细胞之间差异最大的表达基因，并证明这两种小鼠品系之间报告的差异不是由 CTSE 引起的。最后，使用 CRISPR-Cas9 基因组编辑，我们通过在 B6 小鼠的Ptprc基因中插入一个核苷酸突变 (A904G)，导致氨基酸变化 (K302E)，生成表达 CD45.1 的B6 小鼠。我们表明，这种新的 B6-Ptprc ^{em(K302E)Jmar} /J 小鼠解决了 B6 和 B6.SJL 小鼠系之间报告的实验偏差，因此应该代表 B6 过继细胞转移实验的新黄金标准。