Chimeric antigen receptors (CARs) are synthetic receptors that usually redirect T cells to surface antigens independent of human leukocyte antigen (HLA). Here, we investigated a T cell receptor-like CAR based on an antibody that recognizes HLA-A*0201 presenting a peptide epitope derived from the cancer-testis antigen NY-ESO-1. We hypothesized that this CAR would efficiently redirect transduced T cells in an HLA-restricted, antigen-specific manner. However, we found that despite the specificity of the soluble Fab, the same antibody in the form of a CAR caused moderate lysis of HLA-A2 expressing targets independent of antigen owing to T cell avidity. We hypothesized that lowering the affinity of the CAR for HLA-A2 would improve its specificity. We undertook a rational approach of mutating residues that, in the crystal structure, were predicted to stabilize binding to HLA-A2. We found that one mutation (DN) lowered the affinity of the Fab to T cell receptor-range and restored the epitope specificity of the CAR. DN CAR T cells lysed native tumor targets in vitro, and, in a xenogeneic mouse model implanted with two human melanoma lines (A2+/NYESO+ and A2+/NYESO-), DN CAR T cells specifically migrated to, and delayed progression of, only the HLA-A2+/NY-ESO-1+ melanoma. Thus, although maintaining MHC-restricted antigen specificity required T cell receptor-like affinity that decreased potency, there is exciting potential for CARs to expand their repertoire to include a broad range of intracellular antigens.

中文翻译：

---

MHC限制的基于抗体的嵌合抗原受体需要TCR样的亲和力来维持抗原特异性。

嵌合抗原受体（CARs）是通常将T细胞重定向至独立于人白细胞抗原（HLA）的表面抗原的合成受体。在这里，我们研究了基于识别HLA-A * 0201的抗体的T细胞受体样CAR，HLA-A * 0201呈现出源自癌症睾丸抗原NY-ESO-1的肽表位。我们假设该CAR将以HLA限制的抗原特异性方式有效地重定向转导的T细胞。但是，我们发现，尽管可溶性Fab具有特异性，但由于T细胞的亲和力，CAR形式的同一抗体会引起中等程度的HLA-A2表达靶标裂解，而与抗原无关。我们假设降低CAR对HLA-A2的亲和力将改善其特异性。我们采用了合理的方法来突变晶体结构中的残基，预测它们稳定与HLA-A2的结合。我们发现一个突变（DN）降低了Fab对T细胞受体范围的亲和力，并恢复了CAR的表位特异性。DN CAR T细胞在体外裂解了天然肿瘤靶标，并且在植入了两种人黑素瘤细胞系（A2 + / NYESO +和A2 + / NYESO-）的异种小鼠模型中，DN CAR T细胞特异性地迁移至并延迟了其发展。 HLA-A2 + / NY-ESO-1 +黑色素瘤。因此，尽管维持MHC限制的抗原特异性需要降低效能的T细胞受体样亲和力，但CARs具有令人兴奋的潜力，可扩展其功能范围以涵盖广泛的细胞内抗原。DN CAR T细胞在体外裂解了天然肿瘤靶标，并且在植入了两种人黑素瘤细胞系（A2 + / NYESO +和A2 + / NYESO-）的异种小鼠模型中，DN CAR T细胞特异性地迁移至并延迟了其发展。 HLA-A2 + / NY-ESO-1 +黑色素瘤。因此，尽管维持MHC限制的抗原特异性需要降低效能的T细胞受体样亲和力，但CARs具有令人兴奋的潜力，可扩展其功能范围以涵盖广泛的细胞内抗原。DN CAR T细胞在体外裂解了天然肿瘤靶标，并且在植入了两种人黑素瘤细胞系（A2 + / NYESO +和A2 + / NYESO-）的异种小鼠模型中，DN CAR T细胞特异性地迁移至并延迟了其发展。 HLA-A2 + / NY-ESO-1 +黑色素瘤。因此，尽管维持MHC限制的抗原特异性需要降低效能的T细胞受体样亲和力，但CARs具有令人兴奋的潜力，可扩展其功能范围以涵盖广泛的细胞内抗原。