Ochi Toshiki, Maruta Masaki, Tanimoto Kazushi, Kondo Fumitake, Yamamoto Toshihiro, Kurata Mie, Fujiwara Hiroshi, Masumoto Junya, Takenaka Katsuto, Yasukawa Masaki
Department of Hematology, Clinical Immunology, and Infectious Diseases, Ehime University Graduate School of Medicine, Toon, Ehime, Japan.
Division of Immune Regulation, Proteo-Science Center, Ehime University, Toon, Ehime, Japan.
Commun Biol. 2021 Mar 2;4(1):273. doi: 10.1038/s42003-021-01791-1.
Cancer immunotherapy using T cells redirected with chimeric antigen receptor (CAR) has shown a lot of promise. We have established a single-chain antibody (scFv) generation system in which scFv library-expressing CAR-T cells can be screened appropriately based on their antitumor functions. A variable region library containing the variable and J regions of the human immunoglobulin light or heavy chain was fused with the variable region of a heavy or light chain encoded by an existing tumor-specific antibody to generate a new scFv library. Then, scFv library-expressing CAR-T cells were generated and stimulated with target cells to concentrate the antigen-specific population. Using this system, target-specific recognition of CAR-T cells appeared to be finely tuned by selecting a new variable region. Importantly, we have demonstrated that the newly optimized scFv-expressing CAR-T cells had better proliferation capacity and durable phenotypes, enabling superior reactivity against advanced tumors in vivo in comparison with the original CAR-T cells. Therefore, the optimization of an scFv is needed to maximize the in vivo antitumor functions of CAR-T cells. This system may allow us to adjust an immunological synapse formed by an scFv expressed by CAR-T cells and a target antigen, representing an ideal form of CAR-T-cell immunotherapy.
使用嵌合抗原受体（CAR）重定向T细胞的癌症免疫疗法已展现出诸多前景。我们建立了一个单链抗体（scFv）生成系统，在该系统中，可根据表达scFv文库的CAR-T细胞的抗肿瘤功能对其进行适当筛选。将包含人免疫球蛋白轻链或重链可变区和J区的可变区文库与现有肿瘤特异性抗体编码的重链或轻链可变区融合，以生成新的scFv文库。然后，生成表达scFv文库的CAR-T细胞并用靶细胞进行刺激，以富集抗原特异性群体。利用该系统，通过选择新的可变区，似乎可对CAR-T细胞的靶标特异性识别进行精细调节。重要的是，我们已证明，新优化的表达scFv的CAR-T细胞具有更好的增殖能力和持久表型，与原始CAR-T细胞相比，在体内对晚期肿瘤具有更强的反应性。因此，需要对scFv进行优化，以使CAR-T细胞的体内抗肿瘤功能最大化。该系统可能使我们能够调节由CAR-T细胞表达的scFv与靶抗原形成的免疫突触，代表了CAR-T细胞免疫疗法的理想形式。
