Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
Crescendo Biologics Ltd, Cambridge, UK.
J Immunother Cancer. 2021 Apr;9(4). doi: 10.1136/jitc-2020-002173.
Chimeric antigen receptor (CAR) T cells are effective in B-cell malignancies. However, heterogeneous antigen expression and antigen loss remain important limitations of targeted immunotherapy in solid tumors. Therefore, targeting multiple tumor-associated antigens simultaneously is expected to improve the outcome of CAR-T cell therapies. Due to the instability of single-chain variable fragments, it remains challenging to develop the simultaneous targeting of multiple antigens using traditional single-chain fragment variable (scFv)-based CARs.
We used Humabody V domains derived from a transgenic mouse to obtain fully human prostate-specific membrane antigen (PSMA) V and mesothelin (MSLN) V sequences and redirect T cell with V based-CAR. The antitumor activity and mode of action of PSMA V and MSLN V were evaluated in vitro and in vivo compared with the traditional scFv-based CARs.
Human V domain-based CAR targeting PSMA and MSLN are stable and functional both in vitro and in vivo. V modules in the bispecific format are capable of binding their specific target with similar affinity as their monovalent counterparts. Bispecific CARs generated by joining two human antibody V domains can prevent tumor escape in tumor with heterogeneous antigen expression.
Fully human antibody V domains can be used to generate functional CAR molecules, and redirected T cells elicit antitumoral responses in solid tumors at least as well as conventional scFv-based CARs. In addition, V domains can be used to generate bispecific CAR-T cells to simultaneously target two different antigens expressed by tumor cells, and therefore, achieve better tumor control in solid tumors.
嵌合抗原受体 (CAR) T 细胞在 B 细胞恶性肿瘤中有效。然而，异质抗原表达和抗原丢失仍然是实体瘤靶向免疫治疗的重要限制。因此，同时靶向多个肿瘤相关抗原有望改善 CAR-T 细胞治疗的效果。由于单链可变片段的不稳定性，使用传统的基于单链片段可变 (scFv) 的 CAR 同时靶向多个抗原仍然具有挑战性。
我们使用源自转基因小鼠的 Humabody V 结构域获得完全人前列腺特异性膜抗原 (PSMA) V 和间皮素 (MSLN) V 序列，并使用基于 V 的 CAR 重新定向 T 细胞。在体外和体内评估 PSMA V 和 MSLN V 的抗肿瘤活性和作用模式，并与传统的基于 scFv 的 CAR 进行比较。
靶向 PSMA 和 MSLN 的基于人 V 结构域的 CAR 在体外和体内均稳定且具有功能。在双特异性形式下的 V 模块能够以与其单价对应物相似的亲和力结合其特定靶标。通过连接两个人抗体 V 结构域生成的双特异性 CAR 可以防止肿瘤在异质抗原表达的肿瘤中发生逃逸。
完全人抗体 V 结构域可用于生成功能性 CAR 分子，并且重定向的 T 细胞在实体瘤中至少与传统的基于 scFv 的 CAR 一样引发抗肿瘤反应。此外，V 结构域可用于生成双特异性 CAR-T 细胞，以同时靶向肿瘤细胞表达的两个不同抗原，从而在实体瘤中实现更好的肿瘤控制。
