Li Sisi, Wang Zhujun, Guo Xiaoping, Tang Yongmin
School of Medicine, Hangzhou City University, #51 Huzhou Street, Hangzhou 310015, China.
Department of Pediatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, China.
Neoplasia. 2025 Jan;59:101084. doi: 10.1016/j.neo.2024.101084. Epub 2024 Nov 20.
Leukemia stem cells (LSCs) play a critical role in the initiation, recurrence, and resistance to treatment of leukemia. Eradicating LSCs is crucial for the complete elimination of the disease. CD45RA is identified as an important marker for LSC subsets in acute myeloid leukemia (AML), providing a strategic target for therapy. In this report, we introduce Hu3A4, an innovative humanized CD45RA antibody devised to target LSCs expressing this antigen. Hu3A4 retains the antigen-recognition ability of its parental antibody while removing sequences from the variable region that could elicit human anti-mouse immune reactions. The modified variable regions of the heavy and light chains were intricately fused with the constant regions of human IgG1 heavy and light chains, respectively, producing a humanized antibody that emulates the structure of natural IgG. Hu3A4 was produced through recombinant expression in Chinese Hamster Ovary (CHO) cells, which ensured stable gene integration. In vitro tests revealed that Hu3A4 could effectively target and lyse the cells. Further, in vivo studies highlighted Hu3A4's substantial anti-leukemic activity, significantly prolonging survival times in treated animal models compared to controls (P < 0.01). To summarize, Hu3A4 exhibits remarkable bioactivity and offers a promising therapeutic potential for the treatment of leukemia patients. Progressing Hu3A4 through additional preclinical and clinical studies is crucial to validate its efficacy as a therapeutic agent for leukemia.
白血病干细胞（LSCs）在白血病的起始、复发及治疗耐药中起着关键作用。根除LSCs对于完全消除该疾病至关重要。CD45RA被确定为急性髓系白血病（AML）中LSC亚群的重要标志物，为治疗提供了一个战略靶点。在本报告中，我们介绍了Hu3A4，一种创新的人源化CD45RA抗体，旨在靶向表达该抗原的LSCs。Hu3A4保留了其亲本抗体的抗原识别能力，同时去除了可变区中可能引发人抗鼠免疫反应的序列。重链和轻链的修饰可变区分别与人类IgG1重链和轻链的恒定区复杂融合，产生了一种模拟天然IgG结构的人源化抗体。Hu3A4通过在中国仓鼠卵巢（CHO）细胞中的重组表达产生，这确保了基因的稳定整合。体外试验表明，Hu3A4能够有效地靶向并裂解细胞。此外，体内研究突出了Hu3A4的显著抗白血病活性，与对照组相比，在治疗的动物模型中显著延长了生存时间（P < 0.01）。总之，Hu3A4表现出显著的生物活性，并为白血病患者的治疗提供了有前景的治疗潜力。通过额外的临床前和临床研究推进Hu3A4对于验证其作为白血病治疗药物的疗效至关重要。
