State key Laboratory of Experimental Hematology, Institute of Hematology and Hospital of Blood Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China.
Cell Oncol (Dordr). 2012 Dec;35(6):423-34. doi: 10.1007/s13402-012-0101-9. Epub 2012 Oct 9.
A diabody is a bispecific antibody that is capable of recruiting a polyclonal T cell to antibody target-expressing tumor cells. However, the two chains of diabodies tend to dissociate because they are integrated non-covalently. Therefore, it is necessary to remodel the diabody to increase its stability in order to enhance the antitumor activity.
We constructed an antiCD3×antiCD19 diabody with one binding site for the T cell antigen receptor (TCRCD3) and the other for the B cell-specific antigen (CD19) by recombinant gene engineering technology. Cysteine residues were introduced into the V domains of the anti-CD3 segment. The stability and cytotoxicity of the two diabodies were compared in vitro and vivo.
The disulfide-stabilized (ds) diabodies produced by Escherichia coli were secreted with high yields in a fully active form without a decrease in affinity. Compared with the parental diabody, the disulfide-stabilized (ds) diabody proved more stable in vitro and in vivo without reducing binding affinity. Both were able to effectively eliminate human lymphoma Raji cells by redirecting T lymphocytes in vitro and in vivo, but the ds diabody was more effective in inhibiting the growth of xenografts transplanted in BALB/C nude mice.
The antiCD3×antiCD19 ds diabody is more suitable for a controlled polyclonal T cell therapy of human CD19-positive B cell malignancies than its parental diabody.
双抗体是一种双特异性抗体，能够招募多克隆 T 细胞到抗体靶标表达的肿瘤细胞。然而，由于双抗体的两条链是非共价整合的，因此它们往往会解离。因此，有必要对双抗体进行改造以增加其稳定性，从而增强其抗肿瘤活性。
我们通过重组基因工程技术构建了一种具有一个结合位点用于 T 细胞抗原受体（TCRCD3）和另一个用于 B 细胞特异性抗原（CD19）的抗 CD3×抗 CD19 双抗体。在抗 CD3 片段的 V 结构域中引入了半胱氨酸残基。比较了两种双抗体在体外和体内的稳定性和细胞毒性。
大肠杆菌分泌的二硫键稳定（ds）双抗体以完全活性形式高产分泌，而亲和力没有降低。与亲本双抗体相比，ds 双抗体在体外和体内更稳定，而结合亲和力没有降低。两者都能够通过体外和体内重定向 T 淋巴细胞有效消除人淋巴瘤 Raji 细胞，但 ds 双抗体在抑制 BALB/C 裸鼠异种移植瘤生长方面更有效。
与亲本双抗体相比，抗 CD3×抗 CD19 ds 双抗体更适合用于人 CD19 阳性 B 细胞恶性肿瘤的受控多克隆 T 细胞治疗。
