A T-cell-engaging B7-H4/CD3-bispecific Fab-scFv Antibody Targets Human Breast Cancer
A T-cell-engaging B7-H4/CD3-bispecific Fab-scFv Antibody Targets Human Breast Cancer
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DOI：
10.1158/1078-0432.ccr-17-3123
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发表时间：
2019-05-01
影响因子：
11.5
通讯作者：
Akiyama, Yasuto
中科院分区：
文献类型：
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作者：
Iizuka, Akira;Nonomura, Chizu;Akiyama, Yasuto
目的：B7同系物4（B7-H4，VTCN 1）是一种免疫检查点分子，负调节免疫反应，已知在许多人类癌症中过表达。先前，我们产生了小鼠抗人B7-H4 mAb，其在体内不具有显著的抗肿瘤作用，这可能是由于分子不稳定性。本研究设计了一种B7-H4/CD 3双特异性抗体（B7-H4/CD 3-bispecific antibody，BsAb），并利用人源化小鼠模型研究了其体内外抗肿瘤活性。实验设计：合成了抗B7-H4/CD 3 BsAb的抗体结合片段（antibody-binding fragment，Fab）-单链抗体（single-chain variable fragment，scFv）和scFv-scFv的cDNA，并在HEK 293细胞中制备了BsAb抗体。结果：抗B7-H4/CD 3 BsAb的人外周血单个核细胞（hPBMC）能有效地杀伤人乳腺癌细胞株MDA-MB-468（EC 50：0.2 ng/mL）和其他B7-H4（+）细胞系。将BsAb注射到人源化小鼠模型中，对MDA-MB-468、HCC-1954和HCC-1569肿瘤以及CD 8（+）和颗粒酶B+ CTL向肿瘤中的浸润具有立即且强烈的抗肿瘤活性，并且经长期观察没有不良反应。结论：抗B7-H4/CD 3 BsAb可能是治疗B7-H4（+）乳腺癌的有效工具。
Purpose: The B7 homolog 4 (B7-H4, VTCN1) is an immune checkpoint molecule that negatively regulates immune responses and is known to be overexpressed in many human cancers. Previously, we generated a mouse anti-human B7-H4 mAb that did not have a significant antitumor effect in vivo probably because of molecule instability. In this study, we designed a B7-H4/CD3-bispecific antibody (BsAb) and investigated its antitumor activity in vitro and in vivo using a humanized mouse model.Experimental Design: cDNAs of the antibody-binding fragment (Fab)-single-chain variable fragment (scFv) and scFv-scFv of the anti-B7-H4/CD3 BsAb were synthesized, and the BsAb antibodies were produced in HEK293 cells. The antitumor activity against human breast cancer cells by human peripheral blood mononuclear cells (hPBMC) with BsAb was measured by lactate dehydrogenase release in vitro, and in vivo using hPBMC-transplanted MHC class I-and class II-deficient NOG mice.Results: hPBMCs with anti-B7-H4/CD3 BsAbs successfully lysed the human breast cancer cell line MDA-MB-468 (EC50: 0.2 ng/mL) and other B7-H4(+) cell lines in vitro. When BsAb was injected in a humanized mouse model, there was an immediate and strong antitumor activity against MDA-MB-468, HCC-1954, and HCC-1569 tumors and CD8(+) and granzyme B+ CTL infiltration into the tumor, and there were no adverse effects after long-term observation. CD8(+) T-cell depletion by an anti-CD8 antibody mostly reduced the antitumor effect of BsAb in vivo.Conclusions: An anti-B7-H4/CD3 BsAb may be a good therapeutic tool for patients with B7-H4(+) breast cancers.