Department of Chemistry, Institute of Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany.
Cancer Immunol Immunother. 2012 Sep;61(9):1565-73. doi: 10.1007/s00262-012-1287-4. Epub 2012 Jun 7.
Monoclonal antibodies have become a mainstay for the targeted treatment of cancer today. Some of the most successful targets of monoclonal antibodies are constituted by the epidermal growth factor receptor family spearheaded by the epidermal growth factor receptor (EGFR). Prompted by studies indicating that IgE compared to IgG may harness alternate effector functions to eradicate malignant cells, we addressed the establishment, engineering, and the potential tumoricidal effects of recombinant anti-EGFR IgE. Therefore, two different therapeutic EGFR-specific antibodies, 225 and 425, were chosen for re-cloning into different chimeric IgE and IgG formats and produced in human cells. Simultaneous antibody binding to the sEGFR demonstrated accessibility of both epitopes for recombinant IgE. Proliferation and cytotoxicity assays demonstrated signal blocking and effector mediating capability of IgE isotypes. Pronounced degranulation in the presence of sEGFR upon activation exclusively with two IgE antibodies verified the epitope proximity and provides evidence that tumor-targeting by anti-EGFR IgE is safe with regard to soluble target structures. Degranulation mediated by tumor cells expressing EGFR could be demonstrated for singular and combined IgE antibodies; however, use of two IgE specificities was not superior to use of one IgE alone. The data suggest that the surface distribution of EGFR is optimally suited to mount a robust effector cell trigger and corroborate the potential and specificity of the IgE/IgE receptor network to react to xenobiotic or pathogenic patterns for targeting malignancies.
单克隆抗体已成为当今癌症靶向治疗的主要手段。单克隆抗体最成功的一些靶点是由表皮生长因子受体家族构成的，其中以表皮生长因子受体（EGFR）为首。有研究表明，与 IgG 相比，IgE 可能利用替代效应功能来消灭恶性细胞，这促使我们研究了重组抗 EGFR IgE 的建立、工程设计和潜在的杀瘤作用。因此，我们选择了两种不同的治疗性 EGFR 特异性抗体 225 和 425，将其重新克隆到不同的嵌合 IgE 和 IgG 形式中，并在人细胞中生产。同时结合 sEGFR 的抗体表明，两种表位都可用于重组 IgE。增殖和细胞毒性测定表明，IgE 同种型具有信号阻断和效应介导能力。在存在 sEGFR 的情况下，仅通过两种 IgE 抗体激活可显著脱颗粒，验证了表位的接近性，并提供了证据，表明针对 EGFR 的抗 EGFR IgE 针对可溶性靶结构是安全的。对于表达 EGFR 的肿瘤细胞，可以证明单一和联合 IgE 抗体介导的脱颗粒；然而，使用两种 IgE 特异性并不优于单独使用一种 IgE。数据表明，EGFR 的表面分布最适合引发强大的效应细胞触发，并证实了 IgE/IgE 受体网络针对外来或致病模式反应以靶向恶性肿瘤的潜力和特异性。
