Humanization of a mouse monoclonal antibody that blocks the epidermal growth factor receptor: Recovery of antagonistic activity
Humanization of a mouse monoclonal antibody that blocks the epidermal growth factor receptor: Recovery of antagonistic activity
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DOI：
10.1016/s1380-2933(97)00065-1
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发表时间：
1997-03-01
期刊：
影响因子：
--
通讯作者：
Perez, R
中科院分区：
文献类型：
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作者：
Mateo, C;Moreno, E;Perez, R
背景资料：通过将鼠抗体的互补决定区（CDR）移植到人框架的抗体人源化旨在降低人免疫系统对外来分子的应答。然而，经常地，必须保留来自框架的一些鼠氨基酸以恢复结合亲和力。目的：将R3（一种结合人表皮生长因子（EGF）受体并抑制EGF结合的小鼠单克隆抗体（mAb））重新设计为人IgG 1。研究设计：基于REI和Eu的轻链和重链与鼠R3的相应序列的高度同源性，分别选择REI和Eu的轻链和重链作为用于CDR移植的人免疫球蛋白（IG）框架。使用分子建模来分析突变作为CDR基础的鼠残基的可能影响。结果：CDR移植显著降低了抗体的结合能力。分子模拟表明，在CDR基础的五个免疫球蛋白重链可变区（VH）残基中，两个氨基酸（Thr 76和Thr 93）对抗原结合至关重要。将五个残基突变回人源化抗体的六个变体中所含的不同组合中的原始鼠氨基酸。与分子模拟分析一致，与原始抗体相比，保留三个鼠残基（Ser 75、Thr 76和Thr 93）的变体表现出类似的抑制I-125标记的EGF与其受体结合的能力。这种人源化抗体在非洲绿色猴中的免疫原性比嵌合抗体低至少2倍。结论：框架中只有非常少的突变可能是恢复人源化抗体的结合能力所必需的。分子建模可以作为一个强大的工具，以确定关键的结合残基。(C)1997年Elsevier Science B.V.
Background: Antibody humanization by transplanting the complementarity determining regions (CDRs) of a murine antibody to a human framework aims to reduce the response of the human immune system against a foreign molecule. Frequently, however, some murine amino acids from the framework have to be retained to recover binding affinity. Objectives: To redesign R3, a mouse monoclonal antibody (mAb) that binds the human epidermal growth factor (EGF)-receptor and inhibits the binding of EGF, to be a human IgG1. Study design: The light and heavy chains of REI and Eu, respectively, were selected as human immunoglobulin (Ig) frameworks for CDR-grafting based on their high homology with the corresponding sequences of murine R3. Molecular modeling was used to analyze the possible effects of mutating murine residues that underlie the CDRs. Results: CDR-grafting dramatically reduced the binding capability of the antibody. Molecular modeling suggested that two amino acids (Thr 76 and Thr 93), among five immunoglobulin heavy chain variable region (VH) residues underlying the CDRs, were critical for antigen binding. The five residues were mutated back to the original murine amino acids in different combinations contained in six variants of humanized antibodies. In agreement with molecular modeling analysis, the variant in which three murine residues were retained (Ser 75, Thr 76 and Thr 93) exhibited a similar capacity to inhibit the binding of I-125-labeled EGF to its receptor as compared with the original antibody. This humanized antibody was at least 2-fold less immunogenic in African Green monkeys than the chimeric antibody. Conclusions: Only very few mutations in the frameworks may be necessary to recover the binding capability of a humanized antibody. Molecular modeling can serve as a powerful tool to identify residues critical for binding. (C) 1997 Elsevier Science B.V.