In many cancers, the epidermal growth factor receptor (EGFR) gene is amplified, mutated, or both. The monoclonal antibody mAb806 binds selectively to cancer cells that overexpress EGFR or express the truncated mutant EGFRvIII, but not to normal cells. This suggests that a promising avenue for developing cancer vaccines may be to design antigens that elicit mAb806-like antibodies. In this study, we designed antigens that present the mAb806-binding epitope in the same conformation as in overexpressed or truncated EGFR. We first used molecular dynamics simulations to identify conformations of EGFR in which the residues of the mAb806-binding epitope are accessible. We then designed antigens by substituting that epitope in place of a structurally similar loop in a different protein and generating mutants that could potentially stabilize the mAb806-binding conformation in this new context. Two mutants in which the epitope remained stable in subsequent simulations were chosen for evaluation in vitro. Binding kinetics experiments with these designed antigens provided strong evidence that the epitope was successfully stabilized in the mAb806-binding conformation, suggesting that they could potentially form the basis of vaccines that elicit cancer-selective antibodies.

中文翻译：

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设计抗原以呈现肿瘤特异性隐藏表位

在许多癌症中，表皮生长因子受体 (EGFR) 基因被扩增、突变或两者兼而有之。单克隆抗体 mAb806 选择性结合过度表达 EGFR 或表达截短突变体 EGFRvIII 的癌细胞，但不结合正常细胞。这表明开发癌症疫苗的一个有前途的途径可能是设计引发 mAb806 样抗体的抗原。在本研究中，我们设计了抗原，其呈现与过表达或截短的 EGFR 相同构象的 mAb806 结合表位。我们首先使用分子动力学模拟来识别 EGFR 的构象，其中 mAb806 结合表位的残基是可接近的。然后，我们通过用该表位替换不同蛋白质中结构相似的环来设计抗原，并生成可能在这种新背景下稳定 mAb806 结合构象的突变体。选择表位在后续模拟中保持稳定的两种突变体进行体外评估。这些设计的抗原的结合动力学实验提供了强有力的证据，证明表位成功稳定在 mAb806 结合构象中，这表明它们有可能成为引发癌症选择性抗体的疫苗的基础。