Developing therapeutic TCR mimic monoclonal antibodies for cancer

T细胞受体模拟(TCRm)单抗。TCRm单抗代表了一类新的单抗，在结构上与 传统的单抗。然而，尽管传统的单抗识别表面蛋白的3D构象结构， TCRm单抗识别来自细胞内蛋白的多肽(9-10个氨基酸)，展示在细胞上 表面被MHC I类分子识别，传统上被TCR识别的络合物。这使得抗体能够 可以接触到绝大多数真正的肿瘤特异性抗原，其中大多数是细胞内蛋白。这个 众所周知，单抗治疗的优点包括靶向性高、疗效高、副作用有限。 有效、延长半衰期、可利用度、低成本和不频繁给药。除了免疫效应器 单抗的功能，单抗也可以作为抗原特异的载体，可以传递更强大的细胞毒 毒物、药物或辐射等物质。最后，单抗可以被改造成嵌合抗原受体。 或双特异性抗体，以增强T细胞治疗的特异性和效力。 本项目旨在开发针对两种重要的、有效的和肿瘤特异性的新型TCRm单抗 抗原，如下所述。结合了TCR识别和灵活性的最佳固有功能 以及作为药物的效力，新的TCRm单抗可以提供一种有效的、可控的和广泛的 适用的治疗方法。 1.在HPV-A*02：01背景下研制抗HPV-E7衍生表位的TCRm单抗。人乳头状瘤 人类乳头瘤病毒(HPV)在全球范围内导致数十万种癌症。大多数宫颈癌细胞构成 表达HPV16型E6和E7癌蛋白，为免疫治疗提供了理想和特异的靶点。 我们选择了HLAA*02：01提出的E7蛋白(E7 p11-19)的一个免疫原性表位作为 TCRm单抗的靶标。该表位已在大多数宫颈癌活检组织中重复检测到。 和细胞系在人类白细胞抗原-A*02：01分子的背景下进行质谱学分析。 2.在人类白细胞抗原-A*02：01背景下研制抗pIRS2的TCRm单抗。蛋白质磷酸化失调 是恶变的标志。丝氨酸和苏氨酸残基的磷酸化被保留在 MHC I类和II类抗原处理过程中的多肽及其在细胞表面的呈递。因此， 恶性肿瘤细胞中各种蛋白质的不适当磷酸化所产生的磷酸肽代表 一类非同寻常的肿瘤特异性新抗原，也广泛表达，但不是患者特有的。 我们推测，磷酸肽可以作为共有的肿瘤特异性新抗原。我们选择了一个 以人类白细胞抗原-A*02：01为靶标的胰岛素受体底物2磷酸肽(pIRS21097-1105) 用于TCRM的开发。该表位已被质谱仪鉴定出存在于多种癌细胞中。 我们有一套实验工具和方法来选择、表征特定的单抗并测试其 体内外疗效观察。

T cell receptor mimic (TCRm) mAbs. TCRm mAbs represent a new class of mAbs, structurally identical to traditional mAbs. However, while traditional mAbs recognize 3D conformational structure of a surface protein, TCRm mAbs recognize peptides (9-10 amino acids) derived from intracellular proteins, displayed on cell surface by MHC class I molecules, the complexes traditionally recognized by TCR. This allows an antibody to have access to vast majority, truly tumor-specific antigens, most of them are intracellular proteins. The advantages of mAb therapy are well known that include their high target specificity, high efficacy, limited side effects, prolonged half-life, availability, low cost, and infrequent dosing. In addition to the immune effector functions of a mAb, mAb can also serve as antigen-specific vehicles that can deliver more potent cytotoxic agents such as toxins, drugs, or radiation. Finally, mAbs can be engineered into chimeric antigen receptors or bi-specific antibodies in order to enhance the specificity and the potency of T cell therapy. This project aimed at developing novel TCRm mAbs specific for two important, validated and tumor-specific antigens, as described below. Combining the best inherent features of both TCR recognition and the flexibility and potency of the mAbs as drugs, the new TCRm mAbs could offer a potent, controllable and widely applicable therapy. 1. Developing TCRm mAb to HPV-E7-derived epitope in the context of HLA-A*02:01. Human papilloma virus (HPV) causes hundreds of thousands of cancers worldwide. Most cervical carcinoma cells constitutively express HPV type 16 E6 and E7 oncoproteins, which provide an ideal and specific target for immunotherapies. We selected an immunogenic epitope derived from E7 protein (E7 p11-19) presented by HLA-A*02:01 as the target for the TCRm mAb. This epitope has been reproducibly detected in a majority of cervical cancer biopsies and cell lines in the context of HLA-A*02:01 molecule by mass spectrometry. 2. Developing TCRm mAb to pIRS2 in the context of HLA-A*02:01. Dysregulated protein phosphorylation is a hallmark of malignant transformation. Phosphorylation of serine and threonine residues is retained on peptides during MHC class I and class II antigen processing and presentation on the cell surface. Therefore, phosphopeptides derived from inappropriate phosphorylation of various proteins in malignant cells represent an extraordinary class of tumor specific neoantigens, that are also widely expressed and not patient-specific. We hypothesize that phosphopeptides could be used as shared tumor specific neoantigens. We selected a phosphopeptide of insulin receptor substrate2 (pIRS21097-1105) in the context of HLA-A*02:01 as the target for the TCRm development. This epitope has been identified in various cancer cells by mass spectrometry. We have a set of experimental tools and methods to select, characterize specific mAbs and to test their therapeutic efficacy both in vitro and in vivo.