TCR-like antibodies for HPV-induced cancer basic research and theranostics

项目摘要/摘要 靶向抗癌治疗的时代是由特异性治疗性抗体的发展所开创的。 主要表达在肿瘤上的抗原，改善了无数癌症患者的生活。当前 然而，抗体仅限于完整的细胞表面配体，如通常也表达的CD20 在正常细胞上。然而，方法上的改进使产生特异性抗体成为可能。 对于主要组织相容性上下文中呈现的来自肿瘤抗原或病毒癌蛋白的多肽 复合体(MHC)I类蛋白(在人类中：HLA-A、-B、-C)，通常更好地限制在肿瘤细胞上。 这些抗体模拟T细胞受体(TCR)识别多肽/MHC复合体(PMHC)的方式。这些“TCR” 模拟“或mTCR抗体将TCR的特异性与抗体的亲和力结合在一起，使 靶向癌细胞表达的抗原，而不针对正常细胞。 然而，由于pMHC上靶面的精确性质，mTCR抗体很难诱导。这个 目前最好的方法需要专门的高通量筛选来分离真正的mTCR抗体。我们 将通过提高mTCR抗体的生成效率来改进这项正在开发的技术 常规的单抗设备。我们将通过改造免疫原来实现这一点 根据我们以前在艾滋病毒疫苗方面的经验，对所需的靶标表位表面做出反应。 为了充分开发和展示我们的平台，我们将专注于人类引发的癌症 以人乳头瘤病毒(HPV)为模型系统。我们将产生的针对HPV的mTCR抗体将是有用的 立即用于HPV pMHC表达的基础研究，并最终用于体外和体内诊断，以及 用于治疗顽固性疾病。虽然这个项目的近期目标是开发我们的mTCR抗体平台 使用HPV作为模型系统，我们的mTCR技术完全可以推广到任何应用。 HPV感染导致了大约5%的人类癌症，几乎所有的宫颈癌，但也提供了良好的 可被mTCR抗体靶向的已定义抗原。我们计划以HPVE6/E7癌蛋白为靶点 负责恶变的诱发和维持。我们将验证这些mTCR抗体在一个 大量HPV诱导的宫颈癌患者的已知HPV株和HLA等位基因的使用通过 FHCRC中国倡议。中国需要改进晚期宫颈癌的治疗方法是 尤其重要的是，由于获得预防性筛查和HPV疫苗的机会有限。 该项目将提供(1)一种针对任何所需的pMHC目标产生mTCR抗体的新技术；(2) 人类白细胞抗原限制性HPVE6/E7表位呈递和表达模式的基础研究；(3)晶体 新型MHC/HPV多肽复合物的结构；以及(4)一组经过生化验证的HPV mTCR抗体 作为临床治疗学的即时基础科学应用和未来发展。

Project Summary/Abstract The era of targeted anti-cancer therapies was ushered in by the development of therapeutic antibodies specific for antigens expressed primarily on tumors, improving the lives of countless cancer patients. Current antibodies, however, are limited to intact cell surface ligands, such as CD20, which are often also expressed on normal cells. However, methodological improvements have made it possible to produce antibodies specific for peptides from tumor antigens or viral oncoproteins presented in the context of major histocompatibility complex (MHC) class I proteins (in humans: HLA-A, -B, -C), which are often better restricted to tumor cells. These antibodies mimic how T cell receptors (TCR) recognize peptide/MHC complexes (pMHCs). These “TCR mimic” or mTCR antibodies combine the specificity of a TCR with the affinity of an antibody, allowing the targeting of antigens expressed by cancerous cells, while sparing normal cells. However, mTCR Abs are difficult to elicit, because of the precise nature of the target surface on a pMHC. The best current approaches require specialized high-throughput screening to isolate true mTCR antibodies. We will improve this developing technology by increasing the efficiency that mTCR antibodies can be generated in conventional monoclonal antibody facilities. We will accomplish this by engineering immunogens to focus responses to the desired target epitope surface, drawing on our previous experience with HIV vaccines. In order to fully develop and demonstrate our platform, we will focus on cancers caused by human papillomavirus (HPV) as a model system. The mTCR antibodies against HPV we will generate will be useful immediately for basic studies of HPV pMHC expression, and eventually as ex vivo and in vivo diagnostics, and for treatment of refractory disease. While the proximate goal of this project is to develop our mTCR Ab platform using HPV as a model system, our mTCR technology is completely generalizable to any application. HPV infection causes about 5% of all human cancers, and virtually all cervical cancers, but also provides well- defined antigens that can be targeted by mTCR antibodies. We plan to target the HPV E6/E7 oncoproteins responsible for the induction and maintenance of malignancy. We will validate these mTCR antibodies in a large cohort of patients with HPV-induced cervical cancers of known HPV strain and HLA allele usage through the FHCRC China initiative. The need for improved treatments for advanced cervical cancer in China is particularly great, because of limited access to preventative screening and HPV vaccines. This project will deliver (1) a novel technology for generating mTCR Abs against any desired pMHC target; (2) basic science on the presentation and expression patterns of HLA-restricted HPV E6/E7 epitopes; (3) crystal structures of novel MHC/HPV peptide complexes; and (4) a panel of biochemically-validated HPV mTCR Abs for immediate basic science applications and future development as clinical theranostics.