ANTIGEN SPECIFIC T CELL ACTIVATION, APPLICATION TO VACCINES FOR CANCER AND AIDS

抗原特异性 T 细胞激活，在癌症和艾滋病疫苗中的应用

• 批准号: 6123644
• 负责人: J A BERZOFSKY
• 金额: --
• 依托单位: DIVISION OF CLINICAL SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6123644
• 关键词: AIDS therapy; AIDS vaccines; HIV envelope protein gp160; MHC class I antigen; T cell receptor; cellular immunity; clinical research; clinical trial phase I; cytotoxic T lymphocyte; drug design /synthesis /production; epitope mapping; human subject; human therapy evaluation; immunotherapy; interleukin 2; laboratory mouse; leukocyte activation /transformation; neoplasm /cancer immunotherapy; neoplasm /cancer vaccine; neutralizing antibody; synthetic vaccines; vaccine development; virus infection mechanism

"We studied mechanisms for T cell recognition of antigens in association with major histocompatibility complex (MHC)-encoded molecules, and applications to the design of synthetic vaccines for AIDS and cancer. We have been characterizing the helper and cytotoxic T lymphocyte (CTL) responses to HIV envelope and reverse transcriptase, mapping the key epitopes, and defining the role of individual residues in these epitopes to be able to modify the structures to make more potent immunogens as vaccines. We have made vaccine constructs in which clusters of helper epitopes are synthesized coupled to a peptide that is a CTL epitope presented promiscuously by multiple class I MHC molecules in the human and mouse as well as a neutralizing antibody epitope. These constructs can induce all three arms of the immune response, neutralizing antibodies, CTL, and Th1 helper cells. Results of the first arm of a phase I clinical trial with one of these peptides show ability to induce CTL, helper T cell responses, and neutralizing antibodies to HIV in at least a subset of human recipients. Meanwhile, we are developing new approaches in mouse models to improve on the peptide vaccine constructs. We have now shown proof of principle that we can modify the sequence of a helper epitope of HIV to make it more immunogenic and also much more potent, when coupled to a CTL epitope, in eliciting CTL. We are applying this ""epitope enhancement"" approach to conserved helper epitopes presented by human class II HLA molecules, as well as to hepatitis C virus epitopes presented by human HLA-A2.1 (see below). We have discovered ways of increasing CTL, helper, and antibody responses and steering them toward desired phenotypes, such as Th1 or Th2 or particular antibody isotypes, by incorporating cytokines into the emulsion adjuvant with the antigen. We compared a panel of 8 cytokines for their effects on 8 types of immune response, and discovered a novel synergy between GM-CSF and IL-12 and between TNF and IL-12 in induction of CTL. We found that all 3 cytokines provide triple synergy for induction of CTL with a peptide vaccine, for induction of interferon-gamma, and for protection against viral challenge in vivo. We have shown that high avidity CTL specific for HIV-1 envelope peptide are much more effective at clearing a recombinant vaccinia virus expressing HIV gp160 from SCID mice than are low avidity CTL specific for the same peptide-MHC complex, and have worked out one mechanism involving the ability of high avidity CTL to kill cells earlier in virus infection before viral progeny are produced. However, we found that high avidity CTL are exquisitely sensitive to high dose antigen and will undergo programmed cell death, mediated by TNF and the TNF receptor II, but also requiring a permissive state involving a decrease in Bcl-2, induced by the signal through the T cell receptor. This effect may explain clonal exhaustion in viral infections. Finally, we have shown for the first time that protection against mucosal transmission of virus can be mediated by CD8 CTL without antibodies, but requires that the CTL be present at the mucosal site of transmission, whereas systemic CTL are not sufficient. The protection can be accomplished by intrarectal immunization with a peptide vaccine and increased by inclusion of IL-12 with the vaccine. With regard to cancer, we identified several CTL epitopes in proteins of hepatitis C virus (HCV), that causes liver cancer, using a novel approach, and have analyzed the role of each amino acid residue in order to modify one of the peptides to make a more potent vaccine. Using this ""epitope enhancement approach, we could increase the immunogenicity of an epitope of the HCV core protein, presented by the most common human class I HLA molecule, HLA-A2.1, both for HLA-A2.1-transgenic mice in vivo and for human T cells in vitro. This ""enhanced"" epitope is being incorporated into a vaccine. We developed peptide cancer vaccines inducing CTL immunity to mutant p53 expressed in cancer cells. We found that mutant p53 peptides, coated on dendritic cells, elicit CTL that kill tumor cells expressing the mutation and suppress established tumors in animals. Common mutations in ras peptides were found to enhance binding to HLA-A2.1, but also to influence antigen processing. We also induced murine CTL against fusion proteins from chromosomal translocations in pediatric tumors, alveolar rhabdomyosarcoma and Ewing's sarcoma, that protect mice. 29 patients have been treated in a phase I/II clinical trial of the mutant p53/ras peptide vaccine approach to treating cancer, and a large fraction have made CTL or cytokine responses, and no adverse effects have been seen. A trial of translocation fusion peptide immunization of patients with alveolar rhabdomyosarcoma and Ewing's sarcoma is underway. We have also started a trial of immunization of cervical cancer patients with peptides from the E6 and E7 oncoproteins of human papillomavirus type 16 that bind to HLA-A2.1 in patients who express this HLA molecule. A phase II trial of autologous dendritic cells pulsed with mutant ras peptides corresponding to the patient's tumor in colon cancer patients with HLA-A2.1 that can present these ras peptides has just received PRMC and IRB approval. (50% AIDS related)"

“我们研究了T细胞识别的机制 抗原与主要的组织相容性复合物相关 （MHC）编码的分子，并应用于设计 艾滋病和癌症的合成疫苗。我们去过 表征助手和细胞毒性T淋巴细胞（CTL） 对HIV信封和逆转录酶的响应，映射 关键表位，并定义各个残留物在这些中的作用 表位能够修改结构以使其更有效 免疫原作为疫苗。我们在 将哪些辅助表位簇合成 肽是一个CTL表位，由多个 人和小鼠中的I类MHC分子以及 中和抗体表位。这些结构可以诱导这三个 免疫反应的臂，中和抗体，CTL和 Th1辅助细胞。 I期临床试验的第一臂的结果 这些肽之一显示出诱导CTL，辅助T细胞的能力 反应，并至少在一部分中对HIV的抗体中和抗体 人类接受者。同时，我们正在开发新方法 小鼠模型可以改善肽疫苗构建体。我们 现在已经显示了原则的证据，我们可以修改 HIV的辅助表位的序列使其更加免疫原性 当耦合到CTL表位时，也更有效 引发CTL。我们正在应用此“ EpiTope增强”“” 人类II级提出的保守辅助表位的方法 HLA分子以及肝炎病毒表位 由人类HLA-A2.1（见下文）。我们发现了 增加CTL，助手和抗体反应并将其转向 走向所需的表型，例如Th1或Th2或特定的表型 通过将细胞因子掺入乳液中，抗体同型 抗原佐剂。我们比较了一组8个细胞因子 它们对8种类型的免疫反应的影响，并发现了一个小说 GM-CSF和IL-12之间以及TNF和IL-12之间的协同作用 在诱导CTL中。我们发现所有3种细胞因子都提供三倍 与肽疫苗诱导CTL的协同作用，用于诱导 干扰素 - 伽玛，以防止病毒挑战 体内。我们已经表明，HIV-1特异性的高潮CTL 信封肽在清除重组方面更有效 来自SCID小鼠的HIV gp160的离发病毒，而不是低 对同一肽-MHC复合物特异性的亲和力CTL，并且具有 制定了一种涉及高潮能力的机制 在病毒后代之前，CTL杀死病毒感染的细胞是 生产。但是，我们发现高潮CTL非常精致 对高剂量抗原敏感，并将经历编程的细胞 死亡，由TNF和TNF受体II介导，但也需要 涉及Bcl-2降低的允许状态，由 通过T细胞受体信号。这种效果可以解释克隆 病毒感染的疲惫。最后，我们展示了第一个 可以保护病毒粘膜传播的时间 由CD8 CTL介导无抗体，但要求 CTL出现在传输的粘膜部位，而 系统性CTL还不够。保护可以是 通过肽疫苗的直肠免疫完成 并通过将IL-12纳入疫苗中增加。就，关于 对于癌症，我们确定了蛋白质中的几个CTL表位 使用新型的肝炎病毒（HCV），导致肝癌 方法，并分析了每个氨基酸残基在 为了修改其中一种肽以进行更有效的疫苗。 使用这种“”表位增强方法，我们可以增加 HCV核心蛋白表位的免疫原性，呈现 根据最常见的人类I级分子，HLA-A2.1， 在体内和人类T细胞中均用于HLA-A2.1-转基因小鼠 体外。这个“增强””表位正在纳入 疫苗。我们开发了诱导CTL的肽癌疫苗 对在癌细胞中表达的突变体p53的免疫力。我们发现 突变体p53肽，涂在树突状细胞上，引起杀死的CTL 表达突变并抑制已建立的肿瘤细胞 动物中的肿瘤。发现RAS肽中的常见突变 增强与HLA-A2.1的结合，但也会影响抗原 加工。我们还诱导鼠CTL针对融合蛋白 来自小儿肿瘤的染色体易位，牙槽 横纹肌肉瘤和尤因的肉瘤，可保护老鼠。 29 患者已在突变体的I/II期临床试验中接受治疗 p53/RAS肽疫苗治疗癌症的方法，并且很大 分数已经产生了CTL或细胞因子反应，并且没有不良反应 已经看到了效果。易位融合肽的试验 肺泡横纹肌肉瘤和 尤因的肉瘤正在进行中。我们还开始了一个试验 宫颈癌的免疫E6诊断患者 和E7人乳头瘤病毒16型的E7癌蛋白结合到 表达该HLA分子的患者中的HLA-A2.1。第二阶段 用突变体Ras肽脉冲的自体树突状细胞的试验 对应于患者在结肠癌患者患者患者的肿瘤 可以呈现这些RAS肽的HLA-A2.1刚刚收到 PRMC和IRB批准。 （50％与艾滋病有关）”