Development of Antibody and T-Cell Inducing Vaccines

通过诱导针对特定碳水化合物和多肽抗原的抗体的疫苗，以及通过激活T淋巴细胞的疫苗，可以打破免疫耐受，在实验动物中引发肿瘤排斥反应。这两种疫苗的目标抗原和最佳设计通常有很大的不同。然而，卵巢癌的免疫治疗应该理想地使用这两种疫苗；我们最初将分别关注每种疫苗。该项目正在从只专注于诱导抗体的疫苗向更广泛的方法过渡。在当前 我们用产生的抗体诱导多价疫苗进行最后的第二阶段试验，并将重点转移到T细胞诱导疫苗上。诱导抗体的疫苗更先进，这主要是因为长期以来一直有血清学检测来监测疫苗的开发。因此，在目前的中期筹资期间，我们将完成一系列单价结合疫苗的试点试验，为我们的多价KLH结合疫苗的第二阶段试验做准备。这项试验基于我们在碳水化合物合成、碳水化合物和多肽与载体蛋白的化学结合以及免疫佐剂方面的独特专业知识和经验。在目标1中，我们将对第四个项目下进行的第二阶段试验进行血清学分析。该试验的主要目的是确定诱导针对卵巢癌细胞表面广泛表达的6至8种卵巢癌抗原(GM2、Globo H、Le-y、STN、Tf、MUC1，可能还有MUC 16和KSA)的抗体的临床后果。该试验的次要目标是：a)确定不同批次疫苗的效力，并确定针对特定抗原的抗体反应与b)临床病程或c)卵巢癌复发中表达的抗原之间的相关性。这三个次要目标将在本项目中阐述。 最近，不需要长时间的体外致敏就能检测疫苗诱导的T细胞反应性的检测方法已经发展起来。这现在允许我们遵循与开发抗体诱导疫苗相同的循序渐进的过程。我们将基于我们在这些检测方面的独特经验、我们在CA125/MUC16和Wilm肿瘤抗原(WT1)抗原方面的经验，以及在使用异源多肽、电穿孔和旨在增强DNA疫苗免疫原性的各种方法方面的经验。我们将通过一系列试点试验来启动这一过程，比较增强CA125/MUC16和WT1免疫原性的不同方法。选择要在这些试验中测试的方法将部分基于正在进行的临床前研究和临床试验的结果。在目标2中，我们将重点研究异源多肽、人MUC16 B4组分蛋白和小鼠WT1蛋白。在目标3中，我们将测试编码人、异种或异种蛋白、C3d和DHBc融合蛋白的DNA疫苗，并与电穿孔或编码GM-CSF的DNA一起接种。

Immune tolerance can be broken and tumor rejection elicited in experimental animals by vaccines that induce antibodies against defined carbohydrate and peptide antigens and by vaccines that activate T-lymphocytes. The target antigens and optimal design for these two types of vaccines are generally quite different. Immunotherapy of ovarian cancer should ideally utilize both types of vaccines, however; we will initially focus on each separately. This Project is in transition from an exclusive focus on vaccines that induce antibodies to a more broad approach. In the current application we perform a final Phase II trial with the resulting antibody-inducing polyvalent vaccine and shift our focus to T-cell-inducing vaccines. Vaccines that induce antibodies are more advanced, largely because of the long availability of serologic assays to monitor vaccine development. Consequently, during the current interim funding period we will conclude a series of pilot trials with monovalent conjugate vaccines in preparation for a Phase II trial with our polyvalent KLH-conjugate vaccine. This trial is based on our unique expertise and experience in carbohydrate synthesis, chemical conjugation of carbohydrates and peptides to carrier proteins, and immunological adjuvants. In Aim 1, we will perform the serological analysis on the Phase II trial conducted under the fourth Project. The primary objective of the trial is to determine the clinical consequences of inducing antibodies against six to eight ovarian cancer antigens (GM2, globo H, Le-y, sTn, TF, MUC1, and possibly MUC 16 and KSA) widely expressed on the ovarian cancer cell surface. The secondary objectives of the trial are to a) confirm the potency of different batches of vaccine prepared over time, and to determine the correlation between antibody response against particular antigens and b) clinical course or c) antigens expressed in ovarian cancer recurrences. These three secondary objectives will be addressed in this Project. Recently, assays capable of detecting vaccine-induced T-cell reactivity without the need for prolonged in vitro sensitization have been developed. This now permits us to follow the same step-by-step process used in developing antibody-inducing vaccines. We will build on our unique experience with these assays, our experience with the CA125/MUC16 and Wilm's Tumor Antigen (WT1) antigens, and with the use of heteroclitic peptides, electroporation, and a variety of approaches designed to augment the immunogenicity of DNA vaccines. We will initiate this process with a series of pilot trials comparing different approaches to augmenting the immunogenicity of CA125/MUC16 and WT1. Selection of the approaches to be tested in these trials will be based in part on results of ongoing preclinical studies and clinical trials. In Aim 2 we will focus on heteroclitic peptides, human MUC16 B4 fraction protein and murine WT1 protein. In Aim 3 we will test DNA vaccines coding for human, xenogeneic or heteroclitic proteins, C3d and DHBc fusion proteins, and administration with electroporation or DNA coding for GM-CSF.