Novel strategy for AL amyloid immunotherapy

AL淀粉样变性是一种由肿瘤浆细胞介导的致死性疾病，其特征是重要器官中纤维原性免疫球蛋白（Ig）轻链的沉积。迄今为止，AL淀粉样变性的治疗主要集中在用化疗药物靶向淀粉样浆细胞。这种方法的成功非常有限，患者的中位生存期为2-3年。因此，迫切需要一种替代疗法。长期以来，免疫疗法一直被视为癌症治疗的重要途径，随着最近技术和理论的进步，免疫疗法再次成为一种可行的治疗策略。我们在转化的浆细胞中发现了几种高表达的靶向免疫附着蛋白，即芳烃/二恶英受体（AhR）、细胞色素P4501B1 （CYP1B1）和Ig重链。使用肽- mhc I类结合算法来预测免疫原性肽，我们和我们的合作者证明了人类细胞毒性T细胞（CTL）反应可以从正常供体和癌症患者的PBMC中产生，并针对这些肿瘤相关蛋白。结果证实了这一点。1)有可能打破对肿瘤相关“自身”蛋白的免疫耐受，2)转化细胞通常呈现靶向肽，以及3)结合生物信息学，人组织培养技术和HLA-A2转基因小鼠的平台的实用性，以诱导和研究潜在的治疗性浆细胞特异性CTL。因此，我们假设来自转化浆细胞的多种肽免疫原，包括致病性IgL链本身，可用于肿瘤/肽特异性AL淀粉样蛋白免疫治疗。以下具体目标已被提出，以验证这一假设，并简化一个全面的系统，以测试肽基疫苗的可行性，有效性和安全性：1)诱导和表征肿瘤相关肽（AhR, cyp1b1， IgH框架4和Ig gamma6框架1）特异性人CTL。在这里，我们将在体外诱导和表征几种特异性的人类CTL，目的是评估AL淀粉样蛋白患者免疫系统的能力，并定义一个可扩展的方案来诱导/促进患者的肿瘤特异性反应。由于对免疫系统在AL淀粉样变性中的一般能力知之甚少，特别是对AL淀粉样变性中肿瘤特异性反应的功效一无所知，因此无论结果如何，都将获得重要的信息。2)利用体内肿瘤肽特异性免疫转基因小鼠模型确定AL淀粉样蛋白免疫治疗的临床策略。利用HLA-A*0201转基因小鼠，我们将优化基于肽的免疫方案，同时考虑临床方案的实用性。目标将是定义最简单，但有效的疫苗接种方案，其中病理性自身免疫反应的风险降到最低。与Seldin博士（项目1）和Skinner博士（项目3）合作，并在A和B核心的帮助下，将在AL淀粉样变性转基因动物模型中直接测试疫苗接种方案的有效性。

AL amyloidosis is a lethal disorder mediated by neoplastic plasma cells and characterized by deposition of fibrillogenic immunoglobulin (Ig) light chains in vital organs. To date, treatment of AL amyloidosis has focused on targeting amyloid plasma cells with chemotherapeutics. This approach has had very limited success, with patient median survival in the 2-3 year range. Therefore, there is a critical need for an alternative therapy. Immunotherapy has long been viewed as an important approach to cancer treatment and, with recent technical and theoretical advances, is again a viable therapeutic strategy. We identified several proteins highly expressed in transformed plasma cells to target for immune attach, i.e. the aryl hydrocarbon/dioxin receptor (AhR), cytochrome P4501B1 (CYP1B1), and Ig heavy chain. Using peptide-MHC class I- binding algorithms to predict immunogenic peptides, we and our collaborators demonstrated that human cytotoxic T cell (CTL) responses can be generated from the PBMC of normal donors and cancer patients and against these tumor-associated proteins. The results confirm. 1) that it is possible to break immune tolerance to tumor-associated "self" proteins, 2) that transformed cells in general present the targeted peptide, and 3) the utility of a platform which combines bioinformatics, human tissue culture techniques, and HLA-A2 transgenic mice to induce and study potentially therapeutic plasma cell-specific CTL. Therefore, we hypothesize that multiple peptide immunogens derived from transformed plasma cells, including the pathogenic IgL chain itself can be used for tumor/peptide-specific AL amyloid immunotherapy. The following specific aims have been proposed to test this hypothesis and to streamline a comprehensive system for testing the feasibility, efficacy, and safety of peptide-based vaccines: 1) Induce and characterize tumor- associated peptide (AhR, cyp1b1, IgH framework 4, and Ig gamma6 framework 1)-specific human CTL. Here we will induce and characterize human CTL of several specificities ex vivo with the goals of evaluating the competence of the immune systems in AL amyloid patients and defining and scalable protocol for inducing/boosting tumor-specific responses in patients. Since little is known about the competence of the immune system in AL amyloidosis in general and nothing is known about the efficacy of tumor-specific responses in AL amyloidosis in particular, important information will e obtained regardless of results. 2) Define clinical strategies for AL amyloid immunotherapy with an in vivo transgenic mouse model of tumor peptide-specific immunity. Using HLA-A*0201 transgenic mice, we will optimize peptide-based immunization schemes, keeping in mind the practicalities of clinical protocols. The goals will be to define the simplest, yet effective vaccination scheme in which the risk of pathologic autoimmune response is minimized. In collaboration with Dr. Seldin (project 1) and Dr. Skinner (project 3), and the help of Cores A and B, the efficacy of the vaccination scheme will be tested directly in a transgenic animal model of AL amyloidosis.