Optimization of Melanoma Vaccine with T Helper Epitope

主要研究者/项目负责人（最后，第一，中间）：Zarour，Hassane，M。 项目总结/摘要 CD 4 +T细胞在诱导和维持抗肿瘤应答中起关键作用。为了发展 并优化免疫刺激方法以刺激体内人抗肿瘤CD 4 + T细胞，我们 先前从癌胚系抗原中鉴定出许多混杂的MHCII类限制性表位 （CAG），包括NY-ESO-1和拉格-1，黑素细胞谱系抗原（Melan-A/MART-1）和最近的 过表达或通用抗原（存活素）。我们已经产生了抗原特异性CD 4 + T细胞， 这些表位并表征了它们的细胞因子谱产生以定义Th 1型和Th 2/Th 0型CD 4 + 细胞我们还设计了修饰的肽，以更好地鉴定肽中涉及的氨基酸（aa）， MHC结合或TCR接触。最近，我们已经开发了研究CAG功能的测定方法， 来源于黑素瘤患者外周血淋巴细胞（PBL）的特异性CD 4 + T细胞。我们 初步数据表明，循环中CAG特异性CD 4 + T细胞可能不仅是Th 1型辅助细胞， 除了CD 4 + T细胞外，还有CD 4+调节性T细胞。因此，这些药物的主动免疫抑制作用可能是由于它们的免疫抑制作用而引起的。 肿瘤抗原特异性CD 4 + T细胞可能是成功接种T- 辅助表位在目前的竞争性更新中，我们建议解决这个重要问题。的理由 对于我们提出的研究项目是几倍，可以说如下：1）T辅助表位， 不仅刺激抗原特异性T辅助型CD 4 + T细胞，而且刺激存在于细胞中的CD 4+调节性T细胞。 肿瘤微环境和循环PBL; 2）肿瘤抗原特异性调节细胞可以作用于 自体B细胞抑制肿瘤抗原特异性抗体产生; 3）基于优化的策略 TCR刺激物和共刺激物的强度将抑制调节功能并促进辅助性T细胞功能。我们长久以来- 长期目标是发展在体内诱导CAG特异性辅助性T细胞应答所需的知识， 我们的具体目标是：1）产生和表征肿瘤抗原- 来自黑素瘤患者和正常供体的PBL的特异性CD 4+调节性T细胞; 2）为了评估 肿瘤抗原特异性调节性T细胞对自体B细胞的影响;和3）定义策略 优先刺激肿瘤抗原特异性T辅助CD 4 + T细胞而不是调节性T细胞。 项目描述 第6页

Principal Investigator/Program Director (Last, first, middle): Zarour, Hassane, M. PROJECT SUMMARY/ABSTRACT CD4+T cells play critical roles in the induction and maintenance of anti-tumor responses. In order to develop and optimize immunotherapeutic approaches to stimulate human anti-tumor CD4+ T cells in vivo, we have previously identified a number of promiscuous MHC class II-restricted epitopes from cancer-germline antigens (CAGs), including NY-ESO-1 and LAGE-1, melanocyte-lineage antigens (Melan-A/MART-1) and most recently overexpressed or universal antigens (Survivin). We have generated antigen-specific CD4+ T cells recognizing these epitopes and characterized their cytokine profile production to define Th1-type and Th2/Th0-type CD4+ cells. We also have engineered modified peptides to better identify the amino acids (aa) involved in peptide- MHC binding or TCR contacts. Most recently, we have developed assays to study the functions of the CAG- specific CD4+ T cells derived from the peripheral blood lymphocytes (PBLs) of patients with melanoma. Our preliminary data have suggested that circulating CAG-specific CD4+ T cells may not only be Th1-type helper CD4+ T cells but also CD4+ regulatory T cells. It is thus possible that active immunosuppression by these tumor antigen-specific CD4+ T cells may represent a major obstacle to the successful vaccination with T- helper epitopes. In the current competitive renewal, we propose to address this important issue. The rationale for our proposed research project is several fold and can be stated as follows: 1) T-helper epitopes may stimulate not only antigen-specific T-helper type CD4+ T cells but also CD4+ regulatory T cells present in the tumor microenvironment and circulating PBLs; 2) Tumor-antigen-specific regulatory cells may act on autologous B cells to inhibit tumor antigen-specific antibody production; 3) strategies based on optimizing strength of TCR stimuli and costimuli will inhibit regulatory functions and promote T-helper functions. Our long- term goal is to develop the knowledge required for the induction of CAG-specific T-helper responses in vivo in patients with advanced melanoma.Our Specific Aims are: 1) To generate and characterize tumor antigen- specific CD4+ regulatory T cells from PBLs of melanoma patients and normal donors; 2) To assess the impact of tumor-antigen-specific regulatory T cells on autologous B cells; and 3) To define strategies to preferentially stimulate tumor antigen-specific T-helper CD4+ T cells instead of regulatory T cells. Project Description Page 6