Genetic Targeting of T cells to B cell malignancies

描述（由申请人提供）：CD19在大多数B细胞恶性肿瘤和正常B细胞上选择性表达，但在血液干细胞上不表达，因此是癌症免疫治疗的一个有吸引力的靶点。一个逆转录病毒载体编码CD19特异性单链片段（scFv）抗体融合到一个TCR zeta链已被开发。T细胞被转导表达这种人工T细胞受体（称为19z1），在体外特异性地裂解表达人CD19 （hCD19）的肿瘤细胞系。此外，与使用不相关的人工T细胞受体（Pz1）转导的T细胞治疗小鼠相比，用19z1修饰的人T细胞治疗携带已建立的系统性hCD19+ Raji肿瘤细胞的SCID-Beige小鼠，肿瘤进展时间和总体生存时间以剂量依赖的方式增加。然而，对这些数据的解释受到SCID-Beige小鼠的T细胞和肿瘤细胞的异质性质以及宿主免疫受损状态的限制。因此，本研究的总体目标是利用同基因免疫小鼠模型更好地确定19z1转导T细胞的活性。为此，本提案的具体目标#1将在具有免疫能力的hCD19转基因小鼠中建立一种同源EL4（hCD19）肿瘤细胞的肿瘤模型，并在该模型中确定19z1+小鼠T细胞是否能够根除疾病。为了验证辅助性T细胞在过继性T细胞治疗中发挥重要作用的假设，目的2将定义转导的CD4+ T细胞在转导的CD8+ T细胞的细胞毒性活性、归巢和增殖中的作用。特异性目标#3将测试一个假设，即治愈小鼠的次级淋巴组织和骨髓将维持一个持续的转导T细胞群。这些T细胞的功能状态将通过用EL4（hCD19）肿瘤细胞重新攻击治愈小鼠来分析。从这些研究中获得的数据将应用于未来B细胞恶性肿瘤患者临床试验的合理发展。

DESCRIPTION (provided by applicant): CD19 is selectively expressed on most B cell malignancies and normal B cells but not on blood stem cells and is therefore an attractive target for cancer immunotherapy. A retroviral vector encoding a CD19 specific single chain fragment (scFv) antibody fused to a TCR zeta chain has been developed. T cells transduced to express this artificial T cell receptor (termed 19z1) specifically lyse human CD19 (hCD19) expressing tumor cell lines in vitro. Furthermore, treatment of SCID-Beige mice bearing established systemic hCD19+ Raji tumor cells with 19z1 modified human T cells results in an increased time to tumor progression and overall survival in a dose dependent manner when compared to mice treated with T cells transduced with an irrelevant artificial T cell receptor (Pz1). However, interpretation of this data is limited by the xenogeneic nature of the T cells and tumor cells to the SCID-Beige mouse, as well as the immune-compromised state of the host. Therefore, the overall objective of this proposal is to better define the activity of the 19z1 transduced T cells using a syngeneic immune competent mouse model. To this end, specific aim #1 of this proposal will establish a tumor model of syngeneic EL4(hCD19) tumor cells in an immune competent hCD19 transgenic mouse and establish whether 19z1+ murine T cells are able to eradicate disease in this model. To test the hypothesis that T helper cells play an important role in adoptive T cell therapy, aim #2 will define the role of transduced CD4+ T cells in the cytotoxic activity, homing and proliferation of transduced CD8+ T cells. Specific aim #3 will test the hypothesis that secondary lymphoid tissues and bone marrow in cured mice will maintain a persistent population of transduced T cells. The functional status of these T cells will be analyzed by rechallenge of cured mice with EL4(hCD19) tumor cells. The data derived from these studies will be applied to the rational development of future clinical trials in human subjects with B cell malignancies.