Genetic Targeting of T cells to B cell malignancies

描述(申请人提供)：CD19选择性地表达在大多数B细胞恶性肿瘤和正常B细胞上，但不表达在血液干细胞上，因此是癌症免疫治疗的一个有吸引力的靶点。构建了融合TCR Zeta链的CD19单链抗体逆转录病毒载体。转导表达这种人工T细胞受体(称为19Z1)的T细胞在体外特异性地杀伤表达人CD19(HCD19)的肿瘤细胞系。此外，与用无关的人工T细胞受体(Pz1)转导T细胞治疗相比，用19z1修饰的人T细胞治疗已建立的系统性hCD19+Raji肿瘤细胞的SCID-Beige小鼠，肿瘤进展时间和总生存时间延长，且呈剂量依赖关系。然而，对这一数据的解释受到T细胞和肿瘤细胞对SCID-Beige小鼠的异种本质以及宿主免疫受损状态的限制。因此，这项建议的总体目标是更好地确定19z1转导的T细胞的活性，使用同基因免疫能力小鼠模型。为此，本提案的具体目标#1将在具有免疫能力的hCD19转基因小鼠中建立同基因EL4(HCD19)肿瘤细胞的肿瘤模型，并确定19z1+小鼠T细胞是否能够在该模型中根除疾病。为了验证T辅助细胞在过继T细胞治疗中发挥重要作用的假设，Aim#2将确定转导的CD4+T细胞在转导的CD8+T细胞的细胞毒活性、归巢和增殖中的作用。具体目标#3将测试治愈小鼠的次级淋巴组织和骨髓将维持持续的转换T细胞数量的假设。这些T细胞的功能状态将通过用EL4(HCD19)肿瘤细胞再次攻击治愈的小鼠来分析。来自这些研究的数据将被应用于未来人类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.