Targeting of cytotoxic T-cells to HIV infected cells

实验和临床数据充分证明t细胞介导的免疫反应在控制人类免疫缺陷病毒（HIV）感染中起重要作用。细胞毒性t细胞可以被改造成表达针对HIV感染细胞的嵌合受体，并且可以作为HIV特异性的、不受mhc限制的效应细胞。我们将使用设计的进入抑制剂5-Helix将细胞毒性效应细胞重定向到HIV感染的细胞。与以前使用的配体（如CD4或抗体片段）相比，这种HIV结合结构域有几个优点：5-Helix模拟gp41包膜糖蛋白外结构域的羧基末端区域，但缺少六螺旋束的一个螺旋。因此，它是gp41的高亲和力结合域，并结合多种HIV毒株。最重要的是，5-Helix表面暴露不支持HIV进入细胞。构建嵌合的5-Helix-zeta受体基因，并稳定地转导到人T淋巴细胞中。基因修饰t细胞对HIV Env表达细胞或HIV感染细胞的特异性细胞毒性将首先在体外进行测试，随后在体内进行测试。建立表达HIV Env细胞的小鼠模型。该项目应证明这种靶向方法的可行性，并应为该策略的未来临床应用提供临床前要求。基因修饰的自体T淋巴细胞应该能够清除在HAART（高活性抗逆转录病毒疗法）治疗或STI（有组织的治疗中断）期间残留的HIV感染细胞。

Experimental and clinical data present good evidence that T-cell mediated immune response plays a major role in controlling human immunodeficiency virus (HIV) infection. Cytotoxic T-cells can be engineered to express chimeric receptors directed against HIV infected cells and can serve as HIV specific, MHC-unrestricted effector cells. We will use the designed entry inhibitor 5-Helix to redirect cytotoxic effector cells to HIV infected cells. This HIV binding domain has several advantages over previously used ligands, like CD4 or antibody fragments: 5-Helix mimics the carboxyl-terminal region of the gp41 envelope glycoprotein ectodomain but lacks one helix of the six-helix bundle. It is therefore a high affinity binding domain for gp41 and binds a wide variety of HIV strains. Most importantly, surface exposure of 5-Helix does not support entry of HIV into the cells. A chimeric 5-Helix-zeta receptor gene will be constructed and stably transduced into human T lymphocytes. Specific cytotoxicity of genetically modified T-cells towards HIV Env expressing cells or HIV infected cells will be first tested in vitro and subsequently in vivo. A mouse model with HIV Env expressing cells will be established. The project should prove the feasibility of this targeting approach and should provide the pre-clinical requirements for a future clinical application of this strategy. Gene mo dified autologous T lymphocytes should eliminate residual HIV infected cells in patients under HAART (highly active antiretroviral therapy) treatment or during STI (structured treatment interruption).