Targeting of cytotoxic T-cells to HIV infected cells

实验和临床数据表明，T细胞介导的免疫应答在控制人类免疫缺陷病毒(HIV)感染中发挥着重要作用。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，并可以作为HIV特异性的、MHC不受限制的效应细胞。我们将使用设计的进入抑制剂5-螺旋将细胞毒效应细胞重定向到HIV感染的细胞。与以前使用的配体相比，这种HIV结合结构域有几个优点，如CD4或抗体片段：5-螺旋模仿gp41包膜糖蛋白胞外结构域的羧基末端区域，但缺少六螺旋束中的一个螺旋。因此，它是gp41的高亲和力结合域，可以与多种HIV毒株结合。最重要的是，表面暴露5-螺旋并不支持艾滋病毒进入细胞。将构建一个嵌合的5-螺旋-Zeta受体基因，并将其稳定地转导到人T淋巴细胞中。转基因T细胞对表达HIV Env的细胞或感染HIV的细胞的特异性细胞毒作用将首先在体外和随后在体内进行测试。建立HIV Env表达细胞的小鼠模型。该项目应该证明这种靶向方法的可行性，并应该为这一策略的未来临床应用提供临床前要求。基因修饰的自体T淋巴细胞在接受HAART(高效抗逆转录病毒治疗)或STI(结构化治疗中断)治疗的患者中可以清除残留的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).