Envelope Gene Products of Feline Leukemia Virus

开发能够特异性进入靶细胞类型的逆转录病毒载体是临床治疗的关键。 逆转录病毒载体用于基因递送和/或基因治疗的用途。本提案的研究重点是 在产生有效的重定向逆转录病毒载体的关键方面。 我们已经开发了一种新的系统来筛选进入靶细胞的选择性逆转录病毒。通过我们 在逆转录病毒进入的研究中，猫白血病病毒（FeLV A）受体结合域的一个区域被 选择用于替换为随机库。最初的概念验证实验已经确定了新的 选择性感染犬骨肉瘤细胞和人293细胞。这些 分离物分为两类。第一种利用与亲本相同的蛋白质家族中的受体 FeLV。最近的数据表明，第二类分离株利用病毒干扰之外的受体 父母的病毒。这表明，随机逆转录病毒Env文库能够选择用于逆转录病毒的基因。 能够重新靶向进入新的受体蛋白的变体。实验旨在测试和 定义这个哺乳动物随机信封库的潜力。实验来表征新的 - 关于Env插入物内的序列要求、感染的宿主范围的变体，以及 提出了所使用的受体。改进的选择方案概述，将产生一个 高复杂性稳定Env库。长期目标是鉴定能够 有效进入有限的人体组织。该系统在基因治疗和癌症治疗方面的应用 非常广泛。将筛选三类转化细胞系的靶向进入， 逆转录病毒文库。这些包括肾细胞癌、胶质母细胞瘤和小细胞肺癌。

The development of retroviral vectors capable of specific entry into targeted cell types is key for the clinical use of retroviral vectors for gene delivery and/or gene therapy. The research in this proposal focuses on critical aspects in the generation of efficient retargeted retroviral vectors. We have developed a new system to screen for selective retroviral entry into targeted cells. Through our studies of retroviral entry, a region of the receptor binding domain of feline leukemia virus (FeLV A) was selected for replacement with a random library. Initial proof-of-concept experiments have identified novel independent variants with selective infection into canine osteosarcoma cells and human 293 cells. These isolates fall into two classes. The first utilize receptors within the same family of proteins as the parental FeLV. Recent data indicate that a second class of isolates utilize receptors outside the viral interference group of the parental virus. This indicates that the random retroviral Env library is capable of selecting for variants capable of retargeting entry to novel receptor proteins. Experiments are aimed at testing and defining the potential of this mammalian random Envelope library. Experiments to characterize the new variants with respect to the sequence requirements within the Env insert, the host range of infection, and the receptors utilized are proposed. Improvements to the selection scheme are outlined that will yield a stable Env library of high complexity. The long term objective is to identify retroviral Env isolates capable of efficient entry into limited human tissues. The applications of this system towards gene and cancer therapy are extremely broad. Three classes of transformed cell lines will be screened for targeted entry by the retroviral library. These include renal cell carcinomas, glioblastomas, and small cell lung cancer.