The goal of this proposal is to utilize autologous CD34+ peripheral blood stem cells (PBSC), which are transduced for ribozymes expression using either retroviral or adeno-associated viral (AAV) vectors, for the treatment of HIV-1 infection. The proposal combines the expertise of City of Hope National Medical Center (COH) in marrow transplantation, the gene therapy experience of Childrens Hospital of Los Angeles (CHLA) and the ribozyme-related expertise at Loma Linda University (LLU) in a focused effort to develop ribozyme-based strategies as gene therapy for AIDS. Because better ribozyme activity would theoretically improve ribozyme- based genetic strategies for HIV-1 treatment, the Project 1 at LLU investigates mechanisms control intracellular trafficking of ribozymes and will provide quantitative measurement of transgene expression in clinical specimens. Project 2, located at CHLA, addresses improved methods for retroviral transduction of CD34+ PBSC. Project 3, located at COH, focuses on methods for AAV transduction of these cells. There are two clinical proposals in this proposal: the first is the development of a safe and efficient method for procuring CD34+ PBSC from HIV-1 infected persons and to demonstrate that these cells can be transduced to express ribozymes and be protected from HIV-1 infection, as already shown in stem cells from non-HIV-1 infected persons. Ten subjects will be enrolled in this apheresis study which will be completed during year 01. The second clinical project will treat 10 patients with retrovirus transduced cells in gene therapy clinical trials. The expression construct and the ribozymes used will be identical, and this will permit an assessment of relative efficiencies not only of transduction but also of engraftment. The protocols will use no conditioning regimen prior to PBSC transplant and will answer the important question of whether the non-ablated HIV-1 infected marrow is sufficient for engraftment after PBSC transplantation. This work is supported by 2 cores: Peripheral blood stem collection, and the virology laboratory. All G-CSF priming and PBSC apheresis will be performed at COH, and CD34-selection and quality control of cell products and of transduced cells with the responsibility of the core. Retroviral transductions will be performed at CHLA and patients will be treated both there and at COH. This study will provide important and necessary information regarding methods for autologous transplantation in HIV-1 infection and for the utility of retrovirus and AAV in stem cell transduction.
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