(PROJECT 3 - KITCHEN) Despite the enormous success of combined anti-retroviral therapy, HIV infection is still a lifelong disease and continues to spread worldwide rapidly. There is a pressing need to develop therapies to cure HIV infection. Eradication of HIV in the body will likely be a combined effort to protect T cells from new infection and eliminate remaining viral reservoirs by enhancing antiviral immune responses. The anti-HIV T cell responses are a critical component in naturally controlling viral replication and play a crucial role in the clearance of most viral infections. However, HIV has evolved numerous ways to escape host immune responses. Chronic inflammation and immune dysfunction usually persists throughout the disease, even during anti-viral therapy. In this project, we propose to utilize a protective human leukocyte antigen (HLA)-unrestricted chimeric antigen receptor (CAR) to redirect T cells to target HIV infected cells in vivo. This protective CAR contains a HIV binding domain fused to an internal T cell receptor (TCR) signaling domain that functions in the same fashion a TCR would when bound to its ligand. Previous studies have shown that HIV-specific CAR modified T cells are functional in vitro and are safe and have prolonged survival in vivo. A key component of this proposal is to prevent CAR modified cells from HIV infection by expressing the CAR from a lentiviral vector that also contains the effective anti-HIV peptide C46 and a CCR5-specific shRNA to prevent HIV entry and replication. We hypothesize that genetic modification and engraftment of autologous peripheral T cells with a protective CAR will result in the production of effector cells that will lower viral load and promote the clearance of the virus. We will explore the development of a CAR-based adoptive T cell transfer therapy using the humanized mouse model of HIV infection, which is a surrogate system that recapitulates human immune system and HIV pathogenesis in a small animal model.
We aim to investigate various strategies to improve function, trafficking, expansion and persistence of protective CAR cells in the humanized mouse model. We will also utilize the non-human primate model of SHIV infection to further assess the approach and ultimately optimize the function and longevity of protective CAR transduced peripheral T cells in vivo. We expect that these studies will provide useful information and basis for further studies to treat chronic HIV infection and eradicating the virus from the body.
