While combination antiretroviral therapy (cART) is effective at suppressing HIV, it fails to eradicate latent provirus or restore virus-specific T-cel responses that can eliminate virus-expressing cells after induction with a latency reversing agent or treatment interruption. One potential way is to create designer HIV-specific T- cells for use by adoptive T-cell therapy, which has shown promise for treating other viral infections and cancer in clinical trials. In this application, we proposed to develop a chimeric antigen receptor (CAR) specific for the HIV-1 envelope protein (Anti-HIV-1 Env-CAR), which when expressed on modified T-cells, is capable of protecting the modified T-cells from infection and triggering T-cel responses required for the clearance of infected cells. Two findings serve as the basis for the anti-HIV-1 Env-CAR. First, our past studies have demonstrated that some single chain variable fragments (scFvs) of anti-HIV Env antibodies are potent inhibitors of HIV-1 when expressed on the surface of target cells. Second, the co-investigator and others have demonstrated the potential for adoptive T-cell therapy for treating viral infections and cancer, and the promise for CARs to improve persistence and anti-tumor activity of engineered T-cells. They have also demonstrate the capacity to expand broadly-specific polyclonal T-cells that can clear HIV-infected cells. We hypothesize that combining a neutralizing anti-HIV Env scFv with a second generation CD28?-CAR having activation and costimulatory properties will result in a bifunctional CAR (anti-HIV Env-CD28?) molecule that promotes proliferation and anti-HIV T-cell responses in modified T-cells while protecting them from HIV infection and cell death. This CAR could be used to recognized and eliminate latently infected cells after induction of viral gene expression with a latency reversing agent. The hypothesis will be addressed in three specific aims.
Aim1 will examine whether ex vivo expanded T-cells modified with the anti-HIV Env-CD28? CAR will direct Env-specific T-cell responses and killing of infected target cells.
Aim2 wil examine whether the anti-HIV Env-CD28? protects modified T-cells from infection by diverse HIV-1 variants.
Aim3 will determine whether anti-Env- CD28? CAR modified T-cells enhance HIV-1 infected cell clearance and decrease viral loads in a humanized mouse model. Successful completion of this project will advance the potential for using CAR modified T-cells for targeting and eliminating latent HIV reservoirs after reactivation, a primary goal of the TaPHIR R21/R33 program.

Public Health Relevance

Although antiretroviral therapy improves survival and quality of life of HIV infected individuals, it fails to cure infection. Thus, new strategies are required o achieve long-term remission in the absence of antiretroviral therapy or to eliminate persistent infection. The goal of this proposal is to develop a bifunctional chimeric antigen receptor that can both protect modified T-cells from HIV infection and direct virus-specific responses that will destroy infected cells and cure infection.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Exploratory/Developmental Grants (R21)
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Study Section
Special Emphasis Panel (ZRG1)
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Poon, Betty
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Baylor College of Medicine
Schools of Medicine
United States
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Auclair, Sarah; Liu, Fengliang; Niu, Qingli et al. (2018) Distinct susceptibility of HIV vaccine vector-induced CD4 T cells to HIV infection. PLoS Pathog 14:e1006888
Misra, Anisha; Gleeson, Emile; Wang, Weiming et al. (2018) Glycosyl-Phosphatidylinositol-Anchored Anti-HIV Env Single-Chain Variable Fragments Interfere with HIV-1 Env Processing and Viral Infectivity. J Virol 92: