Generation of Anti-HIV CAR-T Cells for Preclinical Research

Abstract

The inability of people living with HIV (PLWH) to eradicate human immunodeficiency virus (HIV) infection is due in part to the inadequate HIV-specific cellular immune response. The antiviral function of cytotoxic CD8+ T cells, which are crucial for HIV control, is impaired during chronic viral infection because of viral escape mutations, immune exhaustion, HIV antigen downregulation, inflammation, and apoptosis. In addition, some HIV-infected cells either localize to tissue sanctuaries inaccessible to CD8+ T cells or are intrinsically resistant to CD8+ T cell killing. The novel design of synthetic chimeric antigen receptors (CARs) that enable T cells to target specific antigens has led to the development of potent and effective CAR-T cell therapies. While initial clinical trials using anti-HIV CAR-T cells performed over 20 years ago showed limited anti-HIV effects, the improved CAR-T cell design, which enabled its success in treating cancer, has reinstated CAR-T cell therapy as a strategy for HIV cure with notable progress being made in the recent decade.Effective CAR-T cell therapy against HIV infection requires the generation of anti-HIV CAR-T cells with potent in vivo activity against HIV-infected cells. Preclinical evaluation of anti-HIV efficacy of CAR-T cells and their safety is fundamental for supporting the initiation of subsequent clinical trials in PLWH. For these preclinical studies, we developed a novel humanized mouse model supporting in vivo HIV infection, the development of viremia, and the evaluation of novel HIV therapeutics. Preclinical assessment of anti-HIV CAR-T cells using this mouse model involves a multistep process including peripheral blood mononuclear cells (PBMCs) harvested from human donors, T cell purification, ex vivo T cell activation, transduction with lentiviral vectors encoding an anti-HIV CAR, CAR-T cell expansion and infusion in mice intrasplenically injected with autologous PBMCs followed by the determination of CAR-T cell capacity for HIV suppression. Each of the steps described in the following protocol were optimized in the lab to maximize the quantity and quality of the final anti-HIV CAR-T cell products.

Keywords: CAR-T cell; Cytotoxic CD8+ T cell; HIV; Humanized mouse model; Immunotherapy.