Abstract
Adoptive cellular immunotherapy therapy using broadly neutralizing antibody-based chimeric antigen receptor-T cells (bNAb-based CAR-T) has shown great potency and safety for the functional cure of HIV. The efficacy of bNAb-based CAR-T cells could be compromised by adaptive resistance during HIV chronic infection according to the phenomenon that cellular exhaustion was observed in endogenous cytotoxic T-lymphocytes (CTLs) along with upregulated expression of PD−1. Here, we created HIV-specific CAR-T cells using human peripheral blood mononuclear cells (PBMCs) and a 3BNC117-DNR CAR (3BD CAR) construct that enables the expression of PD-1 dominant negative receptor (DNR) and the single-chain variable fragment of the HIV-1-specific broadly neutralizing antibody 3BNC117 to target native HIV envelope glycoprotein (Env). Compared with HIV CAR expression alone, 3BD CAR-T cells displayed potent lytic and functional responses to Env-expressing cell lines and HIV-infected CD4+ T cells. Moreover, 3BD CAR-T cells can kill HIV-latently-infected cell lines, which are reactivated by the secretory cytokines of effector cells followed by contact with initial HIV-expressing fraction. Furthermore, bioluminescence imaging indicated that 3BD CAR-T cells displayed superior anti-HIV function in an HIV NCG mouse model of transplanting Env+/PD-L1+ cells (LEL6). These studies suggested that our proposed combinational strategy of HIV CAR-T therapy with PD-1 blockade therapy is feasible and potent, making it a promising therapeutic candidate for HIV functional cure.
Highlights
Since the first AIDS case was reported in 1981, more than 38 million people had been infected with HIV worldwide by 2019 [https://aidsinfo.unaids.org/]
To confirm that dominant negative receptor (DNR) was expressed at the 3BNC117-DNR chimeric antigen receptor (CAR) (3BD CAR)-T cell surface, cells were stained with mouse-anti-human CD279
Staining with a CD279 antibody was unable to distinguish exogenous PD1 expression from endogenous PD-1 expression, we found significant differences in PD-1 expression between 3B CART cells (2.95%) and 3BD CAR-T cells (73.8%) (Figure 1C)
Summary
Since the first AIDS case was reported in 1981, more than 38 million people had been infected with HIV worldwide by 2019 [https://aidsinfo.unaids.org/]. The ‘first generation’ CD4CAR was safe and CAR+ cells were detectable for 10 years (Scholler et al, 2012), it has no durable control of virus in HIV patients (Deeks et al, 2002). The efficacy of this approach was likely compromised because of multiple technical parameters including low transduction efficiencies, absence of intracellular costimulatory signaling domain and the potential for HIV infection of T cells expressing the CD4 CAR (Wagner, 2018). Along with the advances achieved in cancer CAR-T therapy, the efficacy of anti-HIV CAR-T cells could be enhanced based on improved ‘second generation’ and ‘third generation’ CARS containing additional intracellular costimulatory domains such as CD28 and 4-1BB (Hombach et al, 2013; Maldini et al, 2020; Ollerton et al, 2020)
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