Background
Background
Despite the success of antiretroviral therapy in controlling HIV-1 replication, achieving a cure remains a significant challenge. One obstacle to blocking HIV-1 replication is the efficient cell-to-cell transmission (C-CT) of HIV-1, which is highly resistant to broadly neutralizing antibodies (bnAbs). Here, we studied the effects of immune-based strategies, including antibody-dependent cellular cytotoxicity (ADCC) and chimeric antigen receptor (CAR) NK/T cells, on HIV-1 transmission between cells.
Methods
Methods
We developed a highly sensitive assay for precise quantification of cell lysis using luciferase activity and built CAR-PBMCs based on the VRC01 and PGT121 bnAbs. We then utilized the assay to assess cellular cytotoxicity mediated by ADCC and CAR-PBMCs against target cells expressing HIV-1 envelope glycoproteins (Envs). We have previously developed an ultrasensitive HIV-1 C-CT assay, using a replication-competent HIV-1 vector and an activated nanoluciferase reporter system to assess viral transmission in primary T cells. Using our nanoluciferase reporter assay, we studied the effects of a) PBMCs and soluble IgGs, and b) CAR-PBMCs on HIV-1 C-CT.
Results
Results
We detected cytotoxic activity of T and NK cells engineered to express VRC01 and PGT121 CARs against CEM.NKR cells that express Luciferase and HIV-1 AD8ΔCT Envs as initial targets. HIV-1 C-CT of the NL43(AD8) molecular clone, which contains all HIV-1 genes, exhibits significant resistance to bnAbs but could be efficiently blocked by ADCC. Moreover, CAR PBMCs exhibited increased specific killing efficiency across various effector: target cell ratios, particularly after 4-hour incubation. Among the CARs tested, the PGT121 bnAb-based CAR consistently outperformed others in mediating cellular cytotoxicity.
Conclusions
Conclusions
These results provide proof of the principle that targeting HIV-1 cell-to-cell transmission through ADCC and CAR NK/T cell therapies can overcome the limitations of bnAbs. This study offers the first evidence to test these approaches to effectively target HIV-1 C-CT, highlighting their potential in studying HIV-1 treatment strategies.
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