PhD Student University of Minnesota - Minneapolis, MN Lauderdale, Minnesota, United States
Disclosure(s):
Tanvi Mathur, MS: No financial relationships to disclose
Introduction/Rationale: Despite the success of antiretroviral therapy in controlling HIV-1 replication, achieving a cure remains a significant challenge. Blocking viral replication has proven particularly challenging due to the highly efficient nature of cell-to-cell transmission (C-CT), as antibodies often fail to access the virological synapse. Here, we studied the effects of immune-based strategies, including ADCC and CAR NK/T cells, on HIV-1 transmission between cells.
Methods: We developed a highly sensitive assay for precise quantification of cell lysis using luciferase activity and built CAR NK/T based on the VRC01 and PGT121 bnAbs. We then utilized the assay to assess cellular cytotoxicity mediated by antibodies and CAR NK/T 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 quantify viral transmission in primary T cells. Using our nanoluciferase reporter assay, we studied the effects of a) PBMCs and soluble IgGs, and b) CAR NK/T on HIV-1 C-CT.
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 Envs as 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 across a range of envelope-expressing target cells at various E: T cell ratios. Among the CARs tested, the PGT121 bnAb-based CAR consistently outperformed others in mediating cellular cytotoxicity.
Conclusion: These results provide proof of concept that targeting HIV-1 C-CT 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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