Engineered Antigen-Specific T Cells Secreting Broadly Neutralizing Antibodies: Combining Innate and Adaptive Immune Response against HIV

Abstract

While antiretroviral therapy (ART) can completely suppress viremia, it is not a cure for HIV. HIV persists as a latent reservoir of infected cells, able to evade host immunity and re-seed infection following cessation of ART. Two promising immunotherapeutic strategies to eliminate both productively infected cells and reactivated cells of the reservoir are the adoptive transfer of potent HIV-specific T cells and the passive administration of HIV-specific broadly neutralizing antibodies also capable of mediating antibody-dependent cellular cytotoxicity (ADCC). The simultaneous use of both as the basis of a single therapeutic has never been explored. We therefore sought to modify HIV-specific T cells from HIV-naive donors (to allow their use in the context of allotransplant, a promising platform for sterilizing cures) so they are able to secrete a broadly neutralizing antibody (bNAb) directed against the HIV envelope to elicit ADCC. We designed an antibody construct comprising bNAb 10-1074 heavy and light chains, fused to IgG3 Fc to elicit ADCC, with truncated cluster of differentiation 19 (CD19) as a selectable marker. HIV-specific T cells were expanded from HIV-naive donors by priming with antigen-presenting cells expressing overlapping HIV antigens in the presence of cytokines. T cells retained specificity against Gag, Nef, and Pol peptides (218.55 ± 300.14 interferon γ [IFNγ] spot-forming cells [SFC]/1 × 10 5 ) following transduction (38.92 ± 25.30) with the 10-1074 antibody constructs. These cells secreted 10-1074 antibodies (139.04 ± 114.42 ng/mL). The HIV-specific T cells maintained T cell function following transduction, and the secreted 10-1074 antibody bound HIV envelope (28.13% ± 19.42%) and displayed ADCC activity (10.47% ± 4.11%). Most critically, the 10-1074 antibody-secreting HIV-specific T cells displayed superior in vitro suppression of HIV replication. In summary, HIV-specific T cells can be engineered to produce antibodies mediating ADCC against HIV envelope-expressing cells. This combined innate/adaptive approach allows for synergy between the two immune arms, broadens the target range of the immune therapy, and provides further insight into what defines an effective anti-HIV response.

Inhibition of the H3K27 demethylase UTX enhances the epigenetic silencing of HIV proviruses and induces HIV-1 DNA hypermethylation but fails to permanently block HIV reactivation

“…The first, often referred to as “kick and kill” [ 3 ], is based on the concept that latent HIV-1, once pharmacologically reactivated by latency reversing agents (LRAs), could subsequently be eliminated by cytotoxicity and/or the enhanced immunological surveillance [ 4 , 5 ]. Unfortunately, “kick and kill” faces formidable challenges in achieving reactivation of the majority of latent provirus [ 6 – 10 ] and difficulties in inducing HIV-1 specific immune-mediated clearance in vivo [ 11 – 13 ]. An alternative approach, referred to as “block and lock”, is designed to permanently suppress the rebound of quiescent HIV-1 by inducing epigenetic silencing [ 14 – 16 ].…”

Brief Report: Rebound HIV Viremia With Meningoencephalitis After Antiretroviral Therapy Interruption After Allogeneic Bone Marrow Transplant

“…12,13 These cases, including the one we report here, demonstrate a unique and serious clinical risk associated with interrupting ART after alloBMT. Possible mechanisms to employ a more effective CD8 + T-cell response after alloBMT include the use of engineered HIV-specific T cells that are capable of secreting broadly neutralizing antibodies against HIV envelope to elicit antibody-dependent cellular cytotoxicity 26 or the use of donor-derived engineered HIV-specific T cells. [27][28][29] The latter is being investigated in an ongoing clinical trials for PLWH who require alloBMT for clinical reasons (NCT04248192).…”

Photothermal Prussian blue nanoparticles generate potent multi‐targeted tumor‐specific T cells as an adoptive cell therapy

“…Target cells were labeled with calcein AM (ThermoFisher Scientific, Waltham, MA) for 30 min at 37°C. Spontaneous and total release of calcein dye from the target cells was measured using a SpectraMax i3X microplate reader (Molecular Devices, San Jose, CA) by treating the cells with media or 2% Triton X‐100 (Millipore Sigma), respectively 76,77 . Expanded T cells were resuspended at different concentrations and were mixed with the target cells to generate E:T ratios of 2.5:1, 5:1, 10:1, or 20:1.…”