EF-1α-driven nanobody-based CD19-redirected CAR-T cells retain the antitumor efficacy, antigen-driven expansion, and cytokine secretion of CMV-driven counterparts

Engineering antigen-driven co-stimulation and T helper cell activity into TCR-T cells with CD8-41BB fusion receptors enhances anti-tumor activity

Engineering T cells in vivo to express a synthetic cytokine receptor enables preferential expansion and enrichment of anti-CD22 CAR T cells.

Ex vivo-manufactured chimeric antigen receptor (CAR) T cells targeting CD19 have transformed treatment strategies for patients with B cell malignancies and shown promising results in autoimmune disease. Yet despite their success, significant barriers remain that impede patient access to these therapies, including their complex manufacturing and the need for lymphodepleting chemotherapy. Moreover, many patients who receive ex vivo-manufactured CD19 CAR T cells do not achieve durable responses, suggesting that the expansion and persistence of CAR T cells may need improvement, and/or that strategies targeting alternative antigens may be needed for patients who are refractory to or relapse following treatment with CD19-directed therapies. Umoja is developing a surface-engineered lentiviral vector (LVV) platform capable of generating CAR T cells in vivo without lymphodepletion. UB-VV400 delivers a payload comprised of a fully human anti-CD22 CAR and the rapamycin-activated cytokine receptor (RACR), which enable preferential expansion and enrichment of CAR T cells in response to rapamycin. Here, we describe preclinical studies demonstrating that UB-VV400 generates anti-CD22 CAR T cells that kill CD22-expressing B cells and tumor cells in vitro and in vivo, and that engagement of RACR results in the selective expansion and enrichment of CAR T cells in vivo leading to complete tumor clearance and B cell depletion.

Parallel 4-1BB Signaling in Dual DLL3/CD56-Targeting CAR-T Cells Triggers Adaptive Proliferation and Functional Persistence to Eradicate Small Cell Lung Cancer.

Limited intratumoral persistence and insufficient proliferative capacity severely restrict the efficacy of chimeric antigen receptor (CAR)-T cell therapies in solid tumors. Here, we demonstrated that DLL3-targeting CAR-T cells co-expressing a CD56 chimeric switch receptor (CSR) and incorporating parallel 4-1BB costimulatory signaling (DBBζ.CBB) effectively address these limitations. In preclinical small cell lung cancer (SCLC) models, DBBζ.CBB exhibited sustained tumor infiltration, prolonged persistence, and superior antitumor activity. Mechanistically, parallel 4-1BB signaling dynamically programed CAR-T cell fate by promoting early expansion and memory maintenance, driving a highly proliferative effector state at the intermediate stage, and delaying terminal exhaustion at the later stage, thereby sustaining in vivo persistence and enabling durable antitumor responses. Building upon the intratumoral T-cell pool established by DBBζ.CBB, subsequent DLL3 trispecific T-cell engager (TriTCE) administration synergistically enhanced tumor eradication by further boosting CD8+ T cell infiltration and overall activation while mitigating exhaustion and terminal differentiation. Collectively, these findings establish a clinically translatable combinatorial framework to enhance the efficacy and durability of CAR-T therapy in solid tumors.

Enhancing HIV-1-specific CAR-T cell functional activity by treatment with a novel cytokine-based scaffold with IL-15 superagonist and TGF-β-neutralizing activity

ABSTRACT Chimeric antigen receptor T cell (CAR-T cell) therapy targeting and eliminating HIV-infected cells offers a promising approach to provide people living with HIV (PLWH) with a functional cure by preventing the recurrence of viremia caused by reactivation of latent HIV-1-infected cells. We previously described a bispecific CAR-T cell targeting two highly conserved gp120 epitopes (duoCAR-T cell) with potent anti-HIV-1 activity that is currently in clinical trials. However, elevated levels of transforming growth factor β (TGF-β) present in many PLWH may hinder the activity of both infused HIV-1-specific CAR-T cells, such as duoCAR-T cells and endogenous HIV-1-specific CD8+ T cells, thereby limiting their effectiveness to achieve a functional HIV-1 cure. We hypothesized that HCW9218, a novel bifunctional immunomodulatory protein composed of TGF-βRII and IL-15/IL-15Rα, would enhance anti-HIV-1 immunity by TGF-βRII binding and neutralizing TGF-β, while IL-15/IL-15Rα would stimulate effector cells and reactivate latent HIV-1-infected cells. We used duoCAR-T cells generated from CD4+ and CD8+ T cells from people without HIV (PWoH) and PLWH donors to demonstrate the in vitro capacity of HCW9218 to block TGF-β activity, and enhance duoCAR-T cell proliferation, cytotoxicity, and anti-HIV-1 activity. HCW9218 also functioned as a latency-reversing agent, stimulating HIV-1 production by CD4+ T cells from ART-suppressed PLWH. Production of HIV-1 by HCW9218-treated CD4+ T cells from ART-suppressed PLWH donors was suppressed by co-culture with autologous duoCAR-T cells. Together, these findings highlight the potential of HCW9218 to augment T cell and CAR-T-based therapies and contribute to strategies aimed at achieving a functional cure for HIV-1. IMPORTANCE The persistence of HIV-1 reservoirs remains the primary barrier to an HIV-1 cure because antiretroviral therapy (ART) suppresses viral replication but does not eliminate latent HIV-1-infected cells. Treatment with anti-HIV-1 duoCAR-T cells is a potential strategy to target and eliminate HIV-1-infected cells, but their activity may be impaired by the immunosuppressive environment in lymphoid tissues of people living with HIV (PLWH). Transforming growth factor β (TGF-β), a pleiotropic cytokine elevated in PLWH, is a key mediator of this immunosuppression. Here, we show that HCW9218, a bifunctional fusion protein with TGF-β-neutralizing activity and IL-15 superagonist activity, preserves duoCAR-T cell function in the presence of TGF-β and reactivates HIV-1 production by latent HIV-1-infected cells in ART-suppressed CD4+ T cells from PLWH. These findings highlight HCW9218 as a unique dual-function immunotherapy that may enhance the efficacy of duoCAR-T cells while facilitating clearance of the HIV reservoir. The persistence of HIV-1 reservoirs remains the primary barrier to an HIV-1 cure because antiretroviral therapy (ART) suppresses viral replication but does not eliminate latent HIV-1-infected cells. Treatment with anti-HIV-1 duoCAR-T cells is a potential strategy to target and eliminate HIV-1-infected cells, but their activity may be impaired by the immunosuppressive environment in lymphoid tissues of people living with HIV (PLWH). Transforming growth factor β (TGF-β), a pleiotropic cytokine elevated in PLWH, is a key mediator of this immunosuppression. Here, we show that HCW9218, a bifunctional fusion protein with TGF-β-neutralizing activity and IL-15 superagonist activity, preserves duoCAR-T cell function in the presence of TGF-β and reactivates HIV-1 production by latent HIV-1-infected cells in ART-suppressed CD4+ T cells from PLWH. These findings highlight HCW9218 as a unique dual-function immunotherapy that may enhance the efficacy of duoCAR-T cells while facilitating clearance of the HIV reservoir.

HIV-1 promotes loss of CD4+ T cell stemness and enrichment of effector-like states via Vpr-mediated TCF7 degradation

Vpr-mediated TCF7 depletion couples enhanced viral fitness to reprogramming of CD4+ T cell identity, generating permissive differentiated cells while impairing the maintenance of effective antiviral immunity via reduced T cell stemness.

Engagement of the T cell receptor against an oncolytic virus generates a population of hypereffector CAR T cells with potent antitumor activity 2256915

We have shown that combining CAR T cells with oncolytic viruses (OVs) generates a subpopulation of highly cytotoxic CAR T cells that can mediate long-term solid tumor therapy. To profile these CAR T cells, we used C57BL/6 mice bearing B16F10 tumors expressing EGFRviii, treated with anti-EGFRviii CAR T cells and the OV vesicular stomatitis virus (VSV). TCR signaling in CAR T cells was investigated using the novel Tocky transgenic mouse model, which reports T cell activation over time using an unstable fluorescent protein reporter of Nr4a3. We further investigated CAR T phenotypes using CyTOF and scRNA-Seq. Using an MHC I tetramer for the dominant VSV epitope VSV N52-59, we found that 20-50% of transfused CAR T adopted TCR specificity against VSV N (referred to as TCR-primed), indicating significant in vivo expansion. Ex vivo, these TCR-primed CAR T produced increased levels of granzyme B and IFNγ over tetramer-negative CAR T against either TCR or CAR targets. However, TCR-primed CAR T cells were notably less activated via Nr4a3 as compared to non-TCR-primed CAR T. CyTOF and scRNA-Seq analyses demonstrated a hypereffector phenotype among TCR-primed CAR, with increased expression of T-bet, CD44, granzyme B, IFNγ, and perforin. TCR sequencing revealed hyperexpansion of VSV N-specific CAR T cells and little overlap in clonotypes between CAR T co-treated with PBS versus VSV. These TCR-primed CAR T cells exhibited a CD4-helped phenotype with increased expression of chemotactic and migratory transcripts. When CAR T and OV were administered with antibody-mediated CD4 depletion, the TCR-primed CAR population was significantly diminished, emphasizing the importance of the immune triad for CAR T expansion. Overall, CAR T cells that undergo endogenous anti-viral TCR priming and signaling adopt a unique phenotype that promotes their expansion and cytotoxic function. Interactions with CD4 T cells appear to be integral for the generation of this subpopulation of CD8 CAR T cells. NIH Tumor Immunology: Checkpoints, Prevention, and Treatment (TIPT)