Monoclonal antibody (mAb)-based therapies have revolutionized cancer treatment; however, their clinical efficacy is often limited by insufficient antibody-dependent cellular cytotoxicity (ADCC), tumor antigen escape, and an immunosuppressive tumor microenvironment (TME). To overcome these limitations, we developed an allogeneic stem cell-derived invariant natural killer T (NKT) cell platform engineered to express a high-affinity non-cleavable CD16 receptor (CD16HSC-NKT) for broad enhancement of mAb-based immunotherapy. Using a clinically guided differentiation platform, we generated highly pure and scalable CD16HSC-NKT cells exhibiting robust expression of NK receptors, potent cytotoxic machinery, and a Th1-biased cytokine profile. CD16HSC-NKT cells demonstrated potent intrinsic antitumor activity and potently enhanced the efficacy of multiple therapeutic antibodies, including Trastuzumab, Tafasitamab, Rituximab, Daratumumab, and Cusatuzumab, across diverse hematologic and solid tumor models. In vivo, combination therapy induced durable tumor eradication and prolonged survival in xenograft models, outperforming the clinically approved antibody-drug conjugate trastuzumab deruxtecan. Mechanistically, therapeutic antibodies promoted the expansion, persistence, and activation of CD16HSC-NKT cells within tumors. CD16HSC-NKT uniquely remodeled the TME by selectively depleting CD1d-expressing tumor-associated macrophages and myeloid-derived suppressor cells. CD16HSC-NKT cells also exhibited minimal alloreactivity, no graft-versus-host disease, and no detectable systemic toxicity. Collectively, these findings establish CD16HSC-NKT cells as a safe, off-the-shelf cellular platform capable of broadly enhancing monoclonal antibody therapy through sustained ADCC, multimodal tumor targeting, and TME remodeling.
Abstract Cytokine release syndrome (CRS) is a major dose-limiting toxicity of chimeric antigen receptor (CAR) T-cell therapy, yet the upstream mechanisms driving macrophage activation remain incompletely understood. In this study, we established a xenograft model of human CAR T-cell therapy that recapitulates key features of CRS and combined single-cell RNA sequencing (scRNA-seq) with pharmacologic intervention to define the inflammatory programs underlying CRS. CAR T-cell treatment induced dose-dependent systemic inflammation and remodeled the host myeloid compartment, leading to the accumulation of a distinct population of CRS-associated macrophages. Analysis of clinical scRNA-seq datasets from patients with CAR-T cell–treated glioblastoma confirmed enrichment of the CRS-associated macrophage gene signature following therapy in patients, supporting the clinical relevance of our findings. Transcriptomic analyses identified marked upregulation of the chemokine receptors CCR1 and CCR2 together with activation of CCL3- and CCL2-associated signaling pathways. Pharmacologic inhibition of CCR1 and CCR2 significantly reduced clinical CRS, inflammatory cytokine production, and macrophage activation while preserving CAR T-cell expansion, effector cytokine production, and in vivo antitumor efficacy. These findings identify CCR1/CCR2-dependent chemokine signaling as a critical regulator of macrophage-driven CRS and support chemokine receptor blockade as a promising strategy to improve the safety of CAR T-cell therapy without compromising therapeutic efficacy. Significance: CCR1- and CCR2-dependent chemokine signaling regulate macrophage-mediated CRS, and pharmacological inhibition of these pathways reduces CAR T-cell toxicity without compromising antitumor efficacy, suggesting targets to enhance the safety of such immunotherapies. See related commentary by Kobold, p. XX .
Abstract Adoptive T-cell therapies require T cells to sustain cytotoxic function for as long as tumor persists. In this issue, two independent studies converge on a ubiquitin-dependent pathway, centered on the cullin-5 (CUL5)–RING E3 ubiquitin ligase (CRL5) complex, as an intrinsic brake on T-cell function under repetitive antigen stimulation. Genetic disruption of individual CRL5 components preserves cytotoxicity during repeated tumor challenge. Saco and colleagues demonstrate similar benefits with pharmacologic inhibition of CRL5 and related ubiquitin ligase complexes, whereas Bachl and colleagues extend the genetic benefit across multiple antigens and receptor architectures. Targeting this pathway offers a strategy to improve T-cell functional persistence and therapeutic durability. See related article by Bachl et al., p. XXX . See related article by Saco et al., p. XXX .
Abstract Chimeric antigen receptor (CAR) T cells can provide cures to patients affected by certain hematologic malignancies. Cytokine release syndrome (CRS) is a major side effect of this treatment, yet its pathophysiology remains incompletely understood and selective therapeutic options are limited. In this issue, Li and colleagues identify the CCR1–CCR2 axis as a key mediator of inflammatory macrophage recruitment to sites of CAR T-cell activation, thereby contributing to CRS. In preclinical models, blockade of this axis prevented macrophage recruitment and substantially diminished CRS severity. This discovery could open a new avenue for targeted intervention against CRS, although further validation of the role of the CCR1/CCR2 axis, particularly in clinically relevant settings, is required. See related article by Li and colleagues et al., p. XX
