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AbstractBackgroundThe pro-inflammatory cytokine, interleukin-18 (IL-18), plays an instrumental role in bolstering anti-tumor immunity. However, the therapeutic application of IL-18 has been limited due to its susceptibility to neutralization by IL-18 binding protein (IL-18BP), short in vivo half-life, and unfavorable physicochemical properties.MethodsIn order to overcome the poor drug-like properties of IL-18, we installed an artificial disulfide bond, removed the native, unpaired cysteines, and fused the stabilized cytokine to an IgG Fc domain. The stability, potency, pharmacokinetic and pharmacodynamic properties as well as efficacy of disulfide-stabilized IL-18 Fc-fusion (dsIL-18-Fc) were assessed via in vitro and in vivo studies.ResultsThe stability and mammalian host cell production yields of dsIL-18-Fc were improved, compared to the wild-type (WT) cytokine, while maintaining its biological potency and interactions with IL-18 receptor α (IL-18Rα) and IL-18BP. Recombinant fusion of the cytokine to an IgG Fc domain provided extended half-life. Notably, despite maintaining sensitivity to IL-18BP, dsIL-18-Fc was effective at activating both T and natural killer (NK) cells, and elicited a strong anti-tumor response, either as a single agent, or in conjunction with anti-programmed cell death-ligand 1 (anti-PD-L1) therapy.ConclusionsWe engineered IL-18 for reinforced stability, extended half-life, and improved manufacturability. The therapeutic benefit of dsIL-18-Fc, coupled with a more favorable manufacturability profile and enhanced drug-like properties, underscores the potential utility of this engineered cytokine in cancer immunotherapy.

Menopause not only affects fertility but also has widespread impact on systemic health. Yet, the molecular mechanisms underlying this process are not fully understood, partly due to the absence of robust, age-relevant preclinical models with comprehensive molecular and phenotypic characterization. To address this, we systematically compared three candidate mouse models of menopause: (1) intact aging, (2) chemical ovarian follicle depletion using 4-vinylcyclohexene diepoxide (VCD) administered at multiple ages, and (3) Foxl2 haploinsufficiency, a genetic model based on a transcription factor linked to human premature ovarian failure. Through histology, serum hormone profiling, single-cell transcriptomics and machine-learning approaches, we uncovered both shared and model-specific features of follicle loss, endocrine disruption, and transcriptional remodeling. The VCD and Foxl2 haploinsufficiency models revealed distinct patterns of hormonal and immune alterations not captured by intact aging alone. This comparative framework enables informed selection of context-appropriate preclinical rodent models to study menopause and the broader physiological consequences of ovarian aging.

Memory T cells are a highly heterogeneous collection of antigen-experienced cells that undergo dynamic adaptations upon antigen re-encounter and environmental signals. This heterogeneity hinders studies on memory T cell durability and age-related dysfunction. Using chronic Epstein-Barr virus (EBV) infection and barcode-enabled antigen tracing, we assess the influence of age on memory states at the level of single antigen-specific CD8+ T cells. In young adults (<40 years), EBV-specific CD8+ T cells recognizing different antigenic peptides assume divergent preferred differentiation phenotypes. In older adults (>65-years), antigen-specific cells show largely distinct phenotypic and transcriptomic aging trajectories. Common to many albeit not all antigen-specific populations are maintained TCR diversity, gained natural killer cell-like, innate signatures and lost stem-like features while no evidence is seen for cellular senescence or exhaustion. TCR avidity contributes to these phenotypic differences and aging-related changes. Collectively, our data uncover divergent antigen-guided aging shifts in memory T cell phenotypes, which are informative for antigen selection in optimizing vaccine design and adoptive T cell therapy. Homeostasis of memory T cells is modulated by each antigen encounter, thereby creating a heterogeneous population preventing precise tracking. Here, the authors use barcode-assisted tracing of Epstein-Barr virus-specific CD8+ memory T cells of young and older individuals to find antigen-guided, clonally divergent aging trajectories.

Imaging macrophage trafficking in solid tumors has major implications for cancer diagnosis, prognosis, and therapy. Here, we show that macrophage labeling with lipid-shelled microbubbles enables ultrasound imaging at single-cell level. Crucially, microbubble labeling and sonication at low mechanical indexes do not affect macrophage viability, migration, phenotype, and cytokine secretion profile, supporting the notion that ultrasound imaging can be used for nondestructive macrophage imaging. Despite the damping exerted on the microbubble oscillations by the cellular compartments, the microbubbles exhibit highly nonlinear behavior upon sonication, allowing for high specificity nonlinear US imaging under in vitro and in vivo conditions. Subsequently, we demonstrate that nonlinear ultrasound imaging can selectively monitor macrophage accumulation and extravasation in solid tumors in rodents for at least 8 h after intravenous administration. These findings establish ultrasound as a noninvasive platform for immune cell trafficking in solid tumors and highlight its potential to advance cancer diagnosis, monitoring, and therapy. Imaging macrophage trafficking in solid tumors has implications for cancer diagnosis and prognosis. by labeling macrophages with lipid-shelled microbubbles in combination with ultrasound, the authors here achieve nondestructive in vivo intravenously administrated macrophage imaging at single cell level with 100 µm resolution till 8 h in solid tumors in rodents.

Achieving a cure is an urgent need for patients with advanced solid tumors. Here, we discover that oncolytic virus (OV) infection enhances IL-18 receptor expression but fails to increase IL-18 ligand expression. Therefore, we engineer armed oncolytic alphavirus M1 expressing wild-type IL-18 (wtIL-18) or a mutant variant (mutIL-18) that evades IL-18 binding protein (IL-18BP) while maintaining IL-18 receptor (IL-18R) binding. Intravenous administration of M1-mutIL-18 suppresses the growth of multiple advanced solid tumors in C57BL/6 and BALB/c mouse models and promotes long-term systemic immune memory. Mechanistically, armed M1-mutIL-18 enhances directed clonal expansion and differentiation of CD8+ T cells and sustains IFN-γ production. Thus, armed M1-mutIL-18 promotes dendritic cell (DC) activation, priming and activation of CD8+ T cells in lymphatic organs, and infiltration of IL-18R+ CD8+ T cells in the tumor microenvironment, establishing a positive feedback loop. We further show that a PD-L1 inhibitor enhances the anti-tumor efficacy of mutIL-18 OVs. These results highlight the importance of the IL-18 pathway in oncolytic virus therapy and implicate reprogramming ligand-receptor interaction as an effective strategy for immunotherapy. Immunotherapy holds great potential, although strategies for durable responses against solid tumors are still needed. Here, the authors combine oncolytic virus (OV) engineering and reprogramming of the IL-18 pathway, showing that armed OVs expressing a decoy-resistant IL-18 elicit anti-tumor immunity and long-term immunological memory against multiple refractory tumors in mice.

Cytoplasmic stress granules (SG) assemble in response to stress-induced translational arrest and are key signaling hubs orchestrating cell fate and regulating various physiological and pathological processes. However, the role of SG formation in the progression of allergic diseases is incompletely understood. Here, by analyzing the nasal tissues of allergic rhinitis (AR) mouse models and AR patients, we find that SGs assemble specifically in the macrophages within the nasal mucosa and promote AR progression by restraining the efferocytotic ability of macrophages, ultimately resulting in reduced Mres generation and IL-10 production. Mechanistically, intracellular m7G-modified Lrp1 mRNA, encoding for a typical efferocytosis receptor, is transported by the m7G reader QKI7 into stress-induced SGs, where Lrp1 mRNA is sequestered away from the translation machinery, ultimately resulting in reduced macrophage efferocytosis. Therefore, SG assembly impairs macrophage efferocytosis and aggravates AR, and the inhibition of SGs bears considerable potential in the targeted therapy. Cytoplasmic stress granules (SG) regulate cell fate and are involved in several physiological and pathological processes. Here, using mouse models of allergic rhinitis (AR), the authors reveal the formation of SGs within macrophages of the nasal mucosa and implicate SGs in the regulation of Lrp1-mediated efferocytosis and Type 2 cytokine production, aggravating AR symptoms.