In adult T-cell leukemia/lymphoma (ATL), tumor cells show a regulatory T-cell (Treg)-type phenotype, which influences their tumor immunity. However, our knowledge of what molecular events are involved in pathogenesis is still missing. Here, we took advantage of this unique phenotype and screened whole transcriptome data from primary ATL cells to search for effective therapeutic targets. Glycoprotein A repetitions predominant (GARP) was identified as a novel tumor antigen in ATL. ATL cells overexpress GARP and release transforming growth factor-β (TGF-β). The GARP-TGF-β axis promotes cell proliferation of ATL cells and human T-cell leukemia virus type 1 (HTLV-1)-infected cells with changes in cell signaling activities and shaping of Treg gene expression patterns, but suppresses the activity of surrounding effector T-cells. Remarkably, this study has provided a breakthrough therapeutic concept that achieves the dual effect of direct tumor cell depletion and indirect immune activation by a single treatment targeting GARP. DS-1055a, an anti-GARP monoclonal antibody, selectively and effectively depleted malignant ATL cells via antibody-dependent cellular cytotoxicity, supporting the proof-of-concept in the preclinical study. Our findings highlight the key to understanding the cell origin of ATL and developing unprecedented therapeutic strategies for refractory diseases.
© 2025. The Author(s).

Vascularized composite allotransplantation (VCA) offers a promising solution for restoring function in patients with severe tissue trauma, yet acute rejection remains a major hurdle. Acute rejection is driven by an immune response against transplanted tissues, requiring lifelong immunosuppression, increasing risks of infections, malignancies, and organ toxicity. This study aims to develop a mouse hindlimb transplant model to investigate immune responses and the phenotype of infiltrating cells in these grafts.
Syngeneic and allogeneic mouse partial hindlimb models were established to evaluate grafted skin and muscle immunogenicity. Male BABL/c and C57BL/6 mice served as donors, C57BL6.sjl mice were recipients. Hindlimbs were procured, including femur, muscle, and skin, and were heterotopically transplanted into recipient mice. Samples were collected at post-operative days 7 (POD7) and 14 (POD14) for histological analysis (H&E staining, immunohistochemistry for CD8, caspase-3, CD31, and TUNEL) to assess cell infiltration, inflammatory T cell presence, apoptosis, and vascularization. Immune cell populations were characterized through flow cytometry.
Both syngeneic and allogeneic skin and muscle showed increased cellular content at both time points. Allogeneic skin at POD14 exhibited higher cellular content and subclinical rejection, while flow cytometry revealed increased donor-derived and recipient-derived T cells, particularly CD4+ and CD8+ T cells. Additionally, Tr1 cells were more abundant, suggesting a regulatory role in the immune response. Apoptotic markers increased in both grafts at POD14, with more TUNEL-positive cells in allogeneic grafts at POD7. Revascularization, assessed by CD31 expression, was notably present in both syngeneic and allogeneic muscle at POD14.
This study provides valuable insights into acute rejection in VCA using a novel mouse hindlimb transplant model. Findings reveal immune response complexity, with increased CD8+ T cells and Tr1 cells in allogeneic skin, and unexpected vascularization in non-vascularized grafts. The rise in Tr1 cells suggests a potential mechanism for immune regulation, offering potential for tolerance induction strategies. These results emphasize the need for tissue-specific immunosuppressive approaches, where targeting Tr1 cells could reduce dependence on broad immunosuppression, improving long-term graft survival and patient outcomes. This work lays the foundation for refining VCA therapies, with more personalized, less toxic immunosuppressive strategies.
Copyright © 2025 Sun, Ligi, Biniazan and Haykal.

Polysaccharides as immunomodulators are increasingly explored in preclinical studies, showing potential applications for preventing or treating different diseases. Among them is starch, an α-glucan formed by amylose and amylopectin chains. Given their abundance in nature, physicochemical characteristics, and applicability in pharmacy, they are versatile molecules that offer important biotechnological and biomedical advantages. Most studies about starch immunostimulant properties focus on modified-soluble and particulate α-glucans. However, little research has been done on the immunostimulant properties of starch in its natural particulate state. Previously, we have used starch microparticles (SMPs) as carriers for nasal administration of antigens in healthy mice and as a nasal boost and adjuvant of the Bacillus Calmette-Guérin (BCG) vaccine in a murine model of tuberculosis. This study aimed to analyze the effect of SMPs on the activation and polarization profile of murine alveolar macrophages of the MH-S cell line. We evaluated the effect of these SMPs on cell viability, phagocytosis, and expression of surface markers on M0 alveolar macrophages. We also explored the effect of SMPs on nitric oxide production, cytokine secretion, glucose consumption, and lactate release on M0 and previously M1 and M2-polarized alveolar macrophages. The results indicate that these SMPs are phagocytosed without cytotoxic effects for alveolar macrophages and have an immunomodulatory effect on previously polarized M1 macrophages. In M0 and M2 macrophages, the SMPs induced a mixed secretion of cytokines such as TNF-α, IL-10, and IL-12p40, and a significant decrease of TGF-β1. Recognizing the effects triggered by these SMPs on these cells of the innate immune system will allow us to propose rational uses for these SMPs in prophylactic and therapeutic vaccines intended to be used by the nasal/pulmonary route.
Copyright: © 2025 Barrera-Rosales et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Human pluripotent stem cells (hPSCs) can be used to investigate hematopoietic development and have the potential to advance cell-based therapies and to facilitate developmental biology studies. However, efficient ex vivo differentiation into hematopoietic lineages, including red blood cells (RBCs) of the erythroid lineage and immune cells such as macrophages of the myeloid lineage, is hampered by the need for precise temporal regulation of cytokines and growth factors. In this study, we developed an optimized protocol for hematopoietic lineage specification from hPSCs by fine-tuning the temporal dynamics of cytokine and growth factor applications. Prolonged mesodermal specification in the absence of hemogenic cytokines significantly enhanced the generation of hematopoietic progenitors (CD34＋CD45＋) with robust functional potential. Early administration of interleukin (IL)-3 during hematopoietic specification promoted progenitor expansion and maturation. Supplementation of bone morphogenetic protein 4 at the hematopoietic maturation stage enhanced the differentiation efficiency and preferentially drove myeloid lineage commitment toward macrophages at the expense of erythroid differentiation. The timing of erythropoietin administration was important in erythroid lineage commitment, and delayed treatment (day 10) enhanced erythroblast expansion and RBC production. By contrast, the timing of IL-6, GM-CSF, and M-CSF exposure did not significantly affect macrophage differentiation efficiency, suggesting that myeloid lineage specification follows a default pathway under optimized differentiation conditions. These findings suggest a refined, time-controlled strategy for directing hematopoietic differentiation from hPSCs, and provide insight into therapeutic blood cell production, regenerative medicine, and ex vivo modeling of hematopoietic disorders.

Impaired differentiation is a hallmark of myeloid malignancies1,2. Therapies that enable cells to circumvent the differentiation block, such as all-trans retinoic acid (ATRA) and arsenic trioxide (ATO), are by and large curative in acute promyelocytic leukaemia3, but whether 'differentiation therapy' is a generalizable therapeutic approach for acute myeloid leukaemia (AML) and beyond remains incompletely understood. Here we demonstrate that simultaneous inhibition of the histone demethylase LSD1 (LSD1i) and the WNT pathway antagonist GSK3 kinase4 (GSK3i) robustly promotes therapeutic differentiation of established AML cell lines and primary human AML cells, as well as reducing tumour burden and significantly extending survival in a patient-derived xenograft mouse model. Mechanistically, this combination promotes differentiation by activating genes in the type I interferon pathway via inducing expression of transcription factors such as IRF7 (LSD1i) and the co-activator β-catenin (GSK3i), and their selective co-occupancy at targets such as STAT1, which is necessary for combination-induced differentiation. Combination treatment also suppresses the canonical, pro-oncogenic WNT pathway and cell cycle genes. Analysis of datasets from patients with AML suggests a correlation between the combination-induced transcription signature and better prognosis, highlighting clinical potential of this strategy. Collectively, this combination strategy rewires transcriptional programs to suppress stemness and to promote differentiation, which may have important therapeutic implications for AML and WNT-driven cancers beyond AML.
© 2025. The Author(s).