bims-hummad 2026-01-04 papers

Front Immunol. 2025 ;16 1717133

Development of a humanized mouse model of graft-versus-host disease to assess human regulatory T cell function.

Charline Beguin, Oswin Kwan, Grégory Ehx, Stéphanie Humblet-Baron, Murat Cem Köse, Sophie Dubois, Lorenzo Canti, Justine Courtois, Coline Daulne, Jo Caers, Yves Beguin, Caroline Ritacco, Frédéric Baron.

Introduction: Regulatory T cells (Treg)-based therapies are increasingly used for treating autoimmune or graft-versus-host (GVHD) disease. Given their low frequency, several approaches aimed at amplifying them or at increasing their immunosuppressive activities are currently investigated. Unfortunately, the impact of these strategies on human Treg function has remained difficult to assess in vivo. Here, we report the development of a novel humanized mouse model of allogeneic and xenogeneic GVHD intended to characterize the immunosuppressive activity of human Treg in vivo.
Methods: In this model, GVHD is induced by injecting CD25-depleted HLA-A2- peripheral blood mononuclear cells (PBMC) into irradiated NSG-HLA-A2-HHD mice. The CD25+ (Treg) fraction is maintained in vitro for 48h during which Treg-promoting treatments can be tested before infusion into mice. We took advantage of this model to investigate whether tumor necrosis factor alpha (TNF-α) priming of Treg would increase their suppressive function and improve their ability at preventing xenogeneic GVHD, after assessing the effect of TNF-α on Treg in vitro.
Results: In vitro, single cell RNAseq analyses showed that eleven Hallmark pathways, including Interferon response, IL-6-JAK-STAT3 signaling, mTORC1 signaling, and TNF-α signaling via NF-κB, were significantly upregulated in Treg following TNF-α priming. In vivo, Treg infusion resulted in higher Treg levels, lower counts of human cells, lower conventional CD4+ (Tconv) and CD8+ T-cell counts, lower KI67 and HLA-DR expression by Tconv and lower Granzyme B expression by CD8+ T-cells in peripheral blood. No significant impact of TNF-α priming of Treg on survival was observed.
Discussion: These results emphasize the importance of reliable techniques to assess Treg in vivo as efficient methods to activate them in vitro do not always result in an enhanced function in the in vivo setting. In summary, we present here the development of a novel humanized model of GVHD designed to evaluate the in vivo functionality of human Treg. Taking advantage of that model, we observed that TNF-α priming of human Treg did not increase their suppressive activity in vivo.

Keywords: GVHD; NSG-HLA-A2/HHD; TNF-α; regulatory T cells; single-cell RNA seq; spectral flow cytometry; xenogeneic

DOI: https://doi.org/10.3389/fimmu.2025.1717133

Diabetes Technol Ther. 2025 Dec 22.

Antigen-Specific Chimeric Antigen Receptor-T Regulatory Cells Home to Human Islets, Suppress Cytotoxic T Lymphocytes and Reverse Type 1 Diabetes.

Shahnawaz Imam, Pervaiz Dar, Shafiya Imtiaz Rafiqi, Maria A Alfonso-Jaume, Ahmed Al-Khudhair, Alexa Jaume, Kerri Ann Simo, Tania A Torres-Ruiz, Nancy Salim, Juan Carlos Jaume.

Background: We have developed pancreatic beta-cell, antigen-specific, chimeric antigen receptor (CAR) T regulatory cells (Tregs) and explored their therapeutic potential for type 1 diabetes (T1D)/latent autoimmune diabetes of adults (LADA) in human pancreatic tissues ex vivo, and in a spontaneous humanized mouse model (T1D mice) in vivo. Results: Using live-cell imaging, we observed these glutamic acid decarboxylase, 65 kD isoform (GAD65)-CAR-Tregs home to human pancreatic islets exvivo and proliferate upon encountering the cognate GAD65 antigen in the islets. Furthermore, human pancreatic-islet activated GAD65-CAR-Tregs also suppressed human T1D cytotoxic T lymphocytes in co-cultures. We confirmed these findings in vivo, in a spontaneous humanized T1D mouse model (T1D mice) by showing that mouse GAD65-CAR-Tregs also suppressed diabetogenic T responsive (Tresp) cells and were superior to normal Tregs. We also show that mouse GAD65-CAR-Tregs homed to mouse pancreatic islets in vivo. Moreover, we conducted a 30-day preclinical trial in T1D mice, and observed normalization of fasting blood glucose, fasting insulin, and glucose tolerance tests in GAD65-CAR-Treg-treated T1D mice. We confirmed by histology, the advancement of Tregs, retreat of T effector cells in GAD65-CAR-Treg-treated mice, that led to the recovery/reconstitution of pancreatic islets. Discussion: Taken together, human GAD65-CAR-Tregs homed to human islets, suppressed diabetogenic T cells, and when used to treat T1D mice that mimic the human pathophysiology of T1D, GAD65-CAR-Tregs reversed T1D. Conceivably, the treatment of T1D with GAD65-CAR-Tregs will allow for recovery/reconstitution of beta cells in human patients as well.

Keywords: glutamic acid decarboxylase; latent autoimmune diabetes of adults (LADA); regulatory T cells; type 1 diabetes (T1D)

DOI: https://doi.org/10.1177/15209156251403551

Vet Pathol. 2026 Jan 02. 3009858251403172

Spontaneous and experimentally induced lesions in NOD-scid gamma and other NOD-derived mouse strains.

Pedro Ruivo, Renata Mammone, Ileana Miranda, Sebastian E Carrasco, Sebastien Monette, Laura Janke, Heather Sheppard, Charles-Antoine Assenmacher, Denise M Imai, Alessandra Piersigilli, Sara F Santagostino, Enrico Radaelli.

Immunodeficient mice, particularly the NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) strain and other non-obese diabetic (NOD)-derived lines are widely used in biomedical research due to their profound immunosuppression, which enables stable engraftment of human cells and tissues with minimal rejection. Despite their broad utility, these models exhibit unique immunologic and anatomic features and are predisposed to infectious and noninfectious diseases that may confound experimental outcomes and limit translational relevance. This review summarizes current knowledge on spontaneous, infectious, and experimentally induced lesions in NSG and related strains. These mice characteristically display hypoplastic lymphoid organs, including the spleen, thymus, and lymph nodes, due to a near-complete absence of lymphocytes. Spontaneous background lesions include splenic osseous metaplasia, neurodegeneration, pancreatic mastocytosis, cochlear degeneration, intervertebral disk disease, skull hyperostosis, and pancreatic duct cysts, among others. Common spontaneous neoplasms include lymphomas, osteosarcomas, and mammary gland tumors. Due to their immunodeficient status, NSG and NOD-derived mice are also highly susceptible to opportunistic infections, such as Corynebacterium bovis, Chlamydia muridarum, Clostridioides difficile, and mouse kidney parvovirus. In humanized models, engraftment of human immune cells can result in distinctive syndromes, including xenogeneic graft-versus-host disease, post-transplant lymphoproliferative disorders, and chimeric myeloid cell hyperactivation syndrome, which can impact study outcomes and lead to mortality and morbidity. This review is intended as a resource for comparative pathologists to become familiar with these widely used immunodeficient mice, so they can interpret strain-specific lesions and recognize experimental confounders in these mouse models.

Keywords: NSG mice; background lesions; chimeric myeloid cell hyperactivation syndrome; graft versus host disease; humanized mice; immunodeficiency; infectious disease; post-transplant lymphoproliferative disorder; spontaneous tumors

DOI: https://doi.org/10.1177/03009858251403172