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Cross-presentation by MHC class I molecules (MHC-I) is critical for priming of cytotoxic T cells. Peptides derived from cross-presented antigens can be loaded on MHC-I in the endoplasmic reticulum and in endocytic or phagocytic compartments of murine DCs. However, the origin of MHC-I in the latter compartments is poorly understood. Recently, Rab22-dependent MHC-I recycling through a Rab11+ compartment has been suggested to be implicated in cross-presentation. We have examined the existence of MHC-I recycling and the role of Arf6, described to regulate recycling in nonprofessional antigen presenting cells, in murine DCs. We confirm folded MHC-I accumulation in a juxtanuclear Rab11+ compartment and partially localize Arf6 to this compartment. MHC-I undergo fast recycling, however, both folded and unfolded internalized MHC-I fail to recycle to the Rab11+Arf6+ compartment. Therefore, the source of MHC-I molecules in DC endocytic compartments remains to be identified. Functionally, depletion of Arf6 compromises cross-presentation of immune complexes but not of soluble, phagocytosed or mannose receptor-targeted antigen, suggesting a role of Fc receptor-regulated Arf6 trafficking in cross-presentation of immune complexes.
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http://dx.doi.org/10.26508/lsa.201900464 | DOI Listing |
Sci Adv
September 2025
Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
(phosphatidylserine synthase 1) encodes an enzyme that facilitates production of phosphatidylserine (PS), which mediates a global immunosuppressive signal. Here, based on in vivo CRISPR screen, we identified PTDSS1 as a target to improve anti-PD-1 therapy. Depletion of in tumor cells increased expression of interferon-γ (IFN-γ)-regulated genes, including , , , and , even in the absence of IFN-γ stimulation in vitro.
View Article and Find Full Text PDFMol Ther Methods Clin Dev
September 2025
Office of Gene Therapy, Office of Therapeutic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA.
genome editing with CRISPR-Cas9 systems is generating worldwide attention and enthusiasm for the possible treatment of genetic disorders. However, the consequences of potential immunogenicity of the bacterial Cas9 protein and the AAV capsid have been the subject of considerable debate. Here, we model the antigen presentation in cells after gene editing by transduction of a human cell line with an AAV2 vector that delivers the Cas9 transgene.
View Article and Find Full Text PDFEMBO J
September 2025
Department of Infectious Diseases, Medical Research Institute, Zhongnan Hospital of Wuhan University; Frontier Science Center for Immunology and Metabolism, Taikang Center for Life and Medical Sciences; Wuhan University, Wuhan, 430071, China.
Inadequate antigen presentation by MHC-I in tumor microenvironment (TME) is a common immune escape mechanism. Here, we show that glycine decarboxylase (GLDC), a key enzyme in glycine metabolism, functions as an inhibitor of MHC-I expression in EGFR-activated tumor cells to induce immune escape by a mechanism independent of its enzymatic activity. Upon EGFR activation, GLDC is phosphorylated by SRC and subsequently translocated to the nucleus in human NSCLC cells.
View Article and Find Full Text PDFFront Immunol
September 2025
Center for Cellular Immunotherapies, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States.
Background: Multiplex gene-edited chimeric antigen receptor (CAR) T-cell therapies face significant challenges, including potential oncogenic risks associated with double-strand DNA breaks. Targeted microRNAs (miRNAs) may provide a safer, functional, and tunable alternative for gene silencing without the need for DNA editing.
Methods: As a proof of concept for multiplex gene silencing, we employed an optimized miRNA backbone and gene architecture to silence T-cell receptor (TCR) and major histocompatibility complex class I (MHC-I) in mesothelin-directed CAR (M5CAR) T cells.
Int J Biol Macromol
September 2025
Department of Tumor Biological Treatment, The Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu, 213003, China; Jiangsu Engineering Research Center for Tumor Immunotherapy, The Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu, 213003, China; Institute of Cell The
Despite its potential as a cancer immunotherapy, wild-type IL-2 is limited by dose-limiting toxicities, including vascular leak syndrome, and its strong activation of regulatory T cells (Tregs), which dampens anti-tumor immunity. These drawbacks are largely driven by IL-2's binding to IL-2Rα, and avoiding this interaction can reduce IL-2-associated toxicities, although it cannot completely eliminate them. To overcome these limitations, βγ-biased IL-2 variants (Non-α-IL-2) have been developed to selectively activate effector T and NK cells.
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