The requirement for Notch signaling during T-cell development has been extensively studied. Nevertheless, the developmental stage at which it is required and whether additional signaling pathways are needed are still poorly understood. By using a stromal-cell-free culture system, we show that sorted double-negative 3 (DN3) thymocytes only require a Delta-like-4-induced Notch signal to differentiate into double-positive (DP) cells. This differentiation process is preTCR-α dependent. DN3 cells undergo 4-5 proliferation cycles, and the addition of the chemokine CXCL12 improves proliferation. IL-7 blocks the differentiation of DN3 cells to DP cells but not the Notch-induced proliferation of cultured DN3 cells. The impaired differentiation correlates with an inhibition of Rag-2 up-regulation. Overall, the in vitro stromal-cell-free culture system presented here also provides a powerful and unique tool for studying the mechanisms involved in the positive and negative selection of T cells.
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http://dx.doi.org/10.1002/eji.201141824 | DOI Listing |
Sci Adv
January 2025
Howard Hughes Medical Institute, Brandeis University, Waltham, MA 02453, USA.
Nat Immunol
January 2025
Department of Medicine, Division of Rheumatology, Lowance Center for Human Immunology, Emory University, Atlanta, GA, USA.
Severe acute respiratory syndrome coronavirus 2 mRNA vaccination has reduced effectiveness in certain immunocompromised individuals. However, the cellular mechanisms underlying these defects, as well as the contribution of disease-induced cellular abnormalities, remain largely unexplored. In this study, we conducted a comprehensive serological and cellular analysis of patients with autoimmune systemic lupus erythematosus (SLE) who received the Wuhan-Hu-1 monovalent mRNA coronavirus disease 2019 vaccine.
View Article and Find Full Text PDFJ Transl Autoimmun
December 2024
Department of Pathology and Immunology, Centre Médical Universitaire, School of Medicine, University of Geneva, Geneva, Switzerland.
Objective: B cells play a major role in the development and maintenance of systemic lupus erythematosus (SLE). Double negative (DN) B cells defined by the lack of surface expression of IgD and CD27 have attracted recent interest for their sensitivity to Toll-like receptor 7 (TLR7) ligands and their potential role in the production of autoantibodies. Here we aimed at investigating the possible association of DN B cells and their subsets with SLE disease activity specifically in female patients, in which TLR7 gene has been reported to escape X chromosome inactivation.
View Article and Find Full Text PDFJ Leukoc Biol
December 2024
Department of Microbiology and Immunology, Institute of Geriatric Immunology, School of Medicine, Jinan University, Guangzhou 510632, China.
Dev Cell
October 2024
Institute of Immunology and Department of Rheumatology at Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China; Shanghai Immune Therapy Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China; Future Health Laboratory, Innovation Center of Yangtze River Delta, Zhejiang University, Jiaxing 314100, China. Electronic address:
Mitochondria and endoplasmic reticulum contacts (MERCs) control multiple cellular processes, including cell survival and differentiation. Based on the observations that MERCs were specifically enriched in the CD4CD8 double-negative (DN) stage, we studied their role in early mouse thymocyte development. We found that T cell-specific knockout of Hspa9, which encodes GRP75, a protein that mediates MERC formation by assembling the IP3R-GRP75-VDAC complex, impaired DN3 thymocyte viability and resulted in thymocyte developmental arrest at the DN3-DN4 transition.
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