The complexity of a self-regulatory system demands a balance between effectors and regulators; that is, it is necessary for both cell types to exist. Regulation of self-reactive T cells can occur at several complementary but different levels: (1) at the level of priming itself: for example, inhibition of expansion of antigen-reactive T cells by regulatory CD4+ CD25+ T cells; (2) after the priming of self-reactive T cells, regulatory T-cell populations with reactivity to distinct self-determinants derived from the T-cell receptor (TCR) can be engaged via a negative feedback mechanism. Thus, these mechanisms ensure induction of effective and appropriately limited responses against foreign antigens while preventing autoreactivity from inflicting self-damage.
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http://dx.doi.org/10.1080/08830180590934967 | DOI Listing |
Nat Commun
January 2025
Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, CA, 94143, USA.
The Nr4a nuclear hormone receptors are transcriptionally upregulated in response to antigen recognition by the T cell receptor (TCR) in the thymus and are implicated in clonal deletion, but the mechanisms by which they operate are not clear. Moreover, their role in central tolerance is obscured by redundancy among the Nr4a family members and by their reported functions in Treg generation and maintenance. Here we take advantage of competitive bone marrow chimeras and the OT-II/RIPmOVA model to show that Nr4a1 and Nr4a3 are essential for the upregulation of Bcl2l11/BIM and thymic clonal deletion by self-antigen.
View Article and Find Full Text PDFImmunity
January 2025
Garvan Institute of Medical Research, Darlinghurst, NSW, Australia; St Vincent's Clinical School, UNSW Sydney, Sydney, NSW, Australia. Electronic address:
The unexplained association between infection and autoimmune disease is strongest for hepatitis C virus-induced cryoglobulinemic vasculitis (HCV-cryovas). To analyze its origins, we traced the evolution of pathogenic rheumatoid factor (RF) autoantibodies in four HCV-cryovas patients by deep single-cell multi-omic analysis, revealing three sources of B cell somatic mutation converged to drive the accumulation of a large disease-causing clone. A method for quantifying low-affinity binding revealed recurring antibody variable domain combinations created by V(D)J recombination that bound self-immunoglobulin G (IgG) but not viral E2 antigen.
View Article and Find Full Text PDFJ Clin Immunol
January 2025
Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA, USA.
Reduced function or hypomorphic variants in recombination-activating genes (RAG) 1 or 2 result in a broad clinical phenotype including common variable immunodeficiency (CVID) and even adult-onset disease. Milder RAG variants are less characterized. Here we describe the longitudinal course of a milder combined RAG deficiency in 3 of 7 siblings sharing the same RAG2 mutations over a 50-year study.
View Article and Find Full Text PDFNat Immunol
January 2025
Institute for Immunity, Transplantation, and Infection, Stanford University, Stanford, CA, USA.
Here we analyzed the relative contributions of CD4 regulatory T cells expressing Forkhead box protein P3 (FOXP3) and CD8 regulatory T cells expressing killer cell immunoglobulin-like receptors to the control of autoreactive T and B lymphocytes in human tonsil-derived immune organoids. FOXP3 and GZMB respectively encode proteins FOXP3 and granzyme B, which are critical to the suppressive functions of CD4 and CD8 regulatory T cells. Using CRISPR-Cas9 gene editing, we were able to achieve a reduction of ~90-95% in the expression of these genes.
View Article and Find Full Text PDFImmunity
December 2024
Experimental Immunology, Department of Biomedicine, University Hospital Basel, University of Basel, 4031 Basel, Switzerland. Electronic address:
The major histocompatibility complex (MHC) class I-related molecule MHC-class-I-related protein 1 (MR1) presents metabolites to distinct MR1-restricted T cell subsets, including mucosal-associated invariant T (MAIT) and MR1T cells. However, self-reactive MR1T cells and the nature of recognized antigens remain underexplored. Here, we report a cell endogenous carbonyl adduct of adenine (8-(9H-purin-6-yl)-2-oxa-8-azabicyclo[3.
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