European Journal of Immunology最新文献

Imlifidase (IdeS) is a bacterial protease that hydrolyzes human IgG in their hinge region, decreasing their half-life and abrogating their Fc-mediated properties. It is now successfully used in therapy to prevent graft rejection during kidney transplants and is being clinically evaluated in several IgG-mediated autoimmune diseases. IdeS short half-life however limits its clinical use, particularly in the case of chronic diseases that would request repeated administrations. Here, we developed IdeS-Fc fusion proteins as a divalent homodimer (IdeS-Fc^div) or a monovalent heterodimer (IdeS-Fc^monov), in order to extend the IgG-depleting action of IdeS over time. Both IdeS-Fc efficiently separated monoclonal and polyclonal human IgG into F(ab')₂ and Fc fragments, although with slower kinetics than their native counterpart. IdeS-Fc^monov exhibited a seven-fold half-life extension in vivo as compared with IdeS, and a significantly better residual cleavage of human IgG at later time points after injection. Our results provide proof of concept for the use of an IdeS with extended IgG-hydrolyzing functions in vivo that could rapidly translate to the clinic.

Genetic engineering of regulatory T cells (Tregs) presents a promising avenue for advancing immunotherapeutic strategies, particularly in autoimmune diseases and transplantation. This study explores the modification of Tregs via mRNA electroporation, investigating the influence of T-cell activation status on transfection efficiency, phenotype, and functionality. For this CD45RA⁺ Tregs were isolated, expanded, and modified to overexpress brain-derived neurotrophic factor (BDNF). Kinetics of BDNF expression and secretion were explored. Treg activation state was assessed by checking the expression of activation markers CD69, CD71, and CD137. Our findings show that only activated Tregs secrete BDNF post-genetic engineering, even though both activated and resting Tregs express BDNF intracellularly. Notably, the mTOR pathway and CD137 are implicated in the regulation of protein secretion in activated Tregs, indicating a complex interplay of signalling pathways. This study contributes to understanding the mechanisms governing protein expression and secretion in engineered Tregs, offering insights for optimizing cell-based therapies and advancing immune regulation strategies.

The human fetal immune system starts to develop in the first trimester and likely plays a crucial role in fetal development and maternal-fetal tolerance. Innate lymphoid cells (ILCs) are the earliest lymphoid cells to arise in the human fetus. ILCs consist of natural killer (NK) cells, ILC1s, ILC2s, and ILC3s that all share a common lymphoid origin. Here, we studied fetal ILC subsets, mainly NK cells and ILC3s and their potential progenitors, across human fetal tissues. Our results show that fetal ILC subsets have distinct distribution, developmental kinetics, and gene expression profiles across human fetal tissues. Furthermore, we identify CD34⁺RORγt⁺Eomes⁻ and CD34⁺RORγt⁺Eomes⁺ cells in the fetal intestine, indicating that tissue-specific ILC progenitors exist already during fetal development.

Mast cell (MC)-driven allergic diseases are constantly expanding and require the development of novel pharmacological MC stabilizers. Allergen/antigen (Ag)-triggered activation via crosslinking of the high-affinity receptor for IgE (FcεRI) is fundamentally regulated by SRC family kinases, for example, LYN and FYN, exhibiting positive and negative functions. We report that KIRA6, an inhibitor for the endoplasmic reticulum stress sensor IRE1α, suppresses IgE-mediated MC activation by inhibiting both LYN and FYN. KIRA6 attenuates Ag-stimulated early signaling and effector functions such as degranulation and proinflammatory cytokine production/secretion in murine bone marrow-derived MCs. Moreover, Ag-triggered bronchoconstriction in an ex vivo model and IgE-mediated stimulation of human MCs were repressed by KIRA6. The interaction of KIRA6 with three MC-relevant tyrosine kinases, LYN, FYN, and KIT, and the potential of KIRA6 structure as a pharmacophore for the development of respective single-, dual-, or triple-specificity inhibitors, was evaluated by homology modeling and molecular dynamics simulations. We found that KIRA6 particularly strongly binds the inactive state of LYN, FYN, and KIT with comparable affinities. In conclusion, our data suggest that the chemical structure of KIRA6 as a pharmacophore can be further developed to obtain an effective MC stabilizer.

GLUT1 deficiency prevents glucose uptake in T cells resulting in lower intracellular ATP generation and IFNy production.

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) often associated with a Type 2 immune response. Although previous reports hint at a role for signal transducer and activator of transcription (STAT) 6 signaling in non-immune cells, the contribution of STAT6-activation particularly in intestinal epithelial cells (IECs) is still unknown. Dextran sodium sulfate (DSS)-induced colitis is a model for UC in mice that we applied here on animals with expression of a constitutively active version of STAT6 in IECs (VillinCre_STAT6vt mice). We report increased pathology and mortality due to enhanced and systemic inflammation in these mice. Bulk RNA sequencing of colonic tissue from naïve VillinCre_STAT6vt mice showed differential expression of more than 140 genes compared to control mice. Gene set enrichment analysis revealed STAT6-regulated expression of the unfolded protein response, MTORC- and MYC-signaling, and protein secretion pathways. A comparison of gene expression in the colon of naïve VillinCre_STAT6vt mice and a human single-cell RNA sequencing dataset of a patient cohort with IBD revealed overlapping changes in the epithelial and macrophage compartment compared to corresponding controls. In conclusion, we found that activation of STAT6 in the intestinal epithelium predisposes to exacerbated colitis and gut inflammation.

This article is part of the Dendritic Cell Guidelines article series, which provides a collection of state-of-the-art protocols for the preparation, phenotype analysis by flow cytometry, generation, fluorescence microscopy, and functional characterization of mouse and human dendritic cells (DC) from lymphoid organs, and various nonlymphoid tissues. Within this article, detailed protocols are presented that allow for the generation of single-cell suspensions from human nonlymphoid tissues including lung, skin, gingiva, intestine as well as from tumors and tumor-draining lymph nodes with a subsequent analysis of dendritic cells by flow cytometry. Further, prepared single-cell suspensions can be subjected to other applications including cellular enrichment procedures, RNA sequencing, functional assays, etc. While all protocols were written by experienced scientists who routinely use them in their work, this article was also peer-reviewed by leading experts and approved by all co-authors, making it an essential resource for basic and clinical DC immunologists.