European Journal of Immunology最新文献

Mast cells are evolutionarily ancient immune cells located at strategic entry points for pathogens and allergens. Allergen exposure activates signal transduction pathways resembling those downstream of antigen receptors in T and B lymphocytes, leading to mast cell degranulation and cytokine secretion. The paralogous RNA-binding proteins ROQUIN-1 and ROQUIN-2 prevent aberrant T cell activation and differentiation and are cleaved upon antigen receptor engagement. Here, we investigated their roles in connective tissue mast cells using conditional gene knockout in mice. We show that ROQUIN-1 and ROQUIN-2 are dispensable for skin mast cell development and maintenance, while they are essential for serosal mast cells residing in the peritoneal and pleural cavities. Concurrent ablation of both paralogs did not affect mast cell degranulation in vitro and in vivo, nor did it alter activation-induced secretion of TNF and IL-6, cytokines that are regulated by ROQUIN proteins in other cell types. Furthermore, we globally define ROQUIN-regulated mRNAs in mast cells, and validate Runx1t1 and Ebi3 as indirect and Lfng as direct ROQUIN targets. Collectively, our results highlight the essential function of ROQUIN in connective tissue mast cells in serosal cavities.

This is an update to the Guidelines for the use of flow cytometry and cell sorting in immunological studies (third edition), Chapter 3: 12C, by Cossarizza et al. Administration of anti-ARTC2 nanobody(S+16a) prevents cell death during tissue processing. We demonstrate that the phenotype of CD44^midTreg is significantly impacted, whereas the eTreg phenotype remains stable following S+16a treatment, outlining specific protocols for population recovery.

Antibody feedback in germinal center (GC) responses plays a key role in shaping the affinity, specificity, and longevity of humoral immunity. Beyond neutralizing pathogens, antibodies influence B cell selection by modulating antigen availability and masking dominant epitopes, thereby reshaping the competitive landscape for T follicular helper (Tfh) cell support. This review outlines the current understanding of how antibody feedback governs the selection stringency and clonal evolution of GC B cells, facilitates and promotes the emergence of epitope spread, and contributes to GC shutdown. We also examine how it supports the development of broadly neutralizing antibodies. Finally, we discuss how these insights are informing next-generation vaccine strategies—including immunogen design, prime-boost regimens, and adjuvant optimization—to guide affinity maturation toward specific epitopes and overcome feedback-driven constraints. Understanding antibody feedback not only reveals fundamental principles of adaptive immunity but also offers new avenues for rational vaccine design and therapeutic immune modulation.

Group 3 innate lymphoid cells (ILC3s) are tissue-resident lymphocytes distributed across both lymphoid and non-lymphoid tissues, capable of mounting rapid immune responses. They are defined by expression of the transcription factor RORγt and comprise distinct subsets, including lymphoid tissue inducer-like cells expressing major histocompatibility complex class II (MHCII). These MHCII⁺ ILC3s can directly present antigens to CD4⁺ T cells, a function regulated by the transcriptional activator CIITA through a pathway similar to thymic epithelial cells. ILC3s contribute to immune homeostasis by limiting effector T cell responses and promoting regulatory T cell differentiation. However, under the influence of distinct cytokine milieus, such as IL-1β and IFN-γ, ILC3s undergo a maturation process, upregulating costimulatory molecules and enhancing their antigen-presenting capacity to activate CD4⁺ T cells. This dual functionality is highly plastic and influenced by tissue-specific environmental cues, enabling ILC3s to adapt their immunoregulatory roles according to local context. Overall, ILC3s now emerge as critical modulators of T cell activities, balancing tolerance and activation, with significant implications for host defense, autoimmunity, inflammation, and cancer.

Selecting a sensitive test system is crucial to measure IFNα in serum samples. Simoa digital ELISA stands out for its high sensitivity and strong correlation with transcript-based IFN-induced gene (ISG) scores. In SLE, the ISG score is explained by circulating IFNα levels with negligible contribution from IFNβ or IFNγ. Created in BioRender.

The stimulator of interferon genes (STING) pathway plays a pivotal role in innate immunity, acting as a key sensor of cytosolic DNA to initiate type-I Interferon (IFN) and pro-inflammatory cytokine production. This pathway is essential for host defence against bacterial, viral and other pathogenic threats and has emerged as a promising therapeutic target in cancer immunotherapy. However, conventional techniques such as immunoblotting and qPCR are limited in their capacity to study STING pathway activation in complex and heterogeneous biological systems, such as tumour masses or large cell populations. Here, we describe the application of mass cytometry (CyTOF) as a cutting-edge approach to characterize the STING pathway at the sub-population level. Using a high-dimensional panel of metal-labelled antibodies targeting key STING signalling components, we achieved resolution of pathway activation across diverse immune cell populations. This approach promises novel insights into cellular heterogeneity, pathway dynamics and the interplay between STING signalling and other immune pathways and underscores the power of high-dimensional analysis to overcome the limitations of traditional methods to enable a more comprehensive exploration of immune signalling pathways.

Tissue-resident and recruited macrophages are integral to organ development, homeostasis, immunity, and disease pathogenesis. Their remarkable diversity arises from distinct developmental origins, differentiation trajectories, and microenvironmental cues that shape their identity and function. Central to these processes is transcriptional regulation. In this review, we provide a comprehensive overview of the transcription factor (TF) networks that orchestrate resident tissue macrophage (RTM) differentiation from progenitor cells, imprint core macrophage identity, and drive tissue-specific functions. We first delineate the collaborative roles of lineage-determining TFs, such as PU.1 and C/EBPs, which prime macrophage progenitors for commitment. We then examine identity-imprinting TFs that establish and maintain the core macrophage program, and tissue-specific TFs that allow integration of local niche signals to tailor RTM phenotypes across organs. While the focus is on RTMs at steady state, we also highlight how RTMs can undergo transcriptional reprogramming upon tissue perturbation, and how newly recruited macrophages may engage distinct regulatory circuits upon entering diseased tissues, with tumors serving as an example.

Graft-versus-host disease is mediated by donor-derived T cells reactive against the recipient's broadly expressed minor histocompatibility antigens (mHA). Regulatory T cells (Treg) have been explored as a therapeutic approach for chronic GVHD (cGVHD). The promising results from polyclonal Treg trials in this setting have led us to develop a Treg product specific for mismatched minor antigens between patient and donor (mTreg), circumventing broad immune suppression risks. HLA-matched siblings of opposite sexes were used to obtain the sister's CD4⁺CD25^hiCD127^low Treg for co-culture with the respective brother's dendritic cells as a source of mismatched mHA. We have established the optimal culture conditions resulting in the highest mTreg proliferation and viability. Comprehensive phenotyping during the ex vivo selection shows PD-1, CTLA-4, CD39 and HLA-DR expression. Transcriptomic analysis revealed a switch in metabolic process, and up-regulation of functional Treg genes. Furthermore, mTreg possess specific and potent suppressive activity, in which there is a dependency on cell-to-cell contact and a role for HLA class II expression on mTreg. This protocol would allow the generation of Treg specific to an array of mHA from the recipient's healthy tissues, likely providing a directed and strong suppression of cGVHD.