bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.64898/2026.01.22.700802

EBF1 regulates the blood-thymus barrier and ETP influx through Claudin-5 in thymic endothelial cells

Lenaerts, A.·Grosschedl, R.
View original source ↗Export metadata ↓

Abstract

The blood-thymus-barrier (BTB) is essential for regulating the entry of thymic-seeding progenitors into the thymus, an organ lacking self-renewing T cell progenitors. Here, we identify Early B-cell factor 1 (Ebf1), a transcription factor with established roles in hematopoiesis, as specifically expressed in thymic endothelial cells. Tie2-Cre-mediated deletion of Ebf1 results in a significant reduction of early thymic progenitors (ETPs), despite unaltered bone marrow lymphoid progenitor populations, unaltered thymic stromal subset frequencies, and intact downstream thymocyte differentiation. Transcriptome analysis of Ebf1-deficient thymic endothelial cells reveals increased expression of tight-junction-associated genes, in particular Cldn5, a key tight-junction component that restricts the BTB. Consistent with reduced BTB permeability, ETP subset analysis demonstrates a proportional reduction in the ETP1 fraction, the progenitor population that resides in closest proximity to thymic endothelial cells at the cortico-medullary junction. Together, our study implicates Ebf1 in the regulation of the BTB permeability, through modulation of tight-junction programs, thereby enabling thymus-seeding progenitor entry.

Explore related subjects

immunologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Lenaerts, A., Grosschedl, R.. 2026-01-26. EBF1 regulates the blood-thymus barrier and ETP influx through Claudin-5 in thymic endothelial cells. https://doi.org/10.64898/2026.01.22.700802

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Common viral infections seed regionally distinct resident memory T cells in the human CNS

T cells persist in the central nervous system (CNS) and can drive both protection and neurological disease. How these cells are organized in humans and what they recognize is largely unknown. Here, we profiled CD8 T cells across anatomically distinct CNS regions, obtained through on-site autopsies and temporal lobe resection surgeries, using single-cell RNA sequencing, paired T cell receptor sequencing, and DNA-barcoded tetramers. Resident memory T cells (TRM) specific for Epstein-Barr virus, cytomegalovirus, influenza A, and SARS-CoV-2 were identified across CNS compartments. Anatomical location was the strongest correlate of TRM cell state, with leptomeningeal cells adopting a cytokine-poised TRM program, whereas brain TRM cells were transcriptionally restrained. Cells of the same clonotype spanned tissues yet adopted local transcriptional states. Viral specificity added another layer of TRM heterogeneity with GZMK/GZMA-expressing EBV-specific populations and interferon-stimulated gene signatures in SARS-CoV-2 and Influenza A-specific cells. The human CNS thus harbors regionally distinct CD8+ TRM shaped by common viral exposures.

immunology↗
bioRxiv2026

A regulatory T cell signature provides a shared molecular basis for the therapeutic window of opportunity in rheumatic disease

Rheumatic diseases, including rheumatoid arthritis (RA), spondyloarthritis (SpA) and osteoarthritis (OA), show distinct phenotypes yet respond to overlapping therapies, implicating shared immune mechanisms. In the Transimmunom cohort, we profiled peripheral blood from 240 individuals (47 healthy, 44 OA, 91 RA, 58 SpA) across deep immunophenotyping, immunoproteomics and Treg-Teff transcriptomics. Single-layer analyses revealed broader Treg than Teff remodeling, along with a shared pattern of reduced activated Tregs and expanded Helios+ Tregs across all diseases, alongside a decrease in functional Treg subpopulations, including CTLA4+ and CD45RA- Tregs. In RA specifically, LAG3+ Tregs were also expanded. Combining omics layers outperformed single-layer approaches for disease classification. Among individual layers, Treg transcriptomes were most discriminative, and integration uncovered disease-specific programs. Unsupervised clustering identified a cross-disease cluster independent of activity, treatment and age, mapping to early disease (<= years) and dominated by a Treg dysfunction-associated program. These results provide a biological rationale for the therapeutic "window of opportunity" concept and duration-stratified Treg-directed trials.

immunology↗
bioRxiv2026

Inhibitory Fc Receptor sets a time limit on macrophage response to IgG

Antibodies engage both activating Fc Receptors and the inhibitory receptor Fc{gamma}RIIB. Why macrophages need a dedicated inhibitory receptor rather than simply tuning activating receptor signaling is unclear. Using DNA-based chimeric receptors and in silico modeling, we independently controlled activating and inhibitory Fc Receptors. We found that Fc{gamma}RIIB imposed a time limit on macrophage phagocytosis and ERK signaling. The time limit is due to activating Fc Receptors converting PI(4,5)P2 to PI(3,4,5)P3, which is subsequently converted to PI(3,4)P2 by Fc{gamma}RIIB. This leads to a pulse of active signaling, which is sufficient for phagocytosis of small bacteria-sized targets but not phagocytosis of large targets and TNF secretion. Unlike engaging Fc{gamma}RIIB, reducing activating Fc Receptor signaling decreased initiation of phagocytosis, the speed of PI(3,4,5)P3 generation, and the amplitude of ERK signaling. Our results demonstrate that Fc{gamma}RIIB controls the duration of IgG signaling, while the activating Fc Receptors control sensitivity.

immunology↗