Long-lived memory CD8+ T cells are essential for the control of persistent viral infections. The mechanisms that preserve memory cells are poorly understood. Fate mapping of the transcriptional repressor GFI1 identified that GFI1 was differentially regulated in virus-specific CD8+ T cells and was selectively expressed in stem cell memory and central memory cells. Deletion of GFI1 led to reduced proliferation and progressive loss of memory T cells, which in turn resulted in failure to maintain antigen-specific CD8+ T cell populations following infection with chronic lymphocytic choriomeningitis virus or murine cytomegalovirus. Ablation of GFI1 resulted in downregulation of the transcription factors EOMES and BCL-2 in memory CD8+ T cells. Ectopic expression of EOMES rescued the expression of BCL-2, but the persistence of memory CD8+ T cells was only partially rescued. These findings highlight the critical role of GFI1 in the long-term maintenance of memory CD8+ T cells in persistent infections by sustaining their proliferative potential.
© 2025. Crown.

Stem-like CD8+ T cells are regulated by T cell factor 1 (TCF1) and are considered requisite for immune checkpoint blockade (ICB) response. However, recent findings indicate that reliance on TCF1+CD8+ T cells for ICB efficacy may differ across tumor contexts. We find that TCF1 is essential for optimal priming of tumor antigen-specific CD8+ T cells and ICB response in poorly immunogenic tumors that accumulate TOX+ dysfunctional T cells, but is dispensable for T cell priming and therapy response in highly immunogenic tumors that efficiently expand transitory effectors. Importantly, improving T cell priming by vaccination or by enhancing antigen presentation on tumors rescues the defective responses of TCF1-deficient CD8+ T cells upon ICB in poorly immunogenic tumors. Our study highlights TCF1's role during the early stages of anti-tumor CD8+ T cell responses with important implications for guiding optimal therapeutic interventions in cancers with low TCF1+CD8+ T cells and low-neo-antigen expression.
Copyright © 2023 Elsevier Inc. All rights reserved.

Alterations to organ biology caused by transplantation can have major impacts on the outcome. Tissue-resident lymphocytes normally maintain an organ's immunity and function and are transferred during transplantation. Here, we provide a detailed protocol for the isolation of leukocytes, including tissue-resident lymphocytes, from transplanted livers and hearts in mice. Phenotypic and functional analysis of conventional and unconventional T cells by flow cytometry is included. This protocol can also be used for the effective isolation of leukocytes from non-transplanted livers and hearts. For complete details on the use and execution of this protocol, please refer to Prosser et al. (2021).
© 2021 The Authors.

Hi-C is a genome-wide assay based on Chromosome Conformation Capture and high-throughput sequencing to decipher 3D chromatin organization in the nucleus. However, computational methods to detect functional interactions utilizing Hi-C data face challenges including the correction for various sources of biases and the identification of functional interactions with low counts of interacting fragments. We present Chrom-Lasso, a lasso linear regression model that removes complex biases assumption-free and identifies functional interacting loci with increased power by combining information of local reads distribution surrounding the area of interest. We showed that interacting regions identified by Chrom-Lasso are more enriched for 5C validated interactions and functional GWAS hits than that of GOTHiC and Fit-Hi-C. To further demonstrate the ability of Chrom-Lasso to detect interactions of functional importance, we performed time-series Hi-C and RNA-seq during T cell activation and exhaustion. We showed that the dynamic changes in gene expression and chromatin interactions identified by Chrom-Lasso were largely concordant with each other. Finally, we experimentally confirmed Chrom-Lasso's finding that Erbb3 was co-regulated with distinct neighboring genes at different states during T cell activation. Our results highlight Chrom-Lasso's utility in detecting weak functional interaction between cis-regulatory elements, such as promoters and enhancers.
© The Author(s) 2021. Published by Oxford University Press.

Inverse vaccines that tolerogenically target antigens to antigen-presenting cells (APCs) offer promise in prevention of immunity to allergens and protein drugs and treatment of autoimmunity. We have previously shown that targeting hepatic APCs through intravenous injection of synthetically glycosylated antigen leads to effective induction of antigen-specific immunological tolerance. Here, we demonstrate that targeting these glycoconjugates to lymph node (LN) APCs under homeostatic conditions leads to local and increased accumulation in the LNs compared to unmodified antigen and induces a tolerogenic state both locally and systemically. Subcutaneous administration directs the polymeric glycoconjugate to the draining LN, where the glycoconjugated antigen generates robust antigen-specific CD4+ and CD8+ T cell tolerance and hypo-responsiveness to antigenic challenge via a number of mechanisms, including clonal deletion, anergy of activated T cells, and expansion of regulatory T cells. Lag-3 up-regulation on CD4+ and CD8+ T cells represents an essential mechanism of suppression. Additionally, presentation of antigen released from the glycoconjugate to naïve T cells is mediated mainly by LN-resident CD8+ and CD11b+ dendritic cells. Thus, here we demonstrate that antigen targeting via synthetic glycosylation to impart affinity for APC scavenger receptors generates tolerance when LN dendritic cells are the cellular target.
Copyright © 2021 Maulloo, Cao, Watkins, Raczy, Solanki, Nguyen, Reda, Shim, Wilson, Swartz and Hubbell.