Project description:T cells specific for a certain antigen are a heterogeneous population characterized by cells expressing different T Cell Receptors (TCRs). As the TCR determines the avidity of a T cell clone for its cognate antigen, this feature has also a significant impact on the fate of such clone during antigenic challenge. In the context of chronic viral infection, T cells specific for the chronic virus differentiate into exhausted cells with limited functionality. We find that, in the process of exhaustion following infection with LCMV-Clone13, certain clones of CD8 T cells specific for the LCMV immunodominant epitope GP33 are enriched compared to others.
Project description:Altered CD8 T cell differentiation and functional exhaustion prevent control of chronic virus infection and cancer. Yet, how fate commitment and exhaustion are determined and dynamically modulated throughout persistent infection are unclear. We compared the activation and differentiation of LCMV GP33-specific CD8 TCR transgenic cells (P14) primed at the onset versus in the midst of established persistent LCMV-Clone 13 viral infection. LCMV GP33-specific CD8 TCR transgenic (P14) cells were injected into naïve mice immediately infected with LCMV-Cl13 (Early priming) or into mice that had been infected 21 days earlier with LCMV-Cl13 (Late Priming). Sixty hours post-priming P14 cells were sorted from mice and subjected to RNA seq. We show early primed cells very rapidly exhibit a transcriptional profile of robust activation, effector differentiation and dysfunction, while late primed cells have increased expression of genes involved in memory differentiation and maintenance.
Project description:During acute viral infections, naïve CD8+ T cells differentiate into effector CD8+ T cells and, after viral control, into memory CD8+ T cells. Memory CD8+ T cells are highly functional, proliferate rapidly upon reinfection and persist long-term without antigen. In contrast, during chronic infections, CD8+ T cells become “exhausted” and have poor effector function, express multiple inhibitory receptors, possess low proliferative capacity, and cannot persist without antigen. To compare the development of functional memory T cells with poorly functional exhausted T cells, we generated longitudinal transcriptional profiles for each. Naive CD44Lo CD8+ T cells were isolated and sorted from uninfected C57BL/6 mice and H2-Db GP33-specific CD8+ T cells were sorted using MHC-I tetramers at d6, 8, 15, and 30 p.i. with either LCMV Arm or LCMV clone 13. RNA from these CD8+ T cells was processed, amplified, labeled, and hybridized to Affymetrix GeneChip MoGene 1.0 st microarrays
Project description:Brd4 deficient and WT GP33-tetramer+ cells were sorted from spleens on D8 of LCMV infection. Tamoxifen was administered on days 5-7 of infection to induce to deletion of Brd4. KLRG1hiCD127lo TE, KLRG1loCD127lo EEC, and KLRG1loCD127hi MP cells were sorted for RNAseq analysis.
Project description:Chronic viral infection results in CD8 T cell exhaustion. Here, we use paired single-cell RNA sequencing (scRNA-seq) and single-cell T cell receptor sequencing (scTCR-seq) to investigate CD8 T cell phenotypic and clonal heterogeneity in multiple mice during the late stage of LCMV Clone 13 infection.
Project description:CD4 and CD8 T cells display functional defects during chronic infection such as loss of certain cytokines. Recent studies have suggested that CD4 T cells may actually gain other functions, however. Here, we analyzed gene expression profiles from LCMV-specific CD4 and CD8 T cells throughout the response to either acute LCMV or chronic LCMV infection. This alllowed us to identify CD4-specific changes during chronic infection compared to acute infection but also revealed shared core regulators between CD4 and CD8 T cells. LCMV-specific CD4 and CD8 T cells were isolated 6, 8, 15 and 30 days post infection with LCMV Armstrong or LCMV clone 13. Naïve CD4 and CD8 T cells were also isolated from naïve mice as comparisons. Four replicates of each sample were hybridized. The only exception is LCMV-specific CD4 T cells isolated 6 days post infection with LCMV-Arm where only three replicates were hybridized.
Project description:Chronic viruses and cancers thwart immune responses in humans by inducing T cell dysfunction. Using a murine chronic virus that models human infections, we investigated the function of the adhesion molecule, P-selectin glycoprotein ligand-1 (PSGL-1) that is upregulated on responding T cells. PSGL-1-deficient mice unexpectedly cleared the virus due to dramatic increases in the intrinsic survival of multifunctional effector T cells that had downregulated PD-1 and other inhibitory receptors. Notably, this response resulted in CD4+ T cell-dependent immunopathology. Mechanistically, PSGL-1 ligation on exhausted CD8+ T cells inhibited TCR and IL-2 signaling, and upregulated PD-1, leading to diminished survival with TCR stimulation. In models of malignant melanoma where T cell dysfunction occurs, PSGL-1-deficiency led to PD-1 downregulation, improved T cell responses, and tumor control. Thus, PSGL-1 plays a fundamental role in balancing viral control and immunopathology, and also functions as a checkpoint that regulates T cell responses in the tumor microenvironment. WT or PSGL-1 KO mice were infected with 2 x 10^6 PFU LCMV Clone 13. Spleens from 10 WT or 10 PSGL-1 KO animals were pooled and processed. CD8+ T cells were negatively enriched from WT or PSGL-1 KO spleens (EasySep Stemcell). Purified T cells were stained with propidium iodide (PI) for 10 minutes on ice, cells were washed. CD8+ T cells were stained with H2-Db-GP33-41 tetramers (NIH) and FACS sorted (BD FACS Aria). Sorted tetramer+ cells were PI negative and purity was >98%. Experiment was repeated twice to generate 2 WT (WT 1; WT 2) and 2 PSGL-1 KO (KO 1; KO 2) samples that represented 10 pooled spleens per sample.
Project description:Investigating the role of microRNAs (miRs) in CD8 T cells responding to acutely resolved or chronic viral infection identified miR-29a as a key regulator of Tcell exhaustion cells We used miRNA microarrays to understand the role in development of T cell exhaustion in setting of LCMV infection
Project description:Chronic viral infection disrupts memory B cell development. We used single cell ATAC sequencing (scATAC-seq) to analyze chromatin accessibility in antigen-specific B cells responding to acute versus chronic LCMV infection.