Project description:To further understand the chromatin accessibility changes between early and late CD8 T cell populations responding to acute and chronic infections we performed ATAC-seq on early Stem-like, effector and late Stem-like and effector populations.
Project description:The goal of this study was to identify the molecular programming using ATAC-seq of CD8 T cells responding to different viral infections. Mice were infected with either LCMV Armstrong to model an acute infection or LCMV Clone-13 to model a chronic infection. At various time points following infection, virus-specific CD8 T cells were purified and ATAC-seq performed. These data identify the changes in chromatin accessibility associated with acute infections and the establishment of functional memory versus those accessibility changes associated with chronic infection.
Project description:In response to acute infection, naive CD8+ T cells expand, differentiate into effector cells and then contract to a long-lived pool of memory cells after pathogen clearance. During chronic infections or in tumors, CD8+ T cells acquire an “exhausted” phenotype. Here we present genome-wide comparisons of chromatin accessibility and gene expression from endogenous CD8+ T cells responding to acute and chronic viral infection using ATAC-seq and RNA-seq. Acquisition of effector, memory or exhausted phenotypes was associated with stable changes in chromatin accessibility away from the naive T cell state. Regions differentially accessible between functional subsets in vivo were enriched for binding sites of transcription factors known to regulate these subsets, including E2A, BATF, IRF4, T-bet and TCF1. Exhaustion-specific accessible regions were enriched for consensus binding sites for NFAT and Nr4a family members, indicating that chronic stimulation confers a unique accessibility profile on exhausted cells.
Project description:Understanding the response of memory CD8 T cells to persistent antigen re-stimulation and the role of CD4 T cell help is critical to the design of successful vaccines for chronic diseases. However, studies comparing the protective abilities and qualities of memory and naïve cells have been mostly performed in acute infections, and little is known about their roles during chronic infections. Herein, we show that memory cells dominate over naïve cells and are protective when present in large enough numbers to quickly reduce infection. In contrast, when infection is not rapidly reduced, memory cells are quickly lost, unlike naïve cells. This loss of memory cells is due to (i) an early block in cell proliferation, (ii) selective regulation by the inhibitory receptor 2B4, and (iii) increased reliance on CD4 T cell help. These findings have important implications towards the design of T cell vaccines against chronic infections and tumors. 16 samples are analyzed: 3 replicates of secondary effector CD8 P14 T cells at day 8 post-acute lymphocytic choriomeningitis virus (LCMV) infection; 4 replicates of secondary effector CD8 P14 T cells at day 8 post-chronic LCMV infection; 4 replicates of primary effector CD8 P14 T cells at day 8 post-acute LCMV infection; and 5 replicates of primary effector CD8 P14 T cells at day 8 post-chronic LCMV infection.
Project description:We have discovered a small subpopulation of virus-specific CD8 T-cells that sustains the T-cell response in chronic infections. These cells are defined by - and depend on - the expression of the transcription factor Tcf1 (T cell factor 1) and show key characteristics of central memory cells while lacking an effector signature. Unlike conventional memory cells, Tcf1+ T-cells display hallmarks of an âexhaustedâ phenotype, including the expression of certain inhibitory receptors. Naive Tcf1-GFP+ P14 cells (Naive) were transferred into Vb5 recipient mice (CD45.1) prior to infection with LCMV clone 13 (c13). Tcf1-GFP+ P14 cells (chronic Tcf1+) and Tcf1-GFP- P14 cells (chronic Tcf1-) were flow sorted on day 28 post infection. Naive Tcf1-GFP+ P14 cells (Naive) were also transferred into C57BL/6 hosts (CD45.1.2) prior to infection with LCMV Armstrong (Arm). Tcf1-GFP+ P14 cells (memory Tcf1+) and Tcf1-GFP- P14 cells (memory Tcf1-) were flow sorted on day 28 post infection. Total RNA was extracted, cDNA libraries prepared and sequencing was performed using Illumina HiSeq 2500 technology.
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:We have discovered a small subpopulation of virus-specific CD8 T-cells that sustains the T-cell response in chronic infections. These cells are defined by - and depend on - the expression of the transcription factor Tcf1 (T cell factor 1) and show key characteristics of central memory cells while lacking an effector signature. Unlike conventional memory cells, Tcf1+ T-cells display hallmarks of an “exhausted” phenotype, including the expression of certain inhibitory receptors.
Project description:Understanding the response of memory CD8 T cells to persistent antigen re-stimulation and the role of CD4 T cell help is critical to the design of successful vaccines for chronic diseases. However, studies comparing the protective abilities and qualities of memory and naïve cells have been mostly performed in acute infections, and little is known about their roles during chronic infections. Herein, we show that memory cells dominate over naïve cells and are protective when present in large enough numbers to quickly reduce infection. In contrast, when infection is not rapidly reduced, memory cells are quickly lost, unlike naïve cells. This loss of memory cells is due to (i) an early block in cell proliferation, (ii) selective regulation by the inhibitory receptor 2B4, and (iii) increased reliance on CD4 T cell help. These findings have important implications towards the design of T cell vaccines against chronic infections and tumors.
Project description:Recent implication of microRNAs (miRNAs) in the intricate cross-talk between the host and the pathogen in viral infections reveals a new layer of mechanism for host-virus interactions. In the present study, we investigated human miRNAs which may be involved in the acute and chronic HBV infections via microarray profiling. We determined the global miRNA expression profiles elicited in the uninfected control model (HepG2), the acute infection model (HepG2 transfected with a 1.3 full-length HBV genome) and the chronic infection model (HepG2.2.15) using CapitalBio corporation’s mammalian miRNA arrays. Three cellular models were used in this study: the human hepatoblastoma cell line HepG2 as a blank control representing the condition without virus infection; HepG2 transfected with a 1.3 full-length HBV genome as an acute infection model; and HepG2.2.15, a well-established cell line derived from HepG2 transfected with a full-length HBV genome and constitutively expressing HBV, as a chronic infection model.
Project description:Stem-like CD8 T cells maintain long-term antiviral CD8 immunity during chronic infection, and share regulatory pathways with memory precursor effector cells generated after acute infection. However, it is unclear whether stem-like CD8 T cells require distinct transcriptional and epigenetic regulation for their longevity and adaptation to the immunosuppressive environment in chronic infection. Here, our comparison of single-cell transcriptomes and epigenetic profiles of CD8 T cells responding to acute and chronic viral infections revealed that stem-like CD8 T cells became distinct from memory precursors before clonal expansion ended. We found that a coexpression gene module containing Tox exhibited higher transcriptional activities and active histone marks in stem-like T cells than memory precursors. Moreover, TOX promoted persistence of antiviral CD8 T cells, and was required for stem-like CD8 differentiation. Our results indicate that stem-like CD8 T cells require unique transcriptional and epigenetic programs for their differentiation and persistence during chronic viral infection.