Project description:During a T cell response, naïve CD8 T cells differentiate into effector cells. Subsequently, a subset of effector cells termed memory precursor effector cells (MPECs) further differentiates into functionally mature memory CD8 T cells. The transcriptional network underlying this carefully scripted process is not well understood. Here, we report that the transcription factor FoxO1 plays an integral role in facilitating effector to memory transition and functional maturation of memory CD4 and CD8 T cells. We find that FoxO1 is not required for differentiation of effector cells, but in the absence of FoxO1, memory CD8 T cells displayed features of scenescence and progressive attrition in polyfunctionality, which in turn led to impared recall responses and poor protective immunity. These data suggest that FoxO1 is essential for active maintenance of functional CD8 T cell memory and protective immunity. Under competing conditions in bone marrow Single-cell suspensions from splenocytes of eight samples WT (control) and FoxO1-/- (experimental) LCMV-immune mice were prepared using standard procedures. CD8 T cells were then isoloated using Thy1.2 (CD90.2) (30-H12) microbeads (Miltenyi Biotec). Cells were then stained with anti-CD8, anti-CD44 and Db/NP396 MHC class I tetramer. Activated (CD8+CD44hi), naive (CD8+CD44lo), and virus-specific CD8 T cells were sorted using FACSAria II instrument (BD Biosciences). The purity of the cells was >95%. Total RNA was extracted from the sorted cells by Trizol Reagent. RNA samples were reverse transcribed and Cy3-labeled cDNAs were hyrbidized to Agilent whole Mouse Genome Oligo Microarrays. Fluorscence signals were detected using Agilent's Microarray Scanner system, data was analyzed using the Rosetta Resolver gene expression data analysis system and genes with a fold change < and p-values <0.01 were identified. Microarray data discussed in the paper is focused on virus-specific memory CD8 T cells from samples WT_Tet_2 vs KO_Tet_2.
Project description:During a T cell response, naïve CD8 T cells differentiate into effector cells. Subsequently, a subset of effector cells termed memory precursor effector cells (MPECs) further differentiates into functionally mature memory CD8 T cells. The transcriptional network underlying this carefully scripted process is not well understood. Here, we report that the transcription factor FoxO1 plays an integral role in facilitating effector to memory transition and functional maturation of memory CD4 and CD8 T cells. We find that FoxO1 is not required for differentiation of effector cells, but in the absence of FoxO1, memory CD8 T cells displayed features of scenescence and progressive attrition in polyfunctionality, which in turn led to impared recall responses and poor protective immunity. These data suggest that FoxO1 is essential for active maintenance of functional CD8 T cell memory and protective immunity. Under competing conditions in bone marrow
Project description:Memory T cells provide immunity against pathogen reinvasion, but mechanisms of their long-term maintenance is unclear. Here we show that mice with the deletion of the transcription factor Foxo1 in activated CD8+ T cells had defective secondary but not primary responses to Listeria monocytogenes infection. Compared to short-lived effector T cells, memory precursor effector T cells expressed higher amounts of Foxo1 that promoted their generation and maintenance. Gene expression profiling and chromatin immunoprecipitation sequencing experiments revealed the chemokine receptor CCR7 and the transcription factor TCF1 as novel Foxo1-bound target genes with critical functions in memory T cell trafficking and transcriptional regulation. These findings demonstrate that Foxo1 is selectively incorporated into the genetic program that regulates memory but not effector CD8+ T cell responses to infection. CD8+ T cells were isolated from wild-type or Foxo1tagBirA mice in which Foxo1 is endogenously biotinylated. Foxo1 binding targets in CD8+ cells were identified by using Foxo1 antibody- and Streptavidin- ChIP-Seq approaches.
Project description:Memory T cells provide immunity against pathogen reinvasion, but mechanisms of their long-term maintenance is unclear. Here we show that mice with the deletion of the transcription factor Foxo1 in activated CD8+ T cells had defective secondary but not primary responses to Listeria monocytogenes infection. Compared to short-lived effector T cells, memory precursor effector T cells expressed higher amounts of Foxo1 that promoted their generation and maintenance. Gene expression profiling and chromatin immunoprecipitation sequencing experiments revealed the chemokine receptor CCR7 and the transcription factor TCF1 as novel Foxo1-bound target genes with critical functions in memory T cell trafficking and transcriptional regulation. These findings demonstrate that Foxo1 is selectively incorporated into the genetic program that regulates memory but not effector CD8+ T cell responses to infection. Wild-type and GzmB-cre Foxo1fl/fl CD27hiKLRG1lo OT-I T cells were isolated by FACS sorting at 7 days post LM-OVA infection. RNA was prepared with the miRNeasy kit according to the manufacturer’s instructions (Qiagen). RNA amplification, labeling and hybridization to Mouse 430 2.0 Array chips (Affymetrix) were carried out at the Genomics Core Facility of Memorial Sloan-Kettering Cancer Center.
Project description:Memory T cells provide immunity against pathogen reinvasion, but mechanisms of their long-term maintenance is unclear. Here we show that mice with the deletion of the transcription factor Foxo1 in activated CD8+ T cells had defective secondary but not primary responses to Listeria monocytogenes infection. Compared to short-lived effector T cells, memory precursor effector T cells expressed higher amounts of Foxo1 that promoted their generation and maintenance. Gene expression profiling and chromatin immunoprecipitation sequencing experiments revealed the chemokine receptor CCR7 and the transcription factor TCF1 as novel Foxo1-bound target genes with critical functions in memory T cell trafficking and transcriptional regulation. These findings demonstrate that Foxo1 is selectively incorporated into the genetic program that regulates memory but not effector CD8+ T cell responses to infection.
Project description:Memory T cells provide immunity against pathogen reinvasion, but mechanisms of their long-term maintenance is unclear. Here we show that mice with the deletion of the transcription factor Foxo1 in activated CD8+ T cells had defective secondary but not primary responses to Listeria monocytogenes infection. Compared to short-lived effector T cells, memory precursor effector T cells expressed higher amounts of Foxo1 that promoted their generation and maintenance. Gene expression profiling and chromatin immunoprecipitation sequencing experiments revealed the chemokine receptor CCR7 and the transcription factor TCF1 as novel Foxo1-bound target genes with critical functions in memory T cell trafficking and transcriptional regulation. These findings demonstrate that Foxo1 is selectively incorporated into the genetic program that regulates memory but not effector CD8+ T cell responses to infection.
Project description:The forkhead O transcription factors (FOXO) integrate a range of extracellular signals including growth factor signaling, inflammation, oxidative stress and nutrient availability, to substantially alter the program of gene expression and modulate cell survival, cell cycle progression, and many cell-type specific responses yet to be unraveled. Naive antigen-specific CD8+ T cells undergo a rapid expansion and arming of effector function within days of pathogen exposure, but in addition, by the peak of expansion, they form precursors to memory T cells capable of self-renewal and indefinite survival. We used microarrays to determine whether FOXO1 broadly affects effector and memory differentiation, and to what extent FOXO1 determines the program of memory T cell gene expression. To obtain an unbiased analysis of genes differentially expressed in antigen-specific Foxo1-/- CD8+ T cells responding to infection, we obtained RNA and performed Affymetrix microarray analysis from KLRG1low and KLRG1high FACS-sorted congenically-marked WT and Foxo1-/- P14 cells obtained from mixed transfers, eight days post-infection with LCMV-Armstrong. We carried out gene deletion in Rosa26Cre-ERT2 Foxo1f/f (Foxo1-/-) P14 mice just prior to adoptive transfer (Kerdiles et al., 2009), and transfer equal numbers of P14 cells from the spleens of KO (Foxo1-/- P14) and WT P14 mice. Day8 post infection
Project description:Immune memory cells are poised to rapidly expand and elaborate effector functions upon reinfection. However, despite heightened readiness to respond, memory cells exist in a functionally quiescent state. The paradigm is that memory cells remain inactive due to lack of TCR stimuli. Here we report a unique role of Tregs in orchestrating memory quiescence by inhibiting effector and proliferation programs through CTLA-4. Loss of Tregs resulted in activation of genome-wide transcriptional programs characteristic of potent effectors, and both developing and established memory quickly reverted to a terminally differentiated (KLRG-1hi/IL-7R±lo/GzmBhi) phenotype, with compromised metabolic fitness, longevity, polyfunctionality and protective efficacy. CTLA-4, an inhibitory receptor overexpressed on Tregs, functionally replaced Tregs in trans to rescue Treg-less memory defects and restore homeostasis of secondary mediators as well. These studies present CD28-CTLA-4-CD80/CD86 axis as a novel target to potentially accelerate vaccine-induced immunity and improve T-cell memory quality in current cancer immunotherapies proposing transient Treg-depletion. We used microarray analysis to detail the global programming of gene expression in LCMV GP33-specific CD8 T cells differentiated in the presence or absence of regulatory T cells Differentiation of memory CD8 T cells entails a progressive transition of highly activated effector program to a quiescent memory program. A key question in the field is to understand the factors that aid in the differentiation of memory cells from effector cells. It is a generally accepted paradigm that effector cells transition to a memory state by default after antigen clearance, since TCR stimuli is the key driver of effector programs in CD8 T cells. We hypothesized that the effector to memory transition of CD8 T cells involves active immunological brakes through regulatory T cells (Tregs) that allow the highly activated effector cells to convert into quiescent memory cells. To address this hypothesis, we used FoxP3-DTR mice to deplete Tregs during the window following antigen clearance, during which the effector CD8 T cells convert to long-lived memory cells. To get a deeper understanding of the global transcriptome of CD8 T cells as they transition from an effector to a memory state, we isolated and arrayed the antigen-specific CD8 T cells at day 16 post-infection that have experienced the transitional environment with and without the presence of Tregs.