RNA-Seq of CD8+ T cell subsets during LCMV infection III
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ABSTRACT: Memory CD8 T lymphocytes are a long-lived population of immune cells that provide formidable protection against infections and malignancy, and are thus often central to vaccine and cancer immunotherapy efficacy. Here we refine the identity, developmental relationships, and functional roles of memory CD8 T cells through delineation of a descrete population that confers robust protection against reinfection and exhibits an unexpected molecular program bearing typically divergent characteristics of short-lived effector cells and long-lived memory T cells. Mass-cytometry and single-cell RNA sequencing analyses revealed an analogous population of cells in humans. These findings hold broad implications for both informing immunotherapy treatments and predicting their efficacy.
Project description:CD8+ T cells play a crucial role in the clearance of intracellular pathogens through the generation of cytotoxic effector cells that eliminate infected cells and long-lived memory cells that provide enhanced protection against reinfection. We have previously shown that the inhibitor of E protein transcription factors, Id2, is necessary for accumulation of effector and memory CD8+ T cells during infection. Here we show that CD8+ T cells lacking Id2 did not generate a robust terminally-differentiated KLRG1hi effector population, but displayed a cell-surface phenotype and cytokine profile consistent with memory precursors, raising the question as to whether loss of Id2 impairs the differentiation and/or survival of effector-memory cells. We found that deletion of Bim rescued Id2-deficient CD8+ cell survival during infection. However, the dramatic reduction in KLRG1hi cells caused by loss of Id2 remained in the absence of Bim, such that Id2/Bim double-deficient cells form an exclusively KLRG1loCD127hi memory precursor population. Thus we describe a role for Id2 in both the survival and differentation of normal CD8+ effector and memory populations. Gene-expression analysis of Wild-type, Id2KO, Id2KOBimKO and BimKO effector CD8+ cells on day 6 of Listeria infection. 2 or more replicates per sample were analyzed.
Project description:During acute infections, CD8+ T cells form various memory subpopulations to provide long-lasting protection against reinfection. Central memory (TCM), Effector memory (TEM), and long-lived effector (LLE) cells are circulating memory populations with distinct plasticity, migration patterns, and effector functions. Tissue-resident memory (TRM) cells permanently reside in the frontline sites of pathogen entry and provide tissue-specific protection upon reinfection. Here, using scRNA-seq and bulk RNA-seq, we examined the different and shared transcriptomes and regulators of TRMs with other circulating memory populations. Furthermore, we identified heterogeneity within the TRM pool from small intestine and novel transcriptional regulators that may control the phenotypic and functional heterogeneity of TRM cells during acute infection. Our findings provide a resource for future studies to identify novel pathways for enhancing vaccination and immunotherapeutic approaches.
Project description:During acute infections, CD8+ T cells form various memory subpopulations to provide long-lasting protection against reinfection. Central memory (TCM), Effector memory (TEM), and long-lived effector (LLE) cells are circulating memory populations with distinct plasticity, migration patterns, and effector functions. Tissue-resident memory (TRM) cells permanently reside in the frontline sites of pathogen entry and provide tissue-specific protection upon reinfection. Here, using scRNA-seq and bulk RNA-seq, we examined the different and shared transcriptomes and regulators of TRMs with other circulating memory populations. Furthermore, we identified heterogeneity within the TRM pool from small intestine and novel transcriptional regulators that may control the phenotypic and functional heterogeneity of TRM cells during acute infection. Our findings provide a resource for future studies to identify novel pathways for enhancing vaccination and immunotherapeutic approaches.
Project description:CD8+ T cells play a crucial role in the clearance of intracellular pathogens through the generation of cytotoxic effector cells that eliminate infected cells and long-lived memory cells that provide enhanced protection against reinfection. We have previously shown that the inhibitor of E protein transcription factors, Id2, is necessary for accumulation of effector and memory CD8+ T cells during infection. Here we show that CD8+ T cells lacking Id2 did not generate a robust terminally-differentiated KLRG1hi effector population, but displayed a cell-surface phenotype and cytokine profile consistent with memory precursors, raising the question as to whether loss of Id2 impairs the differentiation and/or survival of effector-memory cells. We found that deletion of Bim rescued Id2-deficient CD8+ cell survival during infection. However, the dramatic reduction in KLRG1hi cells caused by loss of Id2 remained in the absence of Bim, such that Id2/Bim double-deficient cells form an exclusively KLRG1loCD127hi memory precursor population. Thus we describe a role for Id2 in both the survival and differentation of normal CD8+ effector and memory populations.
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.
Project description:The success of the CD8 T cell-mediated immune response against infections and tumors depends on the formation of a long-lived memory pool, and the protection of effector cells from exhaustion. The advent of checkpoint blockade therapy has significantly improved anti-tumor therapeutic outcomes by reversing CD8 T cell exhaustion, but fails to generate effector cells with memory potential. Here, using in vivo mouse models, we show that let-7 microRNAs determine CD8 T cell fate, where maintenance of let-7 expression during early cell activation results in memory CD8 T cell formation and tumor clearance. Conversely, let-7-deficiency promotes the generation of a terminal effector population that becomes vulnerable to exhaustion and cell death in immunosuppressive environments and fails to reject tumors. Mechanistically, let-7 restrains metabolic changes that occur during T cell activation through the inhibition of the PI3K/AKT/mTOR signaling pathway and production of reactive oxygen species, potent drivers of terminal differentiation and exhaustion. Thus, our results reveal a role for let-7 in the time-sensitive support of memory formation and the protection of effector cells from exhaustion. Overall, our data may suggest a strategy in developing next-generation immunotherapies by preserving the multipotency of effector cells rather than enhancing the efficacy of differentiation.
Project description:CD8 effector T cells with a CD127hi KLRG1- phenotype are considered precursors to the long-lived memory pool, while KLRG1+ CD127low cells are viewed as short-lived effectors. Nevertheless, we and others have shown that a KLRG1+ CD127low population persists into the memory phase and that these T cells (termed long-lived effector cells or LLEC) display robust protective function during acute re-challenge with bacteria or viruses. Whether these T cells represent a true memory population or are instead a remnant effector cell population that failed to undergo initial contraction has remained unclear. Here, we show that LLEC from mice express a distinct phenotypic and transcriptional signature that shares characteristics of both early effectors and long-lived memory cells. Furthermore, we find that LLEC are exclusively derived from day 12 KLRG1+ effector cells. Our work challenges the concept that the KLRG1+ CD127low population is dominated by short-lived cells and shows that KLRG1 downregulation is not a prerequisite to become a long-lived protective memory T cell.
Project description:Cytotoxic T cells are typically expanded ex vivo for adoptive immunotherapy by culture with IL-2. This culture period leads to a differentiated phenotype and acquisition of effector function, as well as a loss of in vivo proliferative capability and anti-tumor efficacy. Here, we report antigen-specific and polyclonal expansion of cytotoxic T cells in a cocktail of cytokines and small molecules that leads to a memory-like phenotype in mouse and human cells even during extended culture, leading to enhanced in vivo expansion and tumor control. OT-I CD8 T cells were cultured for 14 days in either IL-2 or a cocktail of memory inducing small molecules and cytokines (IL-7, IL-21, 2-deoxyglucose and TWS119). Populations were sorted, IL-2 cells were CD44+CD62L-, cocktail cells were sorted into CD44+CD62L-, CD44+CD62L+ and CD44lowCD62L+ populations, and naive OT-I cells were CD44-CD62L+. Total RNA was extracted from each population and prepared for sequencing as three technical replicates.
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