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CD8 + T cells are critical mediators of cytotoxic effector function in infection, cancer and autoimmunity. In cancer and chronic viral infection, CD8 + T cells undergo a progressive loss of cytokine production and cytotoxicity, a state termed T cell exhaustion. In autoimmunity, autoreactive CD8 + T cells retain the capacity to effectively mediate the destruction of host tissues. Although the clinical outcome differs in each context, CD8 + T cells are chronically exposed to antigen in all three. These chronically stimulated CD8 + T cells share some common phenotypic features, as well as transcriptional and epigenetic programming, across disease contexts. A better understanding of these CD8 + T cell states may reveal novel strategies to augment clearance of chronic viral infection and cancer and to mitigate self-reactivity leading to tissue damage in autoimmunity. Sharpe and colleagues review salient aspects of CD8 + T cell dysfunction in cancer, chronic viral infections and autoimmunity, with a view of developing new ways to alleviate T cell exhaustion and enhance CD8 + T cell functions in cancer and chronic viral infection, as well as strategies to induce or augment exhaustion-like features to treat autoimmunity.

In modern industrial environments, camera-based monitoring is essential for workflow optimization, safety, and process control, yet it raises significant privacy concerns when people are recorded. Realistic full-body anonymization offers a potential solution by obscuring visual identity while preserving information needed for automated analysis. Whether such methods also conceal biometric traits from human pose and gait remains uncertain, although these biomarkers enable person identification without appearance cues. This study investigates the impact of full-body anonymization on gait-related identity recognition using DeepPrivacy2 and a custom CCTV-like industrial dataset comprising original and anonymized sequences. This study provides the first systematic evaluation of whether pose-preserving anonymization disrupts identity-relevant gait characteristics. The analysis quantifies keypoint shifts introduced by anonymization, examines their influence on downstream gait-based person identification, and tests cross-domain linkability between original and anonymized recordings. Identification accuracy, domain transfer between data types, and distortions in derived pose keypoints are measured to assess anonymization effects while retaining operational utility. Findings show that anonymization removes appearance but leaves gait identity largely intact, indicating that pose-driven anonymization is insufficient for privacy protection. Effective privacy requires anonymization strategies that explicitly target gait characteristics or incorporate domain-adaptation mechanisms.

T cell dysfunction is a hallmark of many cancers, but the basis for T cell dysfunction and the mechanisms by which antibody blockade of the inhibitory receptor PD-1 (anti-PD-1) reinvigorates T cells are not fully understood. Here we show that such therapy acts on a specific subpopulation of exhausted CD8 + tumor-infiltrating lymphocytes (TILs). Dysfunctional CD8 + TILs possess canonical epigenetic and transcriptional features of exhaustion that mirror those seen in chronic viral infection. Exhausted CD8 + TILs include a subpopulation of ‘progenitor exhausted’ cells that retain polyfunctionality, persist long term and differentiate into ‘terminally exhausted’ TILs. Consequently, progenitor exhausted CD8 + TILs are better able to control tumor growth than are terminally exhausted T cells. Progenitor exhausted TILs can respond to anti-PD-1 therapy, but terminally exhausted TILs cannot. Patients with melanoma who have a higher percentage of progenitor exhausted cells experience a longer duration of response to checkpoint-blockade therapy. Thus, approaches to expand the population of progenitor exhausted CD8 + T cells might be an important component of improving the response to checkpoint blockade. Exhausted cytotoxic T lymphocytes (CTLs) express the receptor PD-1 as a key signature. Haining and colleagues show that there are different ‘depths’ of exhaustion with a subset of exhausted CTLs that retain polyfunctionality and are responsive to PD-1 blockade.

T cell exhaustion is an induced state of dysfunction that arises in response to chronic infection and cancer. Exhausted CD8 + T cells acquire a distinct epigenetic state, but it is not known whether that chromatin landscape is fixed or plastic following the resolution of a chronic infection. Here we show that the epigenetic state of exhaustion is largely irreversible, even after curative therapy. Analysis of chromatin accessibility in HCV- and HIV-specific responses identifies a core epigenetic program of exhaustion in CD8 + T cells, which undergoes only limited remodeling before and after resolution of infection. Moreover, canonical features of exhaustion, including super-enhancers near the genes TOX and HIF1A , remain ‘epigenetically scarred.’ T cell exhaustion is therefore a conserved epigenetic state that becomes fixed and persists independent of chronic antigen stimulation and inflammation. Therapeutic efforts to reverse T cell exhaustion may require new approaches that increase the epigenetic plasticity of exhausted T cells. The degree of plasticity in the epigenetic landscape of exhausted T cells has been unclear. Sen and colleagues find that exhausted CD8 + T cells demonstrate a stable core epigenetic exhaustion signature that persists independent of inflammation or viral antigen.

Immunotherapy with PD-1 checkpoint blockade is effective in only a minority of patients with cancer, suggesting that additional treatment strategies are needed. Here we use a pooled in vivo genetic screening approach using CRISPR–Cas9 genome editing in transplantable tumours in mice treated with immunotherapy to discover previously undescribed immunotherapy targets. We tested 2,368 genes expressed by melanoma cells to identify those that synergize with or cause resistance to checkpoint blockade. We recovered the known immune evasion molecules PD-L1 and CD47, and confirmed that defects in interferon-γ signalling caused resistance to immunotherapy. Tumours were sensitized to immunotherapy by deletion of genes involved in several diverse pathways, including NF-κB signalling, antigen presentation and the unfolded protein response. In addition, deletion of the protein tyrosine phosphatase PTPN2 in tumour cells increased the efficacy of immunotherapy by enhancing interferon-γ-mediated effects on antigen presentation and growth suppression. In vivo genetic screens in tumour models can identify new immunotherapy targets in unanticipated pathways. In vivo CRISPR screening reveals that loss of Ptpn2 increases the response of tumour cells to immunotherapy and increases IFNγ signalling, suggesting that PTPN2 inhibition may potentiate the effect of immunotherapies that invoke an IFNγ response. Ptpn2 deletion enhances tumour suppression Cancer immunotherapy treatments, such as PD-1 checkpoint blockade, are only effective in a minority of patients, suggesting the need to investigate new treatment strategies. Nicholas Haining and colleagues describe a functional genomics approach using the CRISPR–Cas9 system to identify genes that affect the response to immune checkpoint blockade in the B16 mouse transplantable tumour model. They show that loss of function of the phosphatase PTPN2 in tumour cells enhances interferon-γ-mediated effects on antigen presentation and growth suppression. This finding suggests that PTPN2 is a potential target for cancer immunotherapy and that in vivo genetic screenings of tumour models could help identify other possible targets.

The etiology and effect of age-related immune dysfunction in cancer is not completely understood. Here we show that limited priming of CD8 + T cells in the aged tumor microenvironment (TME) outweighs cell-intrinsic defects in limiting tumor control. Increased tumor growth in aging is associated with reduced CD8 + T cell infiltration and function. Transfer of T cells from young mice does not restore tumor control in aged mice owing to rapid induction of T cell dysfunction. Cell-extrinsic signals in the aged TME drive a tumor-infiltrating age-associated dysfunctional (T TAD ) cell state that is functionally, transcriptionally and epigenetically distinct from canonical T cell exhaustion. Altered natural killer cell–dendritic cell–CD8 + T cell cross-talk in aged tumors impairs T cell priming by conventional type 1 dendritic cells and promotes T TAD cell formation. Aged mice are thereby unable to benefit from therapeutic tumor vaccination. Critically, myeloid-targeted therapy to reinvigorate conventional type 1 dendritic cells can improve tumor control and restore CD8 + T cell immunity in aging. Cancer and aging are associated with each other, but underlying mechanisms contributing to this correlation are unclear. Here the authors identify a dysfunctional T cell state that is distinct from typical T cell exhaustion and only occurs in the tumor microenvironment during later life.

Therapies that target the function of immune cells have significant clinical efficacy in diseases such as cancer and autoimmunity. Although functional genomics has accelerated therapeutic target discovery in cancer, its use in primary immune cells is limited because vector delivery is inefficient and can perturb cell states. Here we describe CHIME: CHimeric IMmune Editing, a CRISPR-Cas9 bone marrow delivery system to rapidly evaluate gene function in innate and adaptive immune cells in vivo without ex vivo manipulation of these mature lineages. This approach enables efficient deletion of genes of interest in major immune lineages without altering their development or function. We use this approach to perform an in vivo pooled genetic screen and identify Ptpn2 as a negative regulator of CD8 + T cell-mediated responses to LCMV Clone 13 viral infection. These findings indicate that this genetic platform can enable rapid target discovery through pooled screening in immune cells in vivo. The use of functional genomics in primary immune cells has been limited by inefficient vector delivery and risk of perturbing cell states. Here the authors present CHimeric IMmune Editing (CHIME) for in vivo evaluation of gene function and pooled screening approaches.

Cell survival and normal cell function require a highly coordinated and precise regulation of basal cytosolic Ca2+ concentrations. The primary source of Ca2+ entry into the cell is mediated by the Ca2+ release-activated Ca2+ (CRAC) channel. Its action is stimulated in response to internal Ca2+ store depletion. The fundamental constituents of CRAC channels are the Ca2+ sensor, stromal interaction molecule 1 (STIM1) anchored in the endoplasmic reticulum, and a highly Ca2+-selective pore-forming subunit Orai1 in the plasma membrane. The precise nature of the Orai1 pore opening is currently a topic of intensive research. This review describes how Orai1 gating checkpoints in the middle and cytosolic extended transmembrane regions act together in a concerted manner to ensure an opening-permissive Orai1 channel conformation. In this context, we highlight the effects of the currently known multitude of Orai1 mutations, which led to the identification of a series of gating checkpoints and the determination of their role in diverse steps of the Orai1 activation cascade. The synergistic action of these gating checkpoints maintains an intact pore geometry, settles STIM1 coupling, and governs pore opening. We describe the current knowledge on Orai1 channel gating mechanisms and summarize still open questions of the STIM1–Orai1 machinery.

Genetically removing PKM-ζ in mice has no effect on memory, and despite absence of this kinase, the original peptide inhibitor of PKM-ζ still disrupts memory in these mutant mice; these data re-open the exploration for key molecules regulating maintenance of long-term plasticity processes. Rethink on memory mechanisms Long-term potentiation (LTP), a persistent enhancement of signalling between nerve cells, has long been considered the likely cellular correlate of memory, but only now are the specific molecular mechanisms underlying the maintenance of LTP beginning to emerge. Some time ago, it was proposed that sustained activity of protein kinase M-ζ (PKM-ζ) may be a key factor in sustaining LTP, based mainly on experiments using pharmacological inhibitors. Two groups have now engineered mice lacking PKM-ζ to test more directly for its role in LTP and memory. Studies from the labs of Richard Huganir and Robert Messing find that loss of PKM-ζ has no effect on LTP or memory formation. And despite the absence of this kinase, pharmacological inhibitors of PKM-ζ still disrupt memory in these mutant mice. These data cast doubt on the role of PKM-ζ in LTP maintenance and re-open the exploration for key molecules regulating long-term plasticity. Protein kinase M-ζ (PKM-ζ) is a constitutively active form of atypical protein kinase C that is exclusively expressed in the brain and implicated in the maintenance of long-term memory 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . Most studies that support a role for PKM-ζ in memory maintenance have used pharmacological PKM-ζ inhibitors such as the myristoylated zeta inhibitory peptide (ZIP) or chelerythrine. Here we use a genetic approach and target exon 9 of the Prkcz gene to generate mice that lack both protein kinase C-ζ (PKC-ζ) and PKM-ζ ( Prkcz −/− mice). Prkcz −/− mice showed normal behaviour in a cage environment and in baseline tests of motor function and sensory perception, but displayed reduced anxiety-like behaviour. Notably, Prkcz −/− mice did not show deficits in learning or memory in tests of cued fear conditioning, novel object recognition, object location recognition, conditioned place preference for cocaine, or motor learning, when compared with wild-type littermates. ZIP injection into the nucleus accumbens reduced expression of cocaine-conditioned place preference in Prkcz −/− mice. In vitro , ZIP and scrambled ZIP inhibited PKM-ζ, PKC-ι and PKC-ζ with similar inhibition constant ( K i ) values. Chelerythrine was a weak inhibitor of PKM-ζ ( K i = 76 μM). Our findings show that absence of PKM-ζ does not impair learning and memory in mice, and that ZIP can erase reward memory even when PKM-ζ is not present.