UNASSIGNED: CD8+ cytotoxic T lymphocytes (CTLs) are highly effective in defending against viral infections and tumours. They are activated through the recognition of peptide-MHC-I complex by the T-cell receptor (TCR) and co-stimulation. This cognate interaction promotes the organisation of intimate cell-cell connections that involve cytoskeleton rearrangement to enable effector function and clearance of the target cell. This is key for the asymmetric transport and mobilisation of lytic granules to the cell-cell contact, promoting directed secretion of lytic mediators such as granzymes and perforin. Mitochondria play a role in regulating CTL function by controlling processes such as calcium flux, providing the necessary energy through oxidative phosphorylation, and its own protein translation on 70S ribosomes. However, the effect of acute inhibition of cytosolic translation in the rapid response after TCR has not been studied in mature CTLs.
UNASSIGNED: Here, we investigated the importance of cytosolic protein synthesis in human CTLs after early TCR activation and CD28 co-stimulation for the dynamic reorganisation of the cytoskeleton, mitochondria, and lytic granules through short-term chemical inhibition of 80S ribosomes by cycloheximide and 80S and 70S by puromycin.
UNASSIGNED: We observed that eukaryotic ribosome function is required to allow proper asymmetric reorganisation of the tubulin cytoskeleton and mitochondria and mTOR pathway activation early upon TCR activation in human primary CTLs.
UNASSIGNED: Cytosolic protein translation is required to increase glucose metabolism and degranulation capacity upon TCR activation and thus to regulate the full effector function of human CTLs.

Glofitamab, an anti-CD20 antibody, is approved as a third-line treatment for relapsed or refractory (r/r) diffuse large-cell B lymphoma (DLBCL), achieving a complete response in nearly 40% of patients. This humanized IgG1 bispecific monoclonal antibody binds to CD20 on malignant B lymphocytes and to CD3 on cytotoxic T cells. This dual binding forms an immunological synapse, activating T lymphocytes and leading to the lysis of tumor cells. Salvage radiotherapy is also effective for r/r DLBCL, but its combination with systemic treatments like glofitamab may increase radiation-induced toxicity. We report the first case of a patient with r/r DLBCL receiving concurrent salvage radiotherapy and glofitamab. A 68-year-old female diagnosed with stage IV DLBCL underwent initial treatment with R-CHOP, then Car-T cell therapy, followed by glofitamab for recurrence. Upon early metabolic progression detected by 18FDG-PET/CT, salvage radiotherapy was administered to the refractory site concurrently with glofitamab. The patient experienced mild para-spinal pain post-radiotherapy but no other significant toxicities. Three months post-treatment, she showed a complete metabolic response with no radiotherapy toxicity, as evidenced by PET-CT, and no signs of radiation pneumonitis. This case indicates that combining glofitamab with salvage radiotherapy is tolerable and suggests potential efficacy, warranting further investigation in prospective studies for r/r DLBCL.

Crosstalk between dendritic cells (DCs) and T cells plays a crucial role in modulating immune responses in natural and pathological conditions. DC-T cell crosstalk is achieved through contact-dependent (i.e., immunological synapse) and contact-independent mechanisms (i.e., cytokines). Activated DCs upregulate co-stimulatory signals and secrete proinflammatory cytokines to orchestrate T cell activation and differentiation. Conversely, activated T helper cells \"license\" DCs towards maturation, while regulatory T cells (Tregs) silence DCs to elicit tolerogenic immunity. Strategies to efficiently modulate the DC-T cell crosstalk can be harnessed to promote immune activation for cancer immunotherapy or immune tolerance for the treatment of autoimmune diseases. Here, we review the natural crosstalk mechanisms between DC and T cells. We highlight bioengineering approaches to modulate DC-T cell crosstalk, including conventional vaccines, synthetic vaccines, and DC-mimics, and key seminal studies leveraging these approaches to steer immune response for the treatment of cancer and autoimmune diseases.

Conventional type 1 dendritic cells (cDC1) are critical regulators of anti-tumoral T-cell responses. The structure and abundance of intercellular contacts between cDC1 and CD8 T cells in cancer tissues is important to determine the outcome of the T-cell response. However, the molecular determinants controlling the stability of cDC1-CD8 interactions during cancer progression remain poorly investigated. Here, we generated a genetic model of non-small cell lung cancer crossed to a fluorescent cDC1 reporter (KP-XCR1venus) to allow the detection of cDC1-CD8T cell clusters in tumor tissues across tumor stages. We found that cDC1-CD8 clusters are abundant and productive at the early stages of tumor development but progressively diminish in advanced tumors. Transcriptional profiling and flow cytometry identified the adhesion molecule ALCAM/CD166 (Activated Leukocyte Cell Adhesion Molecule, ligand of CD6) as highly expressed by lung cDC1 and significantly downregulated in advanced tumors. Analysis of human datasets indicated that ALCAM is downregulated in non-small cell lung cancer and its expression correlates to better prognosis. Mechanistically, triggering ALCAM on lung cDC1 induces cytoskeletal remodeling and contact formation whereas its blockade prevents T-cell activation. Together, our results indicate that ALCAM is important to stabilize cDC1-CD8 interactions at early tumor stages, while its loss in advanced tumors contributes to immune evasion.

Adaptive immune responses comprise the activation of T cells by peptide antigens that are presented by proteins of the Major Histocompatibility Complex (MHC) on the surface of an antigen-presenting cell. As a consequence of the T cell receptor interacting productively with a certain peptide-MHC complex, a specialized cell-cell junction known as the immunological synapse forms and is accompanied by changes in the spatiotemporal patterning and function of intracellular signaling molecules. Key modifications occurring at the cytoplasmic leaflet of the plasma and internal membranes in activated T cells comprise lipid switches that affect the binding and distribution of proteins within or near the lipid bilayer. Here, we describe two major classes of lipid switches that act at this critical water/membrane interface. Phosphoinositides are derived from phosphatidylinositol, an amphiphilic molecule that contains two fatty acid chains and a phosphate group that bridges the glycerol backbone to the carbohydrate inositol. The inositol ring can be variably (de-)phosphorylated by dedicated kinases and phosphatases, thereby creating phosphoinositide signatures that define the composition and properties of signaling molecules, molecular complexes, or whole organelles. Palmitoylation refers to the reversible attachment of the fatty acid palmitate to a substrate protein\'s cysteine residue. DHHC enzymes, named after the four conserved amino acids in their active site, catalyze this post-translational modification and thereby change the distribution of proteins at, between, and within membranes. T cells utilize these two types of molecular switches to adjust their properties to an activation process that requires changes in motility, transport, secretion, and gene expression.

Tumors employ various strategies to evade immune surveillance. Central nervous system (CNS) has multiple features to restrain immune response. Whether tumors and CNS share similar programs of immunosuppression is elusive. Here, we analyze multi-omics data of tumors from HER2+ breast cancer patients receiving trastuzumab and anti-PD-L1 antibody and find that CNS-enriched N-acetyltransferase 8-like (NAT8L) and its metabolite N-acetylaspartate (NAA) are overexpressed in resistant tumors. In CNS, NAA is released during brain inflammation. NAT8L attenuates brain inflammation and impairs anti-tumor immunity by inhibiting cytotoxicity of natural killer (NK) cells and CD8+ T cells via NAA. NAA disrupts the formation of immunological synapse by promoting PCAF-induced acetylation of lamin A-K542, which inhibits the integration between lamin A and SUN2 and impairs polarization of lytic granules. We uncover that tumor cells mimic the anti-inflammatory mechanism of CNS to evade anti-tumor immunity and NAT8L is a potential target to enhance efficacy of anti-cancer agents.

Adoptive T cellular immunotherapies have emerged as relevant approaches for treating cancer patients who have relapsed or become refractory (R/R) to traditional cancer treatments. Chimeric antigen receptor (CAR) T-cell therapy has improved survival in various hematological malignancies. However, significant limitations still impede the widespread adoption of these therapies in most cancers. To advance in this field, six research groups have created the \"NEXT Generation CART MAD Consortium\" (NEXT CART) in Madrid\'s Community, which aims to develop novel cell-based immunotherapies for R/R and poor prognosis cancers. At NEXT CART, various basic and translational research groups and hospitals in Madrid concur to share and synergize their basic expertise in immunotherapy, gene therapy, and immunological synapse, and clinical expertise in pediatric and adult oncology. NEXT CART goal is to develop new cell engineering approaches and treatments for R/R adult and pediatric neoplasms to evaluate in multicenter clinical trials. Here, we discuss the current limitations of T cell-based therapies and introduce our perspective on future developments. Advancement opportunities include developing allogeneic products, optimizing CAR signaling domains, combining cellular immunotherapies, multi-targeting strategies, and improving tumor-infiltrating lymphocytes (TILs)/T cell receptor (TCR) therapy. Furthermore, basic studies aim to identify novel tumor targets, tumor molecules in the tumor microenvironment that impact CAR efficacy, and strategies to enhance the efficiency of the immunological synapse between immune and tumor cells. Our perspective of current cellular immunotherapy underscores the potential of these treatments while acknowledging the existing hurdles that demand innovative solutions to develop their potential for cancer treatment fully.

Natural killer (NK) cell-based immunotherapy holds promise for cancer treatment; however, its efficacy remains limited, necessitating the development of alternative strategies. Here, we report that venetoclax, an FDA-approved BCL-2 inhibitor, directly activates NK cells, enhancing their cytotoxicity against acute myeloid leukemia (AML) both in vitro and in vivo, likely independent of BCL-2 inhibition. Through comprehensive approaches, including bulk and single-cell RNA sequencing, avidity measurement, and functional assays, we demonstrate that venetoclax increases the avidity of NK cells to AML cells and promotes lytic granule polarization during immunological synapse (IS) formation. Notably, we identify a distinct CD161lowCD218b+ NK cell subpopulation that exhibits remarkable sensitivity to venetoclax treatment. Furthermore, venetoclax promotes mitochondrial respiration and ATP synthesis via the NF-κB pathway, thereby facilitating IS formation in NK cells. Collectively, our findings establish venetoclax as a multifaceted immunometabolic modulator of NK cell function and provide a promising strategy for augmenting NK cell-based cancer immunotherapy.

Tumors weakly infiltrated by T lymphocytes poorly respond to immunotherapy. We aimed to unveil malignancy-associated programs regulating T cell entrance, arrest, and activation in the tumor environment. Differential expression of cell adhesion and tissue architecture programs, particularly the presence of the membrane tetraspanin claudin (CLDN)18 as a signature gene, demarcated immune-infiltrated from immune-depleted mouse pancreatic tumors. In human pancreatic ductal adenocarcinoma (PDAC) and non-small cell lung cancer, CLDN18 expression positively correlated with more differentiated histology and favorable prognosis. CLDN18 on the cell surface promoted accrual of cytotoxic T lymphocytes (CTLs), facilitating direct CTL contacts with tumor cells by driving the mobilization of the adhesion protein ALCAM to the lipid rafts of the tumor cell membrane through actin. This process favored the formation of robust immunological synapses (ISs) between CTLs and CLDN18-positive cancer cells, resulting in increased T cell activation. Our data reveal an immune role for CLDN18 in orchestrating T cell infiltration and shaping the tumor immune contexture.

Molecular forces are increasingly recognized as an important parameter to understand cellular signaling processes. In the recent years, evidence accumulated that also T-cells exert tensile forces via their T-cell receptor during the antigen recognition process. To measure such intercellular pulling forces, one can make use of the elastic properties of spider silk peptides, which act similar to Hookean springs: increased strain corresponds to increased stress applied to the peptide. Combined with Förster resonance energy transfer (FRET) to read out the strain, such peptides represent powerful and versatile nanoscopic force sensing tools. In this paper, we provide a detailed protocol how to synthesize a molecular force sensor for application in T-cell antigen recognition and hands-on guidelines on experiments and analysis of obtained single molecule FRET data.