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The B cell receptor (BCR) signals together with a multi-component co-receptor complex to initiate B cell activation in response to antigen binding. Here, we take advantage of peroxidase-catalyzed proximity labeling combined with quantitative mass spectrometry to track co-receptor signaling dynamics in Raji cells from 10 s to 2 h after BCR stimulation. This approach enables tracking of 2,814 proximity-labeled proteins and 1,394 phosphosites and provides an unbiased and quantitative molecular map of proteins recruited to the vicinity of CD19, the signaling subunit of the co-receptor complex. We detail the recruitment kinetics of signaling effectors to CD19 and identify previously uncharacterized mediators of B cell activation. We show that the glutamate transporter SLC1A1 is responsible for mediating rapid metabolic reprogramming and for maintaining redox homeostasis during B cell activation. This study provides a comprehensive map of BCR signaling and a rich resource for uncovering the complex signaling networks that regulate activation.

Acknowledgements We are grateful to our laboratory members and the Kennedy Institute of Rheumatology community for constructive scientific discussions, especially to James Felce, David Depoil, Jonathan Webber, Štefan Balint, Alexander Mørch, and Kristina Correa. We thank the technical support of Heather Rada, Kellie Johnson, and Ekaterina Zvezdova (the latter two from BioLegend). We thank Professor Catarina E. Hioe for kindly providing the HIV-1 gp120 protein. We would also like to thank all the anonymized blood donors who contributed to our study. This work was funded by Wellcome Trust Principal Research Fellowship 100262Z/12/Z, the ERC Advanced Grant (SYNECT AdG 670930), and the Kennedy Trust for Rheumatology Research (KTRR) (all three to M.L.D.). P.F.C.D was supported by EMBO Long-Term Fellowship (ALTF 1420–2015, in conjunction with the European Commission (LTFCOFUND2013, GA-2013-609409) and Marie Sklodowska-Curie Actions) and Oxford-Bristol Myers Squibb Fellowship. A.K. was supported by H2020 and the Research Council of Norway (in conjunction with Marie Sklodowska-Curie Actions 275466; to A.K.). M.F. and H.C.Y. thank the Wellcome Trust (212343/Z/18/Z) and EPSRC (EP/S004459/1). The eTIRF-SIM platform was built-in collaboration with Micron (www.micronoxford.com), an Oxford-wide advanced microscopy technology consortium supported by Wellcome Strategic Awards (091911 and 107457), and with additional funds from an MRC/EPSRC/BBSRC next-generation imaging award and the Kennedy Trust for Rheumatology Research through the Kennedy Institute Cell Dynamics Platform. We acknowledge the generous support of the Kennedy Trust for Rheumatology Research, IDRM, and Carl Zeiss GMBH for the Airyscan LSM 980 confocal microscope used in this research. Y.P., T.D., and R.F. were supported by the Chinese Academy of Medical Sciences (CAMS) Innovation Fund for Medical Sciences (CIFMS), China (grant number: 2018-I2M-2-002) and UK Medical Research Council (MRC); E.S. was supported by Newton, The immunological synapse is a molecular hub that facilitates the delivery of three activation signals, namely antigen, costimulation/corepression and cytokines, from antigen-presenting cells (APC) to T cells. T cells release a fourth class of signaling entities, trans-synaptic vesicles (tSV), to mediate bidirectional communication. Here we present bead-supported lipid bilayers (BSLB) as versatile synthetic APCs to capture, characterize and advance the understanding of tSV biogenesis. Specifically, the integration of juxtacrine signals, such as CD40 and antigen, results in the adaptive tailoring and release of tSV, which differ in size, yields and immune receptor cargo compared with steadily released extracellular vesicles (EVs). Focusing on CD40L+ tSV as model effectors, we show that PD-L1 trans-presentation together with TSG101, ADAM10 and CD81 are key in determining CD40L vesicular release. Lastly, we find greater RNA-binding protein and microRNA content in tSV compared with EVs, supporting the specialized role of tSV as intercellular messengers., Depto. de Biología Celular, Fac. de Ciencias Biológicas, TRUE, pub

Transplantation of human neural stem cells (hNSCs) is a promising regenerative therapy to promote remyelination in patients with multiple sclerosis (MS). Transplantation of hNSCs has been shown to increase the number of CD4+CD25+Foxp3+ T regulatory cells (Tregs) in the spinal cords of murine models of MS, which is correlated with a strong localized remyelination response. However, the mechanisms by which hNSC transplantation leads to an increase in Tregs in the CNS remains unclear. We report that hNSCs drive the conversion of T conventional (Tconv) cells into Tregs in vitro. Conversion of Tconv cells is Ag driven and fails to occur in the absence of TCR stimulation by cognate antigenic self-peptides. Furthermore, CNS Ags are sufficient to drive this conversion in the absence of hNSCs in vitro and in vivo. Importantly, only Ags presented in the thymus during T cell selection drive this Treg response. In this study, we investigate the mechanisms by which hNSC Ags drive the conversion of Tconv cells into Tregs and may provide key insight needed for the development of MS therapies.

Mature T cells must discriminate between brief interactions with self-peptides and prolonged binding to agonists. The kinetic proofreading model posits that certain T-cell antigen receptor signaling nodes serve as molecular timers to facilitate such discrimination. However, the physiological significance of this regulatory mechanism and the pathological consequences of disrupting it are unknown. Here we report that accelerating the normally slow phosphorylation of the linker for activation of T cells (LAT) residue Y136 by introducing an adjacent Gly135Asp alteration (LATG135D) disrupts ligand discrimination in vivo. The enhanced self-reactivity of LATG135D T cells triggers excessive thymic negative selection and promotes T-cell anergy. During Listeria infection, LATG135D T cells expand more than wild-type counterparts in response to very weak stimuli but display an imbalance between effector and memory responses. Moreover, despite their enhanced engagement of central and peripheral tolerance mechanisms, mice bearing LATG135D show features associated with autoimmunity and immunopathology. Our data reveal the importance of kinetic proofreading in balancing tolerance and immunity.

BackgroundIn preclinical studies of pancreatic ductal adenocarcinoma (PDAC), ibrutinib improved the antitumor efficacy of the standard of care chemotherapy. This led to a phase 1b clinical trial to determine the safety, tolerability, and immunologic effects of ibrutinib treatment in patients with advanced PDAC.MethodsPreviously untreated patients with PDAC were enrolled in a phase 1b clinical trial (ClinicalTrials.gov) to determine the safety, toxicity, and maximal tolerated dose of ibrutinib when administered with the standard regimen of gemcitabine and nab-paclitaxel. To study the immune response to ibrutinib alone, the trial included an immune response arm where patients were administered with ibrutinib daily for a week followed by ibrutinib combined with gemcitabine and nab-paclitaxel. Endoscopic ultrasonography-guided primary PDAC tumor biopsies and blood were collected before and after ibrutinib monotherapy. Changes in abundance and functional state of immune cells in the blood was evaluated by mass cytometry by time of flight and statistical scaffold analysis, while that in the local tumor microenvironment (TME) were assessed by multiplex immunohistochemistry. Changes in B-cell receptor and T-cell receptor repertoire were assessed by sequencing and analysis of clonality.ResultsIn the blood, ibrutinib monotherapy significantly increased the frequencies of activated inducible T cell costimulator+(ICOS+) CD4+ T cells and monocytes. Within the TME, ibrutinib monotherapy led to a trend in decreased B-cell abundance but increased interleukin-10+ B-cell frequency. Monotherapy also led to a trend in increased mature CD208+dendritic cell density, increased late effector (programmed cell death protein 1 (PD-1-) eomesodermin (EOMES+)) CD8+ T-cell frequency, with a concomitantly decreased dysfunctional (PD-1+ EOMES+) CD8+ T-cell frequency. When ibrutinib was combined with chemotherapy, most of these immune changes were not observed. Patients with partial clinical respons

Bystander activation of memory T cells occurs via cytokine signaling alone in the absence of T cell receptor (TCR) signaling and provides a means of amplifying T cell effector responses in an antigen-nonspecific manner. While the role of Programmed Cell Death Protein 1 (PD-1) on antigen-specific T cell responses is extensively characterized, its role in bystander T cell responses is less clear. We examined the role of the PD-1 pathway during human and mouse non-antigen-specific memory T cell bystander activation and observed that PD-1+ T cells demonstrated less activation and proliferation than activated PD-1- populations in vitro. Higher activation and proliferative responses were also observed in the PD-1- memory population in both mice and patients with cancer receiving high-dose IL-2, mirroring the in vitro phenotypes. This inhibitory effect of PD-1 could be reversed by PD-1 blockade in vivo or observed using memory T cells from PD-1-/- mice. Interestingly, increased activation through abrogation of PD-1 signaling in bystander-activated T cells also resulted in increased apoptosis due to activation-induced cell death (AICD) and eventual T cell loss in vivo. These results demonstrate that the PD-1/PD-Ligand 1 (PD-L1) pathway inhibited bystander-activated memory T cell responses but also protected cells from AICD.

HIV post-treatment controllers (PTCs) are rare individuals who maintain low levels of viremia after stopping antiretroviral therapy (ART). Understanding the mechanisms of HIV post-treatment control will inform development of strategies aiming at achieving HIV functional cure. In this study, we evaluated 22 PTCs from 8 AIDS Clinical Trials Group (ACTG) analytical treatment interruption (ATI) studies who maintained viral loads ≤400 copies/mL for ≥24 wk. There were no significant differences in demographics or frequency of protective and susceptible human leukocyte antigen (HLA) alleles between PTCs and post-treatment noncontrollers (NCs, n = 37). Unlike NCs, PTCs demonstrated a stable HIV reservoir measured by cell-associated RNA (CA-RNA) and intact proviral DNA assay (IPDA) during analytical treatment interruption (ATI). Immunologically, PTCs demonstrated significantly lower CD4+ and CD8+ T cell activation, lower CD4+ T cell exhaustion, and more robust Gag-specific CD4+ T cell responses and natural killer (NK) cell responses. Sparse partial least squares discriminant analysis (sPLS-DA) identified a set of features enriched in PTCs, including a higher CD4+ T cell% and CD4+/CD8+ ratio, more functional NK cells, and a lower CD4+ T cell exhaustion level. These results provide insights into the key viral reservoir features and immunological profiles for HIV PTCs and have implications for future studies evaluating interventions to achieve an HIV functional cure.

BACKGROUND: Natural killer (NK) cell-based immunotherapy is a promising treatment approach for multiple myeloma (MM), but obtaining a sufficient number of activated NK cells remains challenging. Here, we report an improved method to generate ex vivo expanded NK (eNK) cells from MM patients based on genetic engineering of K562 cells to express OX40 ligand and membrane-bound (mb) IL-18 and IL-21. METHODS: K562-OX40L-mbIL-18/-21 cells were generated by transducing K562-OX40L cells with a lentiviral vector encoding mbIL-18 and mbIL-21, and these were used as feeder cells to expand NK cells from peripheral blood mononuclear cells of healthy donors (HDs) and MM patients in the presence of IL-2/IL-15. Purity, expansion rate, receptor expression, and functions of eNK cells were determined over four weeks of culture. RESULTS: NK cell expansion was enhanced by short exposure of soluble IL-18 and IL-21 with K562-OX40L cells. Co-culture of NK cells with K562-OX40L-mbIL-18/-21 cells resulted in remarkable expansion of NK cells from HDs (9,860-fold) and MM patients (4,929-fold) over the 28-day culture period. Moreover, eNK cells showed increased expression of major activation markers and enhanced cytotoxicity towards target K562, U266, and RPMI8226 cells. CONCLUSIONS: Our data suggest that genetically engineered K562 cells expressing OX40L, mbIL-18, and mbIL-21 improve the expansion of NK cells, increase activation signals, and enhance their cytolytic activity towards MM cells.

This special edition summarizes major advances in our understanding of signaling by T lymphocytes. T cell interactions with antigen-presenting cells (APCs) and other immune cells are characterized by changes in T cell adhesion and major rearrangements of the actin cytoskeleton. This issue describes some of the mediators of these changes both within the T cells and on the T cell surface. The five articles focus on "inside-out integrin signaling" in T cells, components of the immunological synapse between lymphocyte and APCs, an unexpected role for T cell receptor (TCR) signaling from endosomes, transfer of membrane constituents from APCs to T cells via trogocytosis, immune deficiencies in these T cell signaling pathways, and the role of thymocyte-expressed molecule involved in selection (THEMIS) in thymocyte development and peripheral T cell function.

Background Adenosine is a metabolite that suppresses antitumor immune response of T and NK cells via extracellular binding to the two subtypes of adenosine-2 receptors, A(2)ARs. While blockade of the A(2A)ARs subtype effectively rescues lymphocyte activity, with four A(2A)AR antagonists currently in anticancer clinical trials, less is known for the therapeutic potential of the other A(2B)AR blockade within cancer immunotherapy. Recent studies suggest the formation of A(2A)AR/A(2B)AR dimers in tissues that coexpress the two receptor subtypes, where the A(2B)AR plays a dominant role, suggesting it as a promising target for cancer immunotherapy. Methods We report the synthesis and functional evaluation of five potent A(2B)AR antagonists and a dual A(2A)AR/A(2B)AR antagonist. The compounds were designed using previous pharmacological data assisted by modeling studies. Synthesis was developed using multicomponent approaches. Flow cytometry was used to evaluate the phenotype of T and NK cells on A(2B)AR antagonist treatment. Functional activity of T and NK cells was tested in patient-derived tumor spheroid models. Results We provide data for six novel small molecules: five A(2B)AR selective antagonists and a dual A(2A)AR/A(2B)AR antagonist. The growth of patient-derived breast cancer spheroids is prevented when treated with A(2B)AR antagonists. To elucidate if this depends on increased lymphocyte activity, immune cells proliferation, and cytokine production, lymphocyte infiltration was evaluated and compared with the potent A(2A)AR antagonist AZD-4635. We find that A(2B)AR antagonists rescue T and NK cell proliferation, IFN gamma and perforin production, and increase tumor infiltrating lymphocytes infiltration into tumor spheroids without altering the expression of adhesion molecules. Conclusions Our results demonstrate that A(2B)AR is a promising target in immunotherapy, identifying ISAM-R56A as the most potent candidate for A(2B)AR blockade. Inhibition of A(2B)AR signal

Background Adenosine is a metabolite that suppresses antitumor immune response of T and NK cells via extracellular binding to the two subtypes of adenosine-2 receptors, A(2)ARs. While blockade of the A(2A)ARs subtype effectively rescues lymphocyte activity, with four A(2A)AR antagonists currently in anticancer clinical trials, less is known for the therapeutic potential of the other A(2B)AR blockade within cancer immunotherapy. Recent studies suggest the formation of A(2A)AR/A(2B)AR dimers in tissues that coexpress the two receptor subtypes, where the A(2B)AR plays a dominant role, suggesting it as a promising target for cancer immunotherapy. Methods We report the synthesis and functional evaluation of five potent A(2B)AR antagonists and a dual A(2A)AR/A(2B)AR antagonist. The compounds were designed using previous pharmacological data assisted by modeling studies. Synthesis was developed using multicomponent approaches. Flow cytometry was used to evaluate the phenotype of T and NK cells on A(2B)AR antagonist treatment. Functional activity of T and NK cells was tested in patient-derived tumor spheroid models. Results We provide data for six novel small molecules: five A(2B)AR selective antagonists and a dual A(2A)AR/A(2B)AR antagonist. The growth of patient-derived breast cancer spheroids is prevented when treated with A(2B)AR antagonists. To elucidate if this depends on increased lymphocyte activity, immune cells proliferation, and cytokine production, lymphocyte infiltration was evaluated and compared with the potent A(2A)AR antagonist AZD-4635. We find that A(2B)AR antagonists rescue T and NK cell proliferation, IFN gamma and perforin production, and increase tumor infiltrating lymphocytes infiltration into tumor spheroids without altering the expression of adhesion molecules. Conclusions Our results demonstrate that A(2B)AR is a promising target in immunotherapy, identifying ISAM-R56A as the most potent candidate for A(2B)AR blockade. Inhibition of A(2B)AR signal

Background Adenosine is a metabolite that suppresses antitumor immune response of T and NK cells via extracellular binding to the two subtypes of adenosine-2 receptors, A(2)ARs. While blockade of the A(2A)ARs subtype effectively rescues lymphocyte activity, with four A(2A)AR antagonists currently in anticancer clinical trials, less is known for the therapeutic potential of the other A(2B)AR blockade within cancer immunotherapy. Recent studies suggest the formation of A(2A)AR/A(2B)AR dimers in tissues that coexpress the two receptor subtypes, where the A(2B)AR plays a dominant role, suggesting it as a promising target for cancer immunotherapy. Methods We report the synthesis and functional evaluation of five potent A(2B)AR antagonists and a dual A(2A)AR/A(2B)AR antagonist. The compounds were designed using previous pharmacological data assisted by modeling studies. Synthesis was developed using multicomponent approaches. Flow cytometry was used to evaluate the phenotype of T and NK cells on A(2B)AR antagonist treatment. Functional activity of T and NK cells was tested in patient-derived tumor spheroid models. Results We provide data for six novel small molecules: five A(2B)AR selective antagonists and a dual A(2A)AR/A(2B)AR antagonist. The growth of patient-derived breast cancer spheroids is prevented when treated with A(2B)AR antagonists. To elucidate if this depends on increased lymphocyte activity, immune cells proliferation, and cytokine production, lymphocyte infiltration was evaluated and compared with the potent A(2A)AR antagonist AZD-4635. We find that A(2B)AR antagonists rescue T and NK cell proliferation, IFN gamma and perforin production, and increase tumor infiltrating lymphocytes infiltration into tumor spheroids without altering the expression of adhesion molecules. Conclusions Our results demonstrate that A(2B)AR is a promising target in immunotherapy, identifying ISAM-R56A as the most potent candidate for A(2B)AR blockade. Inhibition of A(2B)AR signal

This special edition summarizes major advances in our understanding of signaling by T lymphocytes. T cell interactions with antigen-presenting cells (APCs) and other immune cells are characterized by changes in T cell adhesion and major rearrangements of the actin cytoskeleton. This issue describes some of the mediators of these changes both within the T cells and on the T cell surface. The five articles focus on "inside-out integrin signaling" in T cells, components of the immunological synapse between lymphocyte and APCs, an unexpected role for T cell receptor (TCR) signaling from endosomes, transfer of membrane constituents from APCs to T cells via trogocytosis, immune deficiencies in these T cell signaling pathways, and the role of thymocyte-expressed molecule involved in selection (THEMIS) in thymocyte development and peripheral T cell function.

Background Adenosine is a metabolite that suppresses antitumor immune response of T and NK cells via extracellular binding to the two subtypes of adenosine-2 receptors, A(2)ARs. While blockade of the A(2A)ARs subtype effectively rescues lymphocyte activity, with four A(2A)AR antagonists currently in anticancer clinical trials, less is known for the therapeutic potential of the other A(2B)AR blockade within cancer immunotherapy. Recent studies suggest the formation of A(2A)AR/A(2B)AR dimers in tissues that coexpress the two receptor subtypes, where the A(2B)AR plays a dominant role, suggesting it as a promising target for cancer immunotherapy. Methods We report the synthesis and functional evaluation of five potent A(2B)AR antagonists and a dual A(2A)AR/A(2B)AR antagonist. The compounds were designed using previous pharmacological data assisted by modeling studies. Synthesis was developed using multicomponent approaches. Flow cytometry was used to evaluate the phenotype of T and NK cells on A(2B)AR antagonist treatment. Functional activity of T and NK cells was tested in patient-derived tumor spheroid models. Results We provide data for six novel small molecules: five A(2B)AR selective antagonists and a dual A(2A)AR/A(2B)AR antagonist. The growth of patient-derived breast cancer spheroids is prevented when treated with A(2B)AR antagonists. To elucidate if this depends on increased lymphocyte activity, immune cells proliferation, and cytokine production, lymphocyte infiltration was evaluated and compared with the potent A(2A)AR antagonist AZD-4635. We find that A(2B)AR antagonists rescue T and NK cell proliferation, IFN gamma and perforin production, and increase tumor infiltrating lymphocytes infiltration into tumor spheroids without altering the expression of adhesion molecules. Conclusions Our results demonstrate that A(2B)AR is a promising target in immunotherapy, identifying ISAM-R56A as the most potent candidate for A(2B)AR blockade. Inhibition of A(2B)AR signal, QC 20220602

During an immune response to microbial infection, CD8+ T cells give rise to short-lived effector cells and memory cells that provide sustained protection. Although the transcriptional programs regulating CD8+ T cell differentiation have been extensively characterized, the role of long noncoding RNAs (lncRNAs) in this process remains poorly understood. Using a functional genetic knockdown screen, we identified the lncRNA Malat1 as a regulator of terminal effector cells and the terminal effector memory (t-TEM) circulating memory subset. Evaluation of chromatin-enriched lncRNAs revealed that Malat1 grouped with trans lncRNAs that exhibit increased RNA interactions at gene promoters and gene bodies. Moreover, we observed that Malat1 was associated with increased H3K27me3 deposition at a number of memory cell-associated genes through a direct interaction with Ezh2, thereby promoting terminal effector and t-TEM cell differentiation. Our findings suggest an important functional role of Malat1 in regulating CD8+ T cell differentiation and broaden the knowledge base of lncRNAs in CD8+ T cell biology.

Brain metastasis (BrM) is the most common form of brain cancer, characterized by neurologic disability and an abysmal prognosis. Unfortunately, our understanding of the biology underlying human BrMs remains rudimentary. Here, we present an integrative analysis of >100,000 malignant and non-malignant cells from 15 human parenchymal BrMs, generated by single-cell transcriptomics, mass cytometry, and complemented with mouse model- and in silico approaches. We interrogated the composition of BrM niches, molecularly defined the blood-tumor interface, and revealed stromal immunosuppressive states enriched with infiltrated T cells and macrophages. Specific single-cell interrogation of metastatic tumor cells provides a framework of 8 functional cell programs that coexist or anticorrelate. Collectively, these programs delineate two functional BrM archetypes, one proliferative and the other inflammatory, that are evidently shaped through tumor-immune interactions. Our resource provides a foundation to understand the molecular basis of BrM in patients with tumor cell-intrinsic and host environmental traits.

This Brief Review delves into B cell responses in the context of allergy. The primary contribution of B cells to allergy is the production of IgE, the Ab isotype that triggers immediate hypersensitivity reactions through the release of mediators from mast cells and basophils. B cells may also have protective roles in allergy, such as through the production of IgG or as regulatory B cells. In this review, I focus on the basic principles of B cell differentiation and discuss features relevant to allergic immune responses. In particular, I discuss: (1) class-switch recombination; (2) plasma cell differentiation; (3) germinal centers and affinity maturation; and (4) memory B cells and recall responses, with an emphasis on IgE, IgG1, and IgG4. I also consider how B cells may contribute to allergic responses independent of Ab production-for example, by serving as APCs.

Bispecific T-cell engager (BiTE) molecules are biologic T cell-directing immunotherapies. Blinatumomab is approved for treatment of B-cell malignancies, but BiTE molecule development in solid tumors has been more challenging. Here, we employed intravital imaging to characterize exposure and pharmacodynamic response of an anti-muCD3/anti-huEGFRvIII mouse surrogate BiTE molecule in EGFR variant III (EGFRvIII)-positive breast tumors implanted within immunocompetent mice. Our study revealed heterogeneous temporal and spatial dynamics of BiTE molecule extravasation into solid tumors, highlighting physical barriers to BiTE molecule function. We also discovered that high, homogeneous EGFRvIII expression on cancer cells was necessary for a BiTE molecule to efficiently clear tumors. In addition, we found that resident tumor-infiltrating lymphocytes (TIL) were sufficient for optimal tumor killing only at high BiTE molecule dosage, whereas inclusion of peripheral T-cell recruitment was synergistic at moderate to low dosages. We report that deletion of stimulatory conventional type I DCs (cDC1) diminished BiTE molecule-induced T-cell activation and tumor clearance, suggesting that in situ antigen-presenting cell (APC) engagements modulate the extent of BiTE molecule efficacy. In summary, our work identified multiple requirements for optimal BiTE molecule efficacy in solid tumors, providing insights that could be harnessed for solid cancer immunotherapy development.

Deficiency of the immune checkpoint lymphocyte activation gene-3 (LAG3) protein is significantly associated with both elevated HDL-cholesterol (HDL-C) and myocardial infarction risk. We determined the association of genetic variants within ±500 kb of LAG3 with plasma LAG3 and defined LAG3-associated plasma proteins with HDL-C and clinical outcomes. Whole genome sequencing and plasma proteomics were obtained from the Multi-Ethnic Study of Atherosclerosis (MESA) and the Framingham Heart Study (FHS) cohorts as part of the Trans-Omics for Precision Medicine program. In situ Hi-C chromatin capture was performed in EBV-transformed cell lines isolated from four MESA participants. Genetic association analyses were performed in MESA using multivariate regression models, with validation in FHS. A LAG3-associated protein network was tested for association with HDL-C, coronary heart disease, and all-cause mortality. We identify an association between the LAG3 rs3782735 variant and plasma LAG3 protein. Proteomics analysis reveals 183 proteins significantly associated with LAG3 with four proteins associated with HDL-C. Four proteins discovered for association with all-cause mortality in FHS shows nominal associations in MESA. Chromatin capture analysis reveals significant cis interactions between LAG3 and C1S, LRIG3, TNFRSF1A, and trans interactions between LAG3 and B2M. A LAG3-associated protein network has significant associations with HDL-C and mortality.

Background Adenosine is a metabolite that suppresses antitumor immune response of T and NK cells via extracellular binding to the two subtypes of adenosine-2 receptors, A(2)ARs. While blockade of the A(2A)ARs subtype effectively rescues lymphocyte activity, with four A(2A)AR antagonists currently in anticancer clinical trials, less is known for the therapeutic potential of the other A(2B)AR blockade within cancer immunotherapy. Recent studies suggest the formation of A(2A)AR/A(2B)AR dimers in tissues that coexpress the two receptor subtypes, where the A(2B)AR plays a dominant role, suggesting it as a promising target for cancer immunotherapy. Methods We report the synthesis and functional evaluation of five potent A(2B)AR antagonists and a dual A(2A)AR/A(2B)AR antagonist. The compounds were designed using previous pharmacological data assisted by modeling studies. Synthesis was developed using multicomponent approaches. Flow cytometry was used to evaluate the phenotype of T and NK cells on A(2B)AR antagonist treatment. Functional activity of T and NK cells was tested in patient-derived tumor spheroid models. Results We provide data for six novel small molecules: five A(2B)AR selective antagonists and a dual A(2A)AR/A(2B)AR antagonist. The growth of patient-derived breast cancer spheroids is prevented when treated with A(2B)AR antagonists. To elucidate if this depends on increased lymphocyte activity, immune cells proliferation, and cytokine production, lymphocyte infiltration was evaluated and compared with the potent A(2A)AR antagonist AZD-4635. We find that A(2B)AR antagonists rescue T and NK cell proliferation, IFN gamma and perforin production, and increase tumor infiltrating lymphocytes infiltration into tumor spheroids without altering the expression of adhesion molecules. Conclusions Our results demonstrate that A(2B)AR is a promising target in immunotherapy, identifying ISAM-R56A as the most potent candidate for A(2B)AR blockade. Inhibition of A(2B)AR signal

Common variable immunodeficiency (CVID) is a heterogeneous group of inborn errors of immunity characterized by reduced serum concentrations of different immunoglobulin isotypes. CVID is the most prevalent symptomatic antibody deficiency with a broad range of infectious and non-infectious clinical manifestations. Various genetic and immunological defects are known to be involved in the pathogenesis of CVID. Monogenic defects account for the pathogenesis of about 20-50% of CVID patients, while a variety of cases do not have a defined genetic background. Deficiencies in molecules of B cell receptor signaling or other pathways involving B-cell development, activation, and proliferation could be associated with monogenetic defects of CVID. Genetic defects damping different B cell developmental stages can alter B- and even other lymphocytes' differentiation and might be involved in the clinical and immunologic presentations of the disorder. Reports concerning T and B cell abnormalities have been published in CVID patients, but such comprehensive data on monogenic CVID patients is few and no review article exists to describe the abrogation of lymphocyte subsets in these disorders. Hence, we aimed to review the role of altered B- and T-cell differentiation in the pathogenesis of CVID patients with monogenic defects.

Background Adenosine is a metabolite that suppresses antitumor immune response of T and NK cells via extracellular binding to the two subtypes of adenosine-2 receptors, A(2)ARs. While blockade of the A(2A)ARs subtype effectively rescues lymphocyte activity, with four A(2A)AR antagonists currently in anticancer clinical trials, less is known for the therapeutic potential of the other A(2B)AR blockade within cancer immunotherapy. Recent studies suggest the formation of A(2A)AR/A(2B)AR dimers in tissues that coexpress the two receptor subtypes, where the A(2B)AR plays a dominant role, suggesting it as a promising target for cancer immunotherapy. Methods We report the synthesis and functional evaluation of five potent A(2B)AR antagonists and a dual A(2A)AR/A(2B)AR antagonist. The compounds were designed using previous pharmacological data assisted by modeling studies. Synthesis was developed using multicomponent approaches. Flow cytometry was used to evaluate the phenotype of T and NK cells on A(2B)AR antagonist treatment. Functional activity of T and NK cells was tested in patient-derived tumor spheroid models. Results We provide data for six novel small molecules: five A(2B)AR selective antagonists and a dual A(2A)AR/A(2B)AR antagonist. The growth of patient-derived breast cancer spheroids is prevented when treated with A(2B)AR antagonists. To elucidate if this depends on increased lymphocyte activity, immune cells proliferation, and cytokine production, lymphocyte infiltration was evaluated and compared with the potent A(2A)AR antagonist AZD-4635. We find that A(2B)AR antagonists rescue T and NK cell proliferation, IFN gamma and perforin production, and increase tumor infiltrating lymphocytes infiltration into tumor spheroids without altering the expression of adhesion molecules. Conclusions Our results demonstrate that A(2B)AR is a promising target in immunotherapy, identifying ISAM-R56A as the most potent candidate for A(2B)AR blockade. Inhibition of A(2B)AR signal

Type 1 diabetes (T1D), Hashimoto’s thyroiditis (HT), Graves’ disease (GD), and autoimmune Addison’s disease (AD) appear to share immunogenetic mechanisms. This idea is not novel, as “autoimmune tautology” is an established concept. An issue with previous studies is that no or few simultaneous comparisons between these autoimmune endocrine diseases have been made. Due to methodological limitations, immune deviations associated with these diseases have also been examined for a limited number of immune cell lineages and analytes. High-dimensional single-cell mass cytometry was thus employed to phenotypically characterise all peripheral CD45+ cell lineages, whilst immune-related proteins in plasma and cell supernatants were analysed by proximity extension assay. Patients with new-onset T1D, HT, and AD had altered frequencies of distinct clusters within antigen-presenting and cytotoxic cell lineages. Importantly, previously unreported alterations of rare cell subsets from patients with HT and AD were identified. The systemic immunoprofile of patients with autoimmune endocrine diseases was in general similar. However, an increased abundance of CDCP1 and SLAMF1 in plasma from patients with T1D, HT, and GD might reflect a higher degree of inflammation and lymphocyte activation. Pregnancy in healthy women entails two important features: 1) an increase in fractional β-cell area and 2) peripheral immunomodulation. The effects of pregnancy on T1D remain nevertheless equivocal, as there are conflicting results on β-cell function and longitudinal analyses on peripheral immunity are lacking. β-cell function and the plasma proteome in pregnant women with long-standing T1D (L-T1D) were therefore examined during three occasions: 1) first trimester, 2) third trimester, and 3) two months postpartum. An oral glucose tolerance test was performed to measure both fasting and stimulated C-peptide concentrations in plasma. Plasma proteins related to cell regulatory and immunological processe

Biomaterials can improve the safety and presentation of therapeutic agents for effective immunotherapy, and a high level of control over surface functionalization is essential for immune cell modulation. Here, we developed biocompatible immune cell-engaging particles (ICEp) that use synthetic short DNA as scaffolds for efficient and tunable protein loading. To improve the safety of chimeric antigen receptor (CAR) T cell therapies, micrometre-sized ICEp were injected intratumorally to present a priming signal for systemically administered AND-gate CAR-T cells. Locally retained ICEp presenting a high density of priming antigens activated CAR T cells, driving local tumour clearance while sparing uninjected tumours in immunodeficient mice. The ratiometric control of costimulatory ligands (anti-CD3 and anti-CD28 antibodies) and the surface presentation of a cytokine (IL-2) on ICEp were shown to substantially impact human primary T cell activation phenotypes. This modular and versatile biomaterial functionalization platform can provide new opportunities for immunotherapies.

Anti-CD19 chimeric antigen receptor (CD19-CAR)-engineered T cells are approved therapeutics for malignancies. The impact of the hinge domain (HD) and the transmembrane domain (TMD) between the extracellular antigen-targeting CARs and the intracellular signaling modalities of CARs has not been systemically studied. In this study, a series of 19-CARs differing only by their HD (CD8, CD28, or IgG4) and TMD (CD8 or CD28) was generated. CARs containing a CD28-TMD, but not a CD8-TMD, formed heterodimers with the endogenous CD28 in human T cells, as shown by co-immunoprecipitation and CAR-dependent proliferation of anti-CD28 stimulation. This dimerization was dependent on polar amino acids in the CD28-TMD and was more efficient with CARs containing CD28 or CD8 HD than IgG4-HD. The CD28-CAR heterodimers did not respond to CD80 and CD86 stimulation but had a significantly reduced CD28 cell-surface expression. These data unveiled a fundamental difference between CD28-TMD and CD8-TMD and indicated that CD28-TMD can modulate CAR T-cell activities by engaging endogenous partners.

Due to the durability and persistence of reservoirs of HIV-1-infected cells, combination antiretroviral therapy (ART) is insufficient in eradicating infection. Achieving HIV-1 cure or sustained remission without ART treatment will require the enhanced and persistent effective antiviral immune responses. Chimeric Antigen Receptor (CAR) T-cells have emerged as a powerful immunotherapy and show promise in treating HIV-1 infection. Persistence, trafficking, and maintenance of function remain to be a challenge in many of these approaches, which are based on peripheral T cell modification. To overcome many of these issues, we have previously demonstrated successful long-term engraftment and production of anti-HIV CAR T cells in modified hematopoietic stem cells (HSCs) in vivo. Here we report the development and in vivo testing of second generation CD4-based CARs (CD4CAR) against HIV-1 infection using a HSCs-based approach. We found that a modified, truncated CD4-based CAR (D1D2CAR) allows better CAR-T cell differentiation from gene modified HSCs, and maintains similar CTL activity as compared to the full length CD4-based CAR. In addition, D1D2CAR does not mediate HIV infection or stimulation mediated by IL-16, suggesting lower risk of off-target effects. Interestingly, stimulatory domains of 4-1BB but not CD28 allowed successful hematopoietic differentiation and improved anti-viral function of CAR T cells from CAR modified HSCs. Addition of 4-1BB to CD4 based CARs led to faster suppression of viremia during early untreated HIV-1 infection. D1D2CAR 4-1BB mice had faster viral suppression in combination with ART and better persistence of CAR T cells during ART. In summary, our data indicate that the D1D2CAR-41BB is a superior CAR, showing better HSC differentiation, viral suppression and persistence, and less deleterious functions compared to the original CD4CAR, and should continue to be pursued as a candidate for clinical study.

Anti-viral monoclonal antibody (mAb) treatments may provide immediate but short-term immunity from coronavirus disease 2019 (COVID-19) in high-risk populations, such as people with diabetes and the elderly; however, data on their efficacy in these populations are limited. We demonstrate that prophylactic mAb treatment blocks viral replication in both the upper and lower respiratory tracts in aged, type 2 diabetic rhesus macaques. mAb infusion dramatically curtails severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-mediated stimulation of interferon-induced chemokines and T cell activation, significantly reducing development of interstitial pneumonia. Furthermore, mAb infusion significantly dampens the greater than 3-fold increase in SARS-CoV-2-induced effector CD4 T cell influx into the cerebrospinal fluid. Our data show that neutralizing mAbs administered preventatively to high-risk populations may mitigate the adverse inflammatory consequences of SARS-CoV-2 exposure.

Type 1 diabetes (T1D), Hashimoto’s thyroiditis (HT), Graves’ disease (GD), and autoimmune Addison’s disease (AD) appear to share immunogenetic mechanisms. This idea is not novel, as “autoimmune tautology” is an established concept. An issue with previous studies is that no or few simultaneous comparisons between these autoimmune endocrine diseases have been made. Due to methodological limitations, immune deviations associated with these diseases have also been examined for a limited number of immune cell lineages and analytes. High-dimensional single-cell mass cytometry was thus employed to phenotypically characterise all peripheral CD45+ cell lineages, whilst immune-related proteins in plasma and cell supernatants were analysed by proximity extension assay. Patients with new-onset T1D, HT, and AD had altered frequencies of distinct clusters within antigen-presenting and cytotoxic cell lineages. Importantly, previously unreported alterations of rare cell subsets from patients with HT and AD were identified. The systemic immunoprofile of patients with autoimmune endocrine diseases was in general similar. However, an increased abundance of CDCP1 and SLAMF1 in plasma from patients with T1D, HT, and GD might reflect a higher degree of inflammation and lymphocyte activation. Pregnancy in healthy women entails two important features: 1) an increase in fractional β-cell area and 2) peripheral immunomodulation. The effects of pregnancy on T1D remain nevertheless equivocal, as there are conflicting results on β-cell function and longitudinal analyses on peripheral immunity are lacking. β-cell function and the plasma proteome in pregnant women with long-standing T1D (L-T1D) were therefore examined during three occasions: 1) first trimester, 2) third trimester, and 3) two months postpartum. An oral glucose tolerance test was performed to measure both fasting and stimulated C-peptide concentrations in plasma. Plasma proteins related to cell regulatory and immunological processe

Epigenetic changes have been consistently detected in different cell types in multiple sclerosis (MS). However, their contribution to MS pathogenesis remains poorly understood partly because of sample heterogeneity and limited coverage of array-based methods. To fill this gap, we conducted a comprehensive analysis of genome-wide DNA methylation patterns in four peripheral immune cell populations isolated from 29 MS patients at clinical disease onset and 24 healthy controls. We show that B cells from new-onset untreated MS cases display more significant methylation changes than other disease-implicated immune cell types, consisting of a global DNA hypomethylation signature. Importantly, 4,933 MS-associated differentially methylated regions in B cells were identified, and this epigenetic signature underlies specific genetic programs involved in B cell differentiation and activation. Integration of the methylome to changes in gene expression and susceptibility-associated regions further indicates that hypomethylated regions are significantly associated with the up-regulation of cell activation transcriptional programs. Altogether, these findings implicate aberrant B cell function in MS etiology.

Activation of T cells requires a rapid surge in cellular protein synthesis. However, the role of translation initiation in the early induction of specific genes remains unclear. Here, we show human translation initiation factor eIF3 interacts with select immune system related mRNAs including those encoding the T cell receptor (TCR) subunits TCRA and TCRB. Binding of eIF3 to the TCRA and TCRB mRNA 3'-untranslated regions (3'-UTRs) depends on CD28 coreceptor signaling and regulates a burst in TCR translation required for robust T cell activation. Use of the TCRA or TCRB 3'-UTRs to control expression of an anti-CD19 chimeric antigen receptor (CAR) improves the ability of CAR-T cells to kill tumor cells in vitro. These results identify a new mechanism of eIF3-mediated translation control that can aid T cell engineering for immunotherapy applications.

Tobacco smoking is known to impact circulating levels of major immune cells populations, but its effect on specific immune cell subsets remains poorly understood. Here, using high-resolution data from 223 healthy women (25 current and 198 never smokers), we investigated the association between smoking status and 35,651 immune traits capturing immune cell subset frequencies. Our results confirmed that active tobacco smoking is associated with increased frequencies of circulating CD8+ T cells expressing the CD25 activation marker. Moreover, we identified novel associations between smoking status and relative abundances of CD8+ CD25+ memory T cells, CD8+ memory T cells expressing the CCR4 chemokine receptor, and CD4+CD8+ (double-positive) CD25+ T cells. We also observed, in current smokers, a decrease in the relative frequencies of CD4+ T cells expressing the CD38 activation marker and an increase in class-switched memory B cell isotypes IgA, IgG, and IgE. Finally, using data from 135 former female smokers, we showed that the relative frequencies of immune traits associated with active smoking are usually completely restored after smoking cessation, with the exception of subsets of CD8+ and CD8+ memory T cells, which persist partially altered. Our results are consistent with previous findings and provide further evidence on how tobacco smoking shapes leukocyte cell subsets proportion toward chronic inflammation.

Biomaterials can improve the safety and presentation of therapeutic agents for effective immunotherapy, and a high level of control over surface functionalization is essential for immune cell modulation. Here, we developed biocompatible immune cell-engaging particles (ICEp) that use synthetic short DNA as scaffolds for efficient and tunable protein loading. To improve the safety of chimeric antigen receptor (CAR) T cell therapies, micrometre-sized ICEp were injected intratumorally to present a priming signal for systemically administered AND-gate CAR-T cells. Locally retained ICEp presenting a high density of priming antigens activated CAR T cells, driving local tumour clearance while sparing uninjected tumours in immunodeficient mice. The ratiometric control of costimulatory ligands (anti-CD3 and anti-CD28 antibodies) and the surface presentation of a cytokine (IL-2) on ICEp were shown to substantially impact human primary T cell activation phenotypes. This modular and versatile biomaterial functionalization platform can provide new opportunities for immunotherapies.

B cell clones compete for entry into and dominance within germinal centers (GCs), where the highest-affinity B cell receptors (BCRs) are selected. However, diverse and low-affinity B cells can enter and reside in GCs for extended periods. To reconcile these observations, we hypothesize that a negative feedback loop may operate within B cells to preferentially restrain high-affinity clones from monopolizing the early GC niche. Here, we report a role for the nuclear receptor NUR77/Nr4a1 in this process. We show that NUR77 expression scales with antigen stimulation and restrains B cell expansion. Although NUR77 is dispensable for regulating GC size when GCs are elicited in a largely clonal manner, it serves to curb immunodominance under conditions where diverse clonal populations must compete for a constrained niche. We propose that this is important to preserve early clonal diversity in order to limit holes in the post-immune repertoire and to optimize GC selection.

Due to the durability and persistence of reservoirs of HIV-1-infected cells, combination antiretroviral therapy (ART) is insufficient in eradicating infection. Achieving HIV-1 cure or sustained remission without ART treatment will require the enhanced and persistent effective antiviral immune responses. Chimeric Antigen Receptor (CAR) T-cells have emerged as a powerful immunotherapy and show promise in treating HIV-1 infection. Persistence, trafficking, and maintenance of function remain to be a challenge in many of these approaches, which are based on peripheral T cell modification. To overcome many of these issues, we have previously demonstrated successful long-term engraftment and production of anti-HIV CAR T cells in modified hematopoietic stem cells (HSCs) in vivo. Here we report the development and in vivo testing of second generation CD4-based CARs (CD4CAR) against HIV-1 infection using a HSCs-based approach. We found that a modified, truncated CD4-based CAR (D1D2CAR) allows better CAR-T cell differentiation from gene modified HSCs, and maintains similar CTL activity as compared to the full length CD4-based CAR. In addition, D1D2CAR does not mediate HIV infection or stimulation mediated by IL-16, suggesting lower risk of off-target effects. Interestingly, stimulatory domains of 4-1BB but not CD28 allowed successful hematopoietic differentiation and improved anti-viral function of CAR T cells from CAR modified HSCs. Addition of 4-1BB to CD4 based CARs led to faster suppression of viremia during early untreated HIV-1 infection. D1D2CAR 4-1BB mice had faster viral suppression in combination with ART and better persistence of CAR T cells during ART. In summary, our data indicate that the D1D2CAR-41BB is a superior CAR, showing better HSC differentiation, viral suppression and persistence, and less deleterious functions compared to the original CD4CAR, and should continue to be pursued as a candidate for clinical study.

Anti-viral monoclonal antibody (mAb) treatments may provide immediate but short-term immunity from coronavirus disease 2019 (COVID-19) in high-risk populations, such as people with diabetes and the elderly; however, data on their efficacy in these populations are limited. We demonstrate that prophylactic mAb treatment blocks viral replication in both the upper and lower respiratory tracts in aged, type 2 diabetic rhesus macaques. mAb infusion dramatically curtails severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-mediated stimulation of interferon-induced chemokines and T cell activation, significantly reducing development of interstitial pneumonia. Furthermore, mAb infusion significantly dampens the greater than 3-fold increase in SARS-CoV-2-induced effector CD4 T cell influx into the cerebrospinal fluid. Our data show that neutralizing mAbs administered preventatively to high-risk populations may mitigate the adverse inflammatory consequences of SARS-CoV-2 exposure.

Anti-CD19 chimeric antigen receptor (CD19-CAR)-engineered T cells are approved therapeutics for malignancies. The impact of the hinge domain (HD) and the transmembrane domain (TMD) between the extracellular antigen-targeting CARs and the intracellular signaling modalities of CARs has not been systemically studied. In this study, a series of 19-CARs differing only by their HD (CD8, CD28, or IgG4) and TMD (CD8 or CD28) was generated. CARs containing a CD28-TMD, but not a CD8-TMD, formed heterodimers with the endogenous CD28 in human T cells, as shown by co-immunoprecipitation and CAR-dependent proliferation of anti-CD28 stimulation. This dimerization was dependent on polar amino acids in the CD28-TMD and was more efficient with CARs containing CD28 or CD8 HD than IgG4-HD. The CD28-CAR heterodimers did not respond to CD80 and CD86 stimulation but had a significantly reduced CD28 cell-surface expression. These data unveiled a fundamental difference between CD28-TMD and CD8-TMD and indicated that CD28-TMD can modulate CAR T-cell activities by engaging endogenous partners.

Synovial sarcoma (SS) and myxoid/round cell liposarcoma (MRCL) are ideal solid tumors for the development of adoptive cellular therapy (ACT) targeting NY-ESO-1, as a high frequency of tumors homogeneously express this cancer-testes antigen. Data from early phase clinical trials have shown antitumor activity after the adoptive transfer of NY-ESO-1-specific T cells. In these studies, persistence of NY-ESO-1 specific T cells is highly correlated with response to ACT, but patients often continue to have detectable transferred cells in their peripheral blood following progression. We performed a phase I clinical trial evaluating the safety of NY-ESO-1-specific endogenous T cells (ETC) following cyclophosphamide conditioning. Peripheral blood mononuclear cells (PBMCs) from treated patients were evaluated by flow cytometry and gene expression analysis as well as through ex vivo culture assays with and without IL-15. Four patients were treated in a cohort using ETC targeting NY-ESO-1 following cyclophosphamide conditioning. Treatment was well tolerated without significant toxicity, but all patients ultimately had disease progression. In two of four patients, we obtained post-treatment tumor tissue and in both, NY-ESO-1 antigen was retained despite clear detectable persisting NY-ESO-1-specific T cells in the peripheral blood. Despite a memory phenotype, these persisting cells lacked markers of proliferation or activation. However, in ex vivo culture assays, they could be induced to proliferate and kill tumor using IL-15. These results were also seen in PBMCs from two patients who received gene-engineered T-cell receptor-based products at other centers. ETC targeting NY-ESO-1 with single-agent cyclophosphamide alone conditioning was well tolerated in patients with SS and those with MRCL. IL-15 can induce proliferation and activity in persisting NY-ESO-1-specific T cells even in patients with disease progression following ACT. These results support future work evaluating wheth

Pain is an unpleasant sensation that alerts one to the presence of obnoxious stimuli or sensations. These stimuli are transferred by sensory neurons to the dorsal root ganglia-spinal cord and finally to the brain. Glial cells in the peripheral nervous system, astrocytes in the brain, dorsal root ganglia, and immune cells all contribute to the development, maintenance, and resolution of pain. Both innate and adaptive immune responses modulate pain perception and behavior. Neutrophils, microglial, and T cell activation, essential components of the innate and adaptive immune responses, can play both excitatory and inhibitory roles and are involved in the transition from acute to chronic pain. Immune responses may also exacerbate pain perception by modulating the function of the cortical-limbic brain regions involved in behavioral and emotional responses. The link between an emotional state and pain perception is larger than what is widely acknowledged. In positive psychological states, perception of pain along with other somatic symptoms decreases, whereas in negative psychological states, these symptoms may worsen. Sex differences in mechanisms of pain perception are not well studied. In this review, we highlight what is known, controversies, and the gaps in this field.

Activation of T cells requires a rapid surge in cellular protein synthesis. However, the role of translation initiation in the early induction of specific genes remains unclear. Here, we show human translation initiation factor eIF3 interacts with select immune system related mRNAs including those encoding the T cell receptor (TCR) subunits TCRA and TCRB. Binding of eIF3 to the TCRA and TCRB mRNA 3'-untranslated regions (3'-UTRs) depends on CD28 coreceptor signaling and regulates a burst in TCR translation required for robust T cell activation. Use of the TCRA or TCRB 3'-UTRs to control expression of an anti-CD19 chimeric antigen receptor (CAR) improves the ability of CAR-T cells to kill tumor cells in vitro. These results identify a new mechanism of eIF3-mediated translation control that can aid T cell engineering for immunotherapy applications.

Epigenetic changes have been consistently detected in different cell types in multiple sclerosis (MS). However, their contribution to MS pathogenesis remains poorly understood partly because of sample heterogeneity and limited coverage of array-based methods. To fill this gap, we conducted a comprehensive analysis of genome-wide DNA methylation patterns in four peripheral immune cell populations isolated from 29 MS patients at clinical disease onset and 24 healthy controls. We show that B cells from new-onset untreated MS cases display more significant methylation changes than other disease-implicated immune cell types, consisting of a global DNA hypomethylation signature. Importantly, 4,933 MS-associated differentially methylated regions in B cells were identified, and this epigenetic signature underlies specific genetic programs involved in B cell differentiation and activation. Integration of the methylome to changes in gene expression and susceptibility-associated regions further indicates that hypomethylated regions are significantly associated with the up-regulation of cell activation transcriptional programs. Altogether, these findings implicate aberrant B cell function in MS etiology.

Pulmonary ischemia-reperfusion injury (IRI) is a clinical syndrome of acute lung injury that occurs after lung transplantation or remote organ ischemia. IRI causes early mortality and has no effective therapies. While NK cells are innate lymphocytes capable of recognizing injured cells, their roles in acute lung injury are incompletely understood. Here, we demonstrated that NK cells were increased in frequency and cytotoxicity in 2 different IRI mouse models. We showed that NK cells trafficked to the lung tissue from peripheral reservoirs and were more mature within lung tissue. Acute lung ischemia-reperfusion injury was blunted in a NK cell-deficient mouse strain but restored with adoptive transfer of NK cells. Mechanistically, NK cell NKG2D receptor ligands were induced on lung endothelial and epithelial cells following IRI, and antibody-mediated NK cell depletion or NKG2D stress receptor blockade abrogated acute lung injury. In human lung tissue, NK cells were increased at sites of ischemia-reperfusion injury and activated NK cells were increased in prospectively collected human bronchoalveolar lavage in subjects with severe IRI. These data support a causal role for recipient peripheral NK cells in pulmonary IRI via NK cell NKG2D receptor ligation. Therapies targeting NK cells may hold promise in acute lung injury.

T cells experience complex temporal patterns of stimulus via receptor-ligand-binding interactions with surrounding cells. From these temporal patterns, T cells are able to pick out antigenic signals while establishing self-tolerance. Although features such as duration of antigen binding have been examined, our understanding of how T cells interpret signals with different frequencies or temporal stimulation patterns is relatively unexplored. We engineered T cells to respond to light as a stimulus by building an optogenetically controlled chimeric antigen receptor (optoCAR). We discovered that T cells respond to minute-scale oscillations of activation signal by stimulating optoCAR T cells with tunable pulse trains of light. Systematically scanning signal oscillation period from 1 to 150 min revealed that expression of CD69, a T cell activation marker, reached a local minimum at a period of ∼25 min (corresponding to 5 to 15 min pulse widths). A combination of inhibitors and genetic knockouts suggest that this frequency filtering mechanism lies downstream of the Erk signaling branch of the T cell response network and may involve a negative feedback loop that diminishes Erk activity. The timescale of CD69 filtering corresponds with the duration of T cell encounters with self-peptide-presenting APCs observed via intravital imaging in mice, indicating a potential functional role for temporal filtering in vivo. This study illustrates that the T cell signaling machinery is tuned to temporally filter and interpret time-variant input signals in discriminatory ways.

BackgroundFood insecurity is associated with increased morbidity and mortality in people with human immunodeficiency virus (HIV) on antiretroviral therapy, but its relationship with immune dysregulation, a hallmark of HIV infection and comorbidity, is unknown.MethodsIn 241 women participating in the Women's Interagency HIV Study, peripheral blood mononuclear cells were characterized by flow cytometry to identify cell subsets, comprising surface markers of activation (%CD38+HLADR+), senescence (%CD57+CD28-), exhaustion (%PD-1+), and co-stimulation (%CD57- CD28+) on CD4+ and CD8+ T cells. Mixed-effects linear regression models were used to assess the relationships of food insecurity with immune outcomes, accounting for repeated measures at ≤3 study visits and adjusting for sociodemographic and clinical factors.ResultsAt the baseline study visit, 71% of participants identified as non-Hispanic Black, 75% were virally suppressed, and 43% experienced food insecurity. Food insecurity was associated with increased activation of CD4+ and CD8+ T cells, increased senescence of CD8+ T cells, and decreased co-stimulation of CD4+ and CD8+ T cells (all P < .05), adjusting for age, race/ethnicity, income, education, substance use, smoking, HIV viral load, and CD4 count. In stratified analyses, the association of food insecurity with CD4+ T-cell activation was more pronounced in women with uncontrolled HIV (viral load >40 copies/mL and CD4 <500 cells/mm3) but remained statistically significant in those with controlled HIV.ConclusionsFood insecurity may contribute to the persistent immune activation and senescence in women with HIV on antiretroviral therapy, independently of HIV control. Reducing food insecurity may be important for decreasing non-AIDS-related disease risk in this population.

We described a human regulatory T cell (Treg) population activated by IgG+ B cells presenting peptides of the heavy C region (Fc) via processing of the surface IgG underlying a model for B cell-Treg cooperation in the human immune regulation. Functionally, Treg inhibited the polarization of naive T cells toward a proinflammatory phenotype in both a cognate and a noncognate fashion. Their fine specificities were similar in healthy donors and patients with rheumatoid arthritis, a systemic autoimmune disease. Four immunodominant Fc peptides bound multiple HLA class II alleles and were recognized by most subjects in the two cohorts. The presentation of Fc peptides that stimulate Treg through the processing of IgG by dendritic cells (DC) occurred in myeloid DC classical DC 1 and classical DC 2. Different routes of Ag processing of the IgG impacted Treg expansion in rheumatoid arthritis patients.

B cells constitute a main branch adaptive immune system. They mediate host defence through the production of high-affinity antibodies against an enormous diversity of foreign antigens. Remarkably, B cells undergo multiple types of somatic DNA mutation to achieve this effector function, including class switch recombination (CSR) and somatic hypermutation (SHM). These processes occur in response to antigen recognition and inflammatory signals, and require strict biological control at multiple levels. Transcription within the locus that encodes antibodies plays direct roles in CSR. Additional non-coding RNAs (ncRNAs), including both microRNAs (miRNAs) and long ncRNAs (lncRNAs), also play pivotal roles in B cell activation and terminal effector function through post-transcriptional gene regulation and chromatin remodelling, respectively.

We demonstrate that human immunodeficiency virus (HIV) gag p24 protein is more readily detected in gut and lymph node tissues than in blood CD4+ T cells and correlates better with CD4 count during antiretroviral therapy (ART). Gut p24 levels also measurably decline with ART in natural controllers. During ART, gut p24 expression is more strongly associated both with HIV-specific CD8+ T-cell frequency and plasma soluble CD14 levels than gut HIV RNA expression. This study supports using gag p24 as a marker of HIV expression in HIV+ tissues to study effects of viral persistence and to monitor efficacy of treatment in HIV-based clearance studies.

Memory T cells are thought to rely on oxidative phosphorylation and short-lived effector T cells on glycolysis. Here, we investigated how T cells arrive at these states during an immune response. To understand the metabolic state of rare, early-activated T cells, we adapted mass cytometry to quantify metabolic regulators at single-cell resolution in parallel with cell signaling, proliferation, and effector function. We interrogated CD8+ T cell activation in vitro and in response to Listeria monocytogenes infection in vivo. This approach revealed a distinct metabolic state in early-activated T cells characterized by maximal expression of glycolytic and oxidative metabolic proteins. Cells in this transient state were most abundant 5 days post-infection before rapidly decreasing metabolic protein expression. Analogous findings were observed in chimeric antigen receptor (CAR) T cells interrogated longitudinally in advanced lymphoma patients. Our study demonstrates the utility of single-cell metabolic analysis by mass cytometry to identify metabolic adaptations of immune cell populations in vivo and provides a resource for investigations of metabolic regulation of immune responses across a variety of applications.

Cytotoxic CD8+ T cells play a key role in the elimination of intracellular infections and malignant cells and can provide long-term protective immunity. In the response to infection, CD8+ T cell metabolism is coupled to transcriptional, translational and epigenetic changes that are driven by extracellular metabolites and immunological signals. These programmes facilitate the adaptation of CD8+ T cells to the diverse and dynamic metabolic environments encountered in the circulation and in the tissues. In the setting of disease, both cell-intrinsic and cell-extrinsic metabolic cues contribute to CD8+ T cell dysfunction. In addition, changes in whole-body metabolism, whether through voluntary or disease-induced dietary alterations, can influence CD8+ T cell-mediated immunity. Defining the metabolic adaptations of CD8+ T cells in specific tissue environments informs our understanding of how these cells protect against pathogens and tumours and maintain tissue health at barrier sites. Here, we highlight recent findings revealing how metabolic networks enforce specific CD8+ T cell programmes and discuss how metabolism is integrated with CD8+ T cell differentiation and function and determined by environmental cues.

Foxp3+ T regulatory (Treg) cells promote immunological tumor tolerance, but how their immune-suppressive function is regulated in the tumor microenvironment (TME) remains unknown. Here, we used intravital microscopy to characterize the cellular interactions that provide tumor-infiltrating Treg cells with critical activation signals. We found that the polyclonal Treg cell repertoire is pre-enriched to recognize antigens presented by tumor-associated conventional dendritic cells (cDCs). Unstable cDC contacts sufficed to sustain Treg cell function, whereas T helper cells were activated during stable interactions. Contact instability resulted from CTLA-4-dependent downregulation of co-stimulatory B7-family proteins on cDCs, mediated by Treg cells themselves. CTLA-4-blockade triggered CD28-dependent Treg cell hyper-proliferation in the TME, and concomitant Treg cell inactivation was required to achieve tumor rejection. Therefore, Treg cells self-regulate through a CTLA-4- and CD28-dependent feedback loop that adjusts their population size to the amount of local co-stimulation. Its disruption through CTLA-4-blockade may off-set therapeutic benefits in cancer patients.

Pancreatic ductal adenocarcinoma (PDAC) patients have a 5-year survival rate of only 8% largely due to late diagnosis and insufficient therapeutic options. Neutrophils are among the most abundant immune cell type within the PDAC tumor microenvironment (TME), and are associated with a poor clinical prognosis. However, despite recent advances in understanding neutrophil biology in cancer, therapies targeting tumor-associated neutrophils are lacking. Here, we demonstrate, using pre-clinical mouse models of PDAC, that lorlatinib attenuates PDAC progression by suppressing neutrophil development and mobilization, and by modulating tumor-promoting neutrophil functions within the TME. When combined, lorlatinib also improves the response to anti-PD-1 blockade resulting in more activated CD8 + T cells in PDAC tumors. In summary, this study identifies an effect of lorlatinib in modulating tumor-associated neutrophils, and demonstrates the potential of lorlatinib to treat PDAC.