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The signaling lymphocytic activation molecule family 3 (SLAMF3) is highly expressed on plasma cells from patients with multiple myeloma (MM) and induces high malignant potential by ERK signaling mediated via the interaction with adaptor proteins SHP2 and GRB2. This study focused on the single-nucleotide polymorphism (SNP) of the SLAMF3 gene (rs509749, 1804A>G, M602V) in MM. The SNP G allele was a major type, and the frequencies of the GG, GA, and AA genotypes were 61.8%, 29.4%, and 8.8%, respectively, in patients with MM, which was almost the same as in healthy the control group in the Japanese population. Interestingly, patients with GG genotypes had significantly shorter overall survival times than patients with GA/AA genotypes. Consistent with those results, SLAMF3-overexpressing KMS-34 cells with the G allele (V602) had higher cell proliferation potential and were more resistant to anti-MM agents than those with the A allele (M602). When those cells were subcutaneously inoculated into NOG mice, tumor sizes in mice receiving V602 cells rapidly increased, and survival was significantly shorter than in mice injected with M602 cells. Furthermore, SLAMF3 V602 molecules bound more tightly to SHP2 and GRB2, with increased SHP2 and ERK phosphorylation compared with M602 cells. The mRNA expression of cell cycle-related genes (CCND1 and CCNE1) and anti-apoptotic genes (BCL2L and p21) was increased in V602 cells compared with M602 cells. The results thus suggested that the G allele of SLAMF3 SNP rs509749 may be associated with MM disease progression.

Background Signaling lymphocytic activation molecule family-7 (SLAMF7) functions as an immune checkpoint molecule on macrophages in antitumor immunity. However, its role in bacterial infection remains largely unknown. Methods Bone marrow-derived macrophages (BMDMs) isolated from wild-type (WT) or SLAMF7 knockout (KO) mice were infected with bacteria or treated with lipopolysaccharide/interferon-γ to investigate the expression and function of SLAMF7 in macrophage polarization. A Pseudomonas aeruginosa keratitis murine model was established to explore the effect of SLAMF7 on P. aeruginosa keratitis using WT vs SLAMF7 KO mice, or recombinant SLAMF7 vs phosphate-buffered saline-treated mice, respectively. Results SLAMF7 expression was enhanced on M1-polarized or bacterial-infected macrophages, and infiltrating macrophages in P. aeruginosa-infected mouse corneas. SLAMF7 promoted M2 polarization by inducing STAT6 activation. In vivo data showed that SLAMF7 KO aggravated, while treatment with recombinant SLAMF7 alleviated, corneal inflammation and disease severity. In addition, blockage of M2 polarization by Arg-1 inhibitor abrogated the effect of recombinant SLAMF7 in disease progression. Conclusions SLAMF7 expression in macrophages was induced upon M1 polarization or bacterial infection and alleviated corneal inflammation and disease progression of P. aeruginosa keratitis by promoting M2 polarization. These findings may provide a potential strategy for the treatment of P. aeruginosa keratitis.

SLAM family receptors are involved in humoral immune regulation. In this issue of JEM, Zhong et al. provide evidence that these receptors collectively suppress germinal center reaction but promote production of antigen-specific antibodies., SLAM family receptors are involved in humoral immune regulation. In this issue of JEM, Zhong et al. (2021. J. Exp. Med. https://doi.org/10.1084/jem.20200756) provide evidence that these receptors collectively suppress germinal center reaction but promote production of antigen-specific antibodies.

T cell exhaustion represents one of the most pervasive strategies tumors employ to circumvent the immune system. Although repetitive, cognate TCR signaling is recognized as the primary driving force behind this phenomenon, and it remains unknown what other forces drive T cell exhaustion in the tumor microenvironment (TME). In this study, we show that activation of the self-ligand SLAMF7 immune receptor on T cells induced STAT1 and STAT3 phosphorylation, expression of multiple inhibitory receptors, and transcription factors associated with T cell exhaustion. Analysis of The Cancer Genome Atlas revealed that SLAMF7 transcript levels were strongly correlated with various inhibitory receptors and that high SLAMF7 expression was indicative of poor survival in clear cell renal cell carcinoma (ccRCC). Targeted reanalysis of a CyTOF dataset, which profiled the TME in 73 ccRCC patients, revealed cell-type–specific SLAMF7 expression patterns, strong correlations between exhausted T cells and SLAMF7+ tumor-associated macrophages (TAMs), and a unique subset of SLAMF7highCD38high TAMs. These SLAMF7highCD38high TAMs showed the strongest correlations with exhausted T cells and were an independent prognostic factor in ccRCC. Confirmatory ex vivo coculture studies validated that SLAMF7–SLAMF7 interactions between murine TAMs and CD8+ T cells induce expression of multiple inhibitory receptors. Finally, mice lacking SLAMF7 show restricted growth of B16-F10 tumors, and CD8+ T cells from these mice express less PD-1 and TOX and exhibited an impaired ability to progress through the exhaustion developmental trajectory to terminal exhaustion. These findings suggest that SLAMF7 might play an important role in modulating T cell function in the TME.

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. The pathophysiology core issue is that the body initiates a severe inflammatory reaction in response to the invasion of pathogenic microorganisms at the initial stage of disease. Subsequently, the body begins to fight inflammation in order to balance immunity status and eventually induces the immune paralysis or immunosuppressive state characterized by exhaustion of immune cell. Both in innate immunity and in acquired immunity, some co-suppressor molecules on the surface of immune cells play important roles in immunosuppression, such as, programmed death receptor-1 (PD-1), T cell immunoglobulin and mucin-containing protein-3 (TIM-3), cytotoxic T lymphocyte associated antigen-4 (CTLA-4), natural killer cell receptor 2B4 (CD244), B and T lymphocyte attenuator (BTLA) and NKG2A (CD94), et al. Blocking the interaction between these co-suppressor molecules and their ligands can significantly reverse the immunosuppressive state in septic animal models or patients. In order to provide a reference for the monitoring and treatment of sepsis immune dysfunction, this article mainly summarizes the new findings on the role of those co-suppressor molecules in sepsis immune dysfunction in recent years.

BackgroundDeveloping novel strategies to overcome the immunosuppressive tumor microenvironment is a critically important area of cancer therapy research. Here, we assess the therapeutic potential of CD244 (2B4/signaling lymphocyte activation molecule family 4), an immunoregulatory receptor found on a variety of immune cells, including exhausted CD8+T cells, dendritic cells (DCs), and myeloid-derived suppressor cells (MDSCs).MethodsUsing de-identified human tumor and blood samples from patients with head and neck squamous cell carcinoma (HNSCC) and HNSCC models in WT and CD244-/-mice, we assessed the therapeutic potential of CD244 using flow cytometry, RT-PCR, Luminex immunoassays and histopathological analyses.ResultsCompared with healthy tissues, tumor infiltrating CD8+T cells from HNSCC patients and a HNSCC mouse model showed significant increased expression of CD244 expression that correlated with PD1 expression. Moreover, CD244 was increased on intratumoral DC and MDSC and high CD244 expression correlated with PD-L1 expression and increased spontaneous expression of immune-suppressive mediators. In addition, CD244 activation inhibited production of proinflammatory cytokines in human DC in vitro. Importantly, CD244-/-mice showed significantly impaired tumor growth of HNSCC and interventional treatment of WT mice with anti-CD244 monoclonal antibody significantly impaired the growth of established HNSCC tumors and increased tumor-infiltrating CD8+T cells.ConclusionsTogether these data suggest that CD244 contributes to the overall immune-suppressive environment and therefore has potential as a new immunotherapy target in the treatment of malignancies.

Seven members of signaling lymphocytic activation molecule (SLAM) family receptors (SFRs) are ubiquitously expressed on hematopoietic cells and they play critical roles in immune cell differentiation and activation. The engagement of these receptors transmits intracellular signaling mainly by recruiting SLAM-associated protein (SAP) and its related adaptors, EWS-FLI1-activated transcript-2 (EAT-2) and EAT-2-related transducer (ERT). The critical roles of SFRs and SAP-family adaptors are highlighted by the discovery that SAP is mutated in human X-linked lymphoproliferative (XLP1) disease in which the contact between T and B cells in germinal center and cytotoxic lymphocytes (NK cells and CD8

The prevailing ‘division of labor’ concept in cellular immunity is that CD8+ T cells primarily utilize cytotoxic functions to kill target cells, while CD4+ T cells exert helper/inducer functions. Multiple subsets of CD4+ memory T cells have been characterized by distinct chemokine receptor expression. Here, we demonstrate that analogous CD8+ memory T-cell subsets exist, characterized by identical chemokine receptor expression signatures and controlled by similar generic programs. Among them, Tc2, Tc17 and Tc22 cells, in contrast to Tc1 and Tc17 + 1 cells, express IL-6R but not SLAMF7, completely lack cytotoxicity and instead display helper functions including CD40L expression. CD8+ helper T cells exhibit a unique TCR repertoire, express genes related to skin resident memory T cells (TRM) and are altered in the inflammatory skin disease psoriasis. Our findings reveal that the conventional view of CD4+ and CD8+ T cell capabilities and functions in human health and disease needs to be revised., We classically consider the T cell compartment divided into cytotoxic CD8+ T cells and multiple, different helper CD4+ T cell subsets. Here the authors demonstrate that distinct memory CD8+ T cell subsets phenotypically inhabit CD4+ T cell like populations including some with helper-like characteristics.

Summary Cell-surface protein-protein interactions (PPIs) mediate cell-cell communication, recognition, and responses. We executed an interactome screen of 564 human cell-surface and secreted proteins, most of which are immunoglobulin superfamily (IgSF) proteins, using a high-throughput, automated ELISA-based screening platform employing a pooled-protein strategy to test all 318,096 PPI combinations. Screen results, augmented by phylogenetic homology analysis, revealed ∼380 previously unreported PPIs. We validated a subset using surface plasmon resonance and cell binding assays. Observed PPIs reveal a large and complex network of interactions both within and across biological systems. We identified new PPIs for receptors with well-characterized ligands and binding partners for “orphan” receptors. New PPIs include proteins expressed on multiple cell types and involved in diverse processes including immune and nervous system development and function, differentiation/proliferation, metabolism, vascularization, and reproduction. These PPIs provide a resource for further biological investigation into their functional relevance and may offer new therapeutic drug targets., Graphical Abstract, Highlights • Human IgSF interactome reveals complex network of cell-surface protein interactions • Phylogenetic homology analysis predicts protein-protein interactions • ∼380 previously unknown protein-protein interactions identified • Deorphanization of receptors and new binding partners for well-studied receptors, A high-throughput protein-protein interaction screen, carried out to map human cell-surface receptor-ligand interactions between proteins belonging to the immunoglobulin domain superfamily (IgSF), begins to unravel the complex network of cell-surface interactions that allows cells to recognize and respond to one another and their dynamically changing environment.

Signaling lymphocytic activation molecule family member 8 (SLAMF8), B-lymphocyte activator macrophage expressed/CD353 is a member of the CD2 family. SLAMF8 suppresses macrophage function but enhances the growth of neoplastic mast cells via SHP-2. In this study, we found that some anaplastic large cell lymphoma (ALCL) samples were immunohistochemically positive for SLAMF8. However, we found no significant differences between SLAMF8-positive and SLAMF8-negative ALCL samples with respect to age, gender, site, or prognosis. We also identified SLAMF8 expression in ALCL cell lines, Karpas299, and SU-DHL-1. SLAMF8 knockdown decreased the activation of SHP-2 and the growth of these cell lines, and increased the apoptosis of these cell lines. In addition, we observed the interaction between SLAMF8 and SHP-2 in these cell lines using the DuoLink in situ kit. Taken together, these results suggest that SLAMF8 may enhance the growth of ALCL via SHP-2 interaction.

Multiple myeloma (MM) is a plasma cell malignancy and most patients eventually succumb to the disease. Chimeric antigen receptor (CAR) T cells targeting B-Cell Maturation Antigen (BCMA) on MM cells have shown high-response rates, but limited durability. CD229/LY9 is a cell surface receptor present on B and T lymphocytes that is universally and strongly expressed on MM plasma cells. Here, we develop CD229 CAR T cells that are highly active in vitro and in vivo against MM plasma cells, memory B cells, and MM-propagating cells. We do not observe fratricide during CD229 CAR T cell production, as CD229 is downregulated in T cells during activation. In addition, while CD229 CAR T cells target normal CD229high T cells, they spare functional CD229neg/low T cells. These findings indicate that CD229 CAR T cells may be an effective treatment for patients with MM., CD229 is expressed on the surface of multiple myeloma cells, as well as B and T lymphocytes. Here, the authors engineer CD229-specific CAR T cells and, using patient samples and mouse models, show that treatment with these cells reduces tumour burden and results in limited targeting of T cells.

Myeloid-derived suppressor cells (MDSCs) are innate immune cells that acquire the capacity to suppress adaptive immune responses during cancer. It remains elusive how MDSCs differ from their normal myeloid counterparts, which limits our ability to specifically detect and therapeutically target MDSCs during cancer. Here, we used single-cell RNAseq to compare MDSC-containing splenic myeloid cells from breast tumor-bearing mice to wildtype controls. Our computational analysis of 14,646 single-cell transcriptomes reveals that MDSCs emerge through a previously unrealized aberrant neutrophil maturation trajectory in the spleen giving rise to a unique chemokine-responsive, immunosuppressive cell state that strongly differs from normal myeloid cells. We establish the first MDSC-specific gene signature and identify novel surface markers for improved detection and enrichment of MDSCs in murine and human samples. Our study provides the first single-cell transcriptional map defining the development of MDSCs, which will ultimately enable us to specifically target these cells in cancer patients.One Sentence SummaryWe used single cell transcriptomics to identify the unique molecular features distinguishing myeloid-derived suppressor cells (MDSCs) from their normal, myeloid counterparts, which enabled us to reveal distinct transitory gene expression changes during their maturation in the spleen, and to identify novel cell surface markers for improved detection and isolation of MDSCs.

Mutations in SH2D1A, encoding the intracellular adaptor signaling lymphocyte activation molecule associated protein (SAP), are associated with X-linked lymphoproliferative disease type 1 (XLP1). We identified a novel hemizygous SH2D1A c.49G > A (p.E17K) variant in a 21-year-old patient with fatal Epstein-Barr virus infection-associated hemophagocytic lymphohistiocytosis. Cellular and biochemical assays revealed normal expression of the SAP variant protein, yet binding to phosphorylated CD244 receptor was reduced by >95%. Three healthy brothers carried the SH2D1A c.49G > A variant. Thus, data suggest that this variant represents a pathogenic mutation, but with variable expressivity. Importantly, our results highlight challenges in the clinical interpretation of SH2D1A variants and caution in using functional flow cytometry assays for the diagnosis of XLP1.

Background Follicular helper CD4+ T (Tfh) cells have a critical role in IgG4 production by B cells in IgG4-related disease (IgG4-RD). Recent studies including ours showed that SLAMF7+CD4+ T cells are an important pathological driver of IgG4-RD. In this study, we have sought to elucidate a relationship between helper CD4+ T (Th), particularly Tfh, cells and SLAMF7+ CD4+ T cells in IgG4-RD. Results The patients with IgG4-RD enrolled in this study were aged 66 ± 12 years and their titers of serum IgG4 were 372 ± 336 mg/dl. Th1 cells, activated circulating Tfh1 (cTfh1), and activated cTfh2 cells increased in IgG4-RD. SLAMF7 was mainly expressed on Th1 and cTfh1, but not cTfh2, cells in the patients. SLAMF7+ cTfh1 cells were PD-1/CD28 double-positive, whereas SLAMF7+ Th1 cells were CD28 negative. Positive correlations were noted between serum IgG4 levels and the number of activated cTfh2 cells and SLAMF7+ cTfh1 cells, but not SLAMF7+ Th1 cells. Intriguingly, among cTfh1 cells, activated SLAMF7+ cTfh1 cells were high producers of IL-10 along with IL-21. Blimp-1, but not Bcl-6, mRNA was expressed at high levels in activated SLAMF7+ cTfh1 cells. In addition to CD4+ T cells, the frequency of SLAMF7+ fraction was higher in memory B cells than naïve B cells in patients with IgG4RD. Finally, upon stimulation via B-cell receptor and CD40, Tfh1-associated cytokines, IL-21 and IFN-γ, most significantly induced SLAMF7 expression in memory B cells. Conclusions Together, these results suggest that circulating SLAMF7+ Tfh1 cells, along with Tfh2 cells, play a pathologic role in IgG4 production in IgG4-RD.

[Purpose]: ABBV-838 is an antibody–drug conjugate targeting a unique epitope of CD2 subset 1, a cell-surface glycoprotein expressed on multiple myeloma cells. This phase I/Ib first-in-human, dose-escalation study (trial registration ID: NCT02462525) evaluated the safety, pharmacokinetics, and preliminary activity of ABBV-838 in patients with relapsed and refractory multiple myeloma (RRMM)., [Patients and Methods]: Eligible patients (≥18 years) received ABBV-838 (3+3 design) intravenously starting from 0.6 mg/kg up to 6.0 mg/kg for 3-week dosing intervals (Q3W). Patients could continue ABBV-838 for up to 24 months. Assessment of alternate dosing intervals (Q1W and Q2W) was conducted in parallel., [Results]: As of March 2017, 75 patients received at least one dose of ABBV-838. The most common any-grade treatment-emergent adverse events (TEAE) were neutropenia and anemia (28.0% each), fatigue (26.7%), and nausea (25.3%). Grade 3/4/5 TEAEs were reported in 73.3% of patients across all treatment groups; most common were neutropenia (20.0%), anemia (18.7%), and leukopenia (13.3%). Grade 3/4/5 ABBV-838–related TEAEs were reported by 40.0% of patients across all treatment groups. Overall, 4.0% of patients experienced TEAEs leading to death, none ABBV-838 related. The MTD was not reached; the selected recommended dose for the expansion cohort was 5.0 mg/kg Q3W. Pharmacokinetic analysis showed that exposure was approximately dose proportional. The overall response rate was 10.7%; very good partial responses and partial responses were achieved by 2 (2.7%) and 6 (8.0%) patients, respectively., [Conclusions]: These results demonstrate that ABBV-838 is safe and well-tolerated in patients with RRMM with a very limited efficacy.

The prevailing ‘division of labor’ concept in cellular immunity is that CD8⁺ T cells primarily utilize cytotoxic functions to kill target cells, while CD4⁺ T cells exert helper/inducer functions. Multiple subsets of CD4⁺ memory T cells have been characterized by distinct chemokine receptor expression. Here, we demonstrate that analogous CD8⁺ memory T-cell subsets exist, characterized by identical chemokine receptor expression signatures and controlled by similar generic programs. Among them, Tc2, Tc17 and Tc22 cells, in contrast to Tc1 and Tc17 + 1 cells, express IL-6R but not SLAMF7, completely lack cytotoxicity and instead display helper functions including CD40L expression. CD8⁺ helper T cells exhibit a unique TCR repertoire, express genes related to skin resident memory T cells (TRM) and are altered in the inflammatory skin disease psoriasis. Our findings reveal that the conventional view of CD4⁺ and CD8⁺ T cell capabilities and functions in human health and disease needs to be revised. CA extern

Classical signaling lymphocyte activating molecule (SLAM) family receptors are abundant within many types of immune cells, whereas the nonclassical SLAM family receptors SLAMF8 and SLAMF9, which uniquely lack cytoplasmic signaling motifs, are highly expressed by myeloid cells. Due to the potential redundancy, whether these two receptors regulate macrophage function remains largely unknown. Here, we show that SLAMF8 and SLAMF9 co-regulate macrophage-mediated liver inflammation. To overcome the redundancy, we generated mice that simultaneously lacked SLAMF8 and SLAMF9 using CRISPR-Cas9 technology. Although macrophage differentiation was not altered by the combined deficiency of SLAMF8 and SLAMF9, the loss of these two receptors significantly protected against lipopolysaccharide (LPS)-induced liver injury. SLAMF8 and SLAMF9 double-deficient mice had a prolonged survival rate and less infiltration of inflammatory cells. The depletion of macrophages using clodronate liposomes abolished the effects of SLAMF8 and SLAMF9 deficiencies on LPS-induced liver injury, which demonstrates that these receptors are required for macrophage activation following LPS challenge. Moreover, the deficiency of SLAMF8 and SLAMF9 suppressed the secretion of inflammatory cytokines by downregulating the expression of Toll-like receptor-4 (TLR4), a receptor that specifically binds LPS, which led to decreased mitogen-activated protein kinases (MAPK) signaling activation. Notably, combined injections of truncated extracellular SLAMF8 and SLAMF9 proteins significantly alleviated LPS-induced liver injury. Thus, our findings provide insights into the role of SLAMF8 and SLAMF9 in endotoxin-induced liver injury and suggest that SLAMF8 and SLAMF9 are potential therapeutic targets for acute hepatic injury.

Despite the arrival of novel therapies, multiple myeloma (MM) remains incurable and new treatment options are needed. Chimeric antigen receptor (CAR) T cells are genetically modified T cells that express a CAR directed against specific tumour antigens. CAR T cells are able to kill target tumour cells and may result in long-lasting immune responses in vivo. The rapid development of CAR technologies has led to clinical trials in haematological cancers including MM, and CAR T cells might evolve into a standard treatment in the next few years. Only small patient cohorts with relapsed or refractory disease have so far been investigated, but promising preliminary results with high response rates have been obtained in phase I clinical trials with B cell maturation antigen (BCMA), CD19, CD38 and κ-light-chain CAR T cells. Additional preclinical studies on CD38 and SLAMF7-CAR T cells in MM treatment yielded preclinical results that merit further investigation. Beyond the T cell approach, recent studies have focussed on CAR natural killer (NK) cells in order to increase the reactivity of these effector cells. Finally, to investigate the targeting of intracellular antigens, cellular therapies based on engineered T cell receptors (TCRs) are in development. In this review, we discuss results from preclinical and early-phase clinical trials testing the feasibility and safety of CAR T cell administration in MM, as well as early studies into approaches that utilise CAR NK cell and genetically modified TCRs.

Multiple myeloma (MM) is an incurable hematologic malignancy of plasma cells, with an estimated 30,000 new cases diagnosed each year in the United States, signifying the need for new therapeutic approaches. We hypothesized that targeting MM using a bispecific antibody (biAb) to simultaneously engage both innate and adaptive cytolytic immune cells could present potent antitumor activity. We engineered a biAb by fusing an anti-CS1 single-chain variable fragment (scFv) and an anti-NKG2D scFv (CS1-NKG2D biAb). Although NKG2D is a potent activation receptor ubiquitously expressed on mostly cytolytic immune cells including NK cells, CD8+ T cells, γδ T cells, and NKT cells, the CS1 tumor-associated antigen on MM represents a promising target. CS1-NKG2D biAb engaged human MM cell lines and NKG2D+ immune cells, forming immune synapses. In effector cells, CS1-NKG2D biAb triggered the phosphorylation of AKT, a downstream protein kinase of the activated NKG2D–DAP10 complex. The EC50 values of CS1-NKG2D biAb for CS1high and for CS1low MM cell lines with effector PBMCs were 10−12 and 10−9 mol/L, respectively. CS1-NKG2D biAb acted through multiple types of immune cells, and this induced cytotoxicity was both CS1- and NKG2D-specific. In vivo, survival was significantly prolonged using CS1-NKG2D biAb in a xenograft NOD-SCIDIL2γc−/− (NSG) mouse model engrafted with both human PBMCs and MM cell lines. Collectively, we demonstrated that the CS1-NKG2D biAb facilitated an enhanced immune synapse between CS1+ MM cells and NKG2D+ cytolytic innate and antigen-specific effector cells, which, in turn, activated these immune cells for improved clearance of MM. Cancer Immunol Res; 6(7); 776–87. ©2018 AACR.

The signaling lymphocytic activation molecule (SLAM) family is comprised of nine distinct receptors (SLAMF1 through SLAMF9) that are expressed on hematopoietic cells. All of these receptors, with the exception of SLAMF4, are homotypic by nature as downstream signaling occurs when hematopoietic cells that express the same SLAM receptor interact. The SLAM family receptor function is largely controlled via SLAM associated protein (SAP) family adaptors. The SAP family adaptors consist of SAP, Ewing sarcoma associated transcript (EAT)-2, and EAT-2-related transducer (ERT). These adaptors associate with the cytoplasmic domain of the SLAM family receptors through phosphorylated tyrosines. Defects in SLAM family members and SAP adaptors have been implicated in causing immune deficiencies. This is exemplified in patients with X-linked lymphoproliferative (XLP) disease, where SAP undergoes a loss of function mutation. Furthermore, evidence has been accumulating that SLAM family members are potential targets for inflammatory and autoimmune diseases. This review will discuss the structure and function of the SLAM family receptors and SAP family adaptors, their role in immune regulation, and potential approaches to target this family of receptors therapeutically.

Atherosclerosis (AS) is a multifactorial disease. Exploration of DNA methylation in regulating gene transcription in a cell type- and stage-specific manner will shed light on understanding the biological processes associated with plaque stability. We identified 174 up-regulated genes with hypo-methylation in the promoter, and 86 down-regulated genes with hyper-methylation in the promoter, in AS vs. healthy controls. Among them, high expression of signaling lymphocytic activation molecule 7 (SLAM7) was examined in carotid plaque vs. intact tissue, in advanced plaque vs. early atherosclerotic tissue, and SLAMF7 protein expressed significantly higher in the unstable plaques than that in the stable plaques, especially in the CD68-positive macrophages. Depletion of SLAMF7 in plaque-derived macrophages induced a suppressed secretion of proinflammatory cytokines, and inhibited proliferation of vascular smooth muscle cells. These data provide emerging evidence that SLAMF7 could be a target of potential therapeutic intervention in carotid AS.

The signalling lymphocytic activation molecule family member 8 (SLAMF8)/CD353 is a member of the CD2 family of proteins. Its ligand has not been identified. SLAMF8 is expressed by macrophages and suppresses cellular functions. No study has yet explored SLAMF8 expression or function in human mastocytosis, which features oncogenic KIT-mediated proliferation of human mast cells. SLAMF8 protein was expressed in human mastocytosis cells, immunohistochemically. SLAMF8 expression was also evident in the human mast cell lines, HMC1.2 (expressing oncogenic KIT) and LAD2 (expressing wild-type KIT) cells. SLAMF8 knock-down significantly reduced the KIT-mediated growth of HMC1.2 cells but not that of LAD2 cells. SLAMF8 knock-down HMC1.2 cells exhibited significant attenuation of SHP-2 activation and oncogenic KIT-mediated RAS-RAF-ERK signalling. An interaction between SLAMF8 and SHP-2 was confirmed in HMC1.2 cells and all pathological mastocytosis specimens examined (19 of 19 cases, 100%). Thus, SLAMF8 is involved in oncogenic KIT-mediated RAS-RAF-ERK signalling and the subsequent growth of human neoplastic mast cells mediated by SHP-2. SLAMF8 is a possible therapeutic target in human mastocytosis patients.

Purpose: Multiple myeloma remains an incurable malignancy of plasma cells despite considerable advances in treatment. The purpose of the study was to develop novel chimeric antigen receptors (CAR) for the treatment of multiple myeloma and explore combinatorial therapy using CAR T cells and immunomodulatory drugs such as lenalidomide for increasing treatment efficacy. Experimental Design: We redirected central memory T cells to express second-generation CAR-specific for CS1 and adoptively transferred them into multiple myeloma tumor-bearing mice to test their anti-multiple myeloma activity. CS1 CAR T cells were transduced and expanded in the presence of lenalidomide in vitro. The phenotype and effector function of CS1 CAR T cells treated with and without lenalidomide were compared. Finally, CS1 CAR T cells and lenalidomide were administered to treat multiple myeloma–bearing mice as combinatorial therapy. Results: CS1 CAR T cells exhibited efficient antitumor activity when adoptively transferred into mice. Mechanistic studies indicated that the addition of lenalidomide during CS1 CAR T-cell expansion in vitro enhanced the immune functions of CS1 CAR T cells, including cytotoxicity, memory maintenance, Th1 cytokine production, and immune synapse formation. Furthermore, lenalidomide enhanced the antitumor activity and persistence of adoptively transferred CS1 CAR T cells in vivo. Conclusions: The study demonstrates that lenalidomide improves the anti-multiple myeloma properties of CS1-directed CAR T cells and provides a basis for a planned clinical trial using the combination of lenalidomide with engineered T cells against CS1 in relapsed myeloma. Clin Cancer Res; 24(1); 106–19. ©2017 AACR.

目的 探讨SLAMF6在重型再生障碍性贫血（SAA）CD8+ T细胞中的表达情况及其与疾病免疫状态的相关性。 方法 选取2017年2月至2018年4月天津医科大学总医院血液科收治的初治SAA患者21例，以15例健康人外周血标本作为正常对照，应用流式细胞术（FCM）检测外周血CD8+ T细胞SLAMF6表达量，并与患者HGB、PLT、中性粒细胞绝对值、网织红细胞绝对值、骨髓造血功能（粒系百分比、红系百分比、淋系百分比、巨核细胞数）等临床指标及CD8+ T细胞功能分子穿孔素、颗粒酶B、IFN-γ表达量进行相关性分析。进一步采用anti-SLAMF6 Ab阻断其功能，FCM检测CD8+ T细胞穿孔素、颗粒酶B、IFN-γ分泌量。 结果 初治SAA患者CD8+ T细胞SLAMF6表达量明显低于正常对照，差异有统计学意义[（56.29±12.97）%对（80.96±7.36）%，t=−7.672，P

Summary Blockade of the CD80/86-CD28 pathway by belatacept after kidney transplantation is associated with an increased risk of rejection compared with standard, calcineurin inhibitor (CNI)-based therapy. CD28− T cells, which express CD57, are not susceptible to belatacept treatment. High numbers of CD4+CD57+programmed death 1 (PD-1)− T cells pretransplantation have been associated with a higher chance of rejection, although conflicting data have been reported. To investigate the working mechanism behind this possible higher chance of rejection, we studied the expression of co-inhibitory molecules (CD223, CD244 and PD-1), proliferative capacity and cytotoxic potential of fluorescence activated cell sorted (FACS) CD4+CD57+PD-1− and CD8+CD57+PD-1− T cells, and their CD57− control populations, after alloantigen stimulation. The effect of belatacept on the cytotoxic capacity of pretransplantation peripheral blood mononuclear cells from 20 patients who received belatacept post-transplantation was also tested. Expression of co-inhibitory molecule CD223 increased by approximately 10-fold after allogeneic stimulation in all four T cell subsets. Proliferation and up-regulation of CD244 and PD-1 was observed for CD4+CD57−PD-1− T cells after allogeneic stimulation, but no up-regulation of these markers occurred on CD8+ T cells or CD4+CD57+PD-1− T cells. However, CD4+CD57+PD-1− T cells and, to a lesser extent, CD8+CD57+PD-1− T cells displayed higher cytotoxicity as indicated by granzyme B expression. Belatacept inhibited the cytotoxic potential of CD4+CD57+PD-1− T cells (median of inhibition 31%, P < 0·01) and CD8+CD57+PD-1− T cells (median of inhibition 10%, P < 0·05). In conclusion, alloantigen-activated CD4+CD57+PD-1− T cells exhibited a less proliferative but more cytotoxic profile than their CD57− counterparts. Their cytotoxic capacity can be inhibited partly by belatacept and was not associated with development of rejection after kidney transplantation.

Systemic mastocytosis (SM), a rare myeloid neoplasm, is caused by the accumulation of abnormal mast cells (MCs) in bone marrow, spleen, gastrointestinal tract, liver, and skin, and is characterized...

Summary: Blockade of the inhibitory checkpoint SIRPα-CD47 promotes phagocytosis of cancer cells by macrophages and is a promising avenue in anti-cancer therapy. Productive phagocytosis is strictly predicated on co-engagement of pro-phagocytic receptors—namely, Fc receptors (FcRs), integrin CD11b, or SLAMF7—by their ligands on cancer cells. Here, we examine whether additional pro-phagocytic receptors could be harnessed to broaden the scope of phagocytosis. Inflammatory stimuli, including multiple cytokines and Toll-like receptor (TLR) ligands, augment phagocytosis efficiency and fully alleviate the requirement of FcRs, CD11b, and SLAMF7 for phagocytosis. These effects are mediated by the unconventional pro-phagocytic integrins CD11a and CD11c, which act with CD18 to initiate actin polarization, leading to phagocytosis. Some inflammatory stimuli enable phagocytosis even in the absence of SIRPα-CD47 blockade. Higher CD11c expression in macrophage-enriched tumors correlates with improved survival in clinical studies. Thus, inflammatory macrophages exploit unconventional pro-phagocytic integrins for improved phagocytosis and anti-tumor immunity.

Invariant natural killer T (iNKT) cells develop into three subsets (NKT1, NKT2, and NKT17) expressing a distinct transcription factor profile, which regulates cytokine secretion upon activation. iNKT cell development in the thymus is modulated by signaling lymphocytic activation molecule family (SLAMF) receptors. In contrast to other SLAMF members, Ly9 (SLAMF3) is a non-redundant negative regulator of iNKT cell development. Here, we show that Ly9 influences iNKT cell lineage differentiation. Ly9-deficient mice in a BALB/c background contained a significantly expanded population of thymic NKT2 cells, while NKT1 cells were nearly absent in BALB/c.Ly9−/− thymus. Conversely, the number of peripheral NKT1 cells in BALB/c.Ly9−/− mice was comparable to that in wild-type mice, indicating that the homeostasis of the different iNKT cell subsets may have distinct requirements depending on their tissue localization. Importantly, Ly9 absence also promoted NKT2 cell differentiation in the NKT1-skewed C57BL/6 background. Furthermore, treatment of wild-type mice with an agonistic monoclonal antibody directed against Ly9 impaired IL-4 and IFN-γ production and reduced by half the number of spleen iNKT cells, with a significant decrease in the proportion of NKT2 cells. Thus, anti-Ly9 targeting could represent a novel therapeutic approach to modulate iNKT cell numbers and activation.

The control of lymphoid homeostasis is the result of a very fine balance between lymphocyte production, proliferation, and apoptosis. In this study, we focused on the role of T cells in the maintenance/survival of the mature naive peripheral B cell population. We show that naive B and T cells interact via the signaling lymphocyte activation molecule (SLAM) family receptor, SLAMF6. This interaction induces cell type–specific signals in both cell types, mediated by the SLAM-associated protein (SAP) family of adaptors. This signaling results in an upregulation of the expression of the cytokine migration inhibitory factor in the T cells and augmented expression of its receptor CD74 on the B cell counterparts, consequently enhancing B cell survival. Furthermore, in X-linked lymphoproliferative disease patients, SAP deficiency reduces CD74 expression, resulting in the perturbation of B cell maintenance from the naive stage. Thus, naive T cells regulate B cell survival in a SLAMF6- and SAP-dependent manner.

Current clinical outcomes using chimeric-antigen receptors (CARs) against multiple myeloma show promise in the eradication of bulk disease. However, these anti-BCMA (CD269) CARs observe relapse as a common phenomenon after treatment due to the reemergence of either antigen-positive or -negative cells. Hence, the development of improvements in CAR design to target antigen loss and increase effector cell persistency represents a critical need. Here, we report on the anti-tumor activity of a CAR T-cell possessing two complete and independent CAR receptors against the multiple myeloma antigens BCMA and CS1. We determined that the resulting compound CAR (cCAR) T-cell possesses consistent, potent and directed cytotoxicity against each target antigen population. Using multiple mouse models of myeloma and mixed cell populations, we are further able to show superior in vivo survival by directed cytotoxicity against multiple populations compared to a single-expressing CAR T-cell. These findings indicate that compound targeting of BCMA and CS1 on myeloma cells can potentially be an effective strategy for augmenting the response against myeloma bulk disease and for initiation of broader coverage CAR therapy.

Background aims Light chain amyloidosis (AL) is a protein deposition disorder that is a result of a plasma cell dyscrasia, similar to multiple myeloma (MM). Immunotherapy is an attractive approach because of the low burden of disease, but the optimal target for AL is unclear. CS1 and B-cell maturation antigen (BCMA) are two potential targets because they are expressed on normal plasma cells and MM cells. Methods We performed a prospective study evaluating bone marrow specimens of 20 patients with plasma cell diseases, 10 with AL and 10 with MM. We evaluated the clonal population of plasma cells for BCMA and CS1 expression. We designed a second-generation CS1 chimeric antigen receptor (CAR) construct, comprising a CS1 antigen-specific scFv, shortened hinge region and CD28 costimulatory domain. Purified central memory T cells were activated and transduced with a lentiviral vector encoding the CS1 CAR. Cytotoxicity was evaluated using 51Cr release assays. Five days after tumor inoculation, NSG mice were injected intravenously with CS1 CAR T cells. Results Whereas CS1 is present on the plasma cells of AL patients, we found BCMA expression in AL to be markedly low. CS1 CAR T cells were cytotoxic against CS1 positive tumor cells and induced durable tumor regressions in mice. Discussion Our work represents a novel application of CS1-directed CAR T cells while revealing that BCMA would not be a suitable target. We expect AL to be particularly susceptible to CAR T-cell therapy because of the low tumor burden in the bone marrow.

Treatment of multiple myeloma has undergone significant change in the last decade with the introduction of new immunomodulatory agents, proteasome inhibitors, and immunotherapeutic approaches. Elotuzumab is a humanized monoclonal antibody targeting CS1, which is a member of the SLAM (Signaling Lymphocyte Activation Molecule) family of proteins, expressed on the surface of myeloma plasma cells. Here we review the preclinical investigations that led to the development of elotuzumab and the clinical studies that resulted in its approval for the treatment of relapsed/refractory multiple myeloma. Although preclinical data looked very promising, elotuzumab monotherapy did not result in objective clinical responses in patients with relapsed/refractory multiple myeloma. However, combination treatment with immunomodulators and proteasome inhibitors resulted in substantial clinical activity in relapsed/refractory MM. Currently, there are several clinical trials ongoing investigating the role of elotuzumab in newly diagnosed myeloma patients and in patients receiving maintenance therapy.

The signalling lymphocyte activation molecule (SLAM) family receptors play important roles in modulating immune responses. Previous studies in murine models and patients have suggested an association of the SLAM family (SLAMF) members with the development of autoimmunity, particularly systemic lupus erythematosus (SLE). Since previous investigations on CD244 expression have focussed on NK and T cells, the aim of this study was to evaluate the surface expression of major SLAMF members across monocytes and polymorphonuclear cells in an Asian SLE cohort and explore their potential associations with SLE-related disease activity and autoantibodies. Thirty-nine SLE patients and twenty-nine healthy controls (HC) were evaluated for the expression of CD150, CD84, CD229, CD48, CD244, CD352 and CD319. We determined a significantly lower expression of CD244 on monocytes in SLE patients compared to HC. Furthermore, monocyte CD244 expression was negatively associated with several serum autoantibody titres. Our findings suggest that this molecule plays an important role in immune tolerance mechanisms and should be investigated further. Electronic supplementary material The online version of this article (doi:10.1007/s10067-017-3698-2) contains supplementary material, which is available to authorized users.

Predicting susceptibility of various species to a virus assists assessment of risk of interspecies transmission. Evaluation of receptor functionality may be useful in screening for susceptibility. In this study, docking simulation was conducted for measles virus hemagglutinin (MV‐H) and immunoglobulin‐like variable domain of signaling lymphocyte activation molecule (SLAM‐V). It was observed that the docking scores for MV‐H and SLAM‐V correlated with the activity of SLAM as an MV receptor. These results suggest that the receptor functionality may be predicted from the docking scores of virion surface proteins and cellular receptor molecules.

Contains fulltext : 174073.pdf (Publisher’s version ) (Closed access) BACKGROUND: The effectiveness of biologics for psoriasis shows heterogeneity among patients. With pharmacogenetic markers, it might be possible to predict treatment response. OBJECTIVES: We aimed to test the association between genetic markers and the response to biologics in psoriasis (etanercept, adalimumab, ustekinumab) in a prospective cohort. METHODS: We investigated the copy number variation in the LCE3B and LCE3C genes, and eight single-nucleotide polymorphisms (SNPs) in HLA-C*06, CD84, IL12B, IL23R, TRAF3IP2, ERAP1, IFIH1 and TNFAIP3. The decrease in Psoriasis Area and Severity Index (PASI) was calculated as PASI (absolute PASI decrease compared with baseline) and PASI 75 (proportion of patients with >/= 75% improvement vs. baseline). Associations between genetic variants and treatment outcome were assessed using multivariable linear regression analysis (PASI corrected for baseline PASI, primary analysis) and Pearson's chi2 -test or Fisher's exact test (PASI 75, secondary analysis). RESULTS: We included 348 treatment episodes in 234 patients. Patients heterozygous (GA) for the SNP in CD84 (rs6427528) had a better PASI response to etanercept after 3 months (P = 0.025) than the homozygous reference group (GG). In addition, patients heterozygous (CT) for the IL12B variant showed a better response (PASI) to ustekinumab (P = 0.017) than the reference group (CC). Patients homozygous (GG) for the SNP in TNFAIP3 showed a worse response (PASI) to ustekinumab (P = 0.031) than the reference group (TT). The associations with ustekinumab resulting from the primary analysis were not confirmed in the secondary (PASI 75) analysis. CONCLUSIONS: We demonstrated a strong association between etanercept use in psoriasis and variations in CD84, a gene that was previously found to be a predictor of response to etanercept in rheumatoid arthritis.

Cancer cells elude anti-tumour immunity through multiple mechanisms, including upregulated expression of ligands for inhibitory immune checkpoint receptors1,2. Phagocytosis by macrophages plays a critical role in cancer control3–6. Therapeutic blockade of signal regulatory protein (SIRP)-α, an inhibitory receptor on macrophages, or of its ligand CD47 expressed on tumour cells, improves tumour cell elimination in vitro and in vivo7–10, suggesting that blockade of the SIRPα–CD47 checkpoint could be useful in treating human cancer11–14. However, the prophagocytic receptor(s) responsible for tumour cell phagocytosis is(are) largely unknown. Here we find that macrophages are much more efficient at phagocytosis of haematopoietic tumour cells, compared with non-haematopoietic tumour cells, in response to SIRPα–CD47 blockade. Using a mouse lacking the signalling lymphocytic activation molecule (SLAM) family of homotypic haematopoietic cell-specific receptors, we determined that phagocytosis of haematopoietic tumour cells during SIRPα–CD47 blockade was strictly dependent on SLAM family receptors in vitro and in vivo. In both mouse and human cells, this function required a single SLAM family member, SLAMF7 (also known as CRACC, CS1, CD319), expressed on macrophages and tumour cell targets. In contrast to most SLAM receptor functions15–17, SLAMF7-mediated phagocytosis was independent of signalling lymphocyte activation molecule-associated protein (SAP) adaptors. Instead, it depended on the ability of SLAMF7 to interact with integrin Mac-1 (refs 18–20) and utilize signals involving immunoreceptor tyrosine-based activation motifs21,22. These findings elucidate the mechanism by which macrophages engulf and destroy haematopoietic tumour cells. They also reveal a novel SAP adaptor-independent function for a SLAM receptor. Lastly, they suggest that patients with tumours expressing SLAMF7 are more likely to respond to SIRPα–CD47 blockade therapy.

Elotuzumab is one of the first monoclonal antibodies to be approved for the treatment of multiple myeloma. It is a humanized immunoglobulin G kappa (IgGκ) antibody that targets signaling lymphocytic activation molecule family member 7 (SLAMF7), a surface marker that is highly expressed on normal and malignant plasma cells. This review summarizes the preclinical and clinical data that led to the approval of elotuzumab, along with a discussion on the ongoing and future clinical investigations.

International audience; The therapeutic landscape of multiple myeloma (MM) has evolved spectacularly over the past decade with the discovery and validation of proteasome inhibitors and immunomodulatory agents as highly active agents, both in front-line therapy as well as in the relapse and maintenance settings. Although previous attempts to apply available monoclonal antibodies (Mabs) to the treatment of patients with MM has until recently been disappointing, novel targets specifically explored in the context of MM have recently lead to the first approvals of Mabs for the treatment of patients with MM. We have performed a literature search to identify preclinical targeting of MM, including in vitro and in vivo models using monoclonal antibodies, as well as clinical trials of monoclonal antibodies in patients with MM. Sources used were peer-reviewed publications, congress abstracts and on-line clinical trials data (such as clinicaltrials.gov). Several targets have been evaluated in preclinical models and a growing number of agents are being evaluated in clinical trials, as single agents or in combination and under various antibody formats. Two agents, targeting for the first time CD38 and SLAMF7, respectively, have recently been approved for the treatment of patients with MM. The recent approval of these two antibodies is expected to have a strong impact on treatment modalities and outcome in patients with MM, including both transplant eligible and elderly patients

Chen et al. dissect SAP-dependent and SAP-independent SLAM family signaling in the regulation of NKT cell development and follicular T helper cell differentiation using a novel mouse model lacking all seven SLAM family receptors., Signaling lymphocytic activation molecule (SLAM)–associated protein (SAP) mutations in X-linked lymphoproliferative disease (XLP) lead to defective NKT cell development and impaired humoral immunity. Because of the redundancy of SLAM family receptors (SFRs) and the complexity of SAP actions, how SFRs and SAP mediate these processes remains elusive. Here, we examined NKT cell development and humoral immunity in mice completely deficient in SFR. We found that SFR deficiency severely impaired NKT cell development. In contrast to SAP deficiency, SFR deficiency caused no apparent defect in follicular helper T (TFH) cell differentiation. Intriguingly, the deletion of SFRs completely rescued the severe defect in TFH cell generation caused by SAP deficiency, whereas SFR deletion had a minimal effect on the defective NKT cell development in SAP-deficient mice. These findings suggest that SAP-dependent activating SFR signaling is essential for NKT cell selection; however, SFR signaling is inhibitory in SAP-deficient TFH cells. Thus, our current study revises our understanding of the mechanisms underlying T cell defects in patients with XLP.

Targeting leukemia initiating cells is considered to be an effective way to cure leukemia, for which it is critical to identify novel therapeutic targets. Herein, we demonstrate that CD244, which was initially reported as a key regulator for natural killer cells, is highly expressed on both mouse and human leukemia initiating cells. Upon CD244 knockdown, human leukemia cell lines and primary leukemia cells have markedly impaired proliferation abilities both in vitro and in vivo. Interestingly, the repopulation ability of both mouse and human hematopoietic stem cells is not impaired upon CD244 knockdown. Using an MLL-AF9-induced murine acute myeloid leukemia model, we show that leukemogenesis is dramatically delayed upon CD244 deletion, together with remarkably reduced Mac1+/c-Kit+ leukemia cells (enriched for leukemia initiating cells). Mechanistically, we reveal that CD244 is associated with c-Kit and p27 except for SHP-2 as previously reported. CD244 co-operates with c-Kit to activate SHP-2 signaling to dephosphorylate p27 and maintain its stability to promote leukemia development. Collectively, we provide intriguing evidence that the surface immune molecule CD244 plays an important role in the maintenance of stemness of leukemia initiating cells, but not in hematopoietic stem cells. CD244 may represent a novel therapeutic target for the treatment of acute myeloid leukemia.

Natural Killer (NK) cells play an essential role in antiviral and anti-tumoral immune responses. In peripheral blood, NK cells are commonly classified into two major subsets: CD56brightCD16neg and CD56dimCD16pos despite the characterization of a CD56negCD16pos subset 25 years ago. Since then, several studies have described the prevalence of an CD56negCD16pos NK cell subset in viral non-controllers as the basis for their NK cell dysfunction. However, the mechanistic basis for their cytotoxic impairment is unclear. Recently, using a strict flow cytometry gating strategy to exclude monocytes, we reported an accumulation of CD56negCD16pos NK cells in Plasmodium falciparum malaria-exposed children and pediatric cancer patients diagnosed with endemic Burkitt lymphoma (eBL). Here, we use live-sorted cells, histological staining, bulk RNA-sequencing and flow cytometry to confirm that this CD56negCD16pos NK cell subset has the same morphological features as the other NK cell subsets and a similar transcriptional profile compared to CD56dimCD16pos NK cells with only 120 genes differentially expressed (fold change of 1.5, p < 0.01 and FDR