Lymphocyte Activation Gene-3 Research Articles

Single-Domain Antibody Nuclear Imaging Allows Noninvasive Quantification of LAG-3 Expression by Tumor-Infiltrating Leukocytes and Predicts Response of Immune Checkpoint Blockade.

Recent advances in the field of immune-oncology led to the discovery of next-generation immune checkpoints (ICPs). Lymphocyte activation gene-3 (LAG-3), being the most widely studied among them, is being explored as a target for the treatment of cancer patients. Several antagonistic anti-LAG-3 antibodies are being developed and are prime candidates for clinical application. Furthermore, validated therapies targeting cytotoxic T-lymphocyte-associated protein-4, programmed cell-death protein-1, or programmed cell-death ligand-1 showed that only subsets of patients respond. This finding highlights the need for better tools for patient selection and monitoring. The potential of molecular imaging to detect ICPs noninvasively in cancer is supported by several preclinical and clinical studies. Here, we report on a single-domain antibody to evaluate whole-body LAG-3 expression in various syngeneic mouse cancer models using nuclear imaging. Methods: SPECT/CT scans of tumor-bearing mice were performed 1 h after injection with radiolabeled single-domain antibody. Organs and tumors of mice were isolated and evaluated for the presence of the radiolabeled tracer and LAG-3-expressing immune cells using a γ-counter and flow cytometry respectively. PD-1/LAG-3-blocking antibodies were injected in MC38-bearing mice. Results: The radiolabeled single-domain antibody detected LAG-3 expression on tumor-infiltrating lymphocytes (TILs) as soon as 1 h after injection in MC38, MO4, and TC-1 cancer models. The single-domain antibody tracer visualized a compensatory upregulation of LAG-3 on TILs in MC38 tumors of mice treated with PD-1-blocking antibodies. When PD-1 blockade was combined with LAG-3 blockade, a synergistic effect on tumor growth delay was observed. Conclusion: These findings consolidate LAG-3 as a next-generation ICP and support the use of single-domain antibodies as tools to noninvasively monitor the dynamic evolution of LAG-3 expression by TILs, which could be exploited to predict therapy outcome.

Lymphocyte Activation Gene 3 (Lag3) Contributes to α-Synucleinopathy in α-Synuclein Transgenic Mice.

Aggregation of misfolded α-synuclein (α-syn) is the major component of Lewy bodies and neurites in Parkinson’s disease (PD) and related α-synucleinopathies. Some α-syn mutations (e.g., A53T) in familial PD recapitulate the α-syn pathology in transgenic mice, which supports the importance of pathologic α-syn in driving the pathogenesis of α-synucleinopathies. Lymphocyte activation gene 3 (Lag3) is a receptor of α-syn fibrils facilitating pathologic α-syn spread; however, the role of Lag3 in mediating the pathogenesis in α-syn transgenic mice is not clear. Here, we report that depletion of Lag3 in human α-syn A53T transgenic (hA53T) mice significantly reduces the level of detergent-insoluble α-syn aggregates and phosphorylated ser129 α-syn, and inhibits activation of microglia and astrocytes. The absence of Lag3 significantly delays disease progression and reduces the behavioral deficits in hA53T transgenic mice leading to prolonged survival. Taken together, these results show that Lag3 contributes to the pathogenesis in the α-syn A53T transgenic mouse model.

LAG-3 expression in the inflammatory microenvironment of glioma

PurposeImmune modulatory therapies including immune checkpoint inhibitors have so far failed to result in clinically meaningful efficacy in glioma. We aimed to investigate lymphocyte activation gene 3 (LAG-3), an inhibitory receptor on immune cells and target of second-generation immune checkpoint inhibitors, in glioma.Methods97 patients with diffuse glioma (68 with glioblastoma, 29 with WHO grade II-III glioma) were identified from the Neuro-Biobank of the Medical University of Vienna. LAG-3 expression in the inflammatory microenvironment was assessed by immunohistochemistry (monoclonal anti-LAG-3 antibody, clone 17B4) and correlated to CD3+ , CD8+ , CD20+ and PD-1+ tumor-infiltrating lymphocytes (TILs) and PD-L1 expression on tumor cells.ResultsLAG-3+ TILs could be observed in 10/97 (10.3%) IDH-wildtype samples and in none of the included IDH-mutant glioma samples (p = 0.057). Further, LAG-3+ TILs were only observed in WHO grade IV glioblastoma, while none of the investigated WHO grade II–III glioma presented with LAG-3+ TILs (p = 0.03). No association of O6-methylguanine-DNA-methyltransferase (MGMT) promoter methylation and presence of LAG-3+ TILs was observed (p = 0.726). LAG-3 expression was associated with the presence of CD3+ (p = 0.029), CD8+ (p = 0.001), PD-1+ (p < 0.001) TILs and PD-L1+ tumor cells (p = 0.021), respectively. No association of overall survival with LAG-3+ TIL infiltration was evident (median OS 9.9 vs. 14.2 months, p = 0.95).ConclusionsLAG-3 is only rarely expressed on TILs in IDH-wildtype glioma and associated with active inflammatory milieu as defined by higher TIL density. Immune microenvironment diversity should be considered in the design of future immunotherapy trials in glioma.

P14.03 Increased Tumor-Associated LAG-3+ Lymphocytes Correlate with Aggressive Tumor Behavior and Worse Prognosis in Lung Adenocarcinoma

Immune checkpoint blockade targeting the PD-1/PD-L1 axis has become a mainstay of treatment for advanced non-small cell lung cancer. However, only a subset of patients benefits, with long-term efficacy limited by primary and secondary resistance. Resistance to PD-1 axis blockade is attributed in part to the upregulation by T-lymphocytes of regulatory molecules such as lymphocyte activation gene-3 (LAG-3). This study examined the role of LAG-3+ T-lymphocytes in the lung adenocarcinoma microenvironment through correlation with clinicopathologic features and patient outcomes. Immunohistochemistry for LAG-3 and CD8 was performed on 225 lung adenocarcinomas resected in 2010-2012 using tissue microarrays (duplicate of 2-mm core). The number of LAG-3+ lymphocytes was quantified in 3 high-power fields (HPF; each 0.24 mm2) for each of the two duplicate samples, and CD8+ tumor-associated lymphocytes (both stromal and tumor-infiltrating) were also quantified. LAG-3+ lymphocytes, CD8+ T-cells, and the ratio of LAG-3+/CD8+ T-cells were correlated with clinicopathologic features, PD-L1 expression, and patient outcomes. In lung adenocarcinomas from 225 patients (141 women, 84 men; age 39-89 [median 69] years; 79% smokers; 88% stages 1-2; 40.4% KRAS-mutant; 21.3% EGFR-mutant), the number of LAG-3+ cells ranged from 0 to 540.1/mm2 (median 7.0/mm2), and the number of CD8+ tumor-associated lymphocytes ranged from 34.8 to 5205.3/mm2 (median 626.7/mm2). Higher numbers of LAG-3+ cells were associated with smoking history (p<0.001) and features of aggressive tumor behavior, including solid-predominant histologic pattern, presence of lymphovascular invasion, and presence of nodal metastasis (all p<0.01). Larger overall tumor size and invasive tumor size correlated with LAG-3+ cells when normalized to CD8+ cell counts (LAG-3/CD8 ratio; p<0.05). In terms of molecular features, KRAS-mutant tumors were associated with significantly higher numbers of LAG-3+ cells versus EGFR-mutant tumors (p<0.01). LAG-3+ cell count was positively correlated with both PD-L1 H score and CD8+ tumor-associated lymphocytes (all p<0.01). Lastly, patients with tumors harboring an increased LAG-3/CD8 ratio (i.e., above the median) showed significantly worse overall survival, irrespective of PD-L1 expression (p=0.027). Increased LAG3+ T-lymphocytes were associated with smoking history, adverse histologic features, worse survival, and increased PD-L1 expression in lung adenocarcinomas. Given the known role of LAG-3 in dampening the immune response, high LAG-3 expression may be associated with decreased efficacy of PD-1 axis blockade. Additional studies to evaluate the predictive value of LAG-3 in patients with lung adenocarcinoma undergoing immune checkpoint blockade are warranted.

Triple-Negative Breast Cancer: Intact Mismatch Repair and Partial Co-Expression of PD-L1 and LAG-3.

Background and AimPoor response to immune checkpoint inhibitors (ICIs) has been observed in most triple-negative breast cancer (TNBC) cases (around 80%). Our aim was to investigate the status of mismatch repair (MMR), microsatellite instability (MSI), programmed death-ligand 1 (PD-L1), and lymphocyte-activation gene 3 (LAG-3) in TNBC.MethodsA total of 74 TNBC samples were retrospectively analyzed. MMR and MSI were evaluated by immunohistochemistry (IHC) and polymerase chain reaction (PCR) using Promega 1.2 and NCI panels, respectively. PD-L1, LAG-3, and CD8 expression was assessed by IHC.ResultsNone of the cases demonstrated deficient MMR (dMMR) or MSI. In total, 43/74 cases (58.1%) were PD-L1+, including 1 tumor PD-L1+, 25 tumor-infiltrating lymphocytes (TILs) PD-L1+, and 17 cases involving concurrence of tumor and TIL PD-L1+. The rate of TIL PD-L1+ was remarkably higher than that of tumor PD-L1+ (P<0.001). We identified 20 LAG-3+ cases (27.0%, 20/74), all of which were PD-L1+. Co-expression of PD-L1 and LAG-3 was noted in 46.5% (20/43) of the PD-L1+ population. In the LAG-3+ subtype (co-expression of PD-L1 and LAG-3), high correlation between TILs PD-L1+ and LAG-3+ was observed (P<0.01). A high frequency of CD8+ (98.6%, 73/74) was observed.ConclusiondMMR/MSI characteristics may not be a practical predictive marker for ICIs in TNBC. PD-L1+ is more common in TILs than in tumors. In the PD-L1+ population, approximately half of the cases showed LAG-3 co-expression. For patients with a poor response to PD-1(L1) mono ICI, dual blockade of PD-1(L1) and LAG-3 may be a viable option for the management of TNBC.

IL10- and IL35-Secreting MutuDC Lines Act in Cooperation to Inhibit Memory T Cell Activation Through LAG-3 Expression.

Dendritic cells (DCs) are professional antigen-presenting cells involved in the initiation of immune responses. We generated a tolerogenic DC (tolDC) line that constitutively secretes interleukin-10 (IL10-DCs), expressed lower levels of co-stimulatory and MHCII molecules upon stimulation, and induced antigen-specific proliferation of T cells. Vaccination with IL10-DCs combined with another tolDC line that secretes IL-35, reduced antigen-specific local inflammation in a delayed-type hypersensitivity assay independently on regulatory T cell differentiation. In an autoimmune model of rheumatoid arthritis, vaccination with the combined tolDCs after the onset of the disease impaired disease development and promoted recovery of mice. After stable memory was established, the tolDCs promoted CD4 downregulation and induced lymphocyte activation gene 3 (LAG-3) expression in reactivated memory T cells, reducing T cell activation. Taken together, our findings indicate the benefits of combining anti-inflammatory cytokines in an antigen-specific context to treat excessive inflammation when memory is already established.

Distinct Expression of Coinhibitory Molecules on Alveolar T Cells in Patients With Rheumatoid Arthritis–Associated and Idiopathic Inflammatory Myopathy–Associated Interstitial Lung Disease

To identify immunologic factors in the lungs of patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD) and patients with idiopathic inflammatory myopathy-associated ILD (IIM-ILD) and to examine their pathologic mechanisms. Eleven patients with RA-ILD, 16 with IIM-ILD, 6 with drug-induced ILD (DI-ILD), and 8 healthy controls were enrolled. Peripheral blood (PB) and bronchoalveolar lavage (BAL) fluid were immunophenotyped by flow cytometry. Alveolar macrophages (AMs) were analyzed by coculture assay with PB naive CD4+ T cells from healthy individuals and RNA sequencing. Several coinhibitory molecules were coexpressed on BAL fluid T cells (CTLA-4, programmed death 1 [PD-1], T cell immunoglobulin and mucin domain-containing protein 3 [TIM-3], and lymphocyte activation gene 3 protein, from most to least), whereas only PD-1 was expressed on PB T cells. CTLA-4+PD-1+CD4+ T cells were characteristic of RA-ILD, whereas CTLA-4+PD-1+TIM-3+CD8+ T cells were characteristic of IIM-ILD. BAL fluid PD-1+CD4+ T cells rarely expressed CXCR5, but their levels correlated with levels of plasmablasts and plasma cells (ρ = 0.57, P = 0.006), indicating that most of them would be considered peripheral helper T cells. In coculture experiments, AMs from patients with RA-ILD and IIM-ILD induced more PD-1 and TIM-3 on T cells (P < 0.05), suggesting that coinhibitory molecule expression on BAL fluid T cells was partly due to AMs. RNA sequencing showed significant down-regulation of PD ligand 1/2 genes in AMs from patients with RA-ILD compared to those with DI-ILD. We have identified differences in coinhibitory molecule expression between patients with RA-ILD and those with IIM-ILD. PD-1 on T cells in RA-ILD and TIM-3 on CD8+ T cells in IIM-ILD might be key factors in the disease process. Evaluation of coinhibitory molecules on BAL fluid T cells could be clinically useful.

The landscape of immune checkpoints expression in non-small cell lung cancer: a narrative review.

With the increasing clinical potential of tumor immunotherapy, more and more clinical trials are undergoing with immune checkpoint inhibitors (ICIs). Immune checkpoints (ICs) have been identified as crucial regulators of the immune response and have improved ICIs-inhibitor therapeutic strategies. The most important ICs in lung cancer include programmed cell death-1 (PD-1), programmed cell death ligand-1 (PD-L1), lymphocyte activation gene-3 (LAG-3), major histocompatibility complex class II (MHC II), T cell immunoglobulin and mucin-domain containing-3 (TIM-3), and Galectin-9 (GAL-9), OX-40, OX40L. However, the expression and prognostic value of these ICs are still controversial. Among them, high expression of PD-L1 on tumor cells (>50%) predicts a better therapeutic effect of anti-PD-1 monoclonal antibody compared to patients with low PD-L1 expression. However, only 20–30% of non-small cell lung cancer (NSCLC) patients seem to get benefit from immunotherapy. In order to improve the immunotherapy outcomes, more and more attention is paid to combination immunotherapy. Analyzing the co-expression of ICs can give us a more comprehensive basis for combination immunotherapy. This review article summarized our comprehensive expression of ICs based on our previous research, and analyzed their correlation with prognosis in NSCLC patients. We also provided suggestions for potentially personalized combination immunotherapy in NSCLC.

Mucosal Genomics Implicate Lymphocyte Activation and Lipid Metabolism in Refractory Environmental Enteric Dysfunction

Background & AimsEnvironmental enteric dysfunction (EED) limits the Sustainable Development Goals of improved childhood growth and survival. We applied mucosal genomics to advance our understanding of EED.MethodsThe Study of Environmental Enteropathy and Malnutrition (SEEM) followed 416 children from birth to 24 months in a rural district in Pakistan. Biomarkers were measured at 9 months and tested for association with growth at 24 months. The duodenal methylome and transcriptome were determined in 52 undernourished SEEM participants and 42 North American controls and patients with celiac disease.ResultsAfter accounting for growth at study entry, circulating insulin-like growth factor-1 (IGF-1) and ferritin predicted linear growth, whereas leptin correlated with future weight gain. The EED transcriptome exhibited suppression of antioxidant, detoxification, and lipid metabolism genes, and induction of anti-microbial response, interferon, and lymphocyte activation genes. Relative to celiac disease, suppression of antioxidant and detoxification genes and induction of antimicrobial response genes were EED-specific. At the epigenetic level, EED showed hyper-methylation of epithelial metabolism and barrier function genes, and hypo-methylation of immune response and cell proliferation genes. Duodenal coexpression modules showed association between lymphocyte proliferation and epithelial metabolic genes and histologic severity, fecal energy loss, and wasting (weight-for-length/height Z < -2.0). Leptin was associated with expression of epithelial carbohydrate metabolism and stem cell renewal genes. Immune response genes were attenuated by giardia colonization.ConclusionsChildren with reduced circulating IGF-1 are more likely to experience stunting. Leptin and a gene signature for lymphocyte activation and dysregulated lipid metabolism are implicated in wasting, suggesting new approaches for EED refractory to nutritional intervention.ClinicalTrials.gov, Number: NCT03588013. (https://clinicaltrials.gov/ct2/show/NCT03588013)

Immune profiling of pituitary tumors reveals variations in immune infiltration and checkpoint molecule expression.

Pituitary tumors are the second most common primary brain tumors. Functional tumors demonstrate increased PD-L1 expression, but expression of other checkpoint regulators has not been characterized. We sought to characterize the immune microenvironment of human pituitary tumors to identify new treatment opportunities. 72 pituitary tumors were evaluated for expression of the immune regulatory markers programmed death ligand 1 (PD-L1), programmed death ligand 2 (PD-L2), V-domain Ig suppressor of T cell activation (VISTA), lymphocyte activation gene 3 (LAG3) and tumor necrosis factor receptor superfamily member 4 (OX40) by immunohistochemistry (IHC). Lymphocyte infiltration, macrophage infiltration, and angiogenesis were analyzed using IHC. Expression of pituitary tumor initiating cell marker CD15 and mismatch repair proteins MutS protein homolog 2 (MSH2) and MutS protein homolog 6 (MSH6) was also assessed. Pituitary tumors were infiltrated by macrophages and T cells, and they expressed varying levels of PD-L1, PD-L2, VISTA, LAG3, and OX40. Functional tumors and tumors with high expression of tumor stem cell markers had higher immune cell infiltration and greater expression of immunosuppressive checkpoint regulators. Increased PD-L1 and LAG3 and reduced VISTA were observed in primary tumors compared to recurrent tumors. Immune cell infiltration and checkpoint regulator expression vary depending on functional status and presence of pituitary tumor initiating cells. Functional tumors may have a particularly immunosuppressive microenvironment. Further studies of immune checkpoint blockade of pituitary tumors, particularly functional tumors, are warranted, though combination therapy may be required.

The Search for an Interesting Partner to Combine with PD-L1 Blockade in Mesothelioma: Focus on TIM-3 and LAG-3.

Simple SummaryMalignant pleural mesothelioma is an aggressive cancer most commonly associated with asbestos exposure. Its prognosis is very poor, and the current treatments have only a limited impact on survival. Therefore, there is an urgent need to develop new treatment strategies. We investigated combinations of different immune checkpoint blocking antibodies that have already shown promising results in several cancer types. We suggested that the effect of a combination treatment might even be better than one, single therapy. Based on our in vitro results about the secretion of several immune related molecules we selected promising treatments for further investigation in a mesothelioma mouse model. We found that monotherapy with an immune checkpoint blocking antibody against programmed death-1 (PD-1), and its combination with another blocking antibody against lymphocyte activation gene-3 (LAG-3), resulted in delayed tumor growth and survival benefit in our mice. Further research is warranted to optimize the treatment schedule of the combination therapy.Malignant pleural mesothelioma (MPM) is an aggressive cancer that is causally associated with previous asbestos exposure in most afflicted patients. The prognosis of patients remains dismal, with a median overall survival of only 9–12 months, due to the limited effectiveness of any conventional anti-cancer treatment. New therapeutic strategies are needed to complement the limited armamentarium against MPM. We decided to focus on the combination of different immune checkpoint (IC) blocking antibodies (Abs). Programmed death-1 (PD-1), programmed death ligand-1 (PD-L1), T-cell immunoglobulin mucin-3 (TIM-3), and lymphocyte activation gene-3 (LAG-3) blocking Abs were tested as monotherapies, and as part of a combination strategy with a second IC inhibitor. We investigated their effect in vitro by examining the changes in the immune-related cytokine secretion profile of supernatant collected from treated allogeneic MPM-peripheral blood mononuclear cell (PBMC) co-cultures. Based on our in vitro results of cytokine secretion, and flow cytometry data that showed a significant upregulation of PD-L1 on PBMC after co-culture, we chose to further investigate the combinations of anti PD-L1 + anti TIM-3 versus anti PD-L1 + anti LAG-3 therapies in vivo in the AB1-HA BALB/cJ mesothelioma mouse model. PD-L1 monotherapy, as well as its combination with LAG-3 blockade, resulted in in-vivo delayed tumor growth and significant survival benefit.

Research Progress Concerning Dual Blockade of Lymphocyte-Activation Gene 3 and Programmed Death-1/Programmed Death-1 Ligand-1 Blockade in Cancer Immunotherapy: Preclinical and Clinical Evidence of This Potentially More Effective Immunotherapy Strategy.

Although various immunotherapies have exerted promising effects on cancer treatment, many patients with cancer continue to exhibit poor responses. Because of its negative regulatory effects on T cells and its biological functions related to immune and inflammatory responses, there has been considerable emphasis on a protein-coding gene named lymphocyte-activation gene 3 (LAG3). Recently, evidence demonstrated marked synergy in its targeted therapy with programmed death-1 and programmed death-1 ligand-1 (PD-1/PD-L1) blockade, and a variety of LAG3 targeted agents are in clinical trials, indicating the important role of LAG3 in immunotherapy. This mini-review discusses preclinical and clinical studies investigating PD-1 pathway blockade in combination with LAG3 inhibition as a potentially more effective immunotherapy strategy for further development in the clinic. This strategy might provide a new approach for the design of more effective and precise cancer immune checkpoint therapies.

Differential PD-1/LAG-3 expression and immune phenotypes in metastatic sites of breast cancer

BackgroundA dual blockade against the novel immune checkpoint inhibitor lymphocyte activation gene-3 (LAG-3) and programmed cell death protein-1 (PD-1) is currently considered in advanced breast cancer. Nevertheless, PD-1 or LAG-3 expression within distant metastatic breast cancer tissue remains understudied.MethodsTo address this knowledge gap, we investigated the PD-1 and LAG-3 expression in combination with the CD8-based immune phenotype in intrapatient matched primary tumor distant metastases, representing 95 breast cancer patients with metastases occurring at four different anatomical locations. The immune phenotype was categorized into 2 categories: inflamed corresponding to the clinical category “hot” and exhausted or desert consistent with clinically “cold” tumors.ResultsMetastases of “cold” primary tumors always remained “cold” at their matched metastatic site. Expression of PD-1/LAG-3 was associated with a “hot” immune phenotype in both the primary tumors and metastases. We could not observe any association between the immune phenotype and the breast cancer molecular subtype. Brain and soft tissue metastases were more commonly inflamed with signs of exhaustion than other anatomical sites of metastases. Taken together, (i) the immune phenotype varied between sites of distant metastases, and (ii) PD-1+/LAG-3+ was strongly associated with a “hot” immune phenotype and (iii) was most prevalent in brain and soft tissue metastases among distant metastases.ConclusionsOur data strongly support an integrated analysis of the immune phenotype together with the PD-1/LAG-3 expression in distant metastases to identify patients with inflamed but exhausted tumors. This may eventually improve the stratification and likelihood for advanced breast cancer patients to profit from immunotherapy.

Lymphocyte-activated gene-3 (LAG3) protein expressed in tumor-infiltrating lymphocytes of colorectal cancer.

Immunotherapy can reverse tumor immune escape by suppressing immune checkpoints. Lymphocyte activation gene 3 (LAG3) is an important checkpoint and its role in colorectal cancer is not clear. In this study, we investigated LAG3 protein expression and its correlation with clinicopathologic parameters. The expression of LAG3 protein was assessed in 150 surgically resected colorectal cancer tissue samples by immunohistochemistry. The relationship between LAG3 expression and clinicopathological parameters, MSI status and survival was statistically analyzed. LAG3 protein was not expressed in colorectal cancer cells, and was expressed on the tumor-infiltrating lymphocytes (TILs) in 31 out of 150 (20.7%) colorectal cancer samples. Positive expression of LAG3 in TILs is associated with lymph node metastasis (p < 0.001), TNM stage (p = 0.024) and MSI-H (p = 0.035). No significant relationship was found between LAG3 expression and gender, age, tumor location, tumor invasion depth, and differentiation. LAG3 expression is associated with longer overall survival (p = 0.045). Our data show LAG3 expression on TILs in parts of CRC tissue. Positive expression of LAG3 was associated with advanced tumor stage, MSI-H and a poor prognosis. We conclude that LAG3 is an important checkpoint gene in CRC and may be a potential marker for prognosis of CRC.

PD-L1/LAG-3 bispecific antibody enhances tumor-specific immunity

ABSTRACT Anti-programmed cell death-1 (PD-1)/PD-ligand-1 (PD-L1) treatments are effective in a fraction of patients with advanced malignancies. However, the majority of patients do not respond to it. Resistance to cancer immunotherapy can be mediated by additional immune checkpoints. We hypothesized that co-targeting of PD-L1 and lymphocyte-activation gene 3 (LAG-3) could provide an alternative therapeutic approach. Here, we developed IBI323, a dual blockade bispecific antibody targeting PD-L1 and LAG-3. We assessed the binding affinity, blocking activity, cell bridging effect, and immunomodulation function of IBI323 using in vitro assays. We also evaluated, in two humanized mouse models, anti-tumor effects and antitumor T cell immunity induced by IBI323. IBI323 bound to PD-L1 and LAG-3 with similar potency as its parental antibodies and blocked the interaction of PD-1/PD-L1, CD80/PD-L1, and LAG-3/MHC-II. Moreover, IBI323 mediated the bridging of PD-L1+ cells and LAG-3+ cells and demonstrated superior immune stimulatory activity compared to each parent antibody in mixed leukocyte reaction. In PD-L1/LAG-3 double knock-in mice bearing human PD-L1 knock-in MC38 tumors, IBI323 showed stronger anti-tumor activity compared to each parental antibody. The better antitumor response correlated with increased tumor-specific CD8+ and CD4+ T cells. IBI323 also induced stronger anti-tumor effect against established A375 tumors compared with combination in mice reconstituted with human immune cells. Collectively, these data demonstrated that IBI323 preserved the blockade activities of parental antibodies while processing a novel cell bridging function. Based on the encouraging preclinical results, IBI323 has significant value in further clinical development.

Single-Cell RNA-Seq Reveals LGALS1 and LAG3 as Novel Drivers of Ibrutinib Resistance in Chronic Lymphocytic Leukemia

Background: Chronic lymphocytic leukemia (CLL) is a highly heterogeneous malignant lymphoproliferative B-cell disorder that can be treated using ibrutinib, a Bruton’s tyrosine kinase inhibitor. However, the ibrutinib resistance of CLL patients has caused widespread concerns, necessitating the development of novel treatment strategies. Methods: Here, we identified lectin galactoside-binding soluble 1 (LGALS1) and lymphocyte-activating gene 3 (LAG3) as potential markers for ibrutinib-resistant CLL using single-cell RNA sequencing (scRNA-seq), and the results were validated in an ibrutinib-resistant CLL cell line (MEC1-IR) and primary cells from CLL patients. Marker-gene expression was detected while functional analyses were conducted with or without OTX008, a selective Galectin-1 inhibitor. ScRNA-seq revealed that the biological features, gene expression profiles, and clonal signatures of peripheral blood mononuclear cells (PBMCs) from patients with ibrutinib-resistant CLL were distinct from those displayed by PBMCs from ibrutinib-sensitive patients. Findings: A close correlation between LGALS1 and LAG3 expression was observed and these factors were found to be highly expressed in ibrutinib-resistant CLL, with diagnostic and prognostic stratification, indicating that they may serve as drivers of ibrutinib-resistant CLL. Concordantly, LGALS1 and LAG3 expression was higher in ibrutinib-resistant CLL cells and primary cells, and OTX008 suppressed proliferation and induced apoptosis in both cells. Interpretation: LGALS1 and LAG3 gene panel is promising indicator of ibrutinib-sensitivity and prognosis marker of CLL. LGALS1 inhibitor OTX008 is effective in CLL patients, both those naive to and those resistant to ibrutinib. This work highlights the pathogenic mechanism and represents a novel therapeutic target for CLL. Funding Statement: This work was supported by grants from National Natural Science Foundation of China (Grant #81720108002, 81970146, 81770166, 81972358 and 91959113), Key Research & Development Program of Jiangsu Province (Grant #BE2017733), Basic Research Program of Jiangsu Province (Grant #BK20180036), Jiangsu Province’s Medical Elite Programme (Grant #ZDRCA2016022), Project of National Key Clinical Specialty, Jiangsu Provincial Special Program of Medical Science (Grant #BE2017751), Six Top Talent Project of Jiangsu Province (Grant #WSN-001). Declaration of Interests: The authors declare that they have no competing interests. Ethics Approval Statement: Human sample study was approved by the Medical Ethics Committee of First Affiliated Hospital of Nanjing Medical University. Written informed consent was obtained from all participants.

Expression of immune checkpoint molecules in Iraqi acute myeloid leukemia patients

BACKGROUND: Acute myeloid leukemia (AML) is a malignant disease of the bone marrow in which hematopoietic precursors are arrested in an early stage of development leading to production of abnormal cells. AML is the most common type of leukemia in adults. The most important advances can be achieved through immune checkpoint (IC) inhibitors, including cytotoxic T lymphocyte antigen 4 (CTLA-4), Programmed Death protein -1 (PD-1), and anti-programmed ligand 1 in cancer treatment over the past decade.OBJECTIVES: The aims of the current study were to evaluate the expression of CD3, CD28, CD152, CD223, and CD279 markers in T cells by flow cytometry and the expression of PD 1, CTLA 4, and lymphocyte activation gene 3 (LAG 3) expression by real time PCR in AML patients.MATERIALS AND METHODS: This is case control study carried out on 50 AML Iraqi patients, in addition to 50 apparently health person. This study was conducted at the National Center for Hematology, Department of Biology, Mustansiriyah University, and in Baghdad teaching hospital in Medical City, from January 2019 to June 2020. Moreover, the study aims to evaluate the expression of CD3, CD28, CD152, CD223, and CD279 markers in T cells by flow cytometry of AML patients and the expression of PD 1, CTLA 4, and lymphocyte activation gene 3 (LAG 3) expression by real time PCR in AML patients.RESULTS: The cellular expression of almost CD markers did not show a relationship between gender and age. Most AML patients had high CD3 and CD28 expression in cellular expression of T cells. Although there were increasing gene expression of PD-1 and LAG-3 in T cells. The cellular expression of CD279 PD-1 was high, gene expression of CTLA-4 had slightly increased, and cellular expression of CD152 CTLA-4 not significant among healthy controls. In the present manuscript, there was an increase in the expression of PD-1 CD279 in the relapse and refectory patients than the complete and partial remission, while CD3, CD28, and CD223 LAG-3 did not show differences in the expression on T cells among AML stages. Finally, the immunophenotyping of 48 from 50 patients (96%) of the present study was CD3+CD28+CD152−CD279+CD223−.CONCLUSION: Elevate the expression of PD 1, LAG 3 in almost all AML patients associated with the progression of the disease. 96% of AML patients' immunophenotyping was CD3+CD28+CD152−CD279+CD223−.

TGFBR2 mutation predicts resistance to immune checkpoint inhibitors in patients with non-small cell lung cancer.

Background:Resistance or even hyper-progression to immune checkpoint inhibitors (ICIs) manifesting as accelerated disease progression or death has impeded the clinical use of ICIs. The transforming growth factor beta (TGFβ) receptor pathway has been identified in contributing to immune dysfunction, which might be associated with resistance to ICIs. We aimed to explore the role of TGFβ in the resistance to ICIs in non-small cell lung cancer (NSCLC) in this study.Methods:Public cohorts with patients treated with ICIs or chemotherapy including POPLAR/OAK (n = 853), MSKCC (n = 1662) and Van Allen (n = 57) and TCGA (n = 3210) cohorts were obtained and analyzed.Results:The expression of immune-checkpoint related genes, including programmed death-ligand 1 (CD274), lymphocyte-activation gene 3 (LAG3), T cell immunoreceptor with Ig and ITIM domains (TIGIT), cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death ligand 1 (PDCD1), and programmed cell death 1 ligand 2 (PDCD1LG2) were significantly upregulated in transforming growth factor beta TGFβ receptor 2 (TGFβR2)-mutated patients than those with wild-type TGFBR2 (p < 0.05). In the POPLAR/OAK cohort, TGFBR2-mutated patients showed shorter progression-free survival (PFS) [ p = 0.004; hazard ratio (HR), 2.83; 95% confidence interval (CI), 1.34–6.00] and overall survival (OS) ( p = 0.0006; HR, 3.46; 95% CI, 1.63–7.35) than those with wild-type TGFBR2 when treated with ICIs but not chemotherapy. In the merged MSKCC and Van Allen cohorts, a similar result was observed that the OS was inferior in patients with mutated TGFBR2 compared with those with wild-type TGFBR2 (p = 0.007; HR, 2.53; 95% CI, 1.25–5.12). The association between TGBFR2 mutation and survival remained significant in multivariable cox regression in both POPLAR/OAK cohort (p = 0.02; HR, 2.53; 95% CI, 1.17–5.45) and merged cohort (p = 0.008; HR, 2.63; 95% CI, 1.29–5.35). We further evaluated the association between TGFBR2 mutations and OS in multiple types of tumors. The association between TGFBR2 mutations and OS remained significant in NSCLC (p = 0.02; HR, 2.47; 95% CI, 1.16–5.26), but not in other type of tumors.Conclusions:We identified that TGFBR2 mutation predicted the resistance to ICIs in NSCLCs. The clinical delivery of ICIs should be cautious in those patients.

Preclinical evaluation of cancer immune therapy using patient-derived tumor antigen-specific T cells in a novel xenograft platform.

ObjectivesWith a rapidly growing list of candidate immune‐based cancer therapeutics, there is a critical need to generate highly reliable animal models to preclinically evaluate the efficacy of emerging immune‐based therapies, facilitating successful clinical translation. Our aim was to design and validate a novel in vivo model (called Xenomimetic or ‘X’ mouse) that allows monitoring of the ability of human tumor‐specific T cells to suppress tumor growth following their entry into the tumor.MethodsTumor xenografts are established rapidly in the greater omentum of globally immunodeficient NOD‐scid IL2Rγnull (NSG) mice following an intraperitoneal injection of melanoma target cells expressing tumor neoantigen peptides, as well as green fluorescent protein and/or luciferase. Changes in tumor burden, as well as in the number and phenotype of adoptively transferred patient‐derived tumor neoantigen‐specific T cells in response to immunotherapy, are measured by imaging to detect fluorescence/luminescence and flow cytometry, respectively.ResultsThe tumors progress rapidly and disseminate in the mice unless patient‐derived tumor‐specific T cells are introduced. An initial T cell‐mediated tumor arrest is later followed by a tumor escape, which correlates with the upregulation of the checkpoint molecules programmed cell death‐1 (PD‐1) and lymphocyte‐activation gene 3 (LAG3) on T cells. Treatment with immune‐based therapies that target these checkpoints, such as anti‐PD‐1 antibody (nivolumab) or interleukin‐12 (IL‐12), prevented or delayed the tumor escape. Furthermore, IL‐12 treatment suppressed PD‐1 and LAG3 upregulation on T cells.ConclusionTogether, these results validate the X‐mouse model and establish its potential to preclinically evaluate the therapeutic efficacy of immune‐based therapies.

Purification and Immunophenotypic Characterization of Murine Plasma Cells.

B cells are primarily known for their capacity to differentiate into antibody-secreting cells (ASCs). ASCs are usually viewed as terminally differentiated cells sharing a unique phenotype. However, it lately became evident that ASCs exist in a variety of subsets differing by their lifespan, anatomic location, and immunological function. Thus, ASCs can exist as long-lived plasma cells (LLPC) that can persist for years in a nonproliferating state within particular niches in the bone marrow (BM), or as short-lived plasma cells (SLPC) that are primarily found in secondary lymphoid organs or inflamed tissues and wane upon the termination of the associated immune response. Another layer of ASC diversity was uncovered with the discovery of their capacity to produce various pro- or anti-inflammatory cytokines. Notably, a subset of natural regulatory plasma cells characterized by the distinctive expression of the inhibitory receptor lymphocyte activation gene (LAG)-3 and a unique capacity to produce interleukin (IL)-10 upon stimulation was recently identified. Here, we describe how to immunophenotypically characterize murine plasma cells as well as how to isolate them using cell sorting, with a special focus on these recently described natural regulatory plasma cells.