Lymphocyte Activation Gene-3 Research Articles

Phase 1b/2 umbrella study of investigational immune and targeted combination therapies for patients with advanced clear cell renal cell carcinoma (ccRCC).

TPS404 Background: New treatments for first and subsequent lines of therapy for ccRCC are needed. An adaptive, open-label, rolling-arm, multicenter, phase 1b/2 umbrella platform trial in advanced ccRCC is being conducted to evaluate the safety and efficacy of multiple combinations of investigational agents targeting CTLA-4 (quavonlimab [MK-1308]), hypoxia-inducible factor 2α (belzutifan [MK-6482]), lymphocyte-activation gene 3 (favezelimab [MK-4280]), immunoglobulinlike transcript 4 (MK-4830), PD-1 (pembrolizumab), and vascular endothelial growth factor–tyrosine kinase inhibitor (VEGF-TKI; lenvatinib) for advanced ccRCC. Substudy 03A (NCT04626479) will evaluate first-line therapy combinations, and substudy 03B (NCT04626518) will evaluate therapies in patients experiencing progression on PD-1/PD-L1 inhibitors and VEGF-TKIs in combination or in sequence. Methods: Adults with histologically confirmed ccRCC and KPS score ≥70% are eligible. Patients in substudy 03A cannot have previously received systemic therapy for advanced ccRCC. Patients in substudy 03B must have progression (per RECIST v1.1) on or after treatment with a PD-1/PD-L1 inhibitor and a VEGF-TKI for advanced ccRCC. Both substudies will have a safety lead-in phase for experimental combinations with investigational agents to establish a recommended phase 2 dose, followed by an efficacy phase. Experimental arms will enroll approximately 80 (03A) and 50 (03B) patients. Patients will be randomly assigned 2:1 (03A) or 1:1 (03B) to an experimental arm or a reference arm (pembrolizumab 400 mg IV every 6 weeks [Q6W] + lenvatinib 20 mg orally once daily [QD]). Experimental arms in 03A are MK-1308A (coformulation of quavonlimab 25 mg and pembrolizumab 400 mg IV Q6W) + lenvatinib (20 mg orally QD), MK-4280A (coformulation of favezelimab 800 mg and pembrolizumab 200 mg IV every 3 weeks [Q3W]) + lenvatinib (20 mg orally QD), and belzutifan (120 mg orally QD) + lenvatinib (20 mg orally QD) + pembrolizumab (400 mg Q6W IV). Experimental arms in 03B are MK-1308A, MK-4280A, pembrolizumab (400 mg Q6W IV) + belzutifan (120 mg orally QD), lenvatinib (20 mg orally QD) + belzutifan (120 mg orally QD), and pembrolizumab (200 mg IV Q3W) + MK-4830 (800 mg IV Q3W). Treatment will continue until disease progression, unacceptable toxicity, or withdrawal of consent. Primary end points for the safety lead-in phase are safety and tolerability; coprimary end points for the efficacy phase are safety and objective response rate per RECIST v1.1 by blinded independent central review (BICR). Secondary end points during the efficacy phase are duration of response, progression-free survival (RECIST v1.1 by BICR), clinical benefit rate, and overall survival. Both substudies are recruiting patients in Australia, Canada, France, Israel, South Korea, Spain, New Zealand, the United Kingdom, and the United States. Clinical trial information: NCT04626479; NCT04626518.

Update on lymphocyte-activation gene 3 (LAG-3) in cancers: from biological properties to clinical applications.

Immunotherapy that targets checkpoints, especially programmed cell death protein 1 and programmed cell death ligand 1, has revolutionized cancer therapy regimens. The overall response rate to mono-immunotherapy, however, is limited, emphasizing the need to potentiate the efficacy of these regimens. The functions of immune cells are modulated by multiple stimulatory and inhibitory molecules, including lymphocyte activation gene 3 (LAG-3). LAG-3 is co-expressed together with other inhibitory checkpoints and plays key roles in immune suppression. Increasing evidence, particularly in the last 5 years, has shown the potential of LAG-3 blockade in anti-tumor immunity. This review provides an update on the biological properties and clinical applications of LAG-3 in cancers.

Fewer LAG-3+ T Cells in Relapsing-Remitting Multiple Sclerosis and Type 1 Diabetes.

The coinhibitory receptor lymphocyte activation gene 3 (LAG-3) is an immune checkpoint molecule that negatively regulates T cell activation, proliferation, and homeostasis. Blockade or deletion of LAG-3 in autoimmune-prone backgrounds or induced-disease models has been shown to exacerbate disease. We observed significantly fewer LAG-3+ CD4 and CD8 T cells from subjects with relapsing-remitting multiple sclerosis (RRMS) and type 1 diabetes. Low LAG-3 protein expression was linked to alterations in mRNA expression and not cell surface cleavage. Functional studies inhibiting LAG-3 suggest that in subjects with RRMS, LAG-3 retains its ability to suppress T cell proliferation. However, LAG-3 expression was associated with the expression of markers of apoptosis, indicating a role for low LAG-3 in T cell resistance to cell death. In T cells from subjects with RRMS, we observed a global dysregulation of LAG-3 expression stemming from decreased transcription and persisting after T cell stimulation. These findings further support the potential clinical benefits of a LAG-3 agonist in the treatment of human autoimmunity.

Clinical significance of LAG-3 on microvessel density in primary hepatocellular carcinoma.

We aimed to determine whether lymphocyte activation gene 3 (LAG-3), also known as CD223, is associated with microvessel density (MVD) in primary hepatocellular carcinoma (HCC), as well as their clinical significance in predicting survival. One hundred and twenty-seven patients were enrolled in the study. Samples were obtained on resection at the Department of Hepatobiliary Surgery of the Qingdao Municipal Hospital from June 2014 to June 2016. Immunohistochemistry was used to determine vessel density and LAG-3 abundance. Statistical analyses were performed to test for correlation of LAG-3 density and other clinicopathological variables with overall survival (OS). High LAG-3 abundance was significantly correlated with increased MVD in primary HCC (P < 0.05). The χ2 test revealed a significant association of LAG-3 with preoperative AFP level, tumor diameter, N stage, and the presence of HBV infection (P < 0.05). Patients with high LAG-3 expression had shorter OS compared to those with low LAG-3 expression (P < 0.05). The Cox proportional hazards model showed that both higher LAG-3 and MVD density, age, the number of tumors, preoperative AFP level, tissue differentiation, Child-Pugh grade, and lymph node metastasis correlated with survival. High expression of LAG-3 is associated with angiogenesis and poor prognosis in HCC patients. With the deepening of research, LAG-3 is likely to become a novel biomarker for clinical diagnosis and prognosis and can even be a therapeutic target of HCC.

Sleeve resection after neoadjuvant chemoimmunotherapy in the treatment of locally advanced non-small cell lung cancer.

BackgroundWe aimed to characterize the outcomes of sleeve resection after neoadjuvant chemoimmunotherapy for the treatment of non-small cell lung cancer (NSCLC), including perioperative and oncologic outcomes, and to identify any impact of operative approach on resultant findings.MethodsWe identified patients with NSCLC who underwent sleeve resection after ≥2 cycles of neoadjuvant chemoimmunotherapy between May 2019 and April 2021 and retrospectively reviewed clinical records. Perioperative data were collected and compared between video-assisted thoracoscopic surgery (VATS) (n=8) and thoracotomy (n=15) groups. Immunohistochemistry (IHC) scores were compared between tumors with and without major pathological response (MPR).ResultsTwenty-three patients met inclusion criteria, with clinical stages as follows: IB, 2 (8.7%); IIIA, 14 (60.9%); and IIIB, 7 (30.4%). Treatment-related adverse events (TRAE) were recorded in 17 patients (73.9%), including anemia and neutropenia, with no patients exhibiting serious TRAE. Radiological evaluation revealed 5 (21.7%) patients with complete response (CR), 14 (60.9%) with partial response (PR), and 4 (17.4%) with stable disease (SD). Complete resection was accomplished for all patients. One VATS procedure was converted to thoracotomy due to extensive pleural adhesions. There were no significant differences in intraoperative blood loss (87.5±51.8 vs. 193.9±145.3 mL), operative time (198.8±79.7 vs. 225.5±55.0 min), number of lymph node examined (16.9±6.6 vs. 18.2±6.5), and hospital stay (5.5±2.8 vs. 9.2±11.2 days) between the VATS and thoracotomy groups (all P>0.05). Postoperative complications occurred in 3 patients, and 1 patient died of bronchopleural fistula (BPF) in the thoracotomy group. Complete pathological response (CPR) and MPR were achieved in seven (30.4%) and 13 (56.5%) patients, respectively. Both preoperative histopathology (P=0.024) and radiological response (P=0.002) were significantly associated with MPR. In postoperative specimens with MPR, the IHC scores of cluster of differentiation (CD)4, CD8, and CD20 were modestly higher, while programmed cell death receptor 1 (PD-1), lymphocyte-activation gene 3 (LAG3) and T cell immunoglobulin and ITIM domain (TIGIT) were lower compared with non-MPR specimens, albeit insignificantly.ConclusionsSleeve resection after neoadjuvant chemoimmunotherapy was feasible in patients with locally advanced NSCLC. Perioperative outcomes were comparable between the VATS and thoracotomy groups.

Altered distribution, activation and increased IL-17 production of mucosal-associated invariant T cells in patients with acute respiratory distress syndrome

ObjectiveMucosal-associated invariant T (MAIT) cells are a subset of innate-like T cells that are engaged in a number of diseases, but their roles in acute respiratory distress syndrome (ARDS) are...

Coexpression of lymphocyte-activation gene 3 and programmed death ligand-1 in tumor infiltrating immune cells predicts worse outcome in renal cell carcinoma.

ObjectivesLymphocyte-activation gene 3 (LAG-3) represents a potential immune checkpoint target for cancer treatment. We investigated LAG-3 expression and its prognostic value in patients with surgically treated clear cell renal cell carcinoma (RCC) and correlated LAG-3 expression with programmed cell death ligand 1(PD-L1).MethodsWe evaluated LAG-3 and PD-L1 expression using immunohistochemistry on tissue microarrays incorporating 134 primary excision specimens of clear cell RCC (ccRCC). The patients were analyzed as two groups: the whole cohort and those with metastatic RCC (mRCC). The cancer genome atlas (TCGA) data analysis of LAG-3 was done through UALCAN web servers.ResultsUsing the UALCAN cancer transcriptional data analysis, we found that LAG-3 was overexpressed in ccRCC. LAG-3 expression was significantly correlated with PD-L1 expression in the whole cohort and in the mRCC group (all, p < 0.05). Both LAG-3⁺ RCC and PD-L1⁺ RCC presented with a higher TNM stage and higher Fuhrman nuclear grade (all, p < 0.05). PD-L1⁺/LAG-3⁺ RCC and PD-L1⁻/LAG-3⁺ RCC showed poorer cancer-specific survival (CSS) than PD-L1⁻/LAG-3⁻ RCC (all, p = 0.01). Similarly, PD-L1⁺/LAG-3⁺ mRCC and PD-L1⁻/LAG-3⁺ mRCC showed poorer CSS than PD-L1⁻/LAG-3⁻ mRCC (all, p < 0.05). Multivariate analysis showed that PD-L1⁺/LAG-3⁺ mRCC (hazard ratio: 3.19; 95% CI: 0.77–13.67; p = 0.033) was a predictor of poor CSS.ConclusionBoth LAG-3⁺ and PD-L1⁺ RCC have adverse pathological features, and their coexpression predicts worse clinical outcomes. Our findings suggest LAG-3 blockade in combination with programmed cell death 1/PD-L1 blockade as a potential therapeutic approach for RCC.

Lag3: From Bench to Bedside.

The introduction of immune checkpoint inhibitors represented a breakthrough treatment for metastatic melanoma, but the effect of these agents is not limited to a single cancer type. Promising results have been reported in various solid tumors, for example, lung cancer. The success of these drugs depends on the activation of tumor-infiltrating lymphocytes and primary and acquired resistance have been reported alongside a high rate of immune-related adverse events when agents targeting different immune checkpoints are given in combination. Numerous other targets have been investigated to overcome the resistance, improve the activity, and reduce the toxicity of checkpoint inhibitor therapy. Among these, the most promising is Lymphocyte-activation gene 3 (LAG-3), a transmembrane protein involved in cytokine release and inhibitory signaling in T cells. Preclinical data showed that LAG-3 is a negative regulator of both CD4+ T cell and CD8+ T cell and the activity on CD8+ T cell is independent of CD4+ activation. On the CD8+ T cell, LAG-3 activation abrogates the antigen presentation whereas on the CD4+ T cell, arrests the S phase of the cell cycle. The blockade of LAG-3 has been tested in several combination therapies, and recent clinical data showed a good safety profile and a synergistic effect with anti-PD-1, suggesting that this combination could become a standard treatment for metastatic melanoma. In this review, we report the available preclinical data and the new clinical data on LAG-3 blockade in different solid tumors, and we discuss LAG-3 as potential prognostic and predictive factor, together with possible future applications.

Implication of the hepatokine, fibrinogen-like protein 1 in liver diseases, metabolic disorders and cancer: The need to harness its full potential.

Fibrinogen-like protein 1 (FGL1) is a novel hepatokine that forms part of the fibrinogen superfamily. It is predominantly expressed in the liver under normal physiological conditions. When the liver is injured by external factors, such as chemical drugs and radiation, FGL1 acts as a protective factor to promote the growth of regenerated cells. However, elevated hepatic FGL1 under high fat conditions can cause lipid accumulation and inflammation, which in turn trigger the development of non-alcoholic fatty liver disease, diabetes, and obesity. FGL1 is also involved in the regulation of insulin resistance in adipose tissues and skeletal muscles as a means of communication between the liver and other tissues. In addition, the abnormally changed FGL1 levels in the plasma of cancer patients make it a potential predictor of cancer incidence in clinical practice. FGL1 was recently identified as a major functional ligand of the immune inhibitory receptor, lymphocyte-activation gene 3 (LAG3), thus making it a promising target for cancer immunotherapy except for the classical programmed cell death protein 1/programmed cell death ligand 1 (PD-1/PD-L1) axis. Despite the potential of FGL1 as a new cancer biomarker and therapeutic target, there are few related studies and much of what has been reported are superficial and lack depth and particularity. Therefore, elucidating the role and underlying mechanisms of FGL1 could be crucial for the development of promising diagnostic and therapeutic strategies for related diseases. Here, we provide a comprehensive review of the cellular mechanisms and clinical prospects of FGL1 in the prevention and treatment of liver diseases, metabolic disorders and cancer, and proffer suggestions for future studies.

Single-Cell Transcriptome Analysis Reveals the M2 Macrophages and Exhausted T Cells and Intratumoral Heterogeneity in Triple-Negative Breast Cancer.

Triple-Negative Breast Cancer (TNBC) is a highly heterogeneous and invasive malignancy that is characterized by high recurrence and mortality rates as well as extremely poor prognosis. The objective of this study is to analyze T cells and Macrophages in the tumor microenvironment with the aim of identifying targets with therapeutic potential. Single-cell sequencing data of TNBC patients from the GSE118389 dataset were analyzed to examine the immune environment and intratumoral heterogeneity of TNBC patients. Polarized alternatively activated macrophages (M2) and exhausted CD8+ T cells were identified in TNBC patients. Immunosuppressive checkpoint analysis revealed that levels of lymphocyte-activation gene 3 (LAG3) and T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3) of exhausted T cells were significantly higher than levels of programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyteassociated protein 4 (CTLA-4). This indicates that these markers are potential immunotherapy targets. Furthermore, analysis of significantly altered immune cell markers showed that several markers were associated with the prognosis of TNBC. Overall, these findings demonstrate inter-tissue heterogeneity of TNBC, and provides novel therapeutic targets for the treatment of TNBC.

Combination Immune Checkpoint Blockade Enhances IL-2 and CD107a Production from HIV-Specific T Cells Ex Vivo in People Living with HIV on Antiretroviral Therapy.

In people with HIV (PWH) on antiretroviral therapy (ART), immune dysfunction persists, including elevated expression of immune checkpoint (IC) proteins on total and HIV-specific T cells. Reversing immune exhaustion is one strategy to enhance the elimination of HIV-infected cells that persist in PWH on ART. We aimed to evaluate whether blocking CTL-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1), T cell Ig domain and mucin domain 3 (TIM-3), T cell Ig and ITIM domain (TIGIT) and lymphocyte activation gene-3 (LAG-3) alone or in combination would enhance HIV-specific CD4+ and CD8+ T cell function ex vivo. Intracellular cytokine staining was performed using human PBMCs from PWH on ART (n = 11) and expression of CD107a, IFN-γ, TNF-α, and IL-2 was quantified with HIV peptides and Abs to IC. We found the following: 1) IC blockade enhanced the induction of CD107a and IL-2 but not IFN-γ and TNF-α in response to Gag and Nef peptides; 2) the induction of CD107a and IL-2 was greatest with multiple combinations of two Abs; and 3) Abs to LAG-3, CTLA-4, and TIGIT in combinations showed synergistic induction of IL-2 in HIV-specific CD8+ and CD107a and IL-2 production in HIV-specific CD4+ and CD8+ T cells. These results demonstrate that the combination of Abs to LAG-3, CTLA-4, or TIGIT can increase the frequency of cells expressing CD107a and IL-2 that associated with cytotoxicity and survival of HIV-specific CD4+ and CD8+ T cells in PWH on ART. These combinations should be further explored for an HIV cure.

The Emerging Role of Lymphocyte Activation Gene 3 in the Cancer Immunotherapy

The emergence of tumor immunotherapy, especially immune checkpoint inhibitors (ICIs), has brought new life to cancer treatment, and ICIs can effectively treat various tumors. Among the immune anti-cancer therapies, PD-1 is undoubtedly the hot target after CTLA-4, but due to the ineffectiveness of PD-1 in treating certain tumors, researchers have shifted their focus to other combination targets, such as LAG-3, TIM3, IDO-1, etc. One of these promising targets is LAG-3, a target with multiple clinical trials, which has increasingly shown to be an inhibitory co-receptor that plays a vital role in autoimmunity, cancer immunity, and anti-infection immunity. Immune combination therapy with LAG-3 is a hot topic, but its limitations in clinical application are also evident. This review briefly describes the molecular structure, biological functions of LAG-3 in the immune cells and cancer cells and prognosis significance, and then an overview of relevant ongoing clinical trials.

Checkpoint protein expression in the tumor microenvironment defines the outcome of classical Hodgkin lymphoma patients

AbstractEmerging evidence indicates a major impact for the tumor microenvironment (TME) and immune escape in the pathogenesis and clinical course of classical Hodgkin lymphoma (cHL). We used gene expression profiling (n = 88), CIBERSORT, and multiplex immunohistochemistry (n = 131) to characterize the immunoprofile of cHL TME and correlated the findings with survival. Gene expression analysis divided tumors into subgroups with T cell-inflamed and -noninflamed TME. Several macrophage-related genes were upregulated in samples with the non–T cell-inflamed TME, and based on the immune cell proportions, the samples clustered according to the content of T cells and macrophages. A cluster with high proportions of checkpoint protein (programmed cell death protein 1, PD-1 ligands, indoleamine 2,3 dioxygenase 1, lymphocyte-activation gene 3, and T-cell immunoglobulin and mucin domain containing protein 3) positive immune cells translated to unfavorable overall survival (OS) (5-year OS 76% vs 96%; P = .010) and remained an independent prognostic factor for OS in multivariable analysis (HR, 4.34; 95% CI, 1.05-17.91; P = .043). cHL samples with high proportions of checkpoint proteins overexpressed genes coding for cytolytic factors, proposing paradoxically that they were immunologically active. This checkpoint molecule gene signature translated to inferior survival in a validation cohort of 290 diagnostic cHL samples (P < .001) and in an expansion cohort of 84 cHL relapse samples (P = .048). Our findings demonstrate the impact of T cell- and macrophage-mediated checkpoint system on the survival of patients with cHL.

Lymphocyte-activating gene-3 expression is associated with tumor-infiltrating lymphocyte levels in HER2-positive breast cancers.

Lymphocyte-activating gene-3 (LAG-3, CD223) is the third inhibitory receptor targeted for immunotherapy. Several clinical trials investigating the use of interventions targeting LAG-3 are underway. The exact signaling mechanism downstream of LAG-3 is largely unknown, especially in breast cancer. The prognostic significance of tumor-infiltrating lymphocytes (TILs) in breast cancer has been previously determined.Among 167 human epidermal growth factor receptor 2 (HER2)-positive breast cancer patients, 90 and 78 patients were positive and negative for the hormone receptor, respectively. LAG-3 mRNA and protein expression levels in TILs were evaluated by quantitative real-time polymerase chain reaction and immunohistochemistry, respectively, among 12 and 167 HER2-positive breast cancer samples, respectively.High expression of LAG-3 in TILs was significantly correlated with high levels of TILs (P = .003) and an abundance of tertiary lymphoid structures around invasive components (P = .014). In addition, high expression of LAG3 was significantly associated with positivity for programmed death-ligand 1 (PD-L1) in tumor cells, a high immunostaining score of PD-L1 in TILs, and a high total immunostaining score for PD-L1 in tumor cells and TILs (all, P < .001). High expression levels of LAG-3 mRNA were associated with high levels of TILs (P = .091).LAG-3 protein expression was not a prognostic factor in HER2-positive breast cancers, and LAG-3 expression in TILs was significantly associated with the levels of TILs in HER2-positive breast cancer, although it was not a prognostic factor.

Fibrinogen-Like Protein 1 Serves as an Anti-Inflammatory Agent for Collagen-Induced Arthritis Therapy in Mice.

Fibrinogen-like protein 1 (FGL1) was recently identified as a major ligand of lymphocyte-activation gene-3 (LAG-3) on activated T cells and serves as an immune suppressive molecule for regulation of immune homeostasis. However, whether FGL1 has therapeutic potential for use in the T cell-induced the autoimmune disease, rheumatoid arthritis (RA), is still unknown. Here, we attempted to evaluate the effect of FGL1 protein on arthritis progression. We also evaluated potential adverse events in a collagen-induced arthritis (CIA) mouse model. We first confirmed that soluble Fgl1 protein could specifically bind to surface Lag-3 receptor on 3T3-Lag-3 cells and further inhibit interleukin (IL-2) and interferon gamma (IFNγ) secretion from activated primary mouse T cells by 95% and 43%, respectively. Intraperitoneal administration of Fgl1 protein significantly decreased the inflammatory cytokine level (i.e., IL-1β and IL-6) in local paw tissue, and prevented joint inflammation, cellular infiltration, bone deformation and attenuated collagen-induced arthritis progression in vivo. We further demonstrated that exogenous Fgl1 does not cause obvious adverse events during treatment by monitoring body weight and liver weight, and assessing the morphology of several organs (i.e., heart, liver, spleen, lung and kidney) by pathological studies. We expect that Fgl1 protein may be suitable to serve as a potential therapeutic agent for treatment of RA or even other types of T cell-induced autoimmune or inflammatory diseases in the future.

The immunogenomic landscape of resected intrahepatic cholangiocarcinoma.

Cholangiocarcinoma (CCA) is a deadly and highly therapy-refractory cancer of the bile ducts, with early results from immune checkpoint blockade trials showing limited responses. Whereas recent molecular assessments have made bulk characterizations of immune profiles and their genomic correlates, spatial assessments may reveal actionable insights. Here, we have integrated immune checkpoint-directed immunohistochemistry with next-generation sequencing of resected intrahepatic CCA samples from 96 patients. We found that both T-cell and immune checkpoint markers are enriched at the tumor margins compared to the tumor center. Using two approaches, we identify high programmed cell death protein 1 or lymphocyte-activation gene 3 and low CD3/CD4/inducible T-cell costimulator specifically in the tumor center as associated with poor survival. Moreover, loss-of-function BRCA1-associated protein-1mutations are associated with and cause elevated expression of the immunosuppressive checkpoint marker, B7 homolog 4. This study provides a foundation on which to rationally improve and tailor immunotherapy approaches for this difficult-to-treat disease.

189P Prognostic significance of lymphocyte activation gene-3 (LAG3 gene) in uveal melanoma patients

Despite the use of CTLA4 and PD1-PDL1-targeted cancer immunotherapy, a large proportion of patients with many tumor types fail to respond including uveal melanoma (UM). Targeting inhibitory immune checkpoint lymphocyte activation gene-3 (LAG3) in tumor microenvironment of UM holds promising potential. LAG3 (CD233) is an inhibitory receptor that plays a critical role in controlling T cell tolerance, preventing autoimmunity and limiting immune-mediated tissue damage. It is highly upregulated on exhausted T cells in tumors.

An engineered oncolytic vaccinia virus encoding a single-chain variable fragment against TIGIT induces effective antitumor immunity and synergizes with PD-1 or LAG-3 blockade

BackgroundIn addition to directly lysing tumors, oncolytic viruses also induce antitumor immunity by recruiting and activating immune cells in the local tumor microenvironment. However, the activation of the immune cells...

T cells expressing multiple co-inhibitory molecules in acute malaria are not exhausted but exert a suppressive function in mice.

Overwhelming activation of T cells in acute malaria is associated with severe outcomes. Thus, counter-regulation by anti-inflammatory mechanisms is indispensable for an optimal resolution of disease. Using Plasmodium berghei ANKA (PbA) infection of C57BL/6 mice, we performed a comprehensive analysis of co-inhibitory molecules expressed on CD4+ and CD8+ T cells using an unbiased cluster analysis approach. We identified similar T cell clusters co-expressing several co-inhibitory molecules like programmed cell death protein 1 (PD-1) and lymphocyte activation gene 3 (LAG-3) in the CD4+ and the CD8+ T cell compartment. Interestingly, despite expressing co-inhibitory molecules, which are associated with T cell exhaustion in chronic settings, these T cells were more functional compared to activated T cells that were negative for co-inhibitory molecules. However, T cells expressing high levels of PD-1 and LAG-3 also conferred suppressive capacity and thus resembled type I regulatory T cells. To our knowledge, this is the first description of malaria-induced CD8+ T cells with suppressive capacity. Importantly, we found an induction of T cells with a similar co-inhibitory rich phenotype in Plasmodium falciparum-infected patients. In conclusion, we demonstrate that malaria-induced T cells expressing co-inhibitory molecules are not exhausted, but acquire additional suppressive capacity, which might represent an immune regulatory pathway to prevent further activation of T cells during acute malaria.

The relationship of GITR, Lag-3 and PD-1 expression with the main indicators of systemic and local immunity in patients with breast cancer

Background. To enhance the antitumor immune response, new promising methods of immunotherapy are being developed. They consist in the blockade and activation of immune check-point molecules, in particular, the blockade of the Lag‐3 molecule (lymphocyte-activation gene 3) and the activation of the GITR receptor (Glucocorticoid induced TNF receptor). In the studies of combined use with PD-1 blockers, encouraging results were obtained, which makes the assessment of the expression of Lag-3 and GITR on immunocompetent cells of peripheral blood (PB) and tumor tissue necessary for the personalization of such treatment and understanding of the mechanisms of the antitumor immune response.&#x0D; Materials and methods. The study included peripheral blood samples and surgical material from 39 breast cancer patients being treated at the Blokhin National Medical Research Center of Oncology. The subpopulation composition and expression of PD-1, Lag-3, and GITR molecules were evaluated by flow cytometry.&#x0D; Results. The analysis of the main populations of PB lymphocytes showed that in patients with breast cancer, the content of NKT-lymphocytes was increased, and the proportions of lymphocytes expressing CD11b and CD25 markers were increased compared to the donor group. It was revealed that the tumor tissue is dominated by T-cells, an increase in the proportion of which occurs due to a reduced content of NK-lymphocytes and B-lymphocytes. The structure of Tumor-infiltrating lymphocytes (TILs) is dominated by subpopulations with immunosuppressive activity, which is indicated by a decrease in the content of CD11b+, CD25+ and perforin-positive cells, increased expression of Lag-3 and PD-1. For PB and tumor tissue, the average degree of dependence of Lag-3 expression on the content of PD-1+ lymphocytes was shown. There is an increase in the content of immunosuppressive subpopulations with high PD-1 values in PB and TILs. The direct dependence of the number of perforin-containing lymphocytes and CD11b expression on the GITR content in the PB was established, but it is not typical for breast cancer tissue.&#x0D; Conclusion. Since the blockade of the Lag-3 molecule by monoclonal antibodies can enhance the effect of anti-PD-1 therapy in cancer patients, it is necessary to evaluate the expression and co-expression of these two markers. A high content of GITR-positive lymphocytes in the tumor tissue, on the one hand, and a decrease in the proportion of effector subpopulations of lymphocytes, on the other, indicates the influence of the tumor microenvironment on the functioning of GITR-mediated activation of the immune response. Further investigation of GITR expression and functional activity is required to understand the nature of this contradiction.