Lymphocyte activation gene-3 expression defines a discrete subset of HIV-specific CD8+ T cells that is associated with lower viral load

Characterization of CD4+ and CD8+ T cells responses in the mixed lymphocyte reaction by flow cytometry and single cell RNA sequencing

Background

The Mixed Lymphocyte Reaction (MLR) consists in the allogeneic co-culture of monocytes derived dendritic cells (MoDCs) with T cells from another donor. This in vitro assay is largely used for the assessment of immunotherapy compounds. Nevertheless, the phenotypic changes associated with lymphocyte responsiveness under MLR have never been thoroughly evaluated.

Methods

Here, we used multiplex cytokine and chemokine assays, multiparametric flow cytometry and single cell RNA sequencing to deeply characterize T cells activation and function in the context of CD4+- and CD8+-specific MLR kinetics.

Results

We showed that CD4+ and CD8+ T cells in MLR share common classical markers of response such as polyfunctionality, increased proliferation and CD25 expression but differ in their kinetics and amplitude of activation as well as their patterns of cytokines secretion and immune checkpoints expression. The analysis of immunoreactive Ki-67+CD25+ T cells identified PBK, LRR1 and MYO1G as new potential markers of MLR response. Using cell-cell communication network inference and pathway analysis on single cell RNA sequencing data, we also highlighted key components of the immunological synapse occurring between T cells and the stimulatory MoDCs together with downstream signaling pathways involved in CD4+ and CD8+ T cells activation.

Conclusion

These results provide a deep understanding of the kinetics of the MLR assay for CD4+ or CD8+ T cells and may allow to better characterize compounds impacting MLR and eventually identify new strategies for immunotherapy in cancer.

Targets of Immune Escape Mechanisms in Cancer: Basis for Development and Evolution of Cancer Immune Checkpoint Inhibitors

Immune checkpoint blockade (ICB) has emerged as a novel therapeutic tool for cancer therapy in the last decade. Unfortunately, a small number of patients benefit from approved immune checkpoint inhibitors (ICIs). Therefore, multiple studies are being conducted to find new ICIs and combination strategies to improve the current ICIs. In this review, we discuss some approved immune checkpoints, such as PD-L1, PD-1, and CTLA-4, and also highlight newer emerging ICIs. For instance, HLA-E, overexpressed by tumor cells, represents an immune-suppressive feature by binding CD94/NKG2A, on NK and T cells. NKG2A blockade recruits CD8+ T cells and activates NK cells to decrease the tumor burden. NKG2D acts as an NK cell activating receptor that can also be a potential ICI. The adenosine A2A and A2B receptors, CD47-SIRPα, TIM-3, LAG-3, TIGIT, and VISTA are targets that also contribute to cancer immunoresistance and have been considered for clinical trials. Their antitumor immunosuppressive functions can be used to develop blocking antibodies. PARPs, mARTs, and B7-H3 are also other potential targets for immunosuppression. Additionally, miRNA, mRNA, and CRISPR-Cas9-mediated immunotherapeutic approaches are being investigated with great interest. Pre-clinical and clinical studies project these targets as potential immunotherapeutic candidates in different cancer types for their robust antitumor modulation.

The Role of TIM-3 and LAG-3 in the Microenvironment and Immunotherapy of Ovarian Cancer

Ovarian cancer has the highest mortality rate among gynecologic malignancies. The main treatment options are surgical removal of the tumor and chemotherapy. Cancer treatment has been revolutionized by immunotherapy, which has developed explosively over the past two decades. Clinical anticancer strategies used in immunotherapy include therapies based on the inhibition of PD-1, PD-L1 or CTLA-4. Despite encouraging results, a large proportion of cancer patients are resistant to these therapies or eventually develop resistance. It is important to perform research that will focus on immunotherapy based on other immune checkpoint inhibitors. The aim of the review was to analyze studies considering the expression of TIM-3 and LAG-3 in the ovarian cancer microenvironment and considering immunotherapy for ovarian cancer that includes antibodies directed against TIM-3 and LAG-3. As the data showed, the expression of the described immune checkpoints was shown in different ways. Higher TIM-3 expression was associated with a more advanced tumor stage. Both TIM-3 and LAG-3 were co-expressed with PD-1 in a large proportion of studies. The effect of LAG-3 expression on progression-free survival and/or overall survival is inconclusive and certainly requires further study. Co-expression of immune checkpoints prompts combination therapies using anti-LAG-3 or anti-TIM-3. Research on immune checkpoints, especially TIM-3 and LAG-3, should be further developed.

Advances in the drug management of basal cell carcinoma

INTRODUCTION

Basal cell carcinoma (BCC) is the most common skin cancer in humans. Recently, BCCs were suggested to be classified into 'easy to treat' and 'difficult to treat,' and different therapeutic options are suggested for their management.

AREAS COVERED

In this review, the authors discuss treatment options that are approved, recommended for, or are still in development for treatment of BCC. The review covers approved local therapies, such as imiquimod and 5-fluorouracil, and systemic therapies, such as hedgehog inhibitors. New medical agents, investigated in clinical trials, are reviewed. These include: targeted therapies, such as GLI antagonists or anti-VEGFR agents, immunotherapies, such as checkpoint inhibitors, recombinant cytokines or silencing RNA, as well as intralesional virotherapies with modified adeno- or herpes viruses.

EXPERT OPINION

The progress made in recent years has improved the management of patients with advanced BCC; however, neither tumor targeting nor immune system engaging agents provide a cure. New treatment approaches directed not only to known targets but also the tumor microenvironment are in development and are anticipated to improve the management of difficult to treat BCC.

Perspectives on the role of breast cancer susceptibility gene in breast cancer

PURPOSE

Breast cancer susceptibility gene 1/2 can repair damaged DNA through homologous recombination. Besides, the local immune microenvironment of breast cancer is closely linked to the prognosis of patients. But the relationship of breast cancer susceptibility gene 1/2 expression and local immunosuppressive microenvironment in breast cancer is not clear. The aim of this study was to discuss the correlation between them.

METHODS

The fresh primary breast tumors and paired normal tissues of 156 cases of breast cancer patients as well as peripheral blood of 156 cases among them in Tianjin Medical University Cancer Institute and Hospital from January 2014 to October 2018 were collected. The association between breast cancer susceptibility gene 1/2 germline mutation and immune status of microenvironment in situ was analyzed.

RESULTS

The results indicated that the germline mutation of breast cancer susceptibility gene 1/2 was inconsistent with the breast cancer susceptibility gene 1/2 protein expression, and the proportion of immune cells in patients with negative expression of breast cancer susceptibility gene 1/2 protein was higher than patients with positive expression of breast cancer susceptibility gene 1/2 protein (p < 0.05). And the expression of programmed cell death protein 1, cytotoxic T-Lymphocyte Antigen 4, programmed death ligand-1 of CD3⁺ T cells in patients with negative expression of breast cancer susceptibility gene 1/2 protein was higher than patients with positive expression of breast cancer susceptibility gene 1/2 protein (p < 0.05). The breast cancer susceptibility gene 1 protein expression was significantly correlated with family history of breast cancer patients (p = 0.006), local lymph node metastases (p = 0.001), and TNM staging (p ≤ 0.001). The breast cancer susceptibility gene 2 protein expression was significantly related to local lymph node metastases (p ≤ 0.001), III stage rate(p = 0.003) and molecular subtyping (p ≤ 0.001). Besides, the 5 years disease free survival was worse for G1 group and pathological III stage patients than other groups and other TNM stage patients.

CONCLUSION

In short, the immune therapy may be a potential therapy method for breast cancer patients with negative expression of breast cancer susceptibility gene 1/2 protein.

Cure the Incurable? Recent Breakthroughs in Immune Checkpoint Blockade for Hepatocellular Carcinoma

HCC usually arises from a chronic inflammation background, driven by several factors including fatty liver, HBV/HCV viral infection and metabolic syndrome. Systemic treatment for advanced HCC remains disappointing due to its strong resistance to chemotherapy and even to tyrosine kinase inhibitors (TKIs). Recently, the use of ICI therapy has revolutionized the systemic treatment of advanced HCC. For the first time, clinical trials testing ICIs, anti-CTLA-4 and anti-PD1/PDL1 reported a survival benefit in patients with sorafenib resistance. However, it took four more years to find the right combination regimen to use ICI in combination with the anti-angiogenic agent bevacizumab to substantially prolong overall survival (OS) of patients with advanced HCC after sorafenib. This review provides a comprehensive history of ICI therapy in HCC, up-to-date information on the latest ICI clinical trials, and discusses the recent development of novel ICIs that would potentially lead to a new checkpoint blockade therapy for advanced HCC.

Progress of immune checkpoint LAG-3 in immunotherapy

Immune checkpoint inhibition has been shown to successfully reactivate T cell responses directed against tumor-associated antigens, resulting in significantly prolonged overall survival in patients with various types of solid tumors. Among them, cytotoxic T-lymphocyte protein 4 (CTLA-4) and programmed cell death protein 1 (PD-1) play key roles in tumor immune escape and are well-established targets of cancer immunotherapy. However, the low response rate PD-1 and CTLA-4 is a limitation and a challenge. Hence, studies have focused on investigating the tumor microenvironment for alternative therapeutic targets. Lymphocyte activation gene 3 protein (LAG-3) negatively regulates T lymphocytes by binding to the extracellular domain of the ligand, thus avoiding autoimmunity caused by T cell overactivation. LAG-3 is an important immune checkpoint in vivo and plays a balanced regulatory role in the human immune system. LAG-3 is now regarded as a new generation of immunotherapy targets. The present review describes the research progress of LAG-3 to provide reference for further investigation of LAG-3. The immune checkpoint of LAG-3 plays a crucial role in cancer development and may be used in future clinical practice of cancer therapy.

Advances toward Curing HIV-1 Infection in Tissue Reservoirs

A disease of more than 39.6 million people worldwide, HIV-1 infection has no curative therapy. To date, one man has achieved a sterile cure, with millions more hoping to avoid the potential pitfalls of lifelong antiretroviral therapy and other HIV-related disorders, including neurocognitive decline. Recent developments in immunotherapies and gene therapies provide renewed hope in advancing efforts toward a sterilizing or functional cure. On the horizon is research concentrated in multiple separate but potentially complementary domains: vaccine research, viral transcript editing, T-cell effector response targeting including checkpoint inhibitors, and gene editing. Here, we review the concept of targeting the HIV-1 tissue reservoirs, with an emphasis on the central nervous system, and describe relevant new work in functional cure research and strategies for HIV-1 eradication.

On the Horizon: Targeting Next-Generation Immune Checkpoints for Cancer Treatment

BACKGROUND

Immune checkpoints are critical regulatory pathways of the immune system which finely tune the response to biological threats. Among them, the CD-28/CTLA-4 and PD-1/PD-L1 axes play a key role in tumour immune escape and are well-established targets of cancer immunotherapy.

SUMMARY

The clinical experience accumulated to date provides unequivocal evidence that anti-CTLA-4, PD-1, or PD-L1 monoclonal antibodies, used as monotherapy or in combination regimes, are effective in a variety of advanced/metastatic types of cancer, with improved clinical outcomes compared to conventional chemotherapy. However, the therapeutic success is currently restricted to a limited subset of patients and reliable predictive biomarkers are still lacking. Key Message: The identification and characterization of additional co-inhibitory pathways as novel pharmacological targets to improve the clinical response in refractory patients has led to the development of different immune checkpoint inhibitors, the activities of which are currently under investigation. In this review, we discuss recent literature data concerning the mechanisms of action of next-generation monoclonal antibodies targeting LAG-3, TIM-3, and TIGIT co-inhibitory molecules that are being explored in clinical trials, as single agents or in combination with other immune-stimulating agents.

Soluble LAG3 acts as a potential prognostic marker of gastric cancer and its positive correlation with CD8+T cell frequency and secretion of IL-12 and INF-γ in peripheral blood

OBJECTIVE

Gastric cancer (GC) is the second most common lethal cancer worldwide and lymphocyte-activation gene 3 (LAG3) as a therapeutic target for cancers has been investigated. Herein, our study is to clarify the value of peripheral blood (PB) soluble LAG-3 (sLAG3) in GC.

METHODS

Peripheral serum samples of GC patients and healthy people were collected for the measurement of serum levels of sLAG3, carcinoembryonic antigen (CEA), IL-12 and IFN-γ. Additionally, ROC and Kaplan-Meier curves were adopted to identify the diagnostic and prognostic values of sLAG-3 in patients with GC. Then, GC-bearing mice were treated with recombinant sLAG3. The tumor volume was measured, and CD8+T cell frequency was detected in PB and tumor-ininfiltrating area. Additionally, the expression of IL-12 and IFN-γ in T cells was assayed and the overall survival of mice was analyzed.

RESULTS

sLAG3 in PB was poorly expressed and its expression was positively correlated with IL-12 and IFN-γ expression in GC patients. sLAG3 was proved to have a higher diagnostic value than CEA in GC. Moreover, high sLAG-3 expression is found in relation to a better prognosis in GC. The in vivo experiments indicated that sLAG-3 might inhibit the tumor growth, and promote the secretion of CD8+T cells, IL-12 and IFN-γ. Furthermore, sLAG-3 was able to prolong overall survival and increase survival rate of GC-bearing mice.

CONCLUSION

Based on these findings, we conclude that sLAG3 positively regulates CD8+T cells, IL-12 and IFN-γ, and function as a prognostic marker for GC, which might be a potential target in the treatment of GC.

The promising immune checkpoint LAG-3: from tumor microenvironment to cancer immunotherapy

Cancer immunotherapy and tumor microenvironment have been at the forefront of research over the past decades. Targeting immune checkpoints especially programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) has made a breakthrough in treating advanced malignancies. However, the low response rate brings a daunting challenge, changing the focus to dig deeply into the tumor microenvironment for alternative therapeutic targets. Strikingly, the inhibitory immune checkpoint lymphocyte activation gene-3 (LAG-3) holds considerable potential. LAG-3 suppresses T cells activation and cytokines secretion, thereby ensuring immune homeostasis. It exerts differential inhibitory impacts on various types of lymphocytes and shows a remarkable synergy with PD-1 to inhibit immune responses. Targeting LAG-3 immunotherapy is moving forward in active clinical trials, and combination immunotherapy of anti-LAG-3 and anti-PD-1 has shown exciting efficacy in fighting PD-1 resistance. Herein, we shed light on the significance of LAG-3 in the tumor microenvironment, highlight its role to regulate different lymphocytes, interplay with other immune checkpoints especially PD-1, and emphasize new advances in LAG-3-targeted immunotherapy.

Lymphocyte-activation gene-3, an important immune checkpoint in cancer

Immunotherapy has recently become widely used in lung cancer. Many oncologists are focused on cytotoxic T lymphocyte antigen-4 (CTLA-4), programmed cell death ligand-1 (PD-L1) and programmed cell death-1 (PD-1). Immunotherapy targeting the PD-1/PD-L1 checkpoints has shown promising efficacy in non-small cell lung cancer (NSCLC), but questions remain to be answered. Among them is whether the simultaneous inhibition of other checkpoints could improve outcomes. Lymphocyte-activation gene-3 (LAG-3) is another vital checkpoint that may have a synergistic interaction with PD-1/PD-L1. Here we review the LAG-3 function in cancer, clinical trials with agents targeting LAG-3 and the correlation of LAG-3 with other checkpoints.

Differential Expression of Immune Checkpoint Modulators on In Vitro Primed CD4(+) and CD8(+) T Cells

PD-1, TIM-3, and LAG-3 are molecules shown to have immune modulatory properties, and although initially classified as indicators of T cell hyporesponsiveness, it has become clear that they are also associated with the normal course of T cell activation. Functional studies have focused mainly on CD8⁺ T cells during chronic inflammation due to interest in co-opting the cellular immune response to eliminate viral or cancerous threats; however, there remains a relative lack of data regarding the expression of these molecules on CD4⁺ T cells. Here, we report that expression of the immune checkpoint (IC) molecules PD-1, LAG-3, and TIM-3 are differentially expressed on CD4⁺ and CD8⁺ T cells in the allogeneic response resulting from a mixed lymphocyte reaction. In these studies, PD-1 expression is higher on CD4⁺ T cells compared to CD8⁺ T cells. In contrast, TIM-3 is expressed at higher levels on CD8⁺ T cells compared to CD4⁺ T cells with an apparent reciprocity in that PD-1⁺ CD4⁺ T cells are frequently TIM-3^lo/−, while TIM-3-expressing CD8⁺ T cells are largely PD-1^lo/−. In addition, there is a decrease in the frequency of TIM-3⁺ CD4⁺ cells producing IFN-γ and IL-5 compared to TIM-3⁺ CD8⁺ cells. Lastly, the memory T cell phenotype within each IC-expressing subset differs between CD4⁺ and CD8⁺ T cells. These findings highlight key differences in IC expression patterns between CD4⁺ and CD8⁺ T cells and may allow for more effective therapeutic targeting of these molecules in the future.

CD4+ T-cell gene expression of healthy donors, HIV-1 and elite controllers: Immunological chaos

OBJECTIVES

T-cell repertoire dysfunction characterizes human immunodeficiency virus type 1 (HIV-1) infection, but the pathogenic mechanisms remain unclear. Disease progression is probably due to a profound dysregulation of Th1, Th2, Th17 and Treg patterns. The aim of this study was to analyze the features of CD4+ T cells in HIV-positive patients with different viroimmunological profile.

METHODS

we used a gene expression dataset of CD4+ T cells from healthy donors, HIV+ naive patients and Elite Controllers (EC), obtained from the NCBI Gene Expression Omnibus (GEO, http://www.ncbi.nlm.nih.gov/geo/, accession number GSE18233).

RESULTS

Principal Component Analysis (PCA) showed an almost complete overlap between the HIV-infected and EC patients, which cannot easily explain the different responses to HIV infection of these two group of patients. We have found that HIV patients and the EC showed an upregulation of the Th1 pro-inflammatory cytokines and chemokines, compared to the controls. Also, we have surprisingly identified IL28B, which resulted downregulated in HIV and EC compared to healthy controls. We focused attention also on genes involved in the constitution of the immunological synapse and we showed that HLA class I and II genes resulted significantly upregulated in HIV and in EC compared to the control. In addition to it, we have found the upregulation of others syncytial molecules, including LAG3, CTLA4, CD28 and CD3, assisting the formation of syncytia with APC cells.

CONCLUSIONS

Understanding the mechanisms of HIV-associated immunological chaos is critical to strategically plan focused interventions.

The upregulation of LAG-3 on T cells defines a subpopulation with functional exhaustion and correlates with disease progression in HIV-infected subjects

T cells develop functional defects during HIV-1 infection, partially due to the upregulation of inhibitory receptors such as programmed death-1 (PD-1) and CTLA-4. However, the role of lymphocyte activation gene-3 (LAG-3; CD223), also known as an inhibitory receptor, in HIV infection remains to be determined. In this study, we revealed that LAG-3 on T cells delivers an inhibitory signal to downregulate T cell functionality, thereby playing an immunoregulatory role during persistent HIV-1 infection. We observed that HIV-1 infection results in a significant increase in LAG-3 expression in both the peripheral blood and the lymph nodes. The upregulation of LAG-3 is dramatically manifested on both CD4(+) and CD8(+) T cells and is correlated with disease progression. As expected, prolonged antiretroviral therapy reduces the expression of LAG-3 on both CD4(+) and CD8(+) T cells. The ex vivo blockade of LAG-3 significantly augments HIV-specific CD4(+) and CD8(+) T cell responses, whereas the overexpression of LAG-3 in T cells or the stimulation of LAG-3 on T cells leads to the reduction of T cell responses. Furthermore, most LAG-3 and PD-1 are expressed in different T cell subsets. Taken together, these data demonstrate that the LAG-3/MHC class II pathway plays an immunoregulatory role, thereby providing an important target for enhancing immune reconstitution in HIV-infected patients. Additionally, the LAG-3/MHC class II pathway may synergize with PD-1/PD ligand to enhance T cell-mediated immune responses.

Elevated expression of LAG-3, but not PD-1, is associated with impaired iNKT cytokine production during chronic HIV-1 infection and treatment

Background

LAG-3 is a potent negative regulator of the immune response but its impact in HIV infection in poorly understood. Unlike exhaustion markers such as PD-1, Tim-3, 2B4 and CD160, LAG-3 is poorly expressed on bulk and antigen-specific T cells during chronic HIV infection and its expression on innate lymphocyte subsets is not well understood. The aim of this study was to assess LAG-3 expression and association with cellular dysfunction on T cells, NK cells and iNKT cells among a cohort of healthy and HIV-infected female sex workers in Nairobi, Kenya.

Results

Ex vivo LAG-3 expression was measured by multiparametric flow cytometry, and plasma cytokine/chemokine concentrations measured by bead array. Although LAG-3 expression on bulk T cells was significantly increased among HIV-infected women, the proportion of cells expressing the marker was extremely low. In contrast, LAG-3 was more highly expressed on NK and iNKT cells and was not reduced among women treated with ART. To assess the functional impact of LAG-3 on iNKT cells, iNKT cytokine production was measured in response to lipid (αGalCer) and PMA/Io stimulation by both flow cytometry and cytokine bead array. iNKT cytokine production is profoundly altered by both HIV infection and treatment, and LAG-3, but not PD-1, expression is associated with a reduction in iNKT IFNγ production.

Conclusions

LAG-3 does not appear to mediate T cell exhaustion in this African population, but is instead expressed on innate lymphocyte subsets including iNKT cells. HIV infection alters iNKT cytokine production patterns and LAG-3 expression is uniquely associated with iNKT dysfunction. The continued expression of LAG-3 during treatment suggests it may contribute to the lack of innate immune reconstitution commonly observed during ART.

Electronic supplementary material

The online version of this article (doi:10.1186/s12977-015-0142-z) contains supplementary material, which is available to authorized users.

TCR affinity associated with functional differences between dominant and subdominant SIV epitope-specific CD8+ T cells in Mamu-A*01+ rhesus monkeys

Many of the factors that contribute to CD8+ T cell immunodominance hierarchies during viral infection are known. However, the functional differences that exist between dominant and subdominant epitope-specific CD8+ T cells remain poorly understood. In this study, we characterized the phenotypic and functional differences between dominant and subdominant simian immunodeficiency virus (SIV) epitope-specific CD8+ T cells restricted by the major histocompatibility complex (MHC) class I allele Mamu-A*01 during acute and chronic SIV infection. Whole genome expression analyses during acute infection revealed that dominant SIV epitope-specific CD8+ T cells had a gene expression profile consistent with greater maturity and higher cytotoxic potential than subdominant epitope-specific CD8+ T cells. Flow-cytometric measurements of protein expression and anti-viral functionality during chronic infection confirmed these phenotypic and functional differences. Expression analyses of exhaustion-associated genes indicated that LAG-3 and CTLA-4 were more highly expressed in the dominant epitope-specific cells during acute SIV infection. Interestingly, only LAG-3 expression remained high during chronic infection in dominant epitope-specific cells. We also explored the binding interaction between peptide:MHC (pMHC) complexes and their cognate TCRs to determine their role in the establishment of immunodominance hierarchies. We found that epitope dominance was associated with higher TCR:pMHC affinity. These studies demonstrate that significant functional differences exist between dominant and subdominant epitope-specific CD8+ T cells within MHC-restricted immunodominance hierarchies and suggest that TCR:pMHC affinity may play an important role in determining the frequency and functionality of these cell populations. These findings advance our understanding of the regulation of T cell immunodominance and will aid HIV vaccine design.