Transcriptome analysis of cynomolgus macaques throughout their lifespan reveals age-related immune patterns

Despite the different perspectives by diverse research sectors spanning several decades, aging research remains uncharted territory for human beings. Therefore, we investigated the transcriptomic characteristics of eight male healthy cynomolgus macaques, and the annual sampling was designed with two individuals in four age groups. As a laboratory animal, the macaques were meticulously shielded from all environmental factors except aging. The results showed recent findings of certain immune response and the age-associated network of primate immunity. Three important aging patterns were identified and each gene clusters represented a different immune response. The increased expression pattern was predominantly associated with innate immune cells, such as Neutrophils and NK cells, causing chronic inflammation with aging whereas the other two decreased patterns were associated with adaptive immunity, especially "B cell activation" affecting antibody diversity of aging. Furthermore, the hub gene network of the patterns reflected transcriptomic age and correlated with human illness status, aiding in future human disease prediction. Our macaque transcriptome profiling results offer systematic insights into the age-related immunological features of primates.

Hypoxia-sensitive cells trigger NK cell activation via the KLF4-ASH1L-ICAM-1 axis, contributing to impairment in the rat epididymis

Male infertility is a global health problem especially prevalent in high-altitude regions. The epididymis is essential for sperm maturation, but the influence of environmental cues on its reshaping remains poorly understood. Here, we use single-cell transcriptomics to track the cellular profiles of epidydimal cells in rats raised under normoxia or extended hypoxia. The results show that hypoxia impairs epididymal function, evident in reduced epithelial cells, compromised blood-epididymis barrier integrity, and increased natural killer cells. Through combined analysis of gene-regulatory networks and cell-cell interaction maps, we identify epididymal hypoxia-sensitive cells that communicate with natural killer (NK) cells via increased intercellular adhesion molecule 1 (ICAM-1) driven by KLF4 recruitment of the histone methyltransferase ASL1L to the Icam1 promoter. Taken together, our study offers a detailed blueprint of epididymal changes during hypoxia and defines a KLF4-ALSH1L-ICAM-1 axis contributing to NK cell activation, yielding a potential treatment targeting hypoxia-induced infertility.

Activation of the transcription factor NFAT5 in the tumor microenvironment enforces CD8+ T cell exhaustion

Persistent exposure to antigen during chronic infection or cancer renders T cells dysfunctional. The molecular mechanisms regulating this state of exhaustion are thought to be common in infection and cancer, despite obvious differences in their microenvironments. Here we found that NFAT5, an NFAT family transcription factor that lacks an AP-1 docking site, was highly expressed in exhausted CD8+ T cells in the context of chronic infections and tumors but was selectively required in tumor-induced CD8+ T cell exhaustion. Overexpression of NFAT5 in CD8+ T cells reduced tumor control, while deletion of NFAT5 improved tumor control by promoting the accumulation of tumor-specific CD8+ T cells that had reduced expression of the exhaustion-associated proteins TOX and PD-1 and produced more cytokines, such as IFNɣ and TNF, than cells with wild-type levels of NFAT5, specifically in the precursor exhausted PD-1+TCF1+TIM-3-CD8+ T cell population. NFAT5 did not promote T cell exhaustion during chronic infection with clone 13 of lymphocytic choriomeningitis virus. Expression of NFAT5 was induced by TCR triggering, but its transcriptional activity was specific to the tumor microenvironment and required hyperosmolarity. Thus, NFAT5 promoted the exhaustion of CD8+ T cells in a tumor-selective fashion.

Natural killer cells in the lung: potential role in asthma and virus-induced exacerbation?

Asthma is a chronic inflammatory airway disorder whose pathophysiological and immunological mechanisms are not completely understood. Asthma exacerbations are mostly driven by respiratory viral infections and characterised by worsening of symptoms. Despite current therapies, asthma exacerbations can still be life-threatening. Natural killer (NK) cells are innate lymphoid cells well known for their antiviral activity and are present in the lung as circulating and resident cells. However, their functions in asthma and its exacerbations are still unclear. In this review, we will address NK cell activation and functions, which are particularly relevant for asthma and virus-induced asthma exacerbations. Then, the role of NK cells in the lungs at homeostasis in healthy individuals will be described, as well as their functions during pulmonary viral infections, with an emphasis on those associated with asthma exacerbations. Finally, we will discuss the involvement of NK cells in asthma and virus-induced exacerbations and examine the effect of asthma treatments on NK cells.

Supervised discovery of interpretable gene programs from single-cell data

Factor analysis decomposes single-cell gene expression data into a minimal set of gene programs that correspond to processes executed by cells in a sample. However, matrix factorization methods are prone to technical artifacts and poor factor interpretability. We address these concerns with Spectra, an algorithm that combines user-provided gene programs with the detection of novel programs that together best explain expression covariation. Spectra incorporates existing gene sets and cell-type labels as prior biological information, explicitly models cell type and represents input gene sets as a gene-gene knowledge graph using a penalty function to guide factorization toward the input graph. We show that Spectra outperforms existing approaches in challenging tumor immune contexts, as it finds factors that change under immune checkpoint therapy, disentangles the highly correlated features of CD8+ T cell tumor reactivity and exhaustion, finds a program that explains continuous macrophage state changes under therapy and identifies cell-type-specific immune metabolic programs.

Determining Optimal Combination Regimens for Patients with Multiple Myeloma

While many novel therapies have been approved in recent years for treating patients with multiple myeloma, there is still no established curative regimen, especially for patients with high-risk disease. In this work, we use a mathematical modeling approach to determine combination therapy regimens that maximize healthy lifespan for patients with multiple myeloma. We start with a mathematical model for the underlying disease and immune dynamics, which was presented and analyzed previously. We add the effects of three therapies to the model: pomalidomide, dexamethasone, and elotuzumab. We consider multiple approaches to optimizing combinations of these therapies. We find that optimal control combined with approximation outperforms other methods, in that it can quickly produce a combination regimen that is clinically-feasible and near-optimal. Implications of this work can be used to optimize doses and advance the scheduling of drugs.

NK Cells in Cancer: Mechanisms of Dysfunction and Therapeutic Potential

Natural killer cells (NK) are innate lymphocytes endowed with the ability to recognize and kill cancer cells. Consequently, adoptive transfer of autologous or allogeneic NK cells represents a novel opportunity in cancer treatment that is currently under clinical investigation. However, cancer renders NK cells dysfunctional, thus restraining the efficacy of cell therapies. Importantly, extensive effort has been employed to investigate the mechanisms that restrain NK cell anti-tumor function, and the results have offered forthcoming solutions to improve the efficiency of NK cell-based therapies. The present review will introduce the origin and features of NK cells, summarize the mechanisms of action and causes of dysfunction of NK cells in cancer, and frame NK cells in the tumoral microenvironment and in the context of immunotherapies. Finally, we will discuss therapeutic potential and current limitations of NK cell adoptive transfer in tumors.

KIR+CD8+ and NKG2A+CD8+ T cells are distinct innate-like populations in humans

Subsets of the human CD8⁺ T cell population express inhibitory NK cell receptors, such as killer immunoglobulin-like receptors (KIRs) and NKG2A. In the present study, we examine the phenotypic and functional characteristics of KIR⁺CD8⁺ T cells and NKG2A⁺CD8⁺ T cells. KIRs and NKG2A tend to be expressed by human CD8⁺ T cells in a mutually exclusive manner. In addition, TCR clonotypes of KIR⁺CD8⁺ T cells barely overlap with those of NKG2A⁺CD8⁺ T cells, and KIR⁺CD8⁺ T cells are more terminally differentiated and replicative senescent than NKG2A⁺CD8⁺ T cells. Among cytokine receptors, IL12Rβ1, IL12Rβ2, and IL18Rβ are highly expressed by NKG2A⁺CD8⁺ T cells, whereas IL2Rβ is expressed by KIR⁺CD8⁺ T cells. IL-12/IL-18-induced production of IFN-γ is prominent in NKG2A⁺CD8⁺ T cells, whereas IL-15-induced NK-like cytotoxicity is prominent in KIR⁺CD8⁺ T cells. These findings suggest that KIR⁺CD8⁺ and NKG2A⁺CD8⁺ T cells are distinct innate-like populations with different cytokine responsiveness.

NK cells are never alone: crosstalk and communication in tumour microenvironments

Immune escape is a hallmark of cancer. The dynamic and heterogeneous tumour microenvironment (TME) causes insufficient infiltration and poor efficacy of natural killer (NK) cell-based immunotherapy, which becomes a key factor triggering tumour progression. Understanding the crosstalk between NK cells and the TME provides new insights for optimising NK cell-based immunotherapy. Here, we present new advances in direct or indirect crosstalk between NK cells and 9 specialised TMEs, including immune, metabolic, innervated niche, mechanical, and microbial microenvironments, summarise TME-mediated mechanisms of NK cell function inhibition, and highlight potential targeted therapies for NK-TME crosstalk. Importantly, we discuss novel strategies to overcome the inhibitory TME and provide an attractive outlook for the future.

Activin-A impairs CD8 T cell-mediated immunity and immune checkpoint therapy response in melanoma

Background

Activin-A, a transforming growth factor β family member, is secreted by many cancer types and is often associated with poor disease prognosis. Previous studies have shown that Activin-A expression can promote cancer progression and reduce the intratumoral frequency of cytotoxic T cells. However, the underlying mechanisms and the significance of Activin-A expression for cancer therapies are unclear.

Methods

We analyzed the expression of the Activin-A encoding gene INHBA in melanoma patients and the influence of its gain- or loss-of-function on the immune infiltration and growth of BRAF-driven YUMM3.3 and iBIP2 mouse melanoma grafts and in B16 models. Using antibody depletion strategies, we investigated the dependence of Activin-A tumor-promoting effect on different immune cells. Immune-regulatory effects of Activin-A were further characterized in vitro and by an adoptive transfer of T cells. Finally, we assessed INHBA expression in melanoma patients who received immune checkpoint therapy and tested whether it impairs the response in preclinical models.

Results

We show that Activin-A secretion by melanoma cells inhibits adaptive antitumor immunity irrespective of BRAF status by inhibiting CD8⁺ T cell infiltration indirectly and even independently of CD4 T cells, at least in part by attenuating the production of CXCL9/10 by myeloid cells. In addition, we show that Activin-A/INHBA expression correlates with anti-PD1 therapy resistance in melanoma patients and impairs the response to dual anti-cytotoxic T-Lymphocyte associated protein 4/anti-PD1 treatment in preclinical models.

Conclusions

Our findings suggest that strategies interfering with Activin-A induced immune-regulation offer new therapeutic opportunities to overcome CD8 T cell exclusion and immunotherapy resistance.

RNA-mediated immunotherapy regulating tumor immune microenvironment: next wave of cancer therapeutics

Accumulating research suggests that the tumor immune microenvironment (TIME) plays an essential role in regulation of tumor growth and metastasis. The cellular and molecular nature of the TIME influences cancer progression and metastasis by altering the ratio of immune- suppressive versus cytotoxic responses in the vicinity of the tumor. Targeting or activating the TIME components show a promising therapeutic avenue to combat cancer. The success of immunotherapy is both astounding and unsatisfactory in the clinic. Advancements in RNA-based technology have improved understanding of the complexity and diversity of the TIME and its effects on therapy. TIME-related RNA or RNA regulators could be promising targets for anticancer immunotherapy. In this review, we discuss the available RNA-based cancer immunotherapies targeting the TIME. More importantly, we summarize the potential of various RNA-based therapeutics clinically available for cancer treatment. RNA-dependent targeting of the TIME, as monotherapy or combined with other evolving therapeutics, might be beneficial for cancer patients’ treatment in the near future.

CD47/SIRPα pathway mediates cancer immune escape and immunotherapy

The adaptive immune checkpoints such as PD-1(programmed death-1)/PD-L1 (programmed death-ligand 1) play an important role in cancer immunotherapy, whereas increasing evidence suggests that cancer cell evades immune surveillance by innate immune checkpoints such as SIRPα (signal-regulatory protein α)/CD47 (cluster of differentiation 47). In multiple types of cancer cells and solid tumor tissues, highly expressed CD47 protein level has been observed, which is triggered by some transcription factors including NFκB, Myc, and HIF. As a transmembrane protein, the binding of CD47 to SIRPα ligand on phagocytes results in phagocytosis resistance and cancer cell immune escape. In contrast, CD47-SIRPα interaction blockade enhances cancer cell clearance by phagocytes such as macrophages and dendritic cells (DCs) to activate an innate immune response, whereas this process could promote antigen cross-presentation by antigen present cells (APCs) leading to T cell priming, consequently, activates an adaptive antitumor immune response. In this review, we discussed the current SIRPα-CD47 axis-mediated cancer cell immune escape and immunotherapy, which could provide an effective antitumor strategy by the innate and adaptive immune response.

Natural killer cells and cytotoxic T lymphocytes are required to clear solid tumor in a patient-derived xenograft

Existing patient-derived xenograft (PDX) mouse models of solid tumors lack a fully tumor donor-matched, syngeneic, and functional immune system. We developed a model that overcomes these limitations by engrafting lymphopenic recipient mice with a fresh, undisrupted piece of solid tumor, whereby tumor-infiltrating lymphocytes (TILs) persisted in the recipient mice for several weeks. Successful tumor engraftment was achieved in 83% to 89% of TIL-PDX mice, and these were seen to harbor exhausted immuno-effector as well as functional immunoregulatory cells persisting for at least 6 months postengraftment. Combined treatment with interleukin-15 stimulation and immune checkpoint inhibition resulted in complete or partial tumor response in this model. Further, depletion of cytotoxic T lymphocytes and/or natural killer cells before combined immunotherapy revealed that both cell types were required for maximal tumor regression. Our TIL-PDX model provides a valuable resource for powerful mechanistic and therapeutic studies in solid tumors.

Natural Killer Cell Interactions With Myeloid Derived Suppressor Cells in the Tumor Microenvironment and Implications for Cancer Immunotherapy

The tumor microenvironment (TME) is a complex and heterogeneous environment composed of cancer cells, tumor stroma, a mixture of tissue-resident and infiltrating immune cells, secreted factors, and extracellular matrix proteins. Natural killer (NK) cells play a vital role in fighting tumors, but chronic stimulation and immunosuppression in the TME lead to NK cell exhaustion and limited antitumor functions. Myeloid-derived suppressor cells (MDSCs) are a heterogeneous group of myeloid cells with potent immunosuppressive activity that gradually accumulate in tumor tissues. MDSCs interact with innate and adaptive immune cells and play a crucial role in negatively regulating the immune response to tumors. This review discusses MDSC-mediated NK cell regulation within the TME, focusing on critical cellular and molecular interactions. We review current strategies that target MDSC-mediated immunosuppression to enhance NK cell cytotoxic antitumor activity. We also speculate on how NK cell-based antitumor immunotherapy could be improved.

CD8+ T-Lymphocyte-Driven Limbic Encephalitis Results in Temporal Lobe Epilepsy

OBJECTIVE

Limbic encephalitis (LE) comprises a spectrum of inflammatory changes in affected brain structures including the presence of autoantibodies and lymphoid cells. However, the potential of distinct lymphocyte subsets alone to elicit key clinicopathological sequelae of LE potentially inducing temporal lobe epilepsy (TLE) with chronic spontaneous seizures and hippocampal sclerosis (HS) is unresolved.

METHODS

Here, we scrutinized pathogenic consequences emerging from CD8+ T cells targeting hippocampal neurons by recombinant adeno-associated virus-mediated expression of the model-autoantigen ovalbumin (OVA) in CA1 neurons of OT-I/RAG1-/- mice (termed "OVA-CD8+ LE model").

RESULTS

Viral-mediated antigen transfer caused dense CD8+ T cell infiltrates confined to the hippocampal formation starting on day 5 after virus transduction. Flow cytometry indicated priming of CD8+ T cells in brain-draining lymph nodes preceding hippocampal invasion. At the acute model stage, the inflammatory process was accompanied by frequent seizure activity and impairment of hippocampal memory skills. Magnetic resonance imaging scans at day 7 of the OVA-CD8+ LE model revealed hippocampal edema and blood-brain barrier disruption that converted into atrophy until day 40. CD8+ T cells specifically targeted OVA-expressing, SIINFEKL-H-2Kb -positive CA1 neurons and caused segmental apoptotic neurodegeneration, astrogliosis, and microglial activation. At the chronic model stage, mice exhibited spontaneous recurrent seizures and persisting memory deficits, and the sclerotic hippocampus was populated with CD8+ T cells escorted by NK cells.

INTERPRETATION

These data indicate that a CD8+ T-cell-initiated attack of distinct hippocampal neurons is sufficient to induce LE converting into TLE-HS. Intriguingly, the role of CD8+ T cells exceeds neurotoxic effects and points to their major pathogenic role in TLE following LE. ANN NEUROL 2021;89:666-685.

Innate Lymphoid Cells and Adaptive Immune Cells Cross-Talk: A Secret Talk Revealed in Immune Homeostasis and Different Inflammatory Conditions

The inflammatory immune response has evolved to protect the host from different pathogens, allergens, and endogenous death or damage-associated molecular patterns. Both innate and adaptive immune components are crucial in inducing an inflammatory immune response depending on the stimulus type and its duration of exposure or the activation of the primary innate immune response. As the source of inflammation is removed, the aggravated immune response comes to its homeostatic level. However, the failure of the inflammatory immune response to subside to its normal level generates chronic inflammatory conditions, including autoimmune diseases and cancer. Innate lymphoid cells (ILCs) are newly discovered innate immune cells, which are present in abundance at mucosal surfaces, including lungs, gastrointestinal tract, and reproductive tract. Also, they are present in peripheral blood circulation, skin, and lymph nodes. They play a crucial role in generating the pro-inflammatory immune response during diverse conditions. On the other hand, adaptive immune cells, including different types of T and B cells are major players in the pathogenesis of autoimmune diseases (type 1 diabetes mellitus, rheumatoid arthritis, psoriasis, and systemic lupus erythematosus, etc.) and cancers. Thus the article is designed to discuss the immunological role of different ILCs and their interaction with adaptive immune cells in maintaining the immune homeostasis, and during inflammatory autoimmune diseases along with other inflammatory conditions (excluding pathogen-induced inflammation), including cancer, graft-versus-host diseases, and human pregnancy.

Differences in Tumor Immune Microenvironment in Metastatic Sites of Breast Cancer

Introduction: Tumor immune microenvironment (TIME) promotes immune escape, allowing for tumor progression and metastasis. In spite of the current evidence of the complicated role of immune cells in promoting or suppressing cancer progression, the heterogeneity of TIME according to the tumor site has been scarcely investigated. Here, we analyzed transcriptomic profiles of metastatic breast cancer to understand how TIME varies according to tumor sites.

Methods: Two gene expression datasets from metastatic breast cancer of various sites and a single-cell RNA sequencing dataset of primary breast cancer and metastatic lymph nodes were analyzed. The immune cell-type enrichment of each tumor was estimated. Immune cell types were identified by clustering analysis, and the proportions of cell types in TIME were assessed according to the tumor site.

Results: Metastatic bone lesions showed more neutrophils than breast lesions. Tumors clustered according to immune cell type were significantly associated with tumor site. In single-cell analyses, the TIMEs of metastatic lymph nodes showed fewer macrophages than those of primary tumors. Differentially expressed gene signatures in the primary tumor and metastatic lymph nodes were associated with macrophage activation.

Conclusion: We conclude that metastatic sites show variable enrichment patterns of immune cells, and that the TIME of metastatic lesions should be considered in precise immuno-oncology treatments.

CD8+ T Lymphocyte and NK Cell Network: Circuitry in the Cytotoxic Domain of Immunity

Multiple effector layers in the immune system ensure an optimal temporal and spatial distribution of immune defense. Cytotoxic innate lymphoid natural killers (NK) and adaptive CD8⁺ T lymphocytes (CTL) interact to elicit specific cytolytic outcomes. The CTL carry antigen-specific T cell receptors (TCR) to recognize cognate peptides bound with major histocompatibility complex class-I (MHC-I) or human leukocyte antigen (HLA) molecules on target cells. Upon TCR engagement with MHC-I:peptide at a threshold of avidity, T cell intracellular programs converge into cytolytic activity. By contrast, NK cells lack antigen-specific receptors but express a repertoire of highly polymorphic and polygenic inhibitory and activating receptors that bind various ligands including MHC and like molecules. A highly calibrated maturation enables NK cells to eliminate target cells with lowered or absent MHC-I or induced MHC-I-related molecules while maintaining their tolerance toward self-MHC. Both CTL and mature NK cells undergo membranous reorganization and express various effector molecules to eliminate aberrant cells undergoing a stress of transformation, infection or other pathological noxa. Here, we present the cellular modules that underlie the CTL–NK circuitry to maximize their effector cooperativity against stressed or cancerous cells.

Methods for determining key components in a mathematical model for tumor-immune dynamics in multiple myeloma

In this work, we analyze a mathematical model we introduced previously for the dynamics of multiple myeloma and the immune system. We focus on four main aspects: (1) obtaining and justifying ranges and values for all parameters in the model; (2) determining a subset of parameters to which the model is most sensitive; (3) determining which parameters in this subset can be uniquely estimated given certain types of data; and (4) exploring the model numerically. Using global sensitivity analysis techniques, we found that the model is most sensitive to certain growth, loss, and efficacy parameters. This analysis provides the foundation for a future application of the model: prediction of optimal combination regimens in patients with multiple myeloma.

Innate immune cells for immunotherapy of autoimmune and cancer disorders

Modulation of the immune system has been widely targeted for the treatment of several immune-related diseases, such as autoimmune disorders and cancer, due to its crucial role in these pathologies. Current available therapies focus mainly on symptomatic treatment and are often associated with undesirable secondary effects. For several years, remission of disease and subsequently recovery of immune homeostasis has been a major goal for immunotherapy. Most current immunotherapeutic strategies are aimed to inhibit or potentiate directly the adaptive immune response by modulating antibody production and B cell memory, as well as the effector potential and memory of T cells. Although these immunomodulatory approaches have shown some success in the clinic with promising therapeutic potential, they have some limitations related to their effectiveness in disease models and clinical trials, as well as elevated costs. In the recent years, a renewed interest has emerged on targeting innate immune cells for immunotherapy, due to their high plasticity and ability to exert a potent and extremely rapid response, which can influence the outcome of the adaptive immune response. In this review, we discuss the immunomodulatory potential of several innate immune cells, as well as they use for immunotherapy, especially in autoimmunity and cancer.

Distinct patterns of cytolytic T-cell activation by different tumour cells revealed by Ca2+ signalling and granule mobilization

Cancer-germline genes in both humans and mice have been shown to encode antigens susceptible to targeting by cytotoxic CD8 T effector cells (CTL). We analysed the ability of CTL to kill different tumour cell lines expressing the same cancer-germline gene P1A (Trap1a). We previously demonstrated that CTL expressing a T-cell receptor specific for the P1A_35-43 peptide associated with H-2L^d , although able to induce regression of P1A-expressing P815 mastocytoma cells, were much less effective against P1A-expressing melanoma cells. Here, we analysed parameters of the in vitro interaction between P1A-specific CTL and mastocytoma or melanoma cells expressing similar levels of the P1A gene and of surface H-2L^d . The mastocytoma cells were more sensitive to cytolysis than the melanoma cells in vitro. Analysis by video-microscopy of early events required for target cell killing showed that similar patterns of increase in cytoplasmic Ca²⁺ concentration ([Ca²⁺ ]i) were induced by both types of P1A-expressing tumour cells. However, the use of CTL expressing a fluorescent granzyme B (GZMB-Tom) showed a delay in the migration of cytotoxic granules to the tumour interaction site, as well as a partially deficient GZMB-Tom exocytosis in response to the melanoma cells. Among surface molecules possibly affecting tumour-CTL interactions, the mastocytoma cells were found to express intercellular adhesion molecule-1, the ligand for LFA-1, which was not detected on the melanoma cells.

Oncolytic virus efficiency inhibited growth of tumour cells with multiple drug resistant phenotype in vivo and in vitro

Background

Tumour resistance to a wide range of drugs (multiple drug resistant, MDR) acquired after intensive chemotherapy is considered to be the main obstacle of the curative treatment of cancer patients. Recent work has shown that oncolytic viruses demonstrated prominent potential for effective treatment of diverse cancers. Here, we evaluated whether genetically modified vaccinia virus (LIVP-GFP) may be effective in treatment of cancers displaying MDR phenotype.

Methods

LIVP-GFP replication, transgene expression and cytopathic effects were analysed in human cervical carcinomas KB-3-1 (MDR−), KB-8-5 (MDR+) and in murine melanoma B-16 (MDR−), murine lymphosarcomas RLS and RLS-40 (MDR+). To investigate the efficacy of this therapy in vivo, we treated immunocompetent mice bearing murine lymphosarcoma RLS-40 (MDR+) (6- to 8-week-old female CBA mice; n = 10/group) or melanoma B-16 (MDR−) (6- to 8-week-old female C57Bl mice; n = 6/group) with LIVP-GFP (5 × 10⁷ PFU of virus in 0.1 mL of IMDM immediately and 4 days after tumour implantation).

Results

We demonstrated that LIVP-GFP replication was effective in human cervical carcinomas KB-3-1 (MDR−) and KB-8-5 (MDR+) and in murine melanoma B-16 (MDR−), whereas active viral production was not detected in murine lymphosarcomas RLS and RLS-40 (MDR+). Additionally, it was found that in tumour models in immunocompetent mice under the optimized regimen intratumoural injections of LIVP-GFP significantly inhibited melanoma B16 (33 % of mice were with complete response after 90 days) and RLS-40 tumour growth (fourfold increase in tumour doubling time) as well as metastasis.

Conclusion

The anti-tumour activity of LIVP-GFP is a result of direct oncolysis of tumour cells in case of melanoma B-16 because the virus effectively replicates and destroys these cells, and virus-mediated activation of the host immune system followed by immunologically mediated destruction of of tumour cells in case of lymphosarcoma RLS-40. Thus, the recombinant vaccinia virus LIVP-GFP is able to inhibit the growth of malignant cells with the MDR phenotype and tumour metastasis when administered in the early stages of tumour development.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-1002-x) contains supplementary material, which is available to authorized users.

Silymarin suppressed lung cancer growth in mice via inhibiting myeloid-derived suppressor cells

In this study, we investigated the antitumor activity of Silymarin in a mouse model of colon cancer xenograft of Lewis lung cancer (LLC) cells. Silymarin significantly suppressed tumor growth and induced apoptosis of cells in tumor tissues at a dose of 25 and 50mg/kg. Silymarin treatment enhanced the infiltration and function of CD8(+) T cells. In the meantime, Silymarin decreased the level of IL-10 while elevated the level of IL-2 and IFN-γ in the serum of tumor-bearing mice. Finally, Silymarin reduced the proportion of myeloid-derived suppressor cells (MDSC) in the tumor tissue and also the mRNA expressions of inducible nitric oxide synthases-2 (iNOS2), arginase-1 (Arg-1) and MMP9, which indicated that the function of MDSC in tumor tissues were suppressed. Altogether, our data here showed that Silymarin inhibited the MDSC and promoted the infiltration and function of CD8(+) T cells thus suppressed the growth of LLC xenografts, which provides evidence for the possible use of Silymarin against lung cancer.

MYC regulates the antitumor immune response through CD47 and PD-L1

The MYC oncogene codes for a transcription factor that is overexpressed in many human cancers. Here we show that MYC regulates the expression of two immune checkpoint proteins on the tumor cell surface: the innate immune regulator CD47 (cluster of differentiation 47) and the adaptive immune checkpoint PD-L1 (programmed death-ligand 1). Suppression of MYC in mouse tumors and human tumor cells caused a reduction in the levels of CD47 and PD-L1 messenger RNA and protein. MYC was found to bind directly to the promoters of the Cd47 and Pd-l1 genes. MYC inactivation in mouse tumors down-regulated CD47 and PD-L1 expression and enhanced the antitumor immune response. In contrast, when MYC was inactivated in tumors with enforced expression of CD47 or PD-L1, the immune response was suppressed, and tumors continued to grow. Thus, MYC appears to initiate and maintain tumorigenesis, in part, through the modulation of immune regulatory molecules.

Clinacanthus nutans (Burm. f.) Lindau Ethanol Extract Inhibits Hepatoma in Mice through Upregulation of the Immune Response

Clinacanthans nutans (Burm. f.) Lindau is a popular medicinal vegetable in Southern Asia, and its extracts have displayed significant anti-proliferative effects on cancer cells in vitro. However, the underlying mechanism for this effect has yet to be established. This study investigated the antitumor and immunomodulatory activity of C. nutans (Burm. f.) Lindau 30% ethanol extract (CN30) in vivo. CN30 was prepared and its main components were identified using high-performance liquid chromatography (HPLC) and mass spectrometry (LC/MS/MS). CN30 had a significant inhibitory effect on tumor volume and weight. Hematoxylin and eosin (H & E) staining and TUNEL assay revealed that hepatoma cells underwent significant apoptosis with CN30 treatment, while expression levels of proliferation markers PCNA and p-AKT were significantly decreased when treated with low or high doses of CN30 treatment. Western blot analysis of PAPR, caspase-3, BAX, and Bcl2 also showed that CN30 induced apoptosis in hepatoma cells. Furthermore, intracellular staining analysis showed that CN30 treatment increased the number of IFN-γ⁺ T cells and decreased the number of IL-4⁺ T cells. Serum IFN-γ and interleukin-2 levels also significantly improved. Our findings indicated that CN30 demonstrated antitumor properties by up-regulating the immune response, and warrants further evaluation as a potential therapeutic agent for the treatment and prevention of cancers.

Perioperative propofol-paravertebral anesthesia decreases the metastasis and progression of breast cancer

Propofol-paravertebral anesthesia (PPA) is a unique combination of paravertebral nerve blocks (PVBs) and propofol that regulates the cellular microenvironment during surgical period. Growing evidence points to its ability to attenuate perioperative immunosuppression of cancers. Abundant studies show that cancer patients who undergo perioperative PPA exhibit less recurrence as well as metastasis. Breast cancer remains a leading cause of cancer-induced death in women. Over the last decades, increasing concerns have been put on the promotional role of PPA in the prognosis of breast cancer patients. Among them, PPA participates in several bioprocesses in the development of breast cancer, including inhibiting hypoxia-inducible factor (HIF) activity, elevating serum concentration of nitric oxide index (NOx), depression of the neuroepithelial cell transforming gene 1 (NET1) signal pathway, blocking the nuclear factor kappa B (NF-κB) pathway following an decreased expression of matrix metalloproteinase (MMP), increasing NK cytotoxicity, and affecting transforming growth factor (TGF)-β-targeted ras and HER2/neu gene pathways. In this review, we discuss the effect of PPA on breast cancer metastasis and progression. This will provide an alteration pattern of surgical anesthesia technique in breast cancer patients with poor prognosis.

Challenges and future perspectives of T cell immunotherapy in cancer

Since the formulation of the tumour immunosurveillance theory, considerable focus has been on enhancing the effectiveness of host antitumour immunity, particularly with respect to T cells. A cancer evades or alters the host immune response by various ways to ensure its development and survival. These include modifications of the immune cell metabolism and T cell signalling. An inhibitory cytokine milieu in the tumour microenvironment also leads to immune suppression and tumour progression within a host. This review traces the development in the field and attempts to summarize the hurdles that the approach of adoptive T cell immunotherapy against cancer faces, and discusses the conditions that must be improved to allow effective eradication of cancer.

Molecular profiling of CD8 T cells in autochthonous melanoma identifies Maf as driver of exhaustion

T cells infiltrating neoplasms express surface molecules typical of chronically virus-stimulated T cells, often termed "exhausted" T cells. We compared the transcriptome of "exhausted" CD8 T cells infiltrating autochthonous melanomas to those of naïve and acutely stimulated CD8 T cells. Despite strong similarities between transcriptional signatures of tumor- and virus-induced exhausted CD8 T cells, notable differences appeared. Among transcriptional regulators, Nr4a2 and Maf were highly overexpressed in tumor-exhausted T cells and significantly upregulated in CD8 T cells from human melanoma metastases. Transduction of murine tumor-specific CD8 T cells to express Maf partially reproduced the transcriptional program associated with tumor-induced exhaustion. Upon adoptive transfer, the transduced cells showed normal homeostasis but failed to accumulate in tumor-bearing hosts and developed defective anti-tumor effector responses. We further identified TGFβ and IL-6 as main inducers of Maf expression in CD8 T cells and showed that Maf-deleted tumor-specific CD8 T cells were much more potent to restrain tumor growth in vivo. Therefore, the melanoma microenvironment contributes to skewing of CD8 T cell differentiation programs, in part by TGFβ/IL-6-mediated induction of Maf.

Control of CD8 T cell proliferation and terminal differentiation by active STAT5 and CDKN2A/CDKN2B

CD8 T cells used in adoptive immunotherapy may be manipulated to optimize their effector functions, tissue-migratory properties and long-term replicative potential. We reported that antigen-stimulated CD8 T cells transduced to express an active form of the transcription factor signal transducer and activator of transcription 5 (STAT5CA) maintained these properties upon adoptive transfer. We now report on the requirements of STAT5CA-expressing CD8 T cells for cell survival and proliferation in vivo. We show that STAT5CA expression allows for greater expansion of T cells in vivo, while preserving dependency on T-cell-receptor-mediated tonic stimulation for their in vivo maintenance and return to a quiescent stage. STAT5CA expression promotes the formation of a large pool of effector memory T cells that respond upon re-exposure to antigen and present an increased sensitivity to γc receptor cytokine engagement for STAT5 phosphorylation. In addition, STAT5CA expression prolongs the survival of what would otherwise be short-lived terminally differentiated KLRG1-positive effector cells with up-regulated expression of the senescence-associated p16(INK) (4A) transcripts. However, development of a KLRG1-positive CD8 T cell population was independent of either p16(INK) (4A) or p19(ARF) expression (as shown using T cells from CDKN2A(-/-) mice) but was associated with expression of transcripts encoding p15(INK) (4B) , another protein involved in senescence induction. We conclude that T-cell-receptor- and cytokine-dependent regulation of effector T cell homeostasis, as well as mechanisms leading to senescent features of a population of CD8 T cells are maintained in STAT5CA-expressing CD8 T cells, even for cells that are genetically deficient in expression of the tumour suppressors p16(INK) (4A) and p19(ARF) .

IFNγ producing CD8+ T cells modified to resist major immune checkpoints induce regression of MHC class I-deficient melanomas

Tumors with reduced expression of MHC class I (MHC-I) molecules may be unrecognized by tumor antigen-specific CD8⁺ T cells and thus constitute a challenge for cancer immunotherapy. Here we monitored development of autochthonous melanomas in TiRP mice that develop tumors expressing a known tumor antigen as well as a red fluorescent protein (RFP) reporter knock in gene. The latter permits non-invasive monitoring of tumor growth by biofluorescence. One developing melanoma was deficient in cell surface expression of MHC-I, but MHC-I expression could be rescued by exposure of these cells to IFNγ. We show that CD8⁺ T cells specific for tumor antigen/MHC-I were efficient at inducing regression of the MHC-I-deficient melanoma, provided that the T cells were endowed with properties permitting their migration into the tumor and their efficient production of IFNγ. This was the case for CD8⁺ T cells transfected to express an active form of STAT5 (STAT5CA). The amount of IFNγ produced ex vivo from T cells present in tumors after adoptive transfer of the CD8⁺ T cells was correlated with an increase in surface expression of MHC-I molecules by the tumor cells. We also show that these CD8⁺ T cells expressed PD-1 and upregulated its ligand PDL-1 on melanoma cells within the tumor. Despite upregulation of this immunosuppressive pathway, efficient IFNγ production in the melanoma microenvironment was found associated with resistance of STAT5CA-expressing CD8⁺ T cells to inhibition both by PD-1/PDL-1 engagement and by TGFβ1, two main immune regulatory mechanisms hampering the efficiency of immunotherapy in patients.

Unleashing antitumor T-cell activation without ensuing autoimmunity: the case for A20-deletion in adoptive CD8+ T-cell therapy

Mechanisms controlling immune reactivity prevent excessive inflammation and autoimmunity, but generally dampen antitumor activity. We recently showed that adoptively transferred antitumor CD8⁺ T cells harboring a deletion of A20/Tnfaip3, a molecule controlling NF-κB activation, possessed heightened antitumor activity in vivo. The boosted immunity of A20-deleted CD8⁺ T cells correlated with a heightened capacity to produce IFNγ and TNFα while expressing reduced levels of the immune checkpoint molecule PD-1.

NK cells and T cells cooperate during the clinical course of colorectal cancer

Recent evidence suggests that natural killer (NK) cells are typically defective in infiltrating solid tumors, with the exception of gastrointestinal stromal tumors (GIST). Interestingly, however, infrequently infiltrating NK cells do not appear to have a direct effect on tumor progression. Here, prompted by the recent evidence that NK cell and T cell crosstalk may trigger, or enhance, tumor antigen-specific immune responses, we have tested the clinical significance of this reciprocal signaling. To this end, a tissue microarray constructed with 1410 colorectal carcinoma (CRC) patient specimens was stained with NK and T cell antigen-specific monoclonal antibodies, utilizing the immunoperoxidase staining technique. Cut-off scores for positive (>4 NK cells) and negative (≤4 NK cells) NK cell CRC patient samples were determined using receiver operating characteristic curve analysis. Using this approach, NK cells were detected in 423 (30%) of the 1410 CRC specimens evaluated. The number of NK cells was >4 in only 132 (9%) of CRC samples. Correlation of the immunohistochemical staining results together with analysis of the clinical course of the disease revealed that the infiltration of colorectal tumors with both NK cells and CD8+ T cells is associated with prolonged patient survival. In contrast, infiltration of tumors with NK cells in combination with CD3⁺ and CD4⁺ T lymphocytes had no detectable effect on the clinical course of the disease. These results suggest that NK cell and CD8⁺ T cell crosstalk in the tumor microenvironment may benefit patient outcome and further, that the enumeration of infiltrating NK and CD8⁺ T cells in CRC tumors may provide useful prognostic information.

The tumor necrosis factor alpha-induced protein 3 (TNFAIP3, A20) imposes a brake on antitumor activity of CD8 T cells

The transcription factor NF-κB is central to inflammatory signaling and activation of innate and adaptive immune responses. Activation of the NF-κB pathway is tightly controlled by several negative feedback mechanisms, including A20, an ubiquitin-modifying enzyme encoded by the tnfaip3 gene. Mice with selective deletion of A20 in myeloid, dendritic, or B cells recapitulate some human inflammatory pathology. As we observed high expression of A20 transcripts in dysfunctional CD8 T cells in an autochthonous melanoma, we analyzed the role of A20 in regulation of CD8 T-cell functions, using mice in which A20 was selectively deleted in mature conventional T cells. These mice developed lymphadenopathy and some organ infiltration by T cells but no splenomegaly and no detectable pathology. A20-deleted CD8 T cells had increased sensitivity to antigen stimulation with production of large amounts of IL-2 and IFNγ, correlated with sustained nuclear expression of NF-κB components reticuloendotheliosis oncogene c-Rel and p65. Overexpression of A20 by retroviral transduction of CD8 T cells dampened their intratumor accumulation and antitumor activity. In contrast, relief from the A20 brake in NF-κB activation in adoptively transferred antitumor CD8 T cells led to improved control of melanoma growth. Tumor-infiltrating A20-deleted CD8 T cells had enhanced production of IFNγ and TNFα and reduced expression of the inhibitory receptor programmed cell death 1. As manipulation of A20 expression in CD8 T cells did not result in pathologic manifestations in the mice, we propose it as a candidate to be targeted to increase antitumor efficiency of adoptive T-cell immunotherapy.

HPV16 CTL epitope peptide-activated dendritic cell and natural killer co-culture for therapy of cervical cancer in an animal model

There is increasing evidence that natural killer (NK) cells play an important role in antitumor immunity following dendritic cell (DC) vaccination. Little is known, however, about the optimal stimulation of DCs by epitopes and NK interactions for cytotoxicity in tumors. In this study, DC cells activated by the HPV16E7.49-57 epitope and LPS were co-cultured with NK cells in vitro, and then used ot immunize mice to study CTL activity of TC-1, which constitutively expresses HPV16E6E7, with an LDH release assay. Cytotoxicity in mice immunized with DC loaded with epitope HPVE7.49-57 vaccine co-cultured with NK was enhanced significantly (p<0.01). In conclusion, talk-across between DC and NK cells enhances their functions, also improving cytotoxicity againsttumor cells, suggesting that activated DC-NK by epitopes has potential application for cancer-specific immuno-cellular therapy.

The clinical significance of tumor-infiltrating neutrophils and neutrophil-to-CD8+ lymphocyte ratio in patients with resectable esophageal squamous cell carcinoma

Background

The interaction between tumor cells and inflammatory cells has not been systematically investigated in esophageal squamous cell carcinoma (ESCC). The main aims of the study were to investigate the clinical significance of tumor-infiltrating neutrophils and neturophil-to-CD8+ lymphocyte ratio (NLR), and to analyze the distribution of tumor-infiltrating neutrophils and CD8+ lymphocytes in ESCC treated by curative resection.

Methods

The expressions of CD66b and CD8 were assessed with double staining immunohistochemistry in the surgical specimens from 90 patients with ESCC treated by curative surgery.

Results

We showed that increased intratumoral neutrophils were significantly associated with lymph node metastasis (P = 0.016), and advanced pathological stages (P = 0.013). Decreased peritumoral CD8+ lymphocyte density was more frequently observed in patients with single positive lymph node (p = 0.045). Peritumoral NLR was significantly associated with advanced T stages (p < 0.001), lymph node metastasis (p = 0.041) and a trend towards advanced pathological stages (p = 0.053). Increased intratumoral neutrophils were significantly associated with decreased disease-free survival (p < 0.001) and overall survival (p < 0.001) in univariate analysis and were identified as an independent prognostic factor for disease-free survival (p = 0.006) and overall survival (p = 0.037) in multivariate analysis. Neither the density nor the distribution of tumor-infiltrating neutrophils was significantly correlated with that of CD8+ lymphocytes. The density of intratumoral CD8+ lymphocytes was significantly lower than (P < 0.001) and moderately correlated with (r = 0.434, p < 0.001) that in peritumoral area.

Conclusions

Increased intratumoral neutrophils were an independent poor prognostic factor and peritumoral NLR was significantly associated with disease progression in ESCC treated by curative surgery, suggesting the possible effect of immune misbalance of tumor microenvironment in facilitating ESCC progression. Immunotherapy targeted to the above predictors should be considered in the future.

Targeting c-MYC with T-cells

Over-expression of the proto-oncogene c-MYC is frequently observed in a variety of tumors and is a hallmark of Burkitt´s lymphoma. The fact that many tumors are oncogene-addicted to c-MYC, renders c-MYC a powerful target for anti-tumor therapy. Using a xenogenic vaccination strategy by immunizing C57BL/6 mice with human c-MYC protein or non-homologous peptides, we show that the human c-MYC protein, despite its high homology between mouse and man, contains several immunogenic epitopes presented in the context of murine H2^b haplotype. We identified an MHC class II-restricted CD4⁺ T-cell epitope and therein an MHC class I-restricted CD8⁺ T-cell epitope (SSPQGSPEPL) that, after prime/boost immunization, protected up to 25% of mice against a lethal lymphoma challenge. Lymphoma-rejecting animals contained MHC multimer-binding CD8⁺ cell within the peripheral blood and displayed in vivo cytolytic activity with specificity for SSPQGSPEPL. Taken together these data suggest that oncogenic c-MYC can be targeted with specific T-cells.

Active STAT5 regulates T-bet and eomesodermin expression in CD8 T cells and imprints a T-bet-dependent Tc1 program with repressed IL-6/TGF-β1 signaling

In adoptive therapy, CD8 T cells expressing active STAT5 (STAT5CA) transcription factors were found to be superior to unmanipulated counterparts in long-term persistence, capacity to infiltrate autochthonous mouse melanomas, thrive in their microenvironment, and induce their regression. However, the molecular mechanisms sustaining these properties were undefined. In this study, we report that STAT5CA induced sustained expression of genes controlling tissue homing, cytolytic granule composition, type 1 CD8 cytotoxic T cell-associated effector molecules granzyme B(+), IFN-γ(+), TNF-α(+), and CCL3(+), but not IL-2, and transcription factors T-bet and eomesodermin (Eomes). Chromatin immunoprecipitation sequencing analyses identified the genes possessing regulatory regions to which STAT5 bound in long-term in vivo maintained STAT5CA-expressing CD8 T cells. This analysis identified 34% of the genes differentially expressed between STAT5CA-expressing and nonexpressing effector T cells as direct STAT5CA target genes, including those encoding T-bet, Eomes, and granzyme B. Additionally, genes encoding the IL-6R and TGFbRII subunits were stably repressed, resulting in dampened IL-17-producing CD8 T cell polarization in response to IL-6 and TGF-β1. The absence of T-bet did not affect STAT5CA-driven accumulation of the T cells in tissue or their granzyme B expression but restored IL-2 secretion and IL-6R and TGFbRII expression and signaling, as illustrated by IL-17 induction. Therefore, concerted STAT5/T-bet/Eomes regulation controls homing, long-term maintenance, recall responses, and resistance to polarization towards IL-17-producing CD8 T cells while maintaining expression of an efficient type 1 CD8 cytotoxic T cell program (granzyme B(+), IFN-γ(+)).

IL-4 induces a suppressive IL-10-producing CD8+ T cell population via a Cdkn2a-dependent mechanism

IL‐4 induced IL‐10‐producing CD8+ T cells possess suppressive function both in vitro and in vivo.

CD8⁺ T cells play an important role in immune regulation and effective immune responses against tumor cells, viral infection, and intracellular pathogens. In this report, using tiger or 10BiT mice, we defined a population of IL‐10‐producing CD8⁺ T cells that were induced by IL‐4. These IL‐10⁺CD8⁺ T cells possessed a strong inhibitory effect on the CD4⁺ T cell proliferation in an IL‐10‐dependent and cell contact‐dependent fashion. In comparison with IL‐10⁻CD8⁺ T cells, IL‐10⁺CD8⁺ T cells expressed an array of Th2‐like cytokines (IL‐4, IL‐5), perforin, and granzymes, as well as the cell cycle regulatory protein Cdkn2a. Interestingly, knockdown of cdkn2a using siRNA reduced IL‐4‐induced IL‐10 production significantly. Furthermore, CD8⁺ T cells from Cdkn2a^−/− mice produced a significantly lower amount of IL‐10, and the effect was limited to CD8⁺ T cells but not observed in CD4⁺ T cells and APCs. Finally, IL‐10⁺CD8⁺ T cells played a protective role in the TNBS‐induced murine colitis model, indicating a critical role of this population of CD8⁺ T cells in regulatory immune responses. Taken together, we have defined a population of IL‐10‐producing CD8⁺ Tregs induced by IL‐4 and mediated by Cdkn2a.

Molecular signatures mostly associated with NK cells are predictive of relapse free survival in breast cancer patients

Background

Recent observations suggest that immune-mediated tissue destruction is dependent upon coordinate activation of immune genes expressed by cells of the innate and adaptive immune systems.

Methods

Here, we performed a retrospective pilot study to investigate whether the coordinate expression of molecular signature mostly associated with NK cells could be used to segregate breast cancer patients into relapse and relapse-free outcomes.

Results

By analyzing primary breast cancer specimens derived from patients who experienced either 58–116 months (~5-9 years) relapse-free survival or developed tumor relapse within 9–76 months (~1-6 years) we found that the expression of molecules involved in activating signaling of NK cells and in NK cells: target interaction is increased in patients with favorable prognosis.

Conclusions

The parameters identified in this study, together with the prognostic signature previously reported by our group, highlight the cooperation between the innate and adaptive immune components within the tumor microenvironment.

T and NK cells: two sides of tumor immunoevasion

Natural Killer (NK) cells are known to reject several experimental murine tumors, but their antineoplastic activity in humans is not generally agreed upon, as exemplified by an interesting correspondence recently appeared in Cancer Research. In the present commentary, we join the discussion and bring to the attention of the readers of the Journal of Translational Medicine a set of recent, related reports. These studies demonstrate that effectors of the adaptive and innate immunity need to actively cooperate in order to reject tumors and, conversely, tumors protect themselves by dampening both T and NK cell responses. The recently reported ability of indoleamine 2,3-dioxygenase (IDO) and prostaglandin E2 (PGE2) expressed by melanoma cells to down-regulate activating NK receptors is yet another piece of evidence supporting combined and highly effective T/NK cell disabling. Major Histocompatibility Complex class I (MHC-I) molecules, including Human Leukocyte Antigen E (HLA-E), represent another class of shared activating/inhibitory ligands. Ongoing clinical trials with small molecules interfering with IDO and PGE2 may be exploiting an immune bonus to control cancer. Conversely, failure to simultaneously engage effectors of both the innate and the adaptive immunity may contribute to explain the limited clinical efficacy of T cell-only vaccination trials. Shared (T/NK cells) natural immunosuppressants and activating/inhibitory ligands expressed by tumor cells may provide mechanistic insight into impaired gathering and function of immune effectors at the tumor site.

Immunosuppression in inflammatory melanoma: can it be resisted by adoptively transferred T cells?

Discovery of tumor antigen (TA) recognized by autologous T cells (TCs) in patients with melanoma has led to clinical protocols using either vaccination or adoptive transfer of TA-specific TCs. However, efficacy of these treatments has been hampered by inhibitory effects exerted on tumor-infiltrating TCs by tumor-intrinsic mediators or by recruitment of immunosuppressive cells. A mouse model of autochthonous melanoma recapitulates some aspects of inflammatory melanoma development in patients. These include a systemic Th2-/Th17-oriented chronic inflammation, recruitment of immunosuppressive myeloid cells and acquisition by tumor-infiltrating TCs of an 'exhausted' phenotype characterized by expression of multiple inhibitory receptors including programmed death-1, also expressed on patients' melanoma-infiltrating TCs. Rather than using extracellular blocking reagents to inhibitory surface molecules on TCs, we sought to dampen negative signaling exerted on them. Adoptively transferred TCs presenting increased cytokine receptor signaling due to expression of an active Stat5 transcription factor were efficient at inducing melanoma regression in the preclinical melanoma model. These transferred TCs thrived and retained expression of effector molecules in the melanoma microenvironment, defining a protocol endowing TCs with the ability to resist melanoma-induced immunosuppression.

P3 mAb: An Immunogenic Anti-NeuGcGM3 Antibody with Unusual Immunoregulatory Properties

P3 is a murine IgM mAb that recognize N-glycosylated gangliosides, sulfatides, and antigens expressed in melanoma, breast, and lung human tumors. This antibody has the ability to trigger an IgG antibody response in the syngeneic BALB/c model, even when it is administered in the absence of adjuvant or carrier protein. The mechanism by which the P3 mAb, a self-immunoglobulin, induce this immune response in the absence of co-stimulatory or classical danger signals is still unknown. In the present paper we show that the high immunogenicity of P3 mAb depends not only on CD4 but also on CD8⁺ T cells, since the depletion of CD8⁺ or CD4⁺ T cells led to the loss of P3 mAb immunogenicity in the syngeneic model. Furthermore, the immunization with P3 mAb enhanced the recovery of the CD8⁺ T cell population in mice treated with an anti-CD8a antibody. Additionally, the immunization with P3 mAb restored the capacity of immunosuppressed mice to reject allogeneic tumors, a mechanism mediated by the action of CD8⁺ T cells. Finally, in mice with cyclophosphamide induced lymphopenia, the administration of P3 mAb accelerated the recovery of both CD4⁺ and CD8⁺ T cells. These results show new possibilities for B and CD8⁺ T cells interactions during the immune response elicited by a self-protein. Furthermore they point to P3 mAb as a potential interesting candidate for the treatment of immunosuppressed patients.

Activated STAT5 promotes long-lived cytotoxic CD8+ T cells that induce regression of autochthonous melanoma

Immunotherapy based on adoptive transfer of tumor antigen-specific CD8(+) T cell (TC) is generally limited by poor in vivo expansion and tumor infiltration. In this study, we report that activated STAT5 transcription factors (STAT5CA) confer high efficiency on CD8(+) effector T cells (eTC) for host colonization after adoptive transfer. Engineered expression of STAT5CA in antigen-experienced TCs with poor replicative potential was also sufficient to convert them into long-lived antigen-responsive eTCs. In transplanted mastocytoma- or melanoma-bearing hosts, STAT5CA greatly enhanced the ability of eTCs to accumulate in tumors, become activated by tumor antigens, and to express the cytolytic factor granzyme B. Taken together, these properties contributed to an increase in tumor regression by STAT5CA-transduced, as compared with untransduced, TCs including when the latter control cells were combined with infusion of interleukin (IL)-2/anti-IL-2 complexes. In tumors arising in the autochthonous TiRP transgenic model of melanoma associated with systemic chronic inflammation, endogenous CD8(+) TCs were nonfunctional. In this setting, adoptive transfer of STAT5CA-transduced TCs produced superior antitumor effects compared with nontransduced TCs. Our findings imply that STAT5CA expression can render TCs resistant to the immunosuppressive environment of melanoma tumors, enhancing their ability to home to tumors and to maintain high granzyme B expression, as well as their capacity to stimulate granzyme B expression in endogenous TCs.

NK cells: immune cross-talk and therapeutic implications

Increased evidence of cross-talk between NK cells and other immune cells has enhanced the possibilities of exploiting the interplay between the activation and inhibition of NK cells for immunotherapeutic purposes. The battery of receptors possessed by NK cells help them to efficiently detect aberrant and infected cells and embark on the signaling pathways necessary to eliminate them. Endogenous expansion of NK cells and their effector mechanisms are under exploration for enhancing adoptive immunotherapy prospects in combination with immunostimulatory and cell-death-sensitizing treatments against cancer, viral infections and other pathophysiological autoimmune conditions. Various modes of NK cell manipulation are being undertaken to overcome issues such as relapse and graft rejections associated with adoptive immunotherapy. While tracing the remarkable properties of NK cells and the major developments in this field, we highlight the role of immune cooperativity in the betterment of current immunotherapeutic approaches.