Types Of Immune Effector Cells Research Articles

Emerging Innate Immune Cells in Cancer Immunotherapy: Promises and Challenges.

Immune checkpoint inhibitor (ICI)-based therapy has made an unprecedented impact on survival benefit for a subset of cancer patients; however, only a subset of cancer patients is benefiting from ICI therapy if all cancer types are considered. With the advanced understanding of interactions of immune effector cell types and tumors, cell-based therapies are emerging as alternatives to patients who could not benefit from ICI therapy. Pioneering work of chimeric antigen receptor T (CAR-T) therapy for hematological malignancies has brought encouragement to a broad range of development for cellular-based cancer immunotherapy, both innate immune cell-based therapies and T-cell-based therapies. Innate immune cells are important cell types due to their rapid response, versatile function, superior safety profiles being demonstrated in early clinical development, and being able to utilize multiple allogeneic cell sources. Efforts on engineering innate immune cells and exploring their therapeutic potential are rapidly emerging. Some of the therapies, such as CD19 CAR natural killer (CAR-NK) cell-based therapy, have demonstrated comparable early efficacy with CD19 CAR-T cells. These studies underscore the significance of developing innate immune cells for cancer therapy. In this review, we focus on the current development of emerging NK cells, γδ T cells, and macrophages. We also present our views on potential challenges and perspectives to overcome these challenges.

Heightened infiltration of immune effector cell types in the hippocampal regions in the APP/PS1 mouse model of Alzheimer’s disease.

Abstract Alzheimer's disease (AD) is among the most common neurodegenerative diseases in which a role for immune cells in its etiology is only beginning to be realized. AD has two molecular pathological hallmarks: the presence of amyloid beta (Aβ) plaques and tau tangles within neuronal cells. The amyloid plaques can be modeled in mice by inserting transgenes that enhance human Aβ to create plaques inside the mouse brain. Amyloid precursor protein (Mo/HuAPP695swe) and a mutant human presenilin 1 (PS1-dE9) are two transgenes inserted into C57BL/6 mice that results in Aβ plaques in the hippocampus and cortex. This mouse is known as the APP/PS1 mouse. Immune cell infiltration into the brain is associated with aged APP/PS1 mice. However, comprehensive immune profiling has not been performed in this model to outline immune cell effectors potentially involved in neuropathology. Therefore, we employed spectral flow cytometry to investigate the immune cell profile in 24-month-old APP/PS1 mice compared to an age matched control. There are increased numbers of CD8 T, γδ T, and NK cells expressing perforin and other activation related surface markers. Using small animal MRI imaging, we also observed enlarged ventricles mice indicative of brain atrophy in APP/PS1 mice when compared to wildtype age matched control. These results provide insight into the regional immune cell infiltration of the brain, setting the stage for further analysis of immune mechanisms of neuropathology in experimental AD.

Abstract 6082: Assessing difference in the tumor and immune microenvironment of BRCA1/2 mutated versus BRCA wild type high grade serous ovarian cancers

Abstract Ovarian cancer (OvCa) is the deadliest gynecological malignancy in the United States. Surgery and chemotherapy are the primary treatments for OvCa, but 80% of late-stage OvCa patients experience chemo-resistant recurrence, which necessitates the development of new treatment strategies. The genomic diversity within a tumor and the interactions among various cell types within its microenvironment are considered key factors contributing to therapeutic efficacy. Specifically, women who harbor germline BRCA1 or BRCA2 mutations are at increased risk of developing high grade serous ovarian cancer (HGSC). To understand the genomic consequences, including somatic alterations, associated with defective DNA repair, tumor DNA and RNA was isolated from fresh frozen OCT embedded sections from 15 HGSC patients with BRCA1/2 mutation and 10 without any alterations in the BRCA genes (BRCA-wt). Whole exome sequencing (WES) and total RNA-seq was performed to determine the association of homologous recombination (HR) DNA repair gene defects with tumor mutation burden (TMB), neoantigen load (NL), and immunological assessment of tumor microenvironment. TMB was calculated from mutation rates of somatic WES. Germline exome analysis was used to validate inherited BRCA mutations. To identify the somatic mutations, somatic single nucleotide variants and InDels were detected using Strelka. TP53 mutations were most common with several other genes showing only modest mutation frequency. Mutation signatures were also detected with maftools and compared to the COSMIC mutational signature database. BRCA-mutated samples displayed a unique mutational signature associated with defects in HR DNA repair pathway. We also observed heterogeneity in copy number variation profiles amongst cases, as determined by the tool Sequenza. Furthermore, gene set enrichment analysis indicated differential enrichment of P53 pathway, MAPK pathway, and PTEN pathway, in addition to numerous pathways related to immune cell signaling and immune response. RNA-seq data was analyzed with CIBERSORTx and revealed different proportions of 22 immune effector cell types that accompany tumor cells within the HGSC microenvironment. Additional analyses are underway, including measuring differences in NL in BRCA-mutated versus BRCA-wt cases. This work will represent a significant advancement in our fundamental knowledge regarding the complexities of the TME and effective immunological responses in OvCa. Citation Format: Jing Qian, Lynda D. Roman, Seeta Rajpara, Monica Neuman, Varun Khetan, David W. Craig, Joseph Carlson, John D. Carpten. Assessing difference in the tumor and immune microenvironment of BRCA1/2 mutated versus BRCA wild type high grade serous ovarian cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6082.

Abstract 2749: iPSC-derived natural killer cells as the front-runner program of the EVOcells Oncology platform: From inception to translational validation using patient samples

Abstract Cancer immunotherapy has transformed the oncology landscape and shown promising therapeutic results in the clinic but it is also clearly facing multiple limitations. So far, the focus of immunotherapies has mainly been on the modulation of T-cells. Natural killer (NK) cells offer promising perspectives for immunotherapies as they directly kill tumor cells and produce pro-inflammatory cytokines to activate and recruit T-cells and other immune cells. Thus, NK cells are considered key players in the anti-tumor immune response that can make a “cold” tumor “hot”. However, in the tumor microenvironment (TME) of cancer patients, the low numbers of NK cells present and their exhaustion due to local immunosuppression often limit tumor cell killing. The development of NK based cell therapy products can overcome these limitations, either as single therapy or in combination with biologics such as e.g. NK cell engagers or monoclonal antibodies for boosting ADCC (antibody dependent cell cytotoxicity). To overcome the main hurdle of current autologous cell therapies, the EVOcells Oncology platform aims at developing a streamlined manufacturing process for iPSC-derived immune effector cells. The goal is to develop “off-the-shelf” cell therapy products for clinical use in large patient populations. We are currently establishing a multi-asset portfolio combining multiple immune effector cell types with different genetic editing strategies that serve to optimize this approach further. iPSC-derived NK cells (iNK cells) offer an attractive option for improving both therapeutic efficacy and safety of CAR cell therapies. Our robust, feeder-free production protocol produces iNK cells that can be reliably frozen with good recovery rates. We have generated multiple genetically modified iNK cells and have validated that the genetic modifications boost iNK function. At the end of the production process, iNK cells show phenotypic properties and single cell RNA sequencing profiles comparable to blood-derived NK cells. Importantly, iNK cells are fully functional with the ability to produce key pro-inflammatory cytokines and to form lytic immunological synapses leading to efficient killing of cancer cell lines. In addition to the killing of established tumor cell lines, we also evaluated the ability of iNK cells to kill primary leukemia cells ex vivo by using blood samples from B-cell chronic lymphocytic leukemia patients. In combination with a standard of care anti-CD20 antibody, iNK cells demonstrated the ability to kill primary leukemia cells via ADCC. Taken together, these promising results obtained with iNK cells show the potential of the EVOcells Oncology platform to deliver the next generation of cell therapies in oncology paving the way to develop a portfolio of iPSC-derived immune effector cells. Citation Format: Michael Esquerré, Audrey Holtzinger, Mélanie Pichery, Stefanie Pfaender, Saniye Yumlu, Mandy Richter, Delphine Betous, Oriane Bombarde, Mylène Gador, Nadja Sailer, Michael Paillasse, Loïc Ysebaert, Fabien Despas, Matthias Austen, Andreas Scheel, Markus Dangl. iPSC-derived natural killer cells as the front-runner program of the EVOcells Oncology platform: From inception to translational validation using patient samples [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2749.

CAR-NK cells from engineered pluripotent stem cells: Off-the-shelf therapeutics for all patients.

Clinical success of adoptive cell therapy with chimeric antigen receptor (CAR) T cells for treating hematological malignancies has revolutionized the field of cellular immunotherapy. However, due to the nature of utilizing autologous T cells, affordability and availability are major hurdles, in addition to scientific challenges relating to CAR‐T therapy optimization. Natural killer (NK) cell is a specialized immune effector cell type that recognizes and kills targets without human leukocyte antigen (HLA) restriction and prior sensitization. CAR‐NK cells do not cause graft vs host disease and can be obtained from unrelated donors as well as pluripotent stem cells (PSC), representing an ideal off‐the‐shelf therapeutics readily available for patients. Furthermore, unlike cytotoxic T cells, NK cells specifically target and eliminate cancer stem cells, which are the cells causing relapse and metastasis. PSCs can be genetically manipulated and engineered with CARs at the pluripotent stage, which allows the establishment of permanent, stable, and clonal PSC‐CAR lines for the manufacture of unlimited homogenous CAR‐NK cells. Multiple master PSC‐CAR cell banks targeting a variety of antigens for cancer, viral infection, and autoimmune diseases provide inexhaustible cell sources for all patients. Development of a next‐generation 3D bioreactor platform for PSC expansion and NK cell production overcomes major barriers related to cost and scalability for CAR‐NK product.

Imaging Tolerance Induction in Neonatal Mice: Hierarchical Interplay Between Allogeneic Adult and Neonatal Immune Cells.

In Medawar's murine neonatal tolerance model, injection of adult semiallogeneic lymphohematopoietic cells (spleen cells [SC] and bone marrow cells [BMC]) tolerizes the neonatal immune system. An eventual clinical application would require fully allogeneic (allo) cells, yet little is known about the complex in vivo/in situ interplay between those cells and the nonconditioned neonatal immune system. To this end, labeled adult SC and BMC were injected into allogeneic neonates; interactions between donor and host cells were analyzed and modulated by systematic depletion/inactivation of specific donor and host immune effector cell types. Consistent with effector cell compositions, allo-SC and allo-SC/BMC each induced lethal acute graft-versus-host disease, whereas allo-BMC alone did so infrequently. CD8 T cells from SC inoculum appeared naïve, while those of BMC were more memory-like. Age-dependent, cell-type dominance defined the interplay between adult donor cells and the neonatal host immune system such that if the dominant adult effector type was removed, then the equivalent neonatal one became dominant. Depletion of donor/host peripheral T cells protected against acute graft-versus-host disease and prolonged heart allograft survival; peripheral CD8 T-cell depletion together with CD4 T cell-costimulation blockade induced more robust tolerance. This comprehensive study provides direct observation of the cellular interplay between allogeneic donor and host immune systems, adds to our previous work with semiallogeneic donor cells, and provides important insights for robust tolerance induction. Induction of transplant tolerance in neonates will likely require "crowd sourcing" of multiple tolerizing cell types and involve depletion of immune effector cells with costimulation blockade.

ONCR-177, an Oncolytic HSV-1 Designed to Potently Activate Systemic Antitumor Immunity.

ONCR-177 is an engineered recombinant oncolytic herpes simplex virus (HSV) with complementary safety mechanisms, including tissue-specific miRNA attenuation and mutant UL37 to inhibit replication, neuropathic activity, and latency in normal cells. ONCR-177 is armed with five transgenes for IL12, FLT3LG (extracellular domain), CCL4, and antagonists to immune checkpoints PD-1 and CTLA-4. In vitro assays demonstrated that targeted miRNAs could efficiently suppress ONCR-177 replication and transgene expression, as could the HSV-1 standard-of-care therapy acyclovir. Although ONCR-177 was oncolytic across a panel of human cancer cell lines, including in the presence of type I IFN, replication was suppressed in human pluripotent stem cell-derived neurons, cardiomyocytes, and hepatocytes. Dendritic cells activated with ONCR-177 tumor lysates efficiently stimulated tumor antigen-specific CD8+ T-cell responses. In vivo, biodistribution analyses suggested that viral copy number and transgene expression peaked approximately 24 to 72 hours after injection and remained primarily within the injected tumor. Intratumoral administration of ONCR-177 mouse surrogate virus, mONCR-171, was efficacious across a panel of syngeneic bilateral mouse tumor models, resulting in partial or complete tumor regressions that translated into significant survival benefits and to the elicitation of a protective memory response. Antitumor effects correlated with local and distant intratumoral infiltration of several immune effector cell types, consistent with the proposed functions of the transgenes. The addition of systemic anti-PD-1 augmented the efficacy of mONCR-171, particularly for abscopal tumors. Based in part upon these preclinical results, ONCR-177 is being evaluated in patients with metastatic cancer (ONCR-177-101, NCT04348916).

The Molecular and Microenvironmental Landscape of Glioblastomas: Implications for the Novel Treatment Choices.

Glioblastoma (GBM) is the most frequent and aggressive primary central nervous system tumor. Surgery followed by radiotherapy and chemotherapy with alkylating agents constitutes standard first-line treatment of GBM. Complete resection of the GBM tumors is generally not possible given its high invasive features. Although this combination therapy can prolong survival, the prognosis is still poor due to several factors including chemoresistance. In recent years, a comprehensive characterization of the GBM-associated molecular signature has been performed. This has allowed the possibility to introduce a more personalized therapeutic approach for GBM, in which novel targeted therapies, including those employing tyrosine kinase inhibitors (TKIs), could be employed. The GBM tumor microenvironment (TME) exerts a key role in GBM tumor progression, in particular by providing an immunosuppressive state with low numbers of tumor-infiltrating lymphocytes (TILs) and other immune effector cell types that contributes to tumor proliferation and growth. The use of immune checkpoint inhibitors (ICIs) has been successfully introduced in numerous advanced cancers as well as promising results have been shown for the use of these antibodies in untreated brain metastases from melanoma and from non-small cell lung carcinoma (NSCLC). Consequently, the use of PD-1/PD-L1 inhibitors has also been proposed in several clinical trials for the treatment of GBM. In the present review, we will outline the main GBM molecular and TME aspects providing also the grounds for novel targeted therapies and immunotherapies using ICIs for GBM.

Abstract PR09: An unexpectedly effective immunotherapy strategy for ovarian cancer

Abstract Ovarian cancer (OvCa) is the most lethal of gynecologic diseases and is known for chemoresistance and frequent reoccurrence with no effective treatment available. Clinical data indicate that antibodies that kill tumor cells by activating the immune system are highly effective against blood and melanoma cancers. However, in the case of OvCa, antibody-based approaches have largely failed due to ineffective killing of tumor cells, below the tumor apoptotic clearance threshold by immune cells. This is mainly attributed to 1) the limited penetration of immune effector cell types into the solid tumor bed and 2) to the presence of large immune inhibitory glycoproteins such as Mucin 16. A long-term goal of research in our lab is to develop a safe and effective therapeutic antibody that achieves efficient clinical response against ovarian tumors despite the limitations of immune penetration and immune inhibitory proteins. Toward this goal, very recently we have engineered and tested a novel Bispecific-anchored Cytotoxicity-activator (BaCa) antibody. The BaCa antibody has dual specificity against: 1) the folate receptor alpha-1 (FOLR1), which is multiple-fold elevated in >80% OvCa patients, but has very minimal expression in healthy tissues; and 2) death receptor-5 (DR5/TRAIL-R2), an extrinsic agonist whose higher-order oligomerization drives apoptotic cell-death of tumor cells independently of immune effector function. We hypothesize that via a high-affinity anti-FOLR1 domain, the BaCa antibody finds a tumor anchor-dependent home to tightly bind to OvCa cells. This retains and selectively intensifies the cell death-inducing DR5 signaling of BaCa to the surface FOLR1-enriched OvCa cells and tumors. As a consequence, the DR5 receptor is exceedingly oligomerized and activated, resulting in a greatly superior apoptosis, well beyond the tumor clearance threshold (Cancer Cell 2018). When tested in OvCa tumor models including platinum-resistant patient-derived xenografts, the BaCa antibody was significantly efficacious over investigational clinical antibodies (Cancer Cell 2018), and was found to be >200 (IC50) and >500 (IC90) fold more effective over clinically tested antibodies in killing OvCa cells. Despite effective tumor clearance due to high-caliber DR5 receptor activation and signaling, two major questions still remain before realizing the true clinical potential of BaCa strategy: 1) Does BaCa antibody have added function to activate adaptive immune system for long-term response against OvCa? 2) Acquired tumor apoptotic resistance to clinical DR5 agonist therapies remains a limitation to their clinical success. Therefore, it is highly imperative to understand and test if amplified apoptotic output by BaCa antibody will differentially affect resistance to cell death. During this meeting I will present key preliminary data that support immunogenicity and effective therapeutic potential of OvCa-specific BaCa antibody. This abstract is also being presented as Poster B06. Citation Format: Jogender Tushir-Singh. An unexpectedly effective immunotherapy strategy for ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr PR09.

Human pDCs Are Superior to cDC2s in Attracting Cytolytic Lymphocytes in Melanoma Patients Receiving DC Vaccination

Plasmacytoid dendritic cells (pDCs) and type 2 conventional dendritic cells (cDC2s) are currently under evaluation for use in cancer vaccines. Although both DC subsets can activate adaptive and innate lymphocytes, their capacity to recruit such cells is rarely considered. Here, we show that pDCs and cDC2s display a striking difference in chemokine secretion, which correlates with the recruitment of distinct types of immune effector cells. Activated pDCs express high levels of CXCR3 ligands and attract more CD8+ Tcells, CD56+ Tcells, and γδ Tcells invitro, compared to cDC2s. Skin from melanoma patients shows an influx of immune effector cells following intradermal vaccination with pDCs or cDC2s, with pDCs inducing the strongest influx of lymphocytes known to possess cytolytic activity. These findings suggest that combining both DC subsets could unite the preferred chemoattractive properties of pDCs with the superior Tcell priming properties of cDC2s to ultimately enhance vaccine efficacy.

Increased DNA methylation variability in type 1 diabetes across three immune effector cell types.

The incidence of type 1 diabetes (T1D) has substantially increased over the past decade, suggesting a role for non-genetic factors such as epigenetic mechanisms in disease development. Here we present an epigenome-wide association study across 406,365 CpGs in 52 monozygotic twin pairs discordant for T1D in three immune effector cell types. We observe a substantial enrichment of differentially variable CpG positions (DVPs) in T1D twins when compared with their healthy co-twins and when compared with healthy, unrelated individuals. These T1D-associated DVPs are found to be temporally stable and enriched at gene regulatory elements. Integration with cell type-specific gene regulatory circuits highlight pathways involved in immune cell metabolism and the cell cycle, including mTOR signalling. Evidence from cord blood of newborns who progress to overt T1D suggests that the DVPs likely emerge after birth. Our findings, based on 772 methylomes, implicate epigenetic changes that could contribute to disease pathogenesis in T1D.

Immunomodulatory and cellular anti-oxidant activities of caffeic, ferulic, and p-coumaric phenolic acids: a structure–activity relationship study

Many studies have been performed to assess the potential utility of natural products as immunomodulatory agents to enhance host responses and to reduce damage to the human body. To determine whether phenolic compounds (caffeic, ferulic, and p-coumaric acids) have immunomodulatory effects and clarify which types of immune effector cells are stimulated in vitro, we evaluated their effect on splenocyte proliferation and lysosomal enzyme activity. We also investigated the activity of natural killer (NK) cells and cytotoxic T lymphocytes (CTL). In addition, induction of the cellular antioxidant activity in splenocytes, macrophages, and red blood cells was determined by measuring the fluorescence of the DCF product. The study first results indicated that caffeic, ferulic, and p-coumaric acids significantly promote LPS-stimulated splenocyte proliferation, suggesting a potential activation of B cells, and enhanced humoral immune response in hosts treated by the tested natural products. Phenolic acids significantly enhanced the killing activity of isolated NK and CTL cells but had negligible effects on mitogen-induced proliferation of splenic T cells. We showed that caffeic acid enhances lysosomal enzyme activity in murine peritoneal macrophages, suggesting a potential role in activating such cells. Immunomodulatory activity was concomitant with the cellular antioxidant effect in macrophages and splenocytes of caffeic and ferulic acids. We conclude from this study that caffeic, ferulic, and p-coumaric acids exhibited an immunomodulatory effect which could be ascribed, in part, to their cytoprotective effect via their antioxidant capacity. Furthermore, these results suggest that these natural products could be potentially used to modulate immune cell functions in physiological and pathological conditions.

Abstract A30: Modeling an immunotherapy of NK mechanism on a NSCLC patient derived xenograft

Abstract The recent clinical successes of immune checkpoint inhibitors have fueled the intense interest in novel immuno-oncology (I/O) therapeutics. The lack of relevant animal models remains a major hurdle in understanding the mechanism of action and evaluating the efficacy of such therapeutics. Patient derived xenograft (PDX), considered to most closely mimic patient tumors in both histo- and molecular pathology1,2, is however rarely used in I/O studies because it grow only in immune-compromised hosts. In reality, many PDXs grow well in nude mice where certain immune functions remain intact, excluding T-cells/T-cell functions. Therefore, PDX could still potentially be of practical use for studying T-cell independent I/O therapy. This study set out to evaluate a biologics for the treatment of a patient derived xenograft disease, by activating mouse natural killer (NK). NK and CD8 T cells are two major immune effector cell types that mediate cytotoxicity to tumor cells in vivo. One of the immunomodulatory agents, an anti-PD-L1 antibody-based IL-15 immunocytokine, was recently tested as a novel I/O treatment of cancer3. This molecule was engineered to be cross-species for both human and mouse PD-L1 and IL-15 that antagonize PD1/PD-L1 checkpoint-mediated immune suppression and also target the PD-L1-expressing tumor with IL-15 stimulated NK and CD8 T effector cells into local tumor sites, thus synergizing tumor-located anti-tumor immunity. In fact, our previous studies have demonstrated a greatly enhanced anti-tumor activity in the PDL-1-expressing syngeneic mouse tumor models via the mobilization of tumor infiltrating lymphocyte (TILs), over the PD-L1 antibody alone3. Since IL-15 also stimulates NKs in addition to T-cells, we reasoned that this bifunctional agent could also have potential activity against a PD-L1-expressing PDX in nude mice where NK remains functional. LU1901 is previously described NSCLC-PDX1, and was confirmed to express high level of PD-L1 by both RNAseq and flow analysis, after screening of a large panel of PDXs. We implanted LU1901 in Balb/c nude mice, and started to treat the mice by the bifunctional agent when the tumor reached to 150 mm3. Our result clearly demonstrated a significant inhibition of LU1901 growth by the bifunctional agent in nude mice, in the apparent absence of T-cells. When the treated tumors were examined at the termination, significantly infiltrate NK cells were found inside the treated tumors, as measured by both flow cytometry and immunohistochemistry (IHC). The number of infiltrating NK also statistically correlates to the amplitude of the tumor responses. Together, our data suggest that one of important mechanisms of action of this bifunctional agent relies on the tumor-targeting NK activation, and also that PDX could be a useful model suitable for in vivo efficacy analysis of T-cell independent immunotherapy.

Investigation of immunomodulatory and anti-inflammatory effects of eriodictyol through its cellular anti-oxidant activity.

Many studies have been performed to assess the potential utility of natural products as immunomodulatory agents to enhance host responses against infection or to ameliorate immune-based pathologies. To determine whether eriodictyol has immunomodulatory effects and clarify which types of immune effector cells are stimulated in vitro, we investigated the stimulatory effect of eriodictyol on spleen cells isolated from BALB/c mice. Eriodictyol significantly stimulated splenocyte proliferation. However, only B lymphocytes (not T lymphocytes) could be stimulated by eriodictyol in a dose-related manner. Studies assessing potential effect of eriodictyol on innate immunity reported that eriodictyol enhanced significantly the killing activity of natural killer (NK) cells, T lymphocytes, and macrophages. We also demonstrated that eriodictyol inhibited nitric oxide (NO) production and lysosomal enzyme activity in murine peritoneal macrophages cultured ex-vivo, suggesting a potential anti-inflammatory effect in situ. Eriodictyol revealed also a cellular anti-oxidant activity in splenocytes and macrophages. Furthermore, eriodictyol increased catalase activity in spleen cells. From this data, it can be concluded that eriodictyol exhibited an immunomodulatory effect that could be ascribed in part to a cytoprotective effect related to its anti-oxidant activity.

Basics of cancer immunotherapy.

The immune system is the body's defense against infectious organisms and other invaders including cancer cells. Cancer immunotherapy, which employs our own immune systems to attack cancer cells, is now emerging as a promising modality of cancer treatment based upon the clinical successes of immune checkpoint blockade and adoptive T cell transfer. In hematologic malignancies, clinical application of anti-PD-1 mAb and CAR (chimeric antigen receptor) T therapy is now being extensively tested in Hodgkin's disease, multiple myeloma, and CD19+ acute lymphocytic leukemia. In sharp contrast to conventional anti-cancer reagents which directly kill cancer cells, cancer immunotherapy activates various types of immune effector cells to attack cancer cells. However, more than half of the treated patients showed no activation of anti-tumor CD8+ killer T cells and CD4+ helper T cells and failed to respond to immune therapies such as immune checkpoint blockade, even when administered in combination regimens. Thus, development of novel immunotherapies to achieve more effective activation of anti-cancer immunity and immuno-monitoring of biomarkers, allowing proper evaluation of immune responses in cancer patients in order to detect responders, are urgent issues. Additionally, we must pay attention to characteristic immunological side effects not observed following treatment with conventional anti-cancer reagents. Herein, we present a summary outline and discuss the future direction of cancer immunotherapy.

CURRENT UNDERSTANDING OF ANTITUMOR IMMUNITY

The review presents analysis of the papers that discuss mechanisms of antitumor immunity. The role of innate and adaptive immune reactions as well as local and systemic is considered in terms of immune defense in clinical and experimental studies. The article discusses characteristics and role tumor-associated antigens for clinical practice. Various types of immune effector cells, including T-cells, NK-cell, DC, tumor associated macrophages, etc., and cytokines, are discussed regarding their contribution into antitumor immune response. The authors also refer to the hypothesis of “immunoediting” and its part in antitumor immunity.

Efficacy and Tolerability of a GD2-Directed Trifunctional Bispecific Antibody in a Preclinical Model: Subcutaneous Administration Is Superior to Intravenous Delivery.

Trifunctional bispecific antibodies (trAb) are novel anticancer drugs that recruit and activate different types of immune effector cells at the targeted tumor. Thus, tumor cells are effectively eliminated and a long-lasting tumor-specific T-cell memory is induced. The trAb Ektomab is directed against human CD3 on T cells and the tumor-associated ganglioside GD2, which is an attractive target for immunotherapy of melanoma in humans. To optimize clinical applicability, we studied different application routes with respect to therapeutic efficacy and tolerability by using the surrogate trAb Surek (anti-GD2 × anti-murine CD3) and a murine melanoma engineered to express GD2. We show that subcutaneous injection of the trAb is superior to the intravenous delivery pathway, which is the standard application route for therapeutic antibodies. Despite lower plasma levels after subcutaneous administration, the same tumor-protective potential was observed in vivo compared with intravenous administration of Surek. However, subcutaneously delivered Surek showed better tolerability. This could be explained by a continuous release of the antibody leading to constant plasma levels and a delayed induction of proinflammatory cytokines. Importantly, the induction of counter-regulatory mechanisms was reduced after subcutaneous application. These findings are relevant for the clinical application of trifunctional bispecific antibodies and, possibly, also other immunoglobulin constructs. Mol Cancer Ther; 14(8); 1877-83. ©2015 AACR.

Adaptive Immune Responses Associated with Breast Cancer Relapse

The generation, survival, and differentiation of breast cancer stem cells (BCSC) in immunocompetent hosts remain elusive. Some investigators have shown that BCSC can be induced from epithelial tumor cells by the pathologic epithelial to mesenchymal transition (EMT). Emerging evidence suggests that the induction of EMT among epithelial tumor cells originates from signals produced by the non-tumor cells that constitute the tumor microenvironment, including the immune effectors that infiltrate the tumors. Thus, this suggests that the immune system not only has anti-tumor function, but also paradoxically immunoedits tumors, facilitating tumor escape and progression. Indeed, many studies in human breast cancers show both positive and negative associations between the infiltration of various immune effectors (e.g., CD4 and CD8 T cells) and the propensity to relapse with metastatic disease. These observations suggest that distinct types of immune effector cells may induce or inhibit tumor relapse. This review focuses on recent advances in identifying components of the immune system that may directly induce tumor escape and relapse. We propose that levels of interferon (IFN)-γ production or levels of the expression of IFN-γ receptor α on tumor cells may determine whether tumor inhibitory or relapse-promoting effect of IFN-γ may prevail.

Multiwalled carbon nanotubes interact with macrophages and influence tumor progression and metastasis.

Macrophages are one of the most important types of immune effector cells and are closely associated with tumor progression and metastasis. In this work, we investigated the influences of oxidized multiwalled carbon nanotubes (o-MWCNT) on macrophages that are resting in the normal subcutis tissue or in the tumor microenvironment in vivo as well as on the macrophage cell line of RAW 264.7 treated with combination of IL4, IL10 and IL13 in vitro. The o-MWCNT were characterized with SEM, DLS, FTIR, TGA, and UV-vis-NIR spectroscopy, and their effects on the RWA 264.7 cell line and breast cancer tumor-bearing mice were analyzed using the MTS assay, flow cytometry analysis, and histological and immunohistochemical observations. Our experimental results showed that subcutaneously injected o-MWCNT not only induced phagocytosis of the local resident macrophages, but also competitively recruited macrophages from other tissues. These interactions resulted in macrophage reduction and decreased vessel density around the tumor mass, which together inhibited tumor progression and metastasis in the lung. In the cell line model, the o-MWCNT inhibited the ability of the interleukin treated RAW macrophages to promote tumor cell migration as well as decreased their proliferation rate.

Role of Interleukin 10 Transcriptional Regulation in Inflammation and Autoimmune Disease

Interleukin 10 (IL-10) is a cytokine with potent anti-inflammatory properties that plays a central role in limiting host immune response to pathogens, thereby preventing damage to the host and maintaining normal tissue homeostasis. Dysregulation of IL-10 is associated with enhanced immunopathology in response to infection as well as increased risk for development of many autoimmune diseases. Thus a fundamental understanding of IL-10 gene expression is critical for our comprehension of disease progression and resolution of host inflammatory response. In this review, we discuss modes of regulation of IL-10 gene expression in immune effector cell types, including signal transduction, epigenetics, promoter architecture, and post-transcriptional regulation, and how aberrant regulation contributes to immunopathology and disease progression.