Synergistic Effects of IL-12 and IL-18 in Skewing Tumor-Reactive T-Cell Responses Towards a Type 1 Pattern

Cytokines and their role as immunotherapeutics and vaccine Adjuvants: The emerging concepts

Cytokines are a protein family comprising interleukins, lymphokines, chemokines, monokines and interferons. They are significant constituents of the immune system, and they act in accordance with specific cytokine inhibiting compounds and receptors for the regulation of immune responses. Cytokine studies have resulted in the establishment of newer therapies which are being utilized for the treatment of several malignant diseases. The advancement of these therapies has occurred from two distinct strategies. The first strategy involves administrating the recombinant and purified cytokines, and the second strategy involves administrating the therapeutics which inhibits harmful effects of endogenous and overexpressed cytokines. Colony stimulating factors and interferons are two exemplary therapeutics of cytokines. An important effect of cytokine receptor antagonist is that they can serve as anti-inflammatory agents by altering the treatments of inflammation disorder, therefore inhibiting the effects of tumour necrosis factor. In this article, we have highlighted the research behind the establishment of cytokines as therapeutics and vaccine adjuvants, their role of immunotolerance, and their limitations.

The Role of the Interleukin-1 Family in Complications of Prematurity

Preterm birth is a major contributor to neonatal morbidity and mortality. Complications of prematurity such as bronchopulmonary dysplasia (BPD, affecting the lung), pulmonary hypertension associated with BPD (BPD-PH, heart), white matter injury (WMI, brain), retinopathy of prematurity (ROP, eyes), necrotizing enterocolitis (NEC, gut) and sepsis are among the major causes of long-term morbidity in infants born prematurely. Though the origins are multifactorial, inflammation and in particular the imbalance of pro- and anti-inflammatory mediators is now recognized as a key driver of the pathophysiology underlying these illnesses. Here, we review the involvement of the interleukin (IL)-1 family in perinatal inflammation and its clinical implications, with a focus on the potential of these cytokines as therapeutic targets for the development of safe and effective treatments for early life inflammatory diseases.

Intra-arterial Versus Intravenous Adoptive Cell Therapy in a Mouse Tumor Model

Adoptive cell transfer therapy for cancer has existed for decades and is experiencing a resurgence in popularity that has been facilitated by improved methods of production, techniques for genetic modification, and host preconditioning. The trafficking of adoptively transferred lymphocytes and infiltration into the tumor microenvironment is sine qua non for successful tumor eradication; however, the paradox of extremely poor trafficking of lymphocytes into the tumor microenvironment raises the issue of how best to deliver these cells to optimize entry into tumor tissue. We examined the route of administration as a potential modifier of both trafficking and antitumor efficacy. Femoral artery cannulation and tail vein injection for the intra-arterial (IA) and IV delivery, respectively, were utilized in the B16-OVA/OT-I mouse model system. Both IV and IA infusions showed decreased tumor growth and prolonged survival. However, although significantly increased T-cell tumor infiltration was observed in IA mice, tumor growth and survival were not improved as compared with IV mice. These studies suggest that IA administration produces increased early lymphocyte trafficking, but a discernable survival benefit was not seen in the murine model examined.

Armed oncolytic viruses: A kick-start for anti-tumor immunity

Oncolytic viruses (OVs), viruses that specifically result in killing tumor cells, represent a promising class of cancer therapy. Recently, the focus in the OV therapy field has shifted from their direct oncolytic effect to their immune stimulatory effect. OV therapy can function as a "kick start" for the antitumor immune response by releasing tumor associated antigens and release of inflammatory signals. Combining OVs with immune modulators could enhance the efficacy of both immune and OV therapies. Additionally, genetic engineering of OVs allows local expression of immune therapeutics, thereby reducing related toxicities. Different options to modify the tumor microenvironment in combination with OV therapy have been explored. The possibilities and obstacles of these combinations will be discussed in this review.

Tune Up In Situ Autovaccination against Solid Tumors with Oncolytic Viruses

With the progress of immunotherapy in cancer, oncolytic viruses (OVs) have attracted more and more attention during the past decade. Due to their cancer-selective and immunogenic properties, OVs are considered ideal candidates to be combined with immunotherapy to increase both specificity and efficacy in cancer treatment. OVs preferentially replicate in and lyse cancer cells, resulting in in situ autovaccination leading to adaptive anti-virus and anti-tumor immunity. The main challenge in OV approaches is how to redirect the host immunity from anti-virus to anti-tumor and optimize the clinical outcome of cancer patients. Here, we summarize the conceptual updates on oncolytic virotherapy and immunotherapy in cancer, and the development of strategies to enhance the virus-mediated anti-tumor immune response, including: (1) arm OVs with cytokines to modulate innate and adaptive immunity; (2) combining OVs with immune checkpoint inhibitors to release T cell inhibition; (3) combining OVs with immune co-stimulators to enhance T cell activation. Future studies need to be enforced on developing strategies to augment the systemic effect on metastasized tumors.

Human Neutrophil Peptide 1 as immunotherapeutic agent against Leishmania infected BALB/c mice

Human Neutrophil Peptide 1 (HNP1) produced by neutrophils, is a well-known antimicrobial peptide which plays a role both in innate as well as in adaptive immunity and is under intensive investigation as a potential therapeutic agent. Previous in vitro experiments have indicated the leishmaniacidal effect of recombinant HNP1 on Leishmania major (L. major) promastigotes and amastigotes. In the current study, we further extended the idea to explore the remedial effect of HNP1 in the two modalities of peptide therapy (folded HNP1) and gene therapy in L. major infected BALB/c mice. To this end, mice in five different groups received synthetic folded HNP1 (G1), pcDNA-HNP1-EGFP (G2), pcDNA-EGFP (G3), Amphotericin B (G4) and PBS (G5), which was started three weeks after infection for three consecutive weeks. Footpad swelling was monitored weekly and a day after the therapy ended, IFN-γ, IL-4, IL-10, IL-6 and nitric oxide produced by splenocytes were analyzed together with the parasite load in draining lymph nodes. Arginase activity and dermal histopathological changes were also analyzed in the infected footpads. We demonstrated that both therapeutic approaches effectively induced Th1 polarization and restricted parasite burden. It can control disease progression in contrast to non-treated groups. However, pcDNA-HNP1-EGFP is more promising in respect to parasite control than folded HNP1, but less effective than AmB treatment. We concluded with the call for a future approach, that is, a DNA-based expression of HNP1 combined with AmB as it can improve the leishmaniacidal efficacy.

The outbreak level of cutaneous leishmaniasis is approximated between one and 1.5 million individuals per year. Owning to several disadvantages of current therapies, special attention to expand novel and efficient therapies has been demanded. Among Anti-Microbial Peptides (AMPs), Human Neutrophil Peptide 1 (HNP1) is one of the most potential defensins. Our promising in vitro experiments have shown the leishmaniacidal effect of recombinant HNP1. Here, we displayed the remedial effect of HNP1 in two approaches including peptide therapy and gene therapy in susceptible mice infected with L. major. Our investigation showed that although both approaches could decrease the parasite load and induce Th1 immune response compared to the control group, pcDNA-HNP1-EGFP has a better effect compared to the folded HNP1. Hence, immunotherapy by HNP1 can help elicit proper immunity despite the direct effect on promastigotes and amastigotes forms of parasite.

Technical Considerations for the Generation of Adoptively Transferred T Cells in Cancer Immunotherapy

A significant function of the immune system is the surveillance and elimination of aberrant cells that give rise to cancer. Even when tumors are well established and metastatic, immune-mediated spontaneous regressions have been documented. While there are have been various forms of immunotherapy, one of the most widely studied for almost 40 years is adoptive cellular immunotherapy, but its success has yet to be fully realized. Adoptive cell transfer (ACT) is a therapeutic modality that has intrigued physicians and researchers for its many theoretical benefits. Preclinical investigations and human trials have utilized natural killer (NK) cells, dendritic cells (DC), macrophages, T-cells or B-cells for ACT with the most intense research focused on T-cell ACT. T-cells are exquisitely specific to the target of its T-cell receptor (TCR), thus potentially reducing the amount of collateral damage and off-target effects from treatment. T-cells also possess a memory subset that may reduce the risk of recurrence of a cancer after the successful treatment of the primary disease. There are several options for the source of T-cells used in the generation of cells for ACT. Perhaps the most widely known source is T-cells generated from tumor-infiltrating lymphocytes (TILs). However, studies have also employed peripheral blood mononuclear cells (PBMCs), lymph nodes, and even induced pluripotent stem cells (IPSCs) as a source of T-cells. Several important technical considerations exist regarding benefits and limitations of each source of T-cells. Unique aspects of T-cells factor into their ability to be efficacious in ACT including the total number of cells available for ACT, the anti-tumor efficacy on a per cell basis, the repertoire of TCRs specific to tumor cells, and their ability to traffic to various organs that harbor tumor. Current research is attempting to unlock the full potential of these cells to effectively and safely treat cancer.

Cancer stem cell vaccination confers significant antitumor immunity

Most studies of cancer stem cells (CSC) involve the inoculation of cells from human tumors into immunosuppressed mice, preventing an assessment on the immunologic interactions and effects of CSCs. In this study, we examined the vaccination effects produced by CSC-enriched populations from histologically distinct murine tumors after their inoculation into different syngeneic immunocompetent hosts. Enriched CSCs were immunogenic and more effective as an antigen source than unselected tumor cells in inducing protective antitumor immunity. Immune sera from CSC-vaccinated hosts contained high levels of IgG which bound to CSCs, resulting in CSC lysis in the presence of complement. CTLs generated from peripheral blood mononuclear cells or splenocytes harvested from CSC-vaccinated hosts were capable of killing CSCs in vitro. Mechanistic investigations established that CSC-primed antibodies and T cells were capable of selective targeting CSCs and conferring antitumor immunity. Together, these proof-of-concept results provide a rationale for a new type of cancer immunotherapy based on the development of CSC vaccines that can specifically target CSCs.

Clinical and experimental approaches to the pathophysiology of interleukin-18 in cancer progression

Interleukin-18 (IL-18, interferon [IFN]-gamma-inducing factor) is a proinflammatory cytokine converted to a biologically active molecule by interleukin (IL)-1beta converting enzyme (caspase-1). A wide range of normal and cancer cell types can produce and respond to IL-18 through a specific receptor (IL-18R) belonging to the toll-like receptor family. The activity of IL-18 is regulated by IL-18-binding protein (IL-18bp), a secreted protein possessing the ability to neutralize IL-18 and whose blood level is affected by renal function and is induced by IFNgamma. IL-18 plays a central role in inflammation and immune response, contributing to the pathogenesis and pathophysiology of infectious and inflammatory diseases. Because immune-stimulating effects of IL-18 have antineoplastic properties, IL-18 has been proposed as a novel adjuvant therapy against cancer. However, IL-18 increases in the blood of the majority of cancer patients and has been associated with disease progression and, in some cancer types, with metastatic recurrence risk and poor clinical outcome and survival. Under experimental conditions, cancer cells can also escape immune recognition, increase their adherence to the microvascular wall and even induce production of angiogenic and tumor growth-stimulating factors via IL-18-dependent mechanism. This is particularly visible in melanoma cells. Thus, the role of IL-18 in cancer progression and metastasis remains controversial. This review examines the clinical correlations and biological effects of IL-18 during cancer development and highlights recent experimental insights into prometastatic and proangiogenic effects of IL-18 and the use of IL-18bp against cancer progression.

Ex vivo Culture with Interleukin (IL)-12 Improves CD8+ T-Cell Adoptive Immunotherapy for Murine Leukemia Independent of IL-18 or IFN-γ but Requires Perforin

In animal models and clinical trials, adoptive transfer of activated, antigen-specific CD8+ T cells mediates tumor regression in a cell dose-dependent manner. The cytokine interleukin (IL)-12 promotes CD8+ T-cell cytotoxicity and, with IL-18, synergistically up-regulates IFN-γ release. We have shown that culturing CD8+ T cells ex vivo with IL-12 and IL-18 enhanced antitumor responses in vivo and in vitro using a model of C1498/ovalbumin, a murine acute myeloid leukemia cell line expressing the antigen ovalbumin. Activated ovalbumin-specific CD8+ T cells cultured with IL-12, IL-18, both, or neither were assayed for antigen-specific cytokine production and cytolytic activity and adoptively transferred to C57BL/6 mice with established tumors. Maximal IFN-γ release occurred after T-cell culture with IL-12 and IL-18. Tumor-specific in vitro cytotoxicity was enhanced by IL-12, unaffected by addition of IL-18, and abrogated in perforin-deficient T cells irrespective of cytokine exposure. T cells cultured with IL-12 more effectively eliminated tumors, and addition of IL-18 did not further augment responses. IFN-γ-deficient CD8+ T cells showed effective antitumor activity that was enhanced by IL-12 with or without IL-18. Perforin-deficient CD8+ T cells were poor mediators of antitumor activity, though, and showed no improvement after culture with IL-12 and/or IL-18. Thus, ex vivo culture with IL-12 was sufficient to augment antigen-specific in vitro cytotoxicity and antitumor activity in vivo in an IFN-γ-independent but perforin-dependent manner. Ex vivo culture with IL-12 may improve CD8+ T-cell immunotherapy of cancer in the absence of donor cell–derived IFN-γ via perforin-mediated cytolysis. (Cancer Res 2006; 66(9): 4913-21)