Expression of CCR-7, MIP-3beta, and Th-1 chemokines in type I IFN-induced monocyte-derived dendritic cells: importance for the rapid acquisition of potent migratory and functional activities

Control of adaptive immunity by pattern recognition receptors

One of the most significant conceptual advances in immunology in recent history is the recognition that signals from the innate immune system are required for induction of adaptive immune responses. Two breakthroughs were critical in establishing this paradigm: the identification of dendritic cells (DCs) as the cellular link between innate and adaptive immunity and the discovery of pattern recognition receptors (PRRs) as a molecular link that controls innate immune activation as well as DC function. Here, we recount the key events leading to these discoveries and discuss our current understanding of how PRRs shape adaptive immune responses, both indirectly through control of DC function and directly through control of lymphocyte function. In this context, we provide a conceptual framework for how variation in the signals generated by PRR activation, in DCs or other cell types, can influence T cell differentiation and shape the ensuing adaptive immune response.

Roles of cGAS-STING Pathway in Radiotherapy Combined with Immunotherapy for Hepatocellular Carcinoma

Although great strides have been made in the management and treatment of hepatocellular carcinoma (HCC), its prognosis is still poor yielding a high mortality. Immunotherapy is recommended for treating advanced HCC, but its efficiency is hampered because of hepatic immunosuppression. Stimulator of interferon genes (STING) pathway, serving as a critical cytoplasmic DNA-sensing process, is reported to initiate the antitumor immune response, and link the innate immunity to the adaptive immune system. Radiotherapy has been well acknowledged to induce destruction and release of tumor-derived DNA into the cytoplasm, which then activates the cGAS-STING pathway. On this basis, radiotherapy can be used as a sensitizer for immunotherapy, and its combination with immunotherapy may bring in changes to the suboptimal efficacy of immune checkpoint inhibitor monotherapy. In this review, we summarized the roles of cGAS-STING pathway in regulation of radiotherapy combined with immunotherapy for treating HCC.

Targeting STING in cancer: Challenges and emerging opportunities

The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway is a key pathway through which the host regulates immune responses by recognizing cytoplasmic double-stranded DNA of abnormal origin, and it plays an important role in tumor growth as well as metastasis, with relevant molecular details constantly being explored and updated. The significant immunomodulatory effects make STING an attractive target for cancer immunotherapy, and STING agonists have been receiving great attention for their development and clinical translation. Despite exciting results in preclinical work, the application of STING agonists to cancer therapy remains challenging due to their poor pharmacokinetic and physicochemical properties, as well as toxic side effects they produce. Here, we summarize the dichotomous role of cGAS-STING in cancer and discuss the limitations of cancer immunotherapy based on STING activation as well as feasible strategies to overcome them to achieve tumor regression.

Inside-out assembly of viral antigens for the enhanced vaccination

Current attempts in vaccine delivery systems concentrate on replicating the natural dissemination of live pathogens, but neglect that pathogens evolve to evade the immune system rather than to provoke it. In the case of enveloped RNA viruses, it is the natural dissemination of nucleocapsid protein (NP, core antigen) and surface antigen that delays NP exposure to immune surveillance. Here, we report a multi-layered aluminum hydroxide-stabilized emulsion (MASE) to dictate the delivery sequence of the antigens. In this manner, the receptor-binding domain (RBD, surface antigen) of the spike protein was trapped inside the nanocavity, while NP was absorbed on the outside of the droplets, enabling the burst release of NP before RBD. Compared with the natural packaging strategy, the inside-out strategy induced potent type I interferon-mediated innate immune responses and triggered an immune-potentiated environment in advance, which subsequently boosted CD40⁺ DC activations and the engagement of the lymph nodes. In both H1N1 influenza and SARS-CoV-2 vaccines, rMASE significantly increased antigen-specific antibody secretion, memory T cell engagement, and Th1-biased immune response, which diminished viral loads after lethal challenge. By simply reversing the delivery sequence of the surface antigen and core antigen, the inside-out strategy may offer major implications for enhanced vaccinations against the enveloped RNA virus.

Harnessing the Immunological Effects of Radiation to Improve Immunotherapies in Cancer

Ionizing radiation (IR) is used to treat 50% of cancers. While the cytotoxic effects related to DNA damage with IR have been known since the early 20th century, the role of the immune system in the treatment response is still yet to be fully determined. IR can induce immunogenic cell death (ICD), which activates innate and adaptive immunity against the cancer. It has also been widely reported that an intact immune system is essential to IR efficacy. However, this response is typically transient, and wound healing processes also become upregulated, dampening early immunological efforts to overcome the disease. This immune suppression involves many complex cellular and molecular mechanisms that ultimately result in the generation of radioresistance in many cases. Understanding the mechanisms behind these responses is challenging as the effects are extensive and often occur simultaneously within the tumor. Here, we describe the effects of IR on the immune landscape of tumors. ICD, along with myeloid and lymphoid responses to IR, are discussed, with the hope of shedding light on the complex immune stimulatory and immunosuppressive responses involved with this cornerstone cancer treatment. Leveraging these immunological effects can provide a platform for improving immunotherapy efficacy in the future.

1,25(OH)2D3 Differently Modulates the Secretory Activity of IFN-DC and IL4-DC: A Study in Cells from Healthy Donors and MS Patients

Immune mechanisms play an essential role in driving multiple sclerosis (MS) and altered trafficking and/or activation of dendritic cells (DC) were observed in the central nervous system and cerebrospinal fluid of MS patients. Interferon β (IFNβ) has been used as a first-line therapy in MS for almost three decades and vitamin D deficiency is a recognized environmental risk factor for MS. Both IFNβ and vitamin D modulate DC functions. Here, we studied the response to 1,25-dihydoxyvitamin D3 (1,25(OH)₂D3) of DC obtained with IFNβ/GM-CSF (IFN-DC) compared to classically derived IL4-DC, in three donor groups: MS patients free of therapy, MS patients undergoing IFNβ therapy, and healthy donors. Except for a decreased CCL2 secretion by IL4-DC from the MS group, no major defects were observed in the 1,25(OH)₂D3 response of either IFN-DC or IL4-DC from MS donors compared to healthy donors. However, the two cell models strongly differed for vitamin D receptor level of expression as well as for basal and 1,25(OH)₂D3-induced cytokine/chemokine secretion. 1,25(OH)₂D3 up-modulated IL6, its soluble receptor sIL6R, and CCL5 in IL4-DC, and down-modulated IL10 in IFN-DC. IFN-DC, but not IL4-DC, constitutively secreted high levels of IL8 and of matrix-metalloproteinase-9, both down-modulated by 1,25(OH)₂D3. DC may contribute to MS pathogenesis, but also provide an avenue for therapeutic intervention. 1,25(OH)₂D3-induced tolerogenic DC are in clinical trial for MS. We show that the protocol of in vitro DC differentiation qualitatively and quantitatively affects secretion of cytokines and chemokines deeply involved in MS pathogenesis.

The innate and T-cell mediated immune response during acute and chronic gammaherpesvirus infection

Immediately after entry into host cells, viruses are sensed by the innate immune system, leading to the activation of innate antiviral effector mechanisms including the type I interferon (IFN) response and natural killer (NK) cells. This innate immune response helps to shape an effective adaptive T cell immune response mediated by cytotoxic T cells and CD4+ T helper cells and is also critical for the maintenance of protective T cells during chronic infection. The human gammaherpesvirus Epstein-Barr virus (EBV) is a highly prevalent lymphotropic oncovirus that establishes chronic lifelong infections in the vast majority of the adult population. Although acute EBV infection is controlled in an immunocompetent host, chronic EBV infection can lead to severe complications in immunosuppressed patients. Given that EBV is strictly host-specific, its murine homolog murid herpesvirus 4 or MHV68 is a widely used model to obtain in vivo insights into the interaction between gammaherpesviruses and their host. Despite the fact that EBV and MHV68 have developed strategies to evade the innate and adaptive immune response, innate antiviral effector mechanisms still play a vital role in not only controlling the acute infection but also shaping an efficient long-lasting adaptive immune response. Here, we summarize the current knowledge about the innate immune response mediated by the type I IFN system and NK cells, and the adaptive T cell-mediated response during EBV and MHV68 infection. Investigating the fine-tuned interplay between the innate immune and T cell response will provide valuable insights which may be exploited to design better therapeutic strategies to vanquish chronic herpesviral infection.

Type I and II interferon signaling in colorectal cancer liver metastasis

Metastatic colorectal cancer is one of the leading causes of cancer-related deaths worldwide. Traditional chemotherapy extended the lifespan of cancer patients by only a few months, but targeted therapies and immunotherapy prolonged survival and led to long-term remissions in some cases. Type I and II interferons have direct pro-apoptotic and anti-proliferative effects on cancer cells and stimulate anti-cancer immunity. As a result, interferon production by cells in the tumor microenvironment is in the spotlight of immunotherapies as it affects the responses of anti-cancer immune cells. However, promoting effects of interferons on colorectal cancer metastasis have also been reported. Here we summarize our knowledge about pro- and anti-metastatic effects of type I and II interferons in colorectal cancer liver metastasis and discuss possible therapeutic implications.

Potential role of cGAS/STING pathway in regulating cancer progression

The activation of innate immune response after the engagement of dsDNA is an evolutionarily preserved sophisticated strategy against invading microbial pathogens. cGAS has been identified as one of the major dsDNA sensor present in the cytoplasm which catalyzes the synthesis of a cyclic dinucleotide 2'3'cGAMP, as the secondary messenger that binds and activates the downstream stimulator of interferon (IFN) genes (STING) for subsequent production of type 1 IFNs and other inflammatory genes. Recent progress in the mechanical understanding of cGAS/STING signalling has unveiled its intricate role in tumor progression and metastasis. In this review, we specifically focus on new developments concerning the role of cGAS/STING signalling in regulating antitumorigenesis and tumorigenesis.

[Pharmacological actions of anifrolumab (Saphnelo®) and clinical trial results as a treatment for systemic lupus erythematosus]

Systemic lupus erythematosus (SLE) is an autoimmune disease which causes damaging inflammation in multiple organs via the accumulation of immune complexes. SLE pathogenesis is associated with type I interferons (IFNs), which are central and reflective of disease activity in SLE. Even before clinical development of disease, genetic and environmental contributions to IFN production lead to abnormal innate and adaptive immune activation. Through the Janus kinase-signal transducer and activator of transcription signaling pathway, IFN play a central role in the immunopathogenicity of SLE. Thus, IFN-blocking therapy may be used to regulate inflammation in individuals with SLE. Food and Drug Administration (FDA)-approved anifrolumab (Saphnelo^®), which is a human IgG1κ monoclonal antibody that binds to subunit 1 of the type I interferon receptor with high specificity and affinity, was also approved for the treatment of adult patients with moderate to severe SLE who are receiving standard therapy by Pharmaceuticals and Medical Device Agency (PMDA), in Japan in September 2021; anifrolumab is administered as an intravenous infusion, 300 mg over a 30-minute period, every 4 weeks. In this article, we reviewed the actions of type I IFN and anifrolumab as a treatment for SLE.

Dendritic Cells and Cancer Immunotherapy: The Adjuvant Effect

Dendritic cells (DCs) are immune specialized cells playing a critical role in promoting immune response against antigens, and may represent important targets for therapeutic interventions in cancer. DCs can be stimulated ex vivo with pro-inflammatory molecules and loaded with tumor-specific antigen(s). Protocols describing the specific details of DCs vaccination manufacturing vary widely, but regardless of the employed protocol, the DCs vaccination safety and its ability to induce antitumor responses is clearly established. Many years of studies have focused on the ability of DCs to provide overall survival benefits at least for a selection of cancer patients. Lessons learned from early trials lead to the hypothesis that, to improve the efficacy of DCs-based immunotherapy, this should be combined with other treatments. Thus, the vaccine’s ultimate role may lie in the combinatorial approaches of DCs-based immunotherapy with chemotherapy and radiotherapy, more than in monotherapy. In this review, we address some key questions regarding the integration of DCs vaccination with multimodality therapy approaches for cancer treatment paradigms.

Interfering With Inflammation: Heterogeneous Effects of Interferons in Graft-Versus-Host Disease of the Gastrointestinal Tract and Inflammatory Bowel Disease

The intestine can be the target of several immunologically mediated diseases, including graft-versus-host disease (GVHD) and inflammatory bowel disease (IBD). GVHD is a life-threatening complication that occurs after allogeneic hematopoietic stem cell transplantation. Involvement of the gastrointestinal tract is associated with a particularly high mortality. GVHD development starts with the recognition of allo-antigens in the recipient by the donor immune system, which elicits immune-mediated damage of otherwise healthy tissues. IBD describes a group of immunologically mediated chronic inflammatory diseases of the intestine. Several aspects, including genetic predisposition and immune dysregulation, are responsible for the development of IBD, with Crohn’s disease and ulcerative colitis being the two most common variants. GVHD and IBD share multiple key features of their onset and development, including intestinal tissue damage and loss of intestinal barrier function. A further common feature in the pathophysiology of both diseases is the involvement of cytokines such as type I and II interferons (IFNs), amongst others. IFNs are a family of protein mediators produced as a part of the inflammatory response, typically to pathogens or malignant cells. Diverse, and partially paradoxical, effects have been described for IFNs in GVHD and IBD. This review summarizes current knowledge on the role of type I, II and III IFNs, including basic concepts and controversies about their functions in the context of GVHD and IBD. In addition, therapeutic options, research developments and remaining open questions are addressed.

Identification of CD56dim subpopulation marked with high expression of GZMB/PRF1/PI-9 in CD56+ interferon-α-induced dendritic cells

As the sentinels of innate and adaptive immune system, dendritic cells (DCs) have been considered to hold a great promise for medical application. Among the diverse types of DCs, monocyte-derived DCs (mo-DCs) generated in vitro have been most commonly employed. We have been improving the culture protocol and devised a protocol to produce mature interferon-α-induced DCs (IFN-DCs), hereinafter called (mat)IFN-DCs. While exploring the relationship between the expression of CD56 and the cytotoxic activity of (mat)IFN-DCs, we unexpectedly found that sorting of (mat)IFN-DCs with CD56 antibody-coated microbeads (MB) resulted in fractionating cells with tumoricidal activity into the flow-through (FT) but not MB-bound fraction. We uncovered that the FT fraction contains cells expressing low but substantial level of CD56. Moreover, those cells express granzyme B (GrB), perforin (PFN), and serpin B9 at high levels. By employing a specific inhibitor of PFN, we confirmed that direct tumoricidal activity relies on the GrB/PFN pathway. We designated subpopulation in FT fraction as CD56^dim and that in CD56 positively sorted fraction as CD56^bright , respectively. This is the first time, to our knowledge, to identify subpopulations of CD56-positive IFN-DCs with distinct tumoricidal activity which is ascribed to high expression of the components of GrB/PFN pathway.

Type I and II Interferons in the Anti-Tumor Immune Response

The interferons (IFNs) are essential components of the immune response against infections and malignancies. IFNs are potent promoters of the anti-tumor response, but there is also evidence that feedback mechanisms regulated by IFNs negatively control immune responses to avoid hyper-activation and limit inflammation. This balance of responses plays an important role in cancer surveillance, immunoediting and response to anticancer therapeutic approaches. Here we review the roles of both type I and type II IFNs on the control of the immune response against malignancies in the context of effects on both malignant cells and cells of the immune system in the tumor microenvironment.

Multimarker scores of Th1 and Th2 immune cellular profiles in peripheral blood predict response and immune related toxicity with CTLA4 blockade and IFNα in melanoma

Neoadjuvant therapy with ipilimumab in combination with high dose IFNα was evaluated in patients with locally/regionally advanced melanoma in a previously reported clinical trial [NCT01608594]. In this study, peripheral immune cell profiling was performed in order to investigate the underlying mechanisms of tumor immune susceptibility and resistance. Peripheral blood mononuclear cells (PBMCs) from treated patients (N = 28) were collected at baseline and then at 6-weeks, 3-months and 12-months. High complexity (14-color) flow cytometry, designed to detect key immunological biomarkers was used to evaluate the frequencies of immune cell subsets. Statistical significance was determined using R-package employing Kruskal's test. We found that higher levels of Th1 cells at baseline (defined as CD45RA- CCR6- CXCR3+ CCR4-) correlated with the preoperative radiological response (p = 0.007) while higher Th2 cells (defined as CD45RA- CCR6- CXCR3- CCR4+) were associated with progressive disease (p = 0.009). A multimarker score consisting of higher levels of Th1 cells and CD8+ central memory T-cells was associated with pathologic complete response (pCR) (p = 0.041) at surgical resection. On the other hand, high TIM3 expression on T-cells correlated with gross viable tumor (p = 0.047). With regard to immune related toxicity, higher levels of phenotypically naive (defined as CCR7+CD45RA+) and effector memory (defined as CCR7-CD45RO+) CD8+ T-cells (p = 0.014) or lower levels of Th2 cells were associated with lower toxicity (p = 0.024). Furthermore, a multimarker score consisting of higher CD19+ and CD8+ cells was associated with lower toxicity (p = 0.0014). In conclusion, our study yielded mechanistic insights related to the immune impact of CTLA4 blockade and IFNα and potential biomarkers of immune response and toxicity.

Type I interferons in pancreatic cancer and development of new therapeutic approaches

Immunotherapy has emerged as a new treatment strategy for cancer. However, its promise in pancreatic cancer has not yet been realized. Understanding the immunosuppressive tumor microenvironment of pancreatic cancer, and identifying new therapeutic targets to increase tumor-specific immune responses, is necessary in order to improve clinical outcomes. Type I interferons, e.g. IFN-α and -β, are considered as an important bridge between the innate and adaptive immune system. Thereby, type I IFNs induce a broad spectrum of anti-tumor effects, including immunologic, vascular, as well as direct anti-tumor effects. While IFN therapies have been around for a while, new insights into exogenous and endogenous activation of the IFN pathway have resulted in new IFN-related cancer treatment strategies. Here, we focus on the pre-clinical and clinical evidence of novel ways to take advantage of the type I IFN pathway, such as IFN based conjugates and activation of the STING and RIG-I pathways.

IFN-Alpha-Mediated Differentiation of Dendritic Cells for Cancer Immunotherapy: Advances and Perspectives

The past decade has seen tremendous developments in novel cancer therapies through targeting immune-checkpoint molecules. However, since increasing the presentation of tumor antigens remains one of the major issues for eliciting a strong antitumor immune response, dendritic cells (DC) still hold a great potential for the development of cancer immunotherapy. A considerable body of evidence clearly demonstrates the importance of the interactions of type I IFN with the immune system for the generation of a durable antitumor response through its effects on DC. Actually, highly active DC can be rapidly generated from blood monocytes in vitro in the presence of IFN-α (IFN-DC), suitable for therapeutic vaccination of cancer patients. Here we review how type I IFN can promote the ex vivo differentiation of human DC and orientate DC functions towards the priming and expansion of protective antitumor immune responses. New epigenetic elements of control on activation of the type I IFN signal will be highlighted. We also review a few clinical trials exploiting IFN-DC in cancer vaccination and discuss how IFN-DC could be exploited for the design of effective strategies of cancer immunotherapy as a monotherapy or in combination with immune-checkpoint inhibitors or immunomodulatory drugs.

The differing pathophysiologies that underlie COVID-19-associated perniosis and thrombotic retiform purpura: a case series

Background

There are two distinctive acral manifestations of COVID‐19 embodying disparate clinical phenotypes. One is perniosis occurring in mildly symptomatic patients, typically children and young adults; the second is the thrombotic retiform purpura of critically ill adults with COVID‐19.

Objectives

To compare the clinical and pathological profiles of these two different cutaneous manifestations of COVID‐19.

Methods

We compared the light microscopic, phenotypic, cytokine and SARS‐CoV‐2 protein and RNA profiles of COVID‐19‐associated perniosis with that of thrombotic retiform purpura in critical patients with COVID‐19.

Results

Biopsies of COVID‐19‐associated perniosis exhibited vasocentric and eccrinotropic T‐cell‐ and monocyte‐derived CD11c⁺, CD14⁺ and CD123⁺ dendritic cell infiltrates. Both COVID‐associated and idiopathic perniosis showed striking expression of the type I interferon‐inducible myxovirus resistance protein A (MXA), an established marker for type I interferon signalling in tissue. SARS‐CoV‐2 RNA, interleukin‐6 and caspase 3 were minimally expressed and confined to mononuclear inflammatory cells. The biopsies from livedo/retiform purpura showed pauci‐inflammatory vascular thrombosis without any MXA decoration. Blood vessels exhibited extensive complement deposition with endothelial cell localization of SARS‐CoV‐2 protein, interleukin‐6 and caspase 3; SARS‐CoV‐2 RNA was not seen.

Conclusions

COVID‐19‐associated perniosis represents a virally triggered exaggerated immune reaction with significant type I interferon signaling. This is important to SARS‐CoV‐2 eradication and has implications in regards to a more generalized highly inflammatory response. We hypothesize that in the thrombotic retiform purpura of critically ill patients with COVID‐19, the vascular thrombosis in the skin and other organ systems is associated with a minimal interferon response. This allows excessive viral replication with release of viral proteins that localize to extrapulmonary endothelium and trigger extensive complement activation.

The Molecular Interactions of ZIKV and DENV with the Type-I IFN Response

Zika Virus (ZIKV) and Dengue Virus (DENV) are related viruses of the Flavivirus genus that cause significant disease in humans. Existing control measures have been ineffective at curbing the increasing global incidence of infection for both viruses and they are therefore prime targets for new vaccination strategies. Type-I interferon (IFN) responses are important in clearing viral infection and for generating efficient adaptive immune responses towards infection and vaccination. However, ZIKV and DENV have evolved multiple molecular mechanisms to evade type-I IFN production. This review covers the molecular interactions, from detection to evasion, of these viruses with the type-I IFN response. Additionally, we discuss how this knowledge can be exploited to improve the design of new vaccine strategies.

cGAS-STING, an important pathway in cancer immunotherapy

Cytosolic DNA sensing, the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway, is an important novel role in the immune system. Multiple STING agonists were developed for cancer therapy study with great results achieved in pre-clinical work. Recent progress in the mechanical understanding of STING pathway in IFN production and T cell priming, indicates its promising role for cancer immunotherapy. STING agonists co-administrated with other cancer immunotherapies, including cancer vaccines, immune checkpoint inhibitors such as anti-programmed death 1 and cytotoxic T lymphocyte-associated antigen 4 antibodies, and adoptive T cell transfer therapies, would hold a promise of treating medium and advanced cancers. Despite the applications of STING agonists in cancer immunotherapy, lots of obstacles remain for further study. In this review, we mainly examine the biological characters, current applications, challenges, and future directions of cGAS-STING in cancer immunotherapy.

Advances and perspectives of dendritic cell-based active immunotherapies in follicular lymphoma

Follicular lymphoma (FL) is a remarkably immune-responsive malignancy, which is still considered incurable. As, standard immunochemotherapy is complex, toxic and not curative, improvement in FL care is now a crucial topic in hemato-oncology. Recently, we and others have shown that dendritic cell (DC)-based therapies allow a specific immune response associated with sustained lymphoma regression in a proportion of low-tumor burden FL patients. Importantly, the rate of objective clinical response (33-50%) and of sustained remission is remarkably higher compared to similar studies in solid tumors, corroborating the assumption of the immune responsiveness of FL. Our experimental intra-tumoral strategy combined injection with rituximab and interferon-α-derived dendritic cells (IFN-DC), a novel DC population particularly efficient in biasing T-helper response toward the Th1 type and in the cross-priming of CD8 + T cells. Noteworthy, intra-tumoral injection of DC is a new therapeutic option based on the assumption that following the induction of cancer-cell immunogenic death, unloaded DC would phagocytize in vivo the tumor associated antigens and give rise to a specific immune response. This approach allows the design of easy and inexpensive schedules. On the other hand, advanced and straightforward methods to produce clinical-grade antigenic formulations are currently under development. Both unloaded DC strategies and DC-vaccines are suited for combination with radiotherapy, immune checkpoint inhibitors, immunomodulators and metronomic chemotherapy. In fact, studies in animal models have already shown impressive results, while early-phase combination trials are ongoing. Here, we summarize the recent advances and the future perspectives of DC-based therapies in the treatment of FL patients.

Flagellin-Stimulated Production of Interferon-β Promotes Anti-Flagellin IgG2c and IgA Responses

Flagellin, a major structural protein of the flagellum found in all motile bacteria, activates the TLR5- or NLRC4 inflammasomedependent signaling pathway to induce innate immune responses. Flagellin can also serve as a specific antigen for the adaptive immune system and stimulate anti-flagellin antibody responses. Failure to recognize commensal-derived flagellin in TLR5-deficient mice leads to the reduction in antiflagellin IgA antibodies at steady state and causes microbial dysbiosis and mucosal barrier breach by flagellated bacteria to promote chronic intestinal inflammation. Despite the important role of anti-flagellin antibodies in maintaining the intestinal homeostasis, regulatory mechanisms underlying the flagellin-specific antibody responses are not well understood. In this study, we show that flagellin induces interferon-β (IFN-β) production and subsequently activates type I IFN receptor signaling in a TLR5- and MyD88-dependent manner in vitro and in vivo . Internalization of TLR5 from the plasma membrane to the acidic environment of endolysosomes was required for the production of IFN-β, but not for other proinflammatory cytokines. In addition, we found that antiflagellin IgG2c and IgA responses were severely impaired in interferon-alpha receptor 1 (IFNAR1)-deficient mice, suggesting that IFN-β produced by the flagellin stimulation regulates anti-flagellin antibody class switching. Our findings shed a new light on the regulation of flagellin-mediated immune activation and may help find new strategies to promote the intestinal health and develop mucosal vaccines.

Dendritic Cells and Immunogenic Cancer Cell Death: A Combination for Improving Antitumor Immunity

The safety and feasibility of dendritic cell (DC)-based immunotherapies in cancer management have been well documented after more than twenty-five years of experimentation, and, by now, undeniably accepted. On the other hand, it is equally evident that DC-based vaccination as monotherapy did not achieve the clinical benefits that were predicted in a number of promising preclinical studies. The current availability of several immune modulatory and targeting approaches opens the way to many potential therapeutic combinations. In particular, the evidence that the immune-related effects that are elicited by immunogenic cell death (ICD)-inducing therapies are strictly associated with DC engagement and activation strongly support the combination of ICD-inducing and DC-based immunotherapies. In this review, we examine the data in recent studies employing tumor cells, killed through ICD induction, in the formulation of anticancer DC-based vaccines. In addition, we discuss the opportunity to combine pharmacologic or physical therapeutic approaches that can promote ICD in vivo with in situ DC vaccination.

Herpes Simplex Virus Type-2 Paralyzes the Function of Monocyte-Derived Dendritic Cells

Herpes simplex viruses not only infect a variety of different cell types, including dendritic cells (DCs), but also modulate important cellular functions in benefit of the virus. Given the relevance of directed immune cell migration during the initiation of potent antiviral immune responses, interference with DC migration constitutes a sophisticated strategy to hamper antiviral immunity. Notably, recent reports revealed that HSV-1 significantly inhibits DC migration in vitro. Thus, we aimed to investigate whether HSV-2 also modulates distinct hallmarks of DC biology. Here, we demonstrate that HSV-2 negatively interferes with chemokine-dependent in vitro migration capacity of mature DCs (mDCs). Interestingly, rather than mediating the reduction of the cognate chemokine receptor expression early during infection, HSV-2 rapidly induces β2 integrin (LFA-1)-mediated mDC adhesion and thereby blocks mDC migration. Mechanistically, HSV-2 triggers the proteasomal degradation of the negative regulator of β2 integrin activity, CYTIP, which causes the constitutive activation of LFA-1 and thus mDC adhesion. In conclusion, our data extend and strengthen recent findings reporting the reduction of mDC migration in the context of a herpesviral infection. We thus hypothesize that hampering antigen delivery to secondary lymphoid organs by inhibition of mDC migration is an evolutionary conserved strategy among distinct members of Herpesviridae.

Interferons α and β in cancer: therapeutic opportunities from new insights

Over the past decade, preclinical and clinical research have confirmed the essential role of interferons for effective host immunological responses to malignant cells. Type I interferons (IFNα and IFNβ) directly regulate transcription of >100 downstream genes, which results in a myriad of direct (on cancer cells) and indirect (through immune effector cells and vasculature) effects on the tumour. New insights into endogenous and exogenous activation of type I interferons in the tumour and its microenvironment have given impetus to drug discovery and patient evaluation of interferon-directed strategies. When combined with prior observations or with other effective modalities for cancer treatment, modulation of the interferon system could contribute to further reductions in cancer morbidity and mortality. This Review discusses new interferon-directed therapeutic opportunities, ranging from cyclic dinucleotides to genome methylation inhibitors, angiogenesis inhibitors, chemoradiation, complexes with neoantigen-targeted monoclonal antibodies, combinations with other emerging therapeutic interventions and associations of interferon-stimulated gene expression with patient prognosis - all of which are strategies that have or will soon enter translational clinical evaluation.

Lenalidomide improves the therapeutic effect of an interferon-α-dendritic cell-based lymphoma vaccine

The perspective of combining cancer vaccines with immunomodulatory drugs is currently regarded as a highly promising approach for boosting tumor-specific T cell immunity and eradicating residual malignant cells. The efficacy of dendritic cell (DC) vaccination in combination with lenalidomide, an anticancer drug effective in several hematologic malignancies, was investigated in a follicular lymphoma (FL) model. First, we evaluated the in vitro activity of lenalidomide in modulating the immune responses of lymphocytes co-cultured with a new DC subset differentiated with IFN-α (IFN-DC) and loaded with apoptotic lymphoma cells. We next evaluated the efficacy of lenalidomide and IFN-DC-based vaccination, either alone or in combination, in hu-PBL-NOD/SCID mice bearing established human lymphoma. We found that lenalidomide reduced Treg frequency and IL-10 production in vitro, improved the formation of immune synapses of CD8 + lymphocytes with lymphoma cells and enhanced anti-lymphoma cytotoxicity. Treatment of lymphoma-bearing mice with either IFN-DC vaccination or lenalidomide led to a significant decrease in tumor growth and lymphoma cell spread. Lenalidomide treatment was shown to substantially inhibit tumor-induced neo-angiogenesis rather than to exert a direct cytotoxic effect on lymphoma cells. Notably, the combined treatment with the vaccine plus lenalidomide was more effective than either single treatment, resulting in the significant regression of established tumors and delayed tumor regrowth upon treatment discontinuation. In conclusion, our data demonstrate that IFN-DC-based vaccination plus lenalidomide exert an additive therapeutic effect in xenochimeric mice bearing established lymphoma. These results may pave the way to evaluate this combination in the clinical ground.

Prospects for combining immune checkpoint blockade with PARP inhibition

The immunogenicity of a cancer cell is derived from accumulated somatic mutations. However, on the contrary to increased immunogenicity, anti-cancer immune response tends to be feeble. This impaired anti-cancer immunity could be attributed to multiple factors including loss of immunodominant epitopes, downregulation of major histocompatibility complex, and immunosuppressive microenvironment, as well as aberrant negative co-stimulatory signals. Immune checkpoint inhibitors block negative co-stimulatory signals such as programmed cell death-1 and cytotoxic T-lymphocyte-associated protein 4, ultimately reactivating anti-cancer immunity. Immune checkpoint inhibitors elicit potent anti-cancer effect and have been approved for multiple cancers. Nevertheless, there still are significant potential improvements for the applications of checkpoint inhibitor, especially considering frequent resistance. Recent studies demonstrated that additional PARP inhibition could alleviate resistance and enhance efficacy of immune checkpoint blockade therapy via promoting cross-presentation and modifying immune microenvironment. We proposed that PARP inhibitors could enhance the priming and tumor-killing activities of T cell, boost the whole cancer-immunity cycle, and thereby improve the response to immune checkpoint blockade. In this review, we focused the latest understanding of the effect of PARP inhibitors on anti-cancer immunity and PARP inhibitors combining immune checkpoint blockade therapy. Moreover, we summarized the preclinical and clinical evidence and discussed the feasibility of this combination therapy in future clinical practice.

The impact of CTLA-4 blockade and interferon-α on clonality of T-cell repertoire in the tumor microenvironment and peripheral blood of metastatic melanoma patients

Patients with metastatic melanoma were treated with tremelimumab and interferon-α (IFN) in a previously reported clinical trial [NCT00610857]. Responses were assessed by RECIST criteria as complete (CR) or partial (PR), stable disease (SD) or progressive disease (PD). In this study, T-cell receptor (TCR) beta-chain repertoire was immunosequenced in peripheral blood mononuclear cells (PBMC) specimens (N = 33) and tumor samples (N = 18) utilizing the immunoSEQ® Assay to determine repertoire clonality and T cell fractions at pre-treatment (tumor and PBMC), one month (PBMC) and 3 months (PBMC) time points and evaluate its association with clinical outcomes. In the pretreatment tumor microenvironment (TME), T cell clonality was significantly (p = .035) different and greater in patients who achieved disease control (CR, PR, SD) versus those with non-disease control (PD) as best response to treatment. Further, there was significantly (p = .001) increased TCR fraction in tissue of responders (CR, PR) versus non-responders (PD, SD). In examining T cell clonality in the circulation (PBMC), no significant associations were found in the pretreatment samples. However, early on-treatment (4 weeks) there was a significant decrease in T cell clonality that was associated with improved overall survival (p = .01) and progression-free survival (p = .04). In addition, analysis of temporal changes in tumor-infiltrating lymphocytes (TIL) and peripheral TCR repertoire revealed that responders had significantly higher clonal expansion of TIL in the circulation at 4 weeks than non-responders (p = .036). Our study provided interesting mechanistic data related to CTLA-4 Blockade and IFN and potential biomarkers of immunotherapeutic benefit.

Transendothelial migration (TEM) of in vitro generated dendritic cell vaccine in cancer immunotherapy

Many efforts have been made to improve the efficacy of dendritic cell (DC) vaccines in DC-based cancer immunotherapy. One of these efforts is to deliver a DC vaccine more efficiently to the regional lymph nodes (rLNs) to induce stronger anti-tumor immunity. Together with chemotaxis, transendothelial migration (TEM) is believed to be a critical and indispensable step for DC vaccine migration to the rLNs after administration. However, the mechanism underlying the in vitro-generated DC TEM in DC-based cancer immunotherapy has been largely unknown. Currently, junctional adhesion molecules (JAMs) were found to play an important role in the TEM of in vitro generated DC vaccines. This paper reviews the TEM of DC vaccines and TEM-associated JAM molecules.

Activating cGAS-STING pathway for the optimal effect of cancer immunotherapy

During tumor progression, a subset of cancer cells escape from immune surveillance and eventually develop into measurable tumor mass. Cancer immunotherapy eradicates tumor cells by enhancing multiple steps in cancer-immunity cycle including antigen presentation, T cell priming, activation, and immune killing activity. Immunotherapy has been verified as an effective strategy in multiple cancers, but some problems still exist in actual clinical practice such as frequent primary and adaptive resistance. Combination with other adjuvant therapies gives us a new perspective to overcome the emerging obstacles in immunotherapy application. Recently, a series of studies demonstrated that the vital component of host innate immunity — cGAS-STING pathway might play an important role in anti-cancer immunity. It is generally acknowledged that the downstream signals of cGAS-STING especially type I interferon (IFN) bridge innate immunity and adaptive immunity. Given the functions of type I IFN in promoting the maturation and migration of dendritic cells, enhancing cytotoxic T lymphocyte- or natural killer cell-mediated cytotoxicity effect, and protecting effector cells from apoptosis, we believe cGAS-STING agonist might be used as sensitizer for multiple immunotherapies such as cancer vaccine, immune checkpoint blockade, and chimeric antigen receptor T cell therapy. In this review, we highlight the latest understanding of cGAS-STING pathway and the advances of the combination therapy of STING agonist and immunotherapy.

E3611-A Randomized Phase II Study of Ipilimumab at 3 or 10 mg/kg Alone or in Combination with High-Dose Interferon-α2b in Advanced Melanoma

PURPOSE

Interferon-α favors a Th1 shift in immunity, and combining with ipilimumab (ipi) at 3 or 10 mg/kg may downregulate CTLA4-mediated suppressive effects, leading to more durable antitumor immune responses. A study of tremelimumab and high-dose interferon-α (HDI) showed promising efficacy, supporting this hypothesis.

PATIENTS AND METHODS

E3611 followed a 2-by-2 factorial design (A: ipi10+HDI; B: ipi10; C: ipi3+HDI; D: ipi3) to evaluate (i) no HDI versus HDI (across ipilimumab doses) and (ii) ipi3 versus ipi10 (across HDI status). We hypothesized that median progression-free survival (PFS) would improve from 3 to 6 months with HDI versus no HDI and with ipi10 versus ipi3.

RESULTS

For eligible and treated patients (N = 81) at a median follow-up time of 29.8 months, median PFS was 4.4 months [95% confidence interval (CI), 2.7-8.2] when ipilimumab was used alone and 7.5 months (95% CI, 5.1-11.0) when HDI was added. Median PFS was 3.8 months (95% CI, 2.6-7.5) with 3 mg/kg ipilimumab and 6.5 months (95% CI, 5.1-13.5) with 10 mg/kg. By study arm, median PFS was 8.0 months (95% CI, 2.8-20.2) in arm A, 6.2 months (95% CI, 2.7-25.7) in B, 5.7 months (95% CI, 1.5-11.1) in C, and 2.8 months (95% CI, 2.6-5.7) in D. The differences in PFS and overall survival (OS) did not reach statistical significance. Adverse events were consistent with the known profiles of ipilimumab and HDI and significantly higher with HDI and ipi10.

CONCLUSIONS

Although PFS was increased, the differences resulting from adding interferon-α or a higher dose of ipilimumab did not reach statistical significance and do not outweigh the added toxicity risks.

Neoadjuvant ipilimumab (3 mg/kg or 10 mg/kg) and high dose IFN-α2b in locally/regionally advanced melanoma: safety, efficacy and impact on T-cell repertoire

BACKGROUND

Neoadjuvant immunotherapy utilizing novel combinations has the potential to transform the standard of care for locally/regionally advanced melanoma. We hypothesized that neoadjuvant ipilimumab in combination with high dose IFNα2b (HDI) is safe and associated with durable pathologic complete responses (pCR).

METHODS

Patients with locally/regionally advanced melanoma were randomized to ipilimumab 3 or 10 mg/kg × 4 doses bracketing definitive surgery, then every 12 weeks × 4. HDI was given concurrently. We evaluated the safety and efficacy of the combination with ipilimumab 3 or 10 mg/kg. The impact on T-cell fraction and clonality were investigated in tumor and blood.

RESULTS

Thirty patients (age 37-76), 15 each at 3 and 10 mg/kg, 18 male and 12 female were treated. Considering immune related adverse events (irAEs) of interest, more grade 3/4 irAEs were seen with ipilimumab 10 mg/kg versus 3 mg/kg (p = 0.042). Among 28 evaluable patients, 11 relapsed, of whom 5 died. Median follow-up for 17 patients who have not relapsed was 32 months. The radiologic preoperative response rate was 36% (95% CI, 21-54); 4 patients at ipilimumab 3 mg/kg and 6 at 10 mg/kg and 2 (at 10 mg/kg) later relapsed. The pCR was 32% (95% CI, 18-51); 5 patients at ipilimumab 3 mg/kg and 4 at 10 mg/kg and one (at 3 mg/kg) had a late relapse. In patients with pCR, T-cell fraction was significantly higher when measured in primary melanoma tumors (p = 0.033). Higher tumor T-cell clonality in primary tumor and more so following neoadjuvant therapy was significantly associated with improved relapse free survival.

CONCLUSIONS

Neoadjuvant ipilimumab-HDI was relatively safe and exhibited promising tumor response rates with an associated measurable impact on T-cell fraction and clonality. Most pCRs were durable supporting the value of pCR as a primary endpoint in neoadjuvant immunotherapy trials.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01608594 . Registered 31 May 2012.

Diagnosis and Management of Acral Lentiginous Melanoma

OPINION STATEMENT

Melanoma is one of the most aggressive malignant skin tumors and its incidence has been increasing worldwide in recent decades. Among the four subtypes, acral lentiginous melanoma (ALM) shows the highest incidence in Asian countries, whereas ALM comprises only 1% of all melanomas in white populations. Early clinical diagnosis of ALM is essential, but early ALM lesions are often difficult to diagnose because the pigmentation of the lesions sometimes follows the skin marking of the palms and soles, resulting in an asymmetrical appearance and an irregular border in both ALM and benign melanocytic nevus. To overcome this difficulty, dermoscopy was introduced, and determination of the patterns by this method is essential for accurate clinical diagnosis of ALM. Although recent clinical trials have demonstrated that immune checkpoint inhibitors and BRAF/MEK inhibitors showed significantly improved overall survival of patients with advanced melanoma, ALM may be less susceptible to immune checkpoint inhibitors because of the poor immune response to the tumor. Therefore, strategies for enhancing the immune response to the tumor cells may be required when we apply immune checkpoint inhibitors in advanced ALM. In this context, imiquimod, dacarbazine, or interferon are possible therapies that may enhance the effectiveness of the immune checkpoint inhibitors. In addition to being known to have poor immunogenicity, ALM is also known to have infrequent BRAF mutation. Therefore, the majority of ALM patients may not benefit from therapy with BRAF/MEK inhibitors. However, some ALMs have mutations such as KIT and NRAS mutations, and therefore, targeted therapies may improve the survival of ALM patients in the future.

Anti-hepatocarcinoma activity of TT-1, an analog of melittin, combined with interferon-α via promoting the interaction of NKG2D and MICA

Hepatocarcinoma is one of the malignant cancers with significant morbidity and mortality. Immunotherapy has emerged in clinical treatment, owing to the limitation and severe side effects of chemotherapy. In the immune system, natural killer (NK) cells are important effectors required to eliminate malignant tumor cells without the limitation of major histocompatibility complex (MHC) molecule issues. Hence, treatment which could stimulate NK cells is of great interest. Here, we investigated the efficacy of the combined therapy of TT-1 (a mutant of melittin) and interferon-α (IFN-α) on NK cells and human liver cancer HepG-2/Huh7 cells in vitro and in vivo, as well as the mechanism involved. The combination therapy significantly inhibited the growth of HepG-2/Huh7 cells in vivo, but this effect was impaired after depleting NK cells. TT-1 not only up-regulated MHC class I-related chain molecules A (MICA) expression, but also prevented the secretion of soluble MICA (sMICA). Both the mRNA and protein of a disintegrin and metallopeptidase 10 (ADAM 10) in HepG-2/Huh7 cells were decreased after TT-1 treatment. The combined therapy of TT-1 and IFN-α could suppress the growth of HepG-2/Huh7 xenografted tumor effectively via promoting the interaction of NK group 2, member D (NKG2D) and MICA, indicating that TT-1+IFN-α would be a potential approach in treating liver cancer.

ISG15 in the tumorigenesis and treatment of cancer: An emerging role in malignancies of the digestive system

The interferon-stimulated gene 15 ubiquitin-like modifier (ISG15) encodes an IFN-inducible, ubiquitin-like protein. The ISG15 protein forms conjugates with numerous cellular proteins that are involved in a multitude of cellular functions, including interferon-induced immune responses and the regulation of cellular protein turnover. The expression of ISG15 and ISG15-mediated conjugation has been implicated in a wide range of human tumors and cancer cell lines, but the roles of ISG15 in tumorigenesis and responses to anticancer treatments remain largely unknown. In this review, we discuss the findings of recent studies with regard to the role of ISG15 pathways in cancers of the digestive system.

Dendritic cells as cancer therapeutics

The ability of immune therapies to control cancer has recently generated intense interest. This therapeutic outcome is reliant on T cell recognition of tumour cells. The natural function of dendritic cells (DC) is to generate adaptive responses, by presenting antigen to T cells, hence they are a logical target to generate specific anti-tumour immunity. Our understanding of the biology of DC is expanding, and they are now known to be a family of related subsets with variable features and function. Most clinical experience to date with DC vaccination has been using monocyte-derived DC vaccines. There is now growing experience with alternative blood-derived DC derived vaccines, as well as with multiple forms of tumour antigen and its loading, a wide range of adjuvants and different modes of vaccine delivery. Key insights from pre-clinical studies, and lessons learned from early clinical testing drive progress towards improved vaccines. The potential to fortify responses with other modalities of immunotherapy makes clinically effective "second generation" DC vaccination strategies a priority for cancer immune therapists.

A robust microparticle platform for a STING-targeted adjuvant that enhances both humoral and cellular immunity during vaccination

Most FDA-approved adjuvants for infectious agents boost humoral but not cellular immunity, and have poorly-understood mechanisms. Stimulator of interferon genes (STING, also known as MITA, MPYS, or ERIS) is an exciting adjuvant target due to its role in cyclic dinucleotide (CDN)-driven anti-viral immunity; however, a major hindrance is STING's cytosolic localization which requires intracellular delivery of its agonists. As a result, STING agonists administered in a soluble form have elicited suboptimal immune responses. Delivery of STING agonists via particle platforms has proven a more successful strategy, but the opportunity for improved formulations and bioactivity remains. In this study we evaluated the adjuvant activity of the potent STING agonist, CDN 3'3'-cGAMP (cGAMP), encapsulated in acid-sensitive acetalated dextran (Ace-DEX) polymeric microparticles (MPs) which passively target antigen-presenting cells for intracellular release. This formulation was superior to all particle delivery systems evaluated and maintained its bioactivity following a sterilizing dose of gamma irradiation. Compared to soluble cGAMP, the Ace-DEX cGAMP MPs enhanced type-I interferon responses nearly 1000-fold in vitro and 50-fold in vivo, caused up to a 104-fold boost in antibody titers, increased Th1-associated responses, and expanded germinal center B cells and memory T cells. Furthermore, the encapsulated cGAMP elicited no observable toxicity in animals and achieved protective immunity against a lethal influenza challenge seven months post-immunization when using CDN adjuvant doses up to 100-fold lower than previous reports. For these reasons, Ace-DEX MP-encapsulated cGAMP represents a potent vaccine adjuvant of humoral and cellular immunity.

The Effects of Dendritic Cell Hypersensitivity on Persistent Viral Infection

Caspase-8 (CASP8) is known as an executioner of apoptosis, but more recent studies have shown that it participates in the regulation of necroptosis and innate immunity. In this study, we show that CASP8 negatively regulates retinoic acid-inducible gene I (RIG-I) signaling such that, in its absence, stimulation of the RIG-I pathway in dendritic cells (DCs) produced modestly enhanced activation of IFN regulatory factor 3 with correspondingly greater amounts of proinflammatory cytokines. In addition, mice lacking DC-specific CASP8 (dcCasp8^-/- mice) develop age-dependent symptoms of autoimmune disease characterized by hyperactive DCs and T cells, spleen and liver immunopathology, and the appearance of Th1-polarized CD4⁺ T cells. Such mice infected with chronic lymphocytic choriomeningitis virus, an RNA virus detected by RIG-I, mounted an enhanced lymphocytic choriomeningitis virus-specific immune response as measured by increased proportions of Ag-specific CD4⁺ T cells and multicytokine-producing CD4⁺ and CD8⁺ T cells. These results show that CASP8 subtly modulates DC maturation, which controls the spontaneous appearance of autoimmune T cells while simultaneously attenuating the acquired immune system and its potential to control a persistent viral infection.

The Immunology of Melanoma

The relatively high DNA mutational burden in melanoma allows for the creation of potentially "foreign," immune-stimulating neoantigens, and leads to its exceptional immunogenicity. Brisk tumor-infiltrating lymphocytes, a marker of immune editing, confer improved overall survival in melanoma, possibly due to reduced sentinel lymph node spread. Meanwhile, T-cell-stimulating drugs, so-called T-cell checkpoint inhibitors, which reverse peripheral tolerance-dependent tumor escape, have demonstrated unparalleled clinical success in metastatic melanoma. Markers to predict response to immunotherapy are currently imperfect, and the subject of intense research, which will guide the future of ancillary pathologic testing in this setting.

Atypical activation of dendritic cells by Plasmodium falciparum

Dendritic cells (DCs) are activated by pathogens to initiate and shape immune responses. We found that the activation of DCs by Plasmodium falciparum, the main causative agent of human malaria, induces a highly unusual phenotype by which DCs up-regulate costimulatory molecules and secretion of chemokines, but not of cytokines typical of inflammatory responses (IL-1β, IL-6, IL-10, TNF). Similar results were obtained with DCs obtained from malaria-naïve US donors and malaria-experienced donors from Mali. Contact-dependent cross-talk between the main DC subsets, plasmacytoid and myeloid DCs (mDCs) was necessary for increased chemokine and IFN-α secretion in response to the parasite. Despite the absence of inflammatory cytokine secretion, mDCs incubated with P. falciparum-infected erythrocytes activated antigen-specific naïve CD4⁺ T cells to proliferate and secrete Th1-like cytokines. This unexpected response of human mDCs to P. falciparum exhibited a transcriptional program distinct from a classical LPS response, pointing to unique P. falciparum-induced activation pathways that may explain the uncharacteristic immune response to malaria.

Exploiting a new strategy to induce immunogenic cell death to improve dendritic cell-based vaccines for lymphoma immunotherapy

Although promising, the clinical benefit provided by dendritic cell (DC)-based vaccines is still limited and the choice of the optimal antigen formulation is still an unresolved issue. We have developed a new DC-based vaccination protocol for aggressive and/or refractory lymphomas which combines the unique features of interferon-conditioned DC (IFN-DC) with highly immunogenic tumor cell lysates (TCL) obtained from lymphoma cells undergoing immunogenic cell death. We show that treatment of mantle cell lymphoma (MCL) and diffuse large B-cell lymphoma (DLBCL) cell lines with 9-cis-retinoic acid and IFNα (RA/IFNα) induces early membrane exposure of Calreticulin, HSP70 and 90 together with CD47 down-regulation and enhanced HMGB1 secretion. Consistently, RA/IFNα-treated apoptotic cells and -TCLs were more efficiently phagocytosed by DCs compared to controls. Notably, cytotoxic T cells (CTLs) generated with autologous DCs pulsed with RA/IFNα-TCLs more efficiently recognized and specifically lysed MCL or DLBCL cells or targets loaded with several HLA-A*0201 cyclin D1 or HLA-B*0801 survivin epitopes. These cultures also showed an expansion of Th1 and Th17 cells and an increased Th17/Treg ratio. Moreover, DCs loaded with RA/IFNα-TCLs showed enhanced functional maturation and activation. NOD/SCID mice reconstituted with human peripheral blood lymphocytes and vaccinated with autologous RA/IFNα-TCL loaded-IFN-DCs showed lymphoma-specific T-cell responses and a significant decrease in tumor growth with respect to mice treated with IFN-DC unpulsed or loaded with untreated TCLs. This study demonstrates the feasibility and efficacy of the use of RA/IFNα to generate a highly immunogenic TCL as a suitable tumor antigen formulation for the development of effective anticancer DC-based vaccines.

Immunomodulatory and antitumor effects of type I interferons and their application in cancer therapy

During the last decades, the pleiotropic antitumor functions exerted by type I interferons (IFNs) have become universally acknowledged, especially their role in mediating interactions between the tumor and the immune system. Indeed, type I IFNs are now appreciated as a critical component of dendritic cell (DC) driven T cell responses to cancer. Here we focus on IFN-α and IFN-β, and their antitumor effects, impact on immune responses and their use as therapeutic agents. IFN-α/β share many properties, including activation of the JAK-STAT signaling pathway and induction of a variety of cellular phenotypes. For example, type I IFNs drive not only the high maturation status of DCs, but also have a direct impact in cytotoxic T lymphocytes, NK cell activation, induction of tumor cell death and inhibition of angiogenesis. A variety of stimuli, including some standard cancer treatments, promote the expression of endogenous IFN-α/β, which then participates as a fundamental component of immunogenic cell death. Systemic treatment with recombinant protein has been used for the treatment of melanoma. The induction of endogenous IFN-α/β has been tested, including stimulation through pattern recognition receptors. Gene therapies involving IFN-α/β have also been described. Thus, harnessing type I IFNs as an effective tool for cancer therapy continues to be studied.

Type I interferon is required for T helper (Th) 2 induction by dendritic cells

Type 2 inflammation is a defining feature of infection with parasitic worms (helminths), as well as being responsible for widespread suffering in allergies. However, the precise mechanisms involved in T helper (Th) 2 polarization by dendritic cells (DCs) are currently unclear. We have identified a previously unrecognized role for type I IFN (IFN‐I) in enabling this process. An IFN‐I signature was evident in DCs responding to the helminth Schistosoma mansoni or the allergen house dust mite (HDM). Further, IFN‐I signaling was required for optimal DC phenotypic activation in response to helminth antigen (Ag), and efficient migration to, and localization with, T cells in the draining lymph node (dLN). Importantly, DCs generated from Ifnar1^−/− mice were incapable of initiating Th2 responses in vivo. These data demonstrate for the first time that the influence of IFN‐I is not limited to antiviral or bacterial settings but also has a central role to play in DC initiation of Th2 responses.

Immunological dynamics associated with rapid virological response during the early phase of type I interferon therapy in patients with chronic hepatitis C

Type I interferons (IFNs) play an important role in antiviral immunity as well as immunopathogenesis of diverse chronic viral infections. However, the precise mechanisms regulating the multifaceted effects of type I IFNs on the immune system and pathological inflammation still remain unclear. In order to assess the immunological dynamics associated with rapid viral clearance in chronic hepatitis C patients during the acute phase of type I IFN therapy, we analyzed multiple parameters of virological and immunological responses in a cohort of 59 Korean hepatitis C patients who received pegylated IFN-α and ribavirin (IFN/RBV). Most of the Korean patients had favorable alleles in the IFN-λ loci for responsiveness to IFN/RBV (i.e., C/C in rs12979860, T/T in rs8099917, and TT/TT in rs368234815). Rapid virological response (RVR) was determined mainly by the hepatitis C virus genotype. Among the cytokines analyzed, higher plasma levels of IL-17A and FGF were observed in non-RVR patients infected with viral genotype 1 and IP-10 was consistently elevated in RVR group infected with genotype 2 during the early phase of antiviral therapy. In addition, these three cytokines were correlated each other, suggesting a functional linkage of the cytokines in antiviral responses during IFN/RBV therapy. A low baseline frequencies of regulatory T cells and γδ T cells, but high level of group 2 innate lymphoid cells, in peripheral bloods were also significantly associated with the RVR group, implicating a potential role of the cellular immunity during the early phase of IFN/RBV therapy. Therefore, the immunological programs established by chronic hepatitis C and rapid disruption of the delicate balance by exogenous type I IFN might be associated with the subsequent virological outcomes in chronic hepatitis C patients.

Regression in primary cutaneous melanoma: etiopathogenesis and clinical significance

Though not required currently for staging, regression is a histopathologic parameter typically reported upon diagnosis of an invasive primary cutaneous melanoma. The studies examining the prognostic significance of regression in patient outcome have yielded controversial findings; likely because the definition and assessment of regression have not been consistent, in addition to subjectivity of pathologists' interpretation. Regression is histologically characterized by variable decrease in the number of melanoma cells accompanied by the presence of a host response consisting of dermal fibrosis, inflammatory infiltrate, melanophages, ectatic blood vessels, epidermal attenuation, and/or apoptosis of keratinocytes or melanocytes; the relative extent of these features depends on the stage of the regression. However, the magnitudes to which these individual changes must be present to meet the threshold of histologic regression have not been well defined or agreed upon, and thus, the definition and classification of histologic regression in melanoma varies considerably among institutions and even among individual pathologists. In order to determine the clinical significance of histologic analysis of regression, there is a compelling need for a universal scheme to objectively define and assess histologic regression in primary cutaneous melanoma, so that the biologic and prognostic significance of this process may be completely understood.Laboratory Investigation advance online publication, 27 February 2017; doi:10.1038/labinvest.2017.8.

The use of immunotherapy in the treatment of melanoma

Patients with advanced melanoma have a compromised anti-tumor immune response leading to tumor immune tolerance and a tumor microenvironment conducive to disease progression. Immunotherapy that successfully overcomes this tumor-mediated immune suppression has made the greatest impact in the management of this disease over the past few years. This progress through immunotherapy builds upon earlier successes that interferon-α had in the treatment of melanoma in the adjuvant setting, as well as that of high-dose interleukin-2 in advanced melanoma. The development of immune checkpoint inhibitors has led to dramatic clinical activity in advanced melanoma. In particular, anti-CTLA4 and anti-PD1 monoclonal antibodies have taken us forward into the realm of longer survival and durable responses with the possibility of cure in a continuously increasing proportion of patients. Combination immunotherapeutic strategies and novel immunotherapeutic agents are being tested at an accelerated pace where the outlook for long-term survival benefits for the majority of patients appears brighter than ever.

3D Microfluidic model for evaluating immunotherapy efficacy by tracking dendritic cell behaviour toward tumor cells

Immunotherapy efficacy relies on the crosstalk within the tumor microenvironment between cancer and dendritic cells (DCs) resulting in the induction of a potent and effective antitumor response. DCs have the specific role of recognizing cancer cells, taking up tumor antigens (Ags) and then migrating to lymph nodes for Ag (cross)-presentation to naïve T cells. Interferon-α-conditioned DCs (IFN-DCs) exhibit marked phagocytic activity and the special ability of inducing Ag-specific T-cell response. Here, we have developed a novel microfluidic platform recreating tightly interconnected cancer and immune systems with specific 3D environmental properties, for tracking human DC behaviour toward tumor cells. By combining our microfluidic platform with advanced microscopy and a revised cell tracking analysis algorithm, it was possible to evaluate the guided efficient motion of IFN-DCs toward drug-treated cancer cells and the succeeding phagocytosis events. Overall, this platform allowed the dissection of IFN-DC-cancer cell interactions within 3D tumor spaces, with the discovery of major underlying factors such as CXCR4 involvement and underscored its potential as an innovative tool to assess the efficacy of immunotherapeutic approaches.

Human Cytomegalovirus-Induced Degradation of CYTIP Modulates Dendritic Cell Adhesion and Migration

As potent antigen-presenting cells, dendritic cells (DCs) are essential for the initiation of effective antiviral immune responses. Viruses and especially herpesviruses, which are able to establish lifelong persistence, exploit several immune evasion mechanisms targeting DC biology. Our group has previously shown that the α-herpesvirus herpes simplex virus type 1 inhibits mature DC (mDC) migration by inducing adhesion via degrading the cellular protein CYTIP (cytohesin-1 interacting protein), an important negative regulator of β2-integrin activity. In the present study, we extended our analysis to the β-herpesvirus human cytomegalovirus (HCMV), to investigate whether other herpesviridae also induce such modulations. Indeed, HCMV impairs mDC transwell migration capability following a CCL19-chemokine gradient, despite equivalent expression levels of the cognate chemokine receptor CCR7 at the corresponding time points post-infection. Remarkably, HCMV infection potently induced β2-integrin activity on mDCs. Furthermore, directly HCMV-infected mDCs, exhibiting viral gene expression, strongly adhere to fibronectin and ICAM-1, in contrast to mDCs lacking infection or viral gene expression. Interestingly, HCMV-positive mDCs display a proteasome-dependent degradation of CYTIP. Contrasting the migration toward CCL19, elevated expression levels of the chemokine receptor CXCR4 in HCMV-infected mDCs were associated with functional CXCL12-chemotaxis under the herein used conditions. In summary, our results show that HCMV shapes mDC adhesion to compromise migration toward CCL19, but retaining CXCL12 responsiveness. Thus, we hypothesize that a preferred migration pattern toward the bone marrow, but not to secondary lymphoid organs, could ultimately cause a failure in the induction of potent antiviral immune responses.

The viral innate immune antagonism and an alternative vaccine design for PRRS virus

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PRRS virus has evolved to suppress the antiviral innate immunity during infection.

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Type I interferons are potent antiviral cytokines and function to stimulate the adaptive immune responses.

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Six viral proteins have been identified as interferon antagonists and characterized for their molecular actions.

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Interferon antagonism-negative viruses are attenuated and have been proven induce protective immunity.

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Interferon suppression-negative PRRS virus may serve as an alternative vaccine for PRRS.

Porcine reproductive and respiratory syndrome (PRRS) remains one of the most economically significant diseases in the swine industry worldwide. The current vaccines are less satisfactory to confer protections from heterologous infections and long-term persistence, and the need for better vaccines are urgent. The immunological hallmarks in PRRSV-infected pigs include the unusually poor production of type I interferons (IFNs-α/β) and the aberrant and delayed adaptive immune responses, indicating that PRRSV has the ability to suppress both innate and adaptive immune responses in the host. Type I IFNs are the potent antiviral cytokines and recent studies reveal their pleiotropic functions in the priming of expansion and maturation of adaptive immunity. Thus, IFN antagonism-negative PRRSV is hypothesized to be attenuated and to build effective and broad- spectrum innate and adaptive immune responses in pigs. Such vaccines are promising alternatives to traditional vaccines for PRRSV.