Dendritic cell biology and regulation of dendritic cell trafficking by chemokines

Immune landscape of the kidney allograft in response to rejection

Preventing kidney graft dysfunction and rejection is a critical step in addressing the nationwide organ shortage and improving patient outcomes. While kidney transplants (KT) are performed more frequently, the overall number of patients on the waitlist consistently exceeds organ availability. Despite improved short-term outcomes in KT, comparable progress in long-term allograft survival has not been achieved. Major cause of graft loss at 5 years post-KT is chronic allograft dysfunction (CAD) characterized by interstitial fibrosis and tubular atrophy (IFTA). Accordingly, proactive prevention of CAD requires a comprehensive understanding of the immune mechanisms associated with either further dysfunction or impaired repair. Allograft rejection is primed by innate immune cells and carried out by adaptive immune cells. The rejection process is primarily facilitated by antibody-mediated rejection (ABMR) and T cell-mediated rejection (TCMR). It is essential to better elucidate the actions of individual immune cell subclasses (e.g. B memory, Tregs, Macrophage type 1 and 2) throughout the rejection process, rather than limiting our understanding to broad classes of immune cells. Embracing multi-omic approaches may be the solution in acknowledging these intricacies and decoding these enigmatic pathways. A transition alongside advancing technology will better allow organ biology to find its place in this era of precision and personalized medicine.

Generation and quality control of mature monocyte-derived dendritic cells for immunotherapy

Dendritic cell vaccination is a form of active immunotherapy that aims to exploit the crucial role of DC in the initiation of T-cell responses. Numerous vaccination trials have been conducted targeting various tumor entities, including glioblastoma, the most frequent and aggressive malignant brain tumor in adults. They have demonstrated feasibility and safety and suggest improved survival, associated with induction of anti-tumoral immunity. Here, we describe in detail a large-scale 2-step protocol for successive GMP-compliant generation of immature and mature dendritic cells, yielding a highly homogenous population of CD83+ mature DC expressing CD40, CD80, CD86 and HLA-DR at high density, lacking activity of the immunosuppressive enzyme indoleamine-2,3-dioxygenase, migrating towards the chemokine CCL19 and showing highly potent T-cell stimulatory activity. Loaded with autologous tumor lysate, these cells are currently being evaluated in a phase II controlled randomized clinical trial (GlioVax) in glioblastoma patients.

Estradiol inhibits HIV-1BaL infection and induces CFL1 expression in peripheral blood mononuclear cells and endocervical mucosa

An inhibitory effect of estradiol (E2) on HIV-1 infection was suggested by several reports. We previously identified increased gene expression of actin-binding protein cofilin 1 (CFL1) in endocervix in the E2-dominated proliferative phase of the menstrual cycle. Actin cytoskeleton has an integral role in establishing and spreading HIV-1 infection. Herein, we studied in vitro effects of E2 on HIV-1 infection and on CFL1 expression to gain insight into the mechanism of HIV-1 inhibition by E2. E2 dose-dependently inhibited HIV-1_BaL infection in peripheral blood mononuclear cells (PBMCs) and endocervix. In PBMCs and endocervix, E2 increased protein expression of total CFL1 and phosphorylated CFL1 (pCFL1) and pCFL1/CFL1 ratios. LIMKi3, a LIM kinase 1 and 2 inhibitor, abrogated the phenotype and restored infection in both PBMCs and endocervix; inhibited E2-induced expression of total CFL1, pCFL1; and decreased pCFL1/CFL1 ratios. Knockdown of CFL1 in PBMCs also abrogated the phenotype and partially restored infection. Additional analysis of soluble mediators revealed decreased concentrations of pro-inflammatory chemokines CXCL10 and CCL5 in infected tissues incubated with E2. Our results suggest a link between E2-mediated anti-HIV-1 activity and expression of CFL1 in PBMCs and endocervical mucosa. The data support exploration of cytoskeletal signaling pathway targets for the development of prevention strategies against HIV-1.

Bayesian Edge Regression in Undirected Graphical Models to Characterize Interpatient Heterogeneity in Cancer

It is well-established that interpatient heterogeneity in cancer may significantly affect genomic data analyses and in particular, network topologies. Most existing graphical model methods estimate a single population-level graph for genomic or proteomic network. In many investigations, these networks depend on patient-specific indicators that characterize the heterogeneity of individual networks across subjects with respect to subject-level covariates. Examples include assessments of how the network varies with patient-specific prognostic scores or comparisons of tumor and normal graphs while accounting for tumor purity as a continuous predictor. In this paper, we propose a novel edge regression model for undirected graphs, which estimates conditional dependencies as a function of subject-level covariates. We evaluate our model performance through simulation studies focused on comparing tumor and normal graphs while adjusting for tumor purity. In application to a dataset of proteomic measurements on plasma samples from patients with hepatocellular carcinoma (HCC), we ascertain how blood protein networks vary with disease severity, as measured by HepatoScore, a novel biomarker signature measuring disease severity. Our case study shows that the network connectivity increases with HepatoScore and a set of hub genes as well as important gene connections are identified under different HepatoScore, which may provide important biological insights to the development of precision therapies for HCC.

Key chemokines direct migration of immune cells in solid tumors

Immune cell infiltration into solid tumors, their movement within the tumor microenvironment (TME), and interaction with other immune cells are controlled by their directed migration towards gradients of chemokines. Dysregulated chemokine signaling in TME favors the growth of tumors, exclusion of effector immune cells, and abundance of immunosuppressive cells. Key chemokines directing the migration of immune cells into tumor tissue have been identified. In this review, we discuss well-studied chemokine receptors that regulate migration of effector and immunosuppressive immune cells in the context of cancer immunology. We discuss preclinical models that have described the role of respective chemokine receptors in immune cell migration into TME and review preclinical and clinical studies that target chemokine signaling as standalone or combination therapies.

Dendritic Cell Vaccination of Glioblastoma: Road to Success or Dead End

Glioblastomas (GBM) are the most frequent and aggressive malignant primary brain tumor and remains a therapeutic challenge: even after multimodal therapy, median survival of patients is only 15 months. Dendritic cell vaccination (DCV) is an active immunotherapy that aims at inducing an antitumoral immune response. Numerous DCV trials have been performed, vaccinating hundreds of GBM patients and confirming feasibility and safety. Many of these studies reported induction of an antitumoral immune response and indicated improved survival after DCV. However, two controlled randomized trials failed to detect a survival benefit. This raises the question of whether the promising concept of DCV may not hold true or whether we are not yet realizing the full potential of this therapeutic approach. Here, we discuss the results of recent vaccination trials, relevant parameters of the vaccines themselves and of their application, and possible synergies between DCV and other therapeutic approaches targeting the immunosuppressive microenvironment of GBM.

Bispecific antibody-mediated redirection of NKG2D-CAR natural killer cells facilitates dual targeting and enhances antitumor activity

BACKGROUND

Natural killer group 2D (NKG2D) is an activating receptor of natural killer (NK) cells and other lymphocytes that mediates lysis of malignant cells through recognition of stress-induced ligands such as MICA and MICB. Such ligands are broadly expressed by cancer cells of various origins and serve as targets for adoptive immunotherapy with effector cells endogenously expressing NKG2D or carrying an NKG2D-based chimeric antigen receptor (CAR). However, shedding or downregulation of NKG2D ligands (NKG2DL) can prevent NKG2D activation, resulting in escape of cancer cells from NKG2D-dependent immune surveillance.

METHODS

To enable tumor-specific targeting of NKG2D-expressing effector cells independent of membrane-anchored NKG2DLs, we generated a homodimeric recombinant antibody which harbors an N-terminal single-chain fragment variable (scFv) antibody domain for binding to NKG2D, linked via a human IgG₄ Fc region to a second C-terminal scFv antibody domain for recognition of the tumor-associated antigen ErbB2 (HER2). The ability of this molecule, termed NKAB-ErbB2, to redirect NKG2D-expressing effector cells to ErbB2-positive tumor cells of different origins was investigated using peripheral blood mononuclear cells, ex vivo expanded NK cells, and NK and T cells engineered with an NKG2D-based chimeric receptor.

RESULTS

On its own, bispecific NKAB-ErbB2 increased lysis of ErbB2-positive breast carcinoma cells by peripheral blood-derived NK cells endogenously expressing NKG2D more effectively than an ErbB2-specific IgG₁ mini-antibody able to induce antibody-dependent cell-mediated cytotoxicity via activation of CD16. Furthermore, NKAB-ErbB2 synergized with NK-92 cells or primary T cells engineered to express an NKG2D-CD3ζ chimeric antigen receptor (NKAR), leading to targeted cell killing and greatly enhanced antitumor activity, which remained unaffected by soluble MICA known as an inhibitor of NKG2D-mediated natural cytotoxicity. In an immunocompetent mouse glioblastoma model mimicking low or absent NKG2DL expression, the combination of NKAR-NK-92 cells and NKAB-ErbB2 effectively suppressed outgrowth of ErbB2-positive tumors, resulting in treatment-induced endogenous antitumor immunity and cures in the majority of animals.

CONCLUSIONS

Our results demonstrate that combining an NKAB antibody with effector cells expressing an activating NKAR receptor represents a powerful and versatile approach to simultaneously enhance tumor antigen-specific as well as NKG2D-CAR and natural NKG2D-mediated cytotoxicity, which may be particularly useful to target tumors with heterogeneous target antigen expression.

Traffic-related particulate matter aggravates ocular allergic inflammation by mediating dendritic cell maturation

The aim of this study was to determine the effects of traffic-related particulate matter (PM) on allergic inflammation of ocular surfaces. BALB/c mice were sensitized with ovalbumin (OVA) and aluminum hydroxide via intraperitoneal injection. Two weeks later, mice were challenged with eye drops containing OVA concomitant with either traffic-related PM_2.5 or vehicle eye drops. Topical OVA challenges were administered following unilateral subconjunctival injection of magnetic-bead-sorted CD11c+ dendritic cells (DC). The following were assessed: (1) clinical signs, (2) infiltration of inflammatory cells into conjunctiva, (3) serum levels of OVA-specific IgE production, and (4) T-cell cytokine secretion with topical application of PM_2.5, compared to saline vehicle. PM_2.5 was found to increase production of OVA-specific IgE in serum and Th2 immune response-related cytokines including interleukin (IL)-4, IL-17A, and IL-13 compared to vehicle control. It is of interest that PM_2.5 treatment also elevated the population of mature DCs in draining lymph nodes (LNs). Exposure with PM_2.5 was associated with a significant rise in conjunctival expression of IL-1β, IL-6, IL-17, and TNF. After subconjunctival injection of CD11c+DCs from PM_2.5-treated allergic conjunctivitis (AC) mice into naïve mice, T cell responses and OVA-specific IgE were also enhanced. Data suggest that traffic-related PM_2.5 exacerbated allergic conjunctivitis as evidenced by increased infiltration of inflammatory cells into the conjunctiva and Th2 responses in the draining LNs associated with enhanced maturation of DCs. Our findings provide new insight into the hazardous potential of traffic-related PM_2.5 on allergic diseases, such as asthma or atopic dermatitis.

Regulation of the Migration of Distinct Dendritic Cell Subsets

Dendritic cells (DCs), a class of antigen-presenting cells, are widely present in tissues and apparatuses of the body, and their ability to migrate is key for the initiation of immune activation and tolerogenic immune responses. The importance of DCs migration for their differentiation, phenotypic states, and immunologic functions has attracted widespread attention. In this review, we discussed and compared the chemokines, membrane molecules, and migration patterns of conventional DCs, plasmocytoid DCs, and recently proposed DC subgroups. We also review the promoters and inhibitors that affect DCs migration, including the hypoxia microenvironment, tumor microenvironment, inflammatory factors, and pathogenic microorganisms. Further understanding of the migration mechanisms and regulatory factors of DC subgroups provides new insights for the treatment of diseases, such as infection, tumors, and vaccine preparation.

Role of Chemokines in the Biology of Cholangiocarcinoma

Cholangiocarcinoma (CCA), a heterogeneous tumor with poor prognosis, can arise at any level in the biliary tree. It may derive from epithelial cells in the biliary tracts and peribiliary glands and possibly from progenitor cells or even hepatocytes. Several risk factors are responsible for CCA onset, however an inflammatory milieu nearby the biliary tree represents the most common condition favoring CCA development. Chemokines play a key role in driving the immunological response upon liver injury and may sustain tumor initiation and development. Chemokine receptor-dependent pathways influence the interplay among various cellular components, resulting in remodeling of the hepatic microenvironment towards a pro-inflammatory, pro-fibrogenic, pro-angiogenic and pre-neoplastic setting. Moreover, once tumor develops, chemokine signaling may influence its progression. Here we review the role of chemokines in the regulation of CCA development and progression, and the modulation of angiogenesis, metastasis and immune control. The potential role of chemokines and their receptors as possible biomarkers and/or therapeutic targets for hepatobiliary cancer is also discussed.

Cytokines and Chemokines in the Pathogenesis of Experimental Autoimmune Encephalomyelitis

Experimental autoimmune encephalomyelitis is a CD4⁺ T cell-mediated demyelinating disease of the CNS that serves as a model for multiple sclerosis. Cytokines and chemokines shape Th1 and Th17 effector responses as well as regulate migration of leukocytes to the CNS during disease. The CNS cellular infiltrate consists of Ag-specific and nonspecific CD4⁺ and CD8⁺ T cells, neutrophils, B cells, monocytes, macrophages, and dendritic cells. The mechanism of immune-mediated inflammation in experimental autoimmune encephalomyelitis has been extensively studied in an effort to develop therapeutic modalities for multiple sclerosis and, indeed, has provided insight in modern drug discovery. The present Brief Review highlights critical pathogenic aspects of cytokines and chemokines involved in generation of effector T cell responses and migration of inflammatory cells to the CNS. Select cytokines and chemokines are certainly important in the regulatory response, which involves T regulatory, B regulatory, and myeloid-derived suppressor cells. However, that discussion is beyond the scope of this brief review.

Oral lichen planus interactome reveals CXCR4 and CXCL12 as candidate therapeutic targets

Today, we face difficulty in generating new hypotheses and understanding oral lichen planus due to the large amount of biomedical information available. In this research, we have used an integrated bioinformatics approach assimilating information from data mining, gene ontologies, protein–protein interaction and network analysis to predict candidate genes related to oral lichen planus. A detailed pathway analysis led us to propose two promising therapeutic targets: the stromal cell derived factor 1 (CXCL12) and the C-X-C type 4 chemokine receptor (CXCR4). We further validated our predictions and found that CXCR4 was upregulated in all oral lichen planus tissue samples. Our bioinformatics data cumulatively support the pathological role of chemokines and chemokine receptors in oral lichen planus. From a clinical perspective, we suggest a drug (plerixafor) and two therapeutic targets for future research.

Down regulation of RANTES in pleural site is associated with inhibition of antigen specific response in tuberculosis

Tuberculosis is the most common infectious reason for death and a major cause of pleural effusion globally. To understand the role of chemokines in trafficking of cells during TB pleurisy, we studied the responses to MTB, Ag85A in cells from pleural fluids and peripheral blood. Patients with TB pleural effusions, malignant effusions and asymptomatic healthy controls were enrolled. High expression (p < 0.05) of IP-10, MCP-1, MIG, IL-8, IFN-γ and IL-23 were observed in pleural fluids of TB patients compared to their plasma where expression of RANTES was significantly higher (p < 0.05). On specific stimulation of PFMCs with Ag85A, expression of RANTES was significantly lower in TB compared to NTB patients. We also observed increased expression of T regs and PD1 on CD8+T cells in PFMC of TB patients. Though some of the inflammatory chemokine/cytokines were up-regulated in pleura of TB patients, antigenic stimulation failed to induce them indicating poor antigenic responses at the site. Low expression of RANTES might be a reason for decreased trafficking of cells to the site and dissemination of infection into pleural site. The pattern of RANTES expression in pleural fluid vs serum is interesting. The observations necessitate further studies to investigate the levels of RANTES for its potential biological relevance in TB immunity and its use as a biomarker for diagnosis of pleural TB.

Dendritic cell trafficking in tumor-bearing mice

Prostate cancer is one of the leading causes of cancer deaths, with no curative treatments once it spreads. Alternative therapies, including immunotherapy, have shown limited efficacy. Dendritic cells (DC) have been widely used in the treatment of various malignancies. DC capture antigens and move to the lymphoid organs where they prime naive T cells. Interaction between DC and T cells are most active in lymph nodes and suppression of DC trafficking to lymph nodes impairs the immune response. In this work, we aimed to study trafficking of DC in vivo via various routes of delivery, to optimize the effectiveness of DC-based therapy. A DC labeling system was developed using 1,1'-dioctadecyltetramethyl indotricarbocyanine Iodine for in vivo fluorescent imaging. DC harvested from C57B/6 mice were matured, labeled, and injected intravenously, subcutaneously, or intratumorally, with or without antigen loading with whole tumor lysate, into C57B/6 mice inoculated with RM-1 murine prostate tumor cells. Signal intensity was measured in vivo and ex vivo. Signal intensity at the tumor site increased over time, suggesting trafficking of DC to the tumor with all modes of injection. Subcutaneous injection showed preferential trafficking to lymph nodes and tumor. Intravenous injection showed trafficking to lungs, intestines, and spleen. Subcutaneous injection of DC pulsed with whole tumor lysate resulted in the highest increase in signal intensity at the tumor site and lymph nodes, suggesting subcutaneous injection of primed DC leads to highest preferential trafficking of DC to the immunocompetent organs.

Clinical Value of CXCL5 for Determining of Colorectal Cancer

Background:

Several studies indicate that chemokines play important roles in colorectal mucosal immunity.The chemokine CXCL5 which is expressed by epithelial cells within colorectal mucosa is a promoter of cell proliferation, migration and invasion, is a novel serum prognostic marker in patients with colorectal cancer. The purpose of this study was to investigate whether serum and tissue CXCL5 levels is altered in colorectal carcinomas (CRC) compared to colonic adenoma and normal mucosa. It also aimed to compare colon adenoma and colorectal cancer for blood CXCL5 and CEA levels, their sensitivity, and specificity.

Methods:

CXCL5 expression was assessed with immunohistochemistry staining in biopsy samples taken during colonoscopy in 22 colonic adenomas, 23 colorectal carcinomas and 23 normal colonic tissue samples. Also all patients’ serum CXCL5 and CEA levels were measured. This stduy was prospective observational study.

Results:

The number of cases who were stained positive with immunohistochemistry was found to be higher in the group with CRC. When compared with the other groups, both levels of serum CXCL5 and CEA were significantly high in the group CRC. Sensitivity and specificity of serum CXCL5 were found to be low as a result of the ROC analysis.

Conclusion:

Although the level of CXCL5 is high in CRC, its level in serum is not significant enough to support the early diagnosis of the disease.

Radiation, inflammation and the immune response in cancer

Radiation is an important component of cancer treatment with more than half of all patients receive radiotherapy during their cancer experience. While the impact of radiation on tumour morphology is routinely examined in the pre-clinical and clinical setting, the impact of radiation on the tumour microenvironment and more specifically the inflammatory/immune response is less well characterised. Inflammation is a key contributor to short- and long-term cancer eradication, with significant tumour and normal tissue consequences. Therefore, the role of radiation in modulating the inflammatory response is highly topical given the current wave of targeted and immuno-therapeutic treatments for cancer. This review provides a general overview of how radiation modulates the inflammatory and immune response—(i) how radiation induces the inflammatory/immune system, (ii) the cellular changes that take place, (iii) how radiation dose delivery affects the immune response, and (iv) a discussion on research directions to improve patient survival, reduce side effects, improve quality of life, and reduce financial costs in the immediate future. Harnessing the benefits of radiation on the immune response will enhance its maximal therapeutic benefit and reduce radiation-induced toxicity.

Functional Plasticity of Gamma Delta T Cells and Breast Tumor Targets in Hypoxia

Interactions between immune and tumor cells in the tumor microenvironment (TME) often impact patient outcome, yet remain poorly understood. In addition, the effects of biophysical features such as hypoxia [low oxygen (O₂)] on cells within the TME may lead to tumor evasion. Gamma delta T cells (γδTcs) naturally kill transformed cells and are therefore under development as immunotherapy for various cancers. Clinical trials have proven the safety of γδTc immunotherapy and increased circulating γδTc levels correlate with improved patient outcome. Yet, the function of γδTc tumor infiltrating lymphocytes in human breast cancer remains controversial. Breast tumors can be highly hypoxic, thus therapy must be effective under low O₂ conditions. We have found increased infiltration of γδTc in areas of hypoxia in a small cohort of breast tumors; considering their inherent plasticity, it is important to understand how hypoxia influences γδTc function. In vitro, the cell density of expanded primary healthy donor blood-derived human γδTc decreased in response to hypoxia (2% O₂) compared to normoxia (20% O₂). However, the secretion of macrophage inflammatory protein 1α (MIP1α)/MIP1β, regulated on activation, normal T cell expressed and secreted (RANTES), and CD40L by γδTc were increased after 40 h in hypoxia compared to normoxia concomitant with the stabilization of hypoxia inducible factor 1-alpha protein. Mechanistically, we determined that natural killer group 2, member D (NKG2D) on γδTc and the NKG2D ligand MHC class I polypeptide-related sequence A (MICA)/B on MCF-7 and T47D breast cancer cell lines are important for γδTc cytotoxicity, but that MIP1α, RANTES, and CD40L do not play a direct role in cytotoxicity. Hypoxia appeared to enhance the cytotoxicity of γδTc such that exposure for 48 h increased cytotoxicity of γδTc against breast cancer cells that were maintained in normoxia; conversely, breast cancer lines incubated in hypoxia for 48 h prior to the assay were largely resistant to γδTc cytotoxicity. MICA/B surface expression on both MCF-7 and T47D remained unchanged upon exposure to hypoxia; however, ELISAs revealed increased MICA shedding by MCF-7 under hypoxia, potentially explaining resistance to γδTc cytotoxicity. Despite enhanced γδTc cytotoxicity upon pre-incubation in hypoxia, these cells were unable to overcome hypoxia-induced resistance of MCF-7. Thus, such resistance mechanisms employed by breast cancer targets must be overcome to develop more effective γδTc immunotherapies.

A randomized controlled phase II trial of vaccination with lysate-loaded, mature dendritic cells integrated into standard radiochemotherapy of newly diagnosed glioblastoma (GlioVax): study protocol for a randomized controlled trial

Background

Despite the combination of surgical resection, radio- and chemotherapy, median survival of glioblastoma multiforme (GBM) patients only slightly increased in the last years. Disease recurrence is definite with no effective therapy existing after tumor removal. Dendritic cell (DC) vaccination is a promising active immunotherapeutic approach. There is clear evidence that it is feasible, results in immunological anti-tumoral responses, and appears to be beneficial for survival and quality of life of GBM patients. Moreover, combining it with the standard therapy of GBM may allow exploiting synergies between the treatment modalities. In this randomized controlled trial, we seek to confirm these promising initial results.

Methods

One hundred and thirty-six newly diagnosed, isocitrate dehydrogenase wildtype GBM patients will be randomly allocated (1:1 ratio, stratified by O6-methylguanine-DNA-methyltransferase promotor methylation status) after near-complete resection in a multicenter, prospective phase II trial into two groups: (1) patients receiving the current therapeutic “gold standard” of radio/temozolomide chemotherapy and (2) patients receiving DC vaccination as an add-on to the standard therapy. A recruitment period of 30 months is anticipated; follow-up will be 2 years. The primary objective of the study is to compare overall survival (OS) between the two groups. Secondary objectives are comparing progression-free survival (PFS) and 6-, 12- and 24-month OS and PFS rates, the safety profile, overall and neurological performance and quality of life.

Discussion

Until now, close to 500 GBM patients have been treated with DC vaccination in clinical trials or on a compassionate-use basis. Results have been encouraging, but cannot provide robust evidence of clinical efficacy because studies have been non-controlled or patient numbers have been low. Therefore, a prospective, randomized phase II trial with a sufficiently large number of patients is now mandatory for clear evidence regarding the impact of DC vaccination on PFS and OS in GBM.

Trial registration

Protocol code: GlioVax, date of registration: 17. February 2017.

Trial identifier: EudraCT-Number 2017–000304-14.

German Registry for Clinical Studies, ID: DRKS00013248 (approved primary register in the WHO network) and at ClinicalTrials.gov, ID: NCT03395587. Registered on 11 March 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2659-7) contains supplementary material, which is available to authorized users.

Distinct Roles of Vaccinia Virus NF-κB Inhibitor Proteins A52, B15, and K7 in the Immune Response

Poxviruses use a complex strategy to escape immune control, by expressing immunomodulatory proteins that could limit their use as vaccine vectors. To test the role of poxvirus NF-κB pathway inhibitors A52, B15, and K7 in immunity, we deleted their genes in an NYVAC (New York vaccinia virus) strain that expresses HIV-1 clade C antigens. After infection of mice, ablation of the A52R, B15R, and K7R genes increased dendritic cell, natural killer cell, and neutrophil migration as well as chemokine/cytokine expression. Revertant viruses with these genes confirmed their role in inhibiting the innate immune system. To different extents, enhanced innate immune responses correlated with increased HIV Pol- and Gag-specific polyfunctional CD8 T cell and HIV Env-specific IgG responses induced by single-, double-, and triple-deletion mutants. These poxvirus proteins thus influence innate and adaptive cell-mediated and humoral immunity, and their ablation offers alternatives for design of vaccine vectors that regulate immune responses distinctly.IMPORTANCE Poxvirus vectors are used in clinical trials as candidate vaccines for several pathogens, yet how these vectors influence the immune system is unknown. We developed distinct poxvirus vectors that express heterologous antigens but lack different inhibitors of the central host-cell signaling pathway. Using mice, we studied the capacity of these viruses to induce innate and adaptive immune responses and showed that these vectors can distinctly regulate the magnitude and quality of these responses. These findings provide important insights into the mechanism of poxvirus-induced immune response and alternative strategies for vaccine vector design.

Rel B-modified dendritic cells possess tolerogenic phenotype and functions on lupus splenic lymphocytes in vitro

Systemic lupus erythematosus (SLE) is an autoimmune disease that is characterized by high morbidity and mortality and its treatment remains challenging. Dendritic cells (DCs) have been shown to participate in the initiation and perpetuation of lupus pathogenesis and the DCs that can induce tolerogenicity appear as potential cell‐based therapy in this condition. In this study, we examined the in vitro tolerogenic properties of bone‐marrow derived DCs (BMDCs) in the murine lupus setting. We used lentiviral transduction of RelB‐silencing short hairpin RNA to modify the expression of RelB, a key transcription factor regulating DC maturation, in BMDCs from MRL/MpJ mice. Tolerogenic properties of RelB‐modified DCs were compared with scrambled control (SC) ‐modified DCs. RelB expression was found to be significantly reduced in RelB‐modified DCs derived from MRL/MpJ mice, wild‐type of the same genetic background as MRL/lpr lupus‐prone mice. These MRL/MpJ RelB‐modified DCs displayed semi‐mature phenotype with expression of lower levels of co‐stimulatory molecules compared with SC‐modified DCs. RelB‐modified DCs were found to be low producers of interleukin‐12p70 (IL‐12p70) and could induce hyporesponsiveness of splenic T cells from MRL/MpJ and MRL/lpr mice. Furthermore, they down‐regulated interferon‐γ expression and induced IL‐10‐producing T cells in MRL/MpJ splenocytes, and attenuated interferon‐γ and IL‐17 expression in MRL/lpr splenic CD4⁺ lymphocytes. Splenocytes primed by RelB‐modified DCs demonstrated antigen‐specific suppressive effects on allogeneic splenocytes. In conclusion, RelB‐silencing in DCs generates DCs of tolerogenic properties with immunomodulatory function and appears as potential option of cell‐targeted therapy.

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.

The role of the chemokine receptor XCR1 in breast cancer cells

Considerable attention has recently been paid to the application of chemokines to cancer immunotherapy due to their complex role in cell proliferation, invasion, metastasis, and tumorigenesis, which extends beyond the regulation of lymphocyte migration during immune responses. The expression and the function of the chemokine receptor XCR1 on breast cancer have remained elusive to date. In this study, the expressions of XCR1 mRNA were tested by quantitative real-time polymerase chain reaction in one breast epithelial cell line (MCF-10A) and nine breast cancer cell lines (MDA-MB-231, 231HM, 231BO, MDA-MB-468, MCF-7, T47D, Bcap-37, ZR-75-30, and SK-BR-3). We established XCR1-overexpressing breast cancer cell line MDA-MB-231 (231/XCR1) in XCR1 low expression cell line MDA-MB-231 (231). The ability of proliferation, invasion, and metastasis was measured by CCK8, plate cloning formation, and transwell analysis, respectively, in XCR1-overexpressing breast cancer cell lines (231/XCR1) and their parental cell line MDA-MB-231/Vector (simplified as “231/Vector”); 5×10⁶/100 μL cells were inoculated in mammary fat pad of BALB/c nude mice. There were six BALB/c nude mice in the experimental group and control group. Protein expression was analyzed by cell immunofluorescence and Western blot. The growth of XCR1-overexpressing human breast cancer cell line MDA-MB-231 in vitro was restrained and tumorigenesis in vivo was also extenuated, its mechanism may involve in the inhibition of MAPK and PI3K/AKT/mTOR signaling pathway, but increase in LC3 expression. However, the overexpression of XCR1 in human breast cancer cell line MDA-MB-231 in vitro can promote the migration and invasion partially due to decreasing the protein level of β-catenin. Therefore, XCR1 can affect the biological characteristics of some special breast cancer cells through complex signal transduction pathway.

TREX1 Knockdown Induces an Interferon Response to HIV that Delays Viral Infection in Humanized Mice

Despite their antiviral effect, the in vivo effect of interferons on HIV transmission is difficult to predict, because interferons also activate and recruit HIV-susceptible cells to sites of infection. HIV does not normally induce type I interferons in infected cells, but does if TREX1 is knocked down. Here, we investigated the effect of topical TREX1 knockdown and local interferon production on HIV transmission in human cervicovaginal explants and humanized mice. In explants in which TREX1 was knocked down, HIV induced interferons, which blocked infection. In humanized mice, even though TREX1 knockdown increased infiltrating immune cells, it delayed viral replication for 3-4 weeks. Similarly intravaginal application of type I interferons the day before HIV infection induced interferon responsive genes, reduced inflammation, and decreased viral replication. However, intravenous interferon enhanced inflammation and infection. Thus, in models of human sexual transmission, a localized interferon response inhibits HIV transmission but systemic interferons do not.

Dendritic Cells in Systemic Lupus Erythematosus: From Pathogenic Players to Therapeutic Tools

System lupus erythematosus (SLE) is a multifactorial systemic autoimmune disease with a wide variety of presenting features. SLE is believed to result from dysregulated immune responses, loss of tolerance of CD4 T cells and B cells to ubiquitous self-antigens, and the subsequent production of anti-nuclear and other autoreactive antibodies. Recent research has associated lupus development with changes in the dendritic cell (DC) compartment, including altered DC subset frequency and localization, overactivation of mDCs and pDCs, and functional defects in DCs. Here we discuss the current knowledge on the role of DC dysfunction in SLE pathogenesis, with the focus on DCs as targets for interventional therapies.

Oral Administration of p-Hydroxycinnamic Acid Attenuates Atopic Dermatitis by Downregulating Th1 and Th2 Cytokine Production and Keratinocyte Activation

Atopic dermatitis (AD) is a complex disease that is caused by various factors, including environmental change, genetic defects, and immune imbalance. We previously showed that p-hydroxycinnamic acid (HCA) isolated from the roots of Curcuma longa inhibits T-cell activation without inducing cell death. Here, we demonstrated that oral administration of HCA in a mouse model of ear AD attenuates the following local and systemic AD manifestations: ear thickening, immune-cell infiltration, production of AD-promoting immunoregulatory cytokines in ear tissues, increased spleen and draining lymph node size and weight, increased pro-inflammatory cytokine production by draining lymph nodes, and elevated serum immunoglobulin production. HCA treatment of CD4+ T cells in vitro suppressed their proliferation and differentiation into Th1 or Th2 and their Th1 and Th2 cytokine production. HCA treatment of keratinocytes lowered their production of the pro-inflammatory cytokines that drive either Th1 or Th2 responses in AD. Thus, HCA may be of therapeutic potential for AD as it acts by suppressing keratinocyte activation and downregulating T-cell differentiation and cytokine production.

Zymosan and PMA activate the immune responses of Mutz3-derived dendritic cells synergistically

Beta-glucan (β-glucan) including zymosan has been known as a super food because of its multifunctional activities, such as the enhancement of immune responses. To study the functional mechanism of β-glucan in immune stimulation, the effect of zymosan on dendritic cell (DC) was investigated by monitoring the production of TNF-α, a pro-inflammatory cytokine. DC was differentiated from Mutz-3, a human acute myeloid leukemia cell line, by cytokine treatment and characterized. DC-specific cell surface markers were increased during the differentiation. Especially, Dectin-1, a β-glucan receptor, was upregulated during DC differentiation, and mediated zymosan-induced TNF-α production, which was inhibited by silencing of dectin-1. Zymosan exhibited synergistic effect with other immune stimuli such as lipopolysaccharide (LPS) and phorbol 12-myristate 13-acetate (PMA), a well-known PKC activator. Simultaneous treatment of zymosan and PMA enhanced the nuclear translocation of NF-κB subunits, p50 and p65, mediating the increase of TNF-α production. Bay 11-7082, an NF-κB inhibitor, blocked morphological changes and TNF-α production induced by zymosan and/or PMA treatment. Western blot analysis has showed zymosan-Dectin-1 pathway mediated destructive phosphorylation of inhibitor of NF-κB (IκB) kinase α subunit (IKKα) in IKK complexes, while PMA-PKC pathway regulated selective phosphorylation and degradation of IKKβ. Simultaneous phosphorylation of separate IKK subunits by co-treatment of zymosan and PMA resulted in cooperative activation of NF-κB and TNF-α production.

Early Defensive Mechanisms against Human Papillomavirus Infection

Cervical cancer is the fourth most common cancer in women and is almost exclusively caused by human papillomavirus (HPV) infection. HPV is also frequently associated with other cancers arising from mucosal epithelium, including anal and oropharyngeal cancers, which are becoming more common in both men and women. Viral persistence and progression through precancerous lesion stages are prerequisites for HPV-associated cancer and reflect the inability of cell-mediated immune mechanisms to clear infections and eliminate abnormal cells in some individuals. Cell-mediated immune responses are initiated by innate pathogen sensing and subsequent secretion of soluble immune mediators and amplified by the recruitment and activation of effector T lymphocytes. This review discusses early defensive mechanisms of innate responders to natural HPV infection, their influence on response polarization, and the underappreciated role of keratinocytes in this process.

Gastric cancer and the epoch of immunotherapy approaches

The incidence of gastric cancer (GC) fell dramatically over the last 50 years, but according to IARC-Globocan 2008, it is the third most frequent cause of cancer-related deaths with a case fatality GC ratio higher than other common malignancies. Surgical resection is the primary curative treatment for GC though the overall 5-year survival rate remains poor (approximately 20%-25%). To improve the outcome of resectable gastric cancer, different treatment strategies have been evaluated such as adjuvant or perioperative chemotherapy. In resected gastric cancer, the addition of radiotherapy to chemotherapy does not appear to provide any additional benefit. Moreover, in metastatic patients, chemotherapy is the mainstay of palliative therapy with a median overall survival of 8-10 mo and objective response rates of merely 20%-40%. Therefore, the potential for making key beneficial progress is to investigate the GC molecular biology to realize innovative therapeutic strategies, such as specific immunotherapy. In this review, we provide a panoramic view of the different immune-based strategies used for gastric cancer treatment and the results obtained in the most significant clinical trials. In detail, firstly we describe the therapeutic approaches that utilize the monoclonal antibodies while in the second part we analyze the cell-based immunotherapies.

Inflammatory conditions distinctively alter immunological functions of Langerhans-like cells and dendritic cells in vitro

The specific function of human skin-resident dendritic cell (DC) subsets in the regulation of immunity or tolerance is still a matter of debate. Langerhans cells (LC) induce anti-viral immune responses but, conversely to dermal DC, maintain tolerance to bacteria. However, the definite function of epidermal LC and cutaneous DC appears even more complex under inflammatory conditions. Here we investigated the immune responses of human immature monocyte-derived DC (MoDC) and LC-like cells (MoLC) upon stimulation with different Toll-like receptor ligands in the presence or absence of pro-inflammatory cytokines tumour necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). In MoDC, bacterial antigens selectively up-regulated CD83 and CD86 expression and induced the release of T helper type 1 (Th1) and Th17 cytokines and led to a higher CCR7-dependent migratory capacity compared with a low responsiveness of MoLC. Importantly, MoLC activation with lipopolysaccharide under inflammatory conditions strongly enhanced a phenotypically mature state, increased IL-12p70, IL-23 and IL-6 production and Th1 cytokine secretion by CD4(+) T cells. Treatment with poly(I:C) specifically up-regulated surface expression of co-stimulatory molecules and increased release of IL-12p70 in MoLC and co-stimulation with TNF-α and IL-1β further elevated Th1 and Th17 cytokine production. Poly(I:C)-induced up-regulation of type I interferon mRNA levels in MoLC and MoDC was Toll-like receptor 3-dependent but not, or only weakly, modulated by pro-inflammatory cytokines. Our results indicate that inflammatory conditions greatly facilitate recognition of bacteria by MoLC. Furthermore, we suggest a critical involvement of both subsets in innate defence against viruses, whereas inflammatory skin environments additionally favour MoLC as potent inducers of Th1 and Th17 cytokines.

In vitro induction of lymph node cell proliferation by mouse bone marrow dendritic cells following stimulation with different Echinococcus multilocularis antigens

The immune response of mice experimentally infected with Echinococcus multilocularis metacestodes becomes impaired so as to allow parasite survival and proliferation. Our study tackled the question on how different classes of E. multilocularis antigens (crude vesicular fluid (VF); purified proteinic rec-14-3-3; purified carbohydrate Em2(G11)) are involved in the maturation process of bone-marrow-derived dendritic cells (BMDCs) and subsequent exposure to lymph node (LN) cells. In our experiments, we used BMDCs cultivated from either naïve (control) or alveolar echinococcosis (AE)-infected C57BL/6 mice. We then tested surface markers (CD80, CD86, MHC class II) and cytokine expression levels (interleukin (IL)-10, IL-12p40 and tumour necrosis factor (TNF)-α) of non-stimulated BMDCs versus BMDCs stimulated with different Em-antigens or lipopolysaccharide (LPS). While LPS and rec-14-3-3-antigen were able to induce CD80, CD86 and (to a lower extent) MHC class II surface expression, Em2(G11) and, strikingly, also VF-antigen failed to do so. Similarly, LPS and rec-14-3-3 yielded elevated IL-12, TNF-α and IL-10 expression levels, while Em2(G11) and VF-antigen didn't. When naïve BMDCs were loaded with VF-antigen, they induced a strong non-specific proliferation of uncommitted LN cells. For both, BMDCs or LN cells, isolated from AE-infected mice, proliferation was abrogated. The most striking difference, revealed by comparing naïve with AE-BMDCs, was the complete inability of LPS-stimulated AE-BMDCs to activate lymphocytes from any LN cell group. Overall, the presenting activity of BMDCs from AE-infected mice seemed to trigger unresponsiveness in T cells, especially in the case of VF-antigen stimulation, thus contributing to the suppression of clonal expansion during the chronic phase of AE infection.

Cervical inflammation and immunity associated with hormonal contraception, pregnancy, and HIV-1 seroconversion

OBJECTIVE

Hormonal contraception (HC), younger age, and pregnancy have been associated with increased HIV risk in some studies. We sought to elucidate the biological mechanisms for these associations.

DESIGN

Case-control selection of specimens from a large, prospective, clinical study.

METHODS

We enrolled and followed 4531 HIV-negative women from Uganda and Zimbabwe using either the injectable depo-medroxyprogesterone acetate (DMPA), combined oral contraception, or no HC (NH). Innate immunity mediators were measured in cervical samples collected from women at their visit before HIV seroconversion (n = 199) and matched visits from women remaining HIV uninfected (n = 633). Generalized linear models were applied after Box-Cox power transformation.

RESULTS

Higher RANTES and lower secretory leukocyte protease inhibitor (SLPI) levels were associated with HIV seroconversion. DMPA users had higher RANTES and lower BD-2 levels. Most inflammation-promoting and/or inflammation-inducible mediators were higher [interleukin (IL)-1β, IL-6, IL-8, MIP-3α, vascular endothelial growth factor, and SLPI], and the protective BD-2 and IL-1RA:IL-1β ratio were lower among combined oral contraception users. Pregnant women showed a similar cervical immunity status (higher IL-1β, IL-6, IL-8, vascular endothelial growth factor, SLPI, and IL-1RA; lower IL-1RA:IL-1β). Age <25 years was associated with lower SLPI, IL-8, MIP-3α but higher IL-1RA:IL-1β. Zimbabwean women (with higher HIV seroconversion rates) had overall higher pro-inflammatory and lower anti-inflammatory protein levels than Ugandan women.

CONCLUSIONS

HC use, pregnancy, and young age alter cervical immunity in different ways known to increase risk of HIV, for example, through increased levels of pro-inflammatory cytokines or decreased levels of SLPI. Higher levels of RANTES may be one factor underlying a possible association between DMPA use and risk of HIV acquisition.

Regulatory dendritic cells for immunotherapy in immunologic diseases

We recognize well the abilities of dendritic cells to activate effector T cell (Teff cell) responses to an array of antigens and think of these cells in this context as pre-eminent antigen-presenting cells, but dendritic cells are also critical to the induction of immunologic tolerance. Herein, we review our knowledge on the different kinds of tolerogenic or regulatory dendritic cells that are present or can be induced in experimental settings and humans, how they operate, and the diseases in which they are effective, from allergic to autoimmune diseases and transplant tolerance. The primary conclusions that arise from these cumulative studies clearly indicate that the agent(s) used to induce the tolerogenic phenotype and the status of the dendritic cell at the time of induction influence not only the phenotype of the dendritic cell, but also that of the regulatory T cell responses that they in turn mobilize. For example, while many, if not most, types of induced regulatory dendritic cells lead CD4⁺ naïve or Teff cells to adopt a CD25⁺Foxp3⁺ Treg phenotype, exposure of Langerhans cells or dermal dendritic cells to vitamin D leads in one case to the downstream induction of CD25⁺Foxp3⁺ regulatory T cell responses, while in the other to Foxp3⁻ type 1 regulatory T cells (Tr1) responses. Similarly, exposure of human immature versus semi-mature dendritic cells to IL-10 leads to distinct regulatory T cell outcomes. Thus, it should be possible to shape our dendritic cell immunotherapy approaches for selective induction of different types of T cell tolerance or to simultaneously induce multiple types of regulatory T cell responses. This may prove to be an important option as we target diseases in different anatomic compartments or with divergent pathologies in the clinic. Finally, we provide an overview of the use and potential use of these cells clinically, highlighting their potential as tools in an array of settings.

Characterization of the chemokine response of RAW264.7 cells to infection by murine norovirus

Noroviruses are an emerging threat to public health, causing large health and economic costs, including at least 200,000 deaths annually. The inability to replicate in cell culture or small animal models has limited the understanding of the interaction between human noroviruses and their hosts. However, an alternative strategy to gain insights into norovirus pathogenesis is to study murine norovirus (MNV-1) that replicates in cultured macrophages. While the innate immune response is central to the resolution of norovirus disease, the adaptive immune response is required for viral clearance. The specific responses of macrophages and dendritic cells to infection drive the adaptive immune response, with chemokines playing an important role. In this study, we have conducted microarray analysis of RAW264.7 macrophages infected with MNV-1 and examined the changes in chemokine transcriptional expression during infection. While the majority of chemokines showed no change, there was specific up-regulation in chemokines reflective of a bias toward a Th1 response, specifically CCL2, CCL3, CCL4, CCL5, CXCL2, CXCL10 and CXCL11. These changes in gene expression were reflected in protein levels as determined by ELISA assay. This virus-induced chemokine response will affect the resolution of infection and may limit the humoral response to norovirus infection.

Gene therapy with beta-defensin 2 induces antitumor immunity and enhances local antitumor effects

Beta-defensins, small antimicrobial peptides, are involved in host immune responses to tumors. In this study, we used beta-defensin 2 (BD2) to explore the possible role of beta-defensins in cancer gene therapy. A recombinant plasmid expressing a secretable form of BD2 was constructed. The biological activities of BD2 in immature dendritic cells (iDCs) were tested in vitro and in vivo. The antitumor effects were investigated in three established tumor models. The secreted BD2 was detected and exhibited chemotactic activity in iDCs both in vitro and in vivo. Recruitment and activation of iDCs in tumor niches resulted in significant tumor growth inhibition. Adoptive transfer of splenocytes and depletion of immune cell subsets revealed that CD8(+) T lymphocyte responses mediated the increased tumor inhibition. Furthermore, we also found that chemotactic and maturation-inducing activities in iDCs in tumor milieu contributed to enhanced local antitumor effects. Our study indicates that gene therapy with BD2 can mediate specific antitumor immunity and augment local antitumor effects. Our study also suggested that beta-defensins may merit further exploration for cancer immunotherapy as promising immunogenes.

Chemokines and other GPCR ligands synergize in receptor-mediated migration of monocyte-derived immature and mature dendritic cells

Dendritic cells (DCs) are potent antigen presenting cells, described as the initiators of adaptive immune responses. Immature monocyte-derived DCs (MDDC) showed decreased CD14 expression, increased cell surface markers DC-SIGN and CD1a and enhanced levels of receptors for the chemokines CCL3 (CCR1/CCR5) and CXCL8 (CXCR1/CXCR2) compared with human CD14⁺ monocytes. After further MDDC maturation by LPS, the markers CD80 and CD83 and the chemokine receptors CXCR4 and CCR7 were upregulated, whereas CCR1, CCR2 and CCR5 expression was reduced. CCL3 dose-dependently synergized with CXCL8 or CXCL12 in chemotaxis of immature MDDC. CXCL12 augmented the CCL3-induced ERK1/2 and Akt phosphorylation in immature MDDC, although the synergy between CCL3 and CXCL12 in chemotaxis of immature MDDC was dependent on the Akt signaling pathway but not on ERK1/2 phosphorylation. CCL2 also synergized with CXCL12 in immature MDDC migration. Moreover, two CXC chemokines not sharing receptors (CXCL12 and CXCL8) cooperated in immature MDDC chemotaxis, whereas two CC chemokines (CCL3 and CCL7) sharing CCR1 did not. Further, the non-chemokine G protein-coupled receptor ligands chemerin and fMLP synergized with respectively CCL7 and CCL3 in immature MDDC signaling and migration. Finally, CXCL12 and CCL3 did not cooperate, but CXCL12 synergized with CCL21 in mature MDDC chemotaxis. Thus, chemokine synergy in immature and mature MDDC migration is dose-dependently regulated by chemokines via alterations in their chemokine receptor expression pattern according to their role in immune responses.

Tumour regression induced by co-administration of MIP-3α and CpG in an experimental model of colon carcinoma

CCL20/macrophage inflammatory protein-3α (MIP-3α) represents one of the potent chemoattractive proteins for dendritic cells (DCs). Herein, we investigated whether in vivo genetic modification of tumour cells aimed at intratumoural production of MIP-3α might lead to accumulation of DCs in tumour tissue. Mice injected with CT26, received recombinant adenovirus (Ad) vectors (AdMIP-3α) expressing MIP-3α protein. This was complemented by injections of CpG. Interestingly, MIP-3α gene therapy combined with CpG injections resulted in specific cytotoxicity. This was associated with significant suppression of tumour growth rate. These findings demonstrate the potential of strategies that utilize in vivo overexpression of chemokines.

The multiple faces of CCL13 in immunity and inflammation

CCL13/MCP-4, is a CC family chemokine that is chemoattractant for eosinophils, basophils, monocytes, macrophages, immature dendritic cells, and T cells, and its capable of inducing crucial immuno-modulatory responses through its effects on epithelial, muscular and endothelial cells. Similar to other CC chemokines, CCL13 binds to several chemokine receptors (CCR1, CCR2 and CCR3), allowing it to elicit different effects on its target cells. A number of studies have shown that CCL13 is involved in many chronic inflammatory diseases, in which it functions as a pivotal molecule involved in the selective recruitment of cell lineages to the inflamed tissues and their subsequent activation. Based on these studies, we suggest that blocking the actions of CCL13 can serve as a novel strategy for the generation of agents with anti-inflammatory activity. The main goal of this review is to present the current information about CCL13, its gene and protein structure and the roles of this chemokine during innate/adaptive immune responses in inflammatory diseases.

Dendritic cells in Barrett's esophagus carcinogenesis: an inadequate microenvironment for antitumor immunity?

Barrett's esophagus corresponds to the replacement of the normal esophageal squamous epithelium by a columnar epithelium through a metaplastic process. This tissue remodeling is associated with chronic gastroesophageal reflux and constitutes a premalignant lesion leading to a 30- to 60-fold increase in the risk to evolve into esophageal adenocarcinoma. The present study aimed to investigate a possible immune evasion in Barrett's esophagus favoring esophageal adenocarcinoma development. We demonstrated that myeloid and plasmacytoid dendritic cells are recruited during the esophageal metaplasia-dysplasia-carcinoma sequence, through the action of their chemoattractants, macrophage inflammatory protein 3α and chemerin. Next, we showed that, in contrast to plasmacytoid dendritic cells, myeloid dendritic cells, co-cultured with Barrett's esophagus and esophageal adenocarcinoma cell lines, display a tolerogenic phenotype. Accordingly, myeloid dendritic cells co-cultured with esophageal adenocarcinoma cell lines stimulated regulatory T cell differentiation from naïve CD4(+) T cells. In agreement with those results, we observed that both metaplastic areas and (pre)malignant lesions of the esophagus are infiltrated by regulatory T cells. In conclusion, soluble factors secreted by epithelial cells during the esophageal metaplasia-dysplasia-carcinoma sequence influence dendritic cell distribution and promote tumor progression by rendering them tolerogenic.

Intrinsic immune alterations in renal cell carcinoma and emerging immunotherapeutic approaches

INTRODUCTION

Individuals affected by kidney cancer present a variety of immune abnormalities including cellular immune dysfunction, cytokine alterations and antigen presentation defects. On the other hand, spontaneous remissions are seen in up to 4% of renal cell carcinoma (RCC) patients and they are thought to occur via immune mechanisms.

AREAS COVERED

The authors comprehensively review the immune abnormalities in RCC patient and describe the kidney cancer immunotherapy candidates that are most advanced in their clinical development. Most relevant publications were identified through searching the PubMed database; the obtained information was thoroughly analyzed and synthesized.

EXPERT OPINION

As cure in advanced RCC cannot be accomplished with the current therapy standards such as tyrosine kinase inhibitors and mammalian target of rapamycin inhibitors, new treatment strategies are being sought. Enhancing the immune system represents an appealing avenue for kidney cancer therapy. Disappointingly, high-dose interleukin-2 and interferon-α cause severe toxicity and produce a questionable clinical benefit. The authors postulate that the 'durable responses' seen with these agents in only a handful of RCC patients represent spontaneous remissions. Promising immune strategies in RCC such as anti-cytotoxic T-lymphocyte-associated protein antibodies, anti-programmed cell death 1 (PD1)/PD1 ligand and tumor vaccines may expand the existing options for kidney cancer in future years.

Potential roles of CCR5(+) CCR6(+) dendritic cells induced by nasal ovalbumin plus Flt3 ligand expressing adenovirus for mucosal IgA responses

We assessed the role of CCR5⁺/CCR6⁺/CD11b⁺/CD11c⁺ dendritic cells (DCs) for induction of ovalbumin (OVA)-specific antibody (Ab) responses following mucosal immunization. Mice given nasal OVA plus an adenovirus expressing Flt3 ligand (Ad-FL) showed early expansion of CCR5⁺/CCR6⁺/CD11b⁺/CD11c⁺ DCs in nasopharyngeal-associated lymphoid tissue (NALT) and cervical lymph nodes (CLNs). Subsequently, this DC subset became resident in submandibular glands (SMGs) and nasal passages (NPs) in response to high levels of CCR-ligands produced in these tissues. CD11b⁺/CD11c⁺ DCs were markedly decreased in both CCR5^−/− and CCR6^−/− mice. Chimera mice reconstituted with bone marrow cells from CD11c-diphtheria toxin receptor (CD11c-DTR) and CCR5^−/− or CD11c-DTR and CCR6^−/− mice given nasal OVA plus Ad-FL had elevated plasma IgG, but reduced IgA as well as low anti-OVA secretory IgA (SIgA )Ab responses in saliva and nasal washes. These results suggest that CCR5⁺CCR6⁺ DCs play an important role in the induction of Ag-specific SIgA Ab responses.

Aurintricarboxylic acid ameliorates experimental autoimmune encephalomyelitis by blocking chemokine-mediated pathogenic cell migration and infiltration

Multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE), are autoimmune diseases characterized by the immune-mediated demyelination and neurodegeneration of the CNS. Overactivation of CD4(+) T cells, especially the Th1 and Th17 subpopulations, is thought to be the direct cause of this disease. Aurintricarboxylic acid (ATA), an inhibitor of protein-nucleic acid interaction, has been reported to block with the JAK/STAT signaling pathway that is critical for Th cell differentiation. In this study, we discovered that ATA treatment significantly reduces the clinical score of EAE, but it does not directly inhibit the differentiation of Th1 and Th17 cells in vitro. ATA was found to block the chemotaxis and accumulation of dendritic cells in the spleen of EAE mice before the onset of the disease and to reduce the percentage of Th1 and Th17 cells in the spleen. Further study revealed that ATA also blocks the infiltration of pathogenic T cells into the CNS and blocks the onset of passive EAE. ATA was found to inhibit the functions of many chemokine receptors. By blocking chemokine-mediated migration of dendritic cells and pathogenic T cells, ATA alleviates the pathogenesis of EAE and might be used to treat autoimmune diseases, including multiple sclerosis.