Analysis of the Expression and Regulation of PD-1 Protein on the Surface of Myeloid-Derived Suppressor Cells (MDSCs)

Myeloid-derived suppressor cells (MDSCs) that are able to suppress T cell function are a heterogeneous cell population frequently observed in cancer, infection, and autoimmune disease. Immune checkpoint molecules, such as programmed death 1 (PD-1) expressed on T cells and its ligand (PD-L1) expressed on tumor cells or antigen-presenting cells, have received extensive attention in the past decade due to the dramatic effects of their inhibitors in patients with various types of cancer. In the present study, we investigated the expression of PD-1 on MDSCs in bone marrow, spleen, and tumor tissue derived from breast tumor-bearing mice. Our studies demonstrate that PD-1 expression is markedly increased in tumor-infiltrating MDSCs compared to expression in bone marrow and spleens and that it can be induced by LPS that is able to mediate NF-κB signaling. Moreover, expression of PD-L1 and CD80 on PD-1+ MDSCs was higher than on PD-1− MDSCs and proliferation of MDSCs in a tumor microenvironment was more strongly induced in PD-1+ MDSCs than in PD-1− MDSCs. Although we could not characterize the inducer of PD-1 expression derived from cancer cells, our findings indicate that the study on the mechanism of PD-1 induction in MDSCs is important and necessary for the control of MDSC activity; our results suggest that PD-1+ MDSCs in a tumor microenvironment may induce tumor development and relapse through the modulation of their proliferation and suppressive molecules.

Polymeric Nanoparticles Containing Both Antigen and Vitamin D₃ Induce Antigen-Specific Immune Suppression

The active form of vitamin D3, 1,25-dihydroxyvitamin D₃ (aVD₃), is known to exert beneficial effects in the treatment of autoimmune diseases because of its immunosuppressive effects. However, clinical application of aVD₃ remains limited because of the potential side effects, particularly hypercalcemia. Encapsulation of aVD₃ within biodegradable nanoparticles (NPs) would enhance the delivery of aVD₃ to antigen presenting cells, while preventing the potential systemic side effects of aVD₃. In the present study, polymeric NPs containing ovalbumin (OVA) and aVD₃ (NP[OVA+aVD₃]) were prepared via the water-in-oil-in-water double emulsion solvent evaporation method, after which their immunomodulatory effects were examined. Bone marrow-derived immature dendritic cells (DCs) treated with NP(OVA+aVD₃) did not mature into immunogenic DCs but were converted into tolerogenic DCs, which express low levels of co-stimulatory molecules and MHC class II molecules, produce lower levels of pro-inflammatory cytokines while increasing the production of IL-10 and TGF-β, and induce the generation of Tregs. Intravenous injection with NP(OVA+aVD₃) markedly suppressed the generation of OVA-specific CTLs in mice. Furthermore, OVA-specific immune tolerance was induced in mice orally administered with NP(OVA+aVD₃). These results show that biodegradable NPs encapsulating both antigen and aVD₃ can effectively induce antigen-specific immune suppression.

Human Immunity Against Campylobacter Infection

Campylobacter is a worldwide foodborne pathogen, associated with human gastroenteritis. The efficient translocation of Campylobacter and its ability to secrete toxins into host cells are the 2 key features of Campylobacter pathophysiology which trigger inflammation in intestinal cells and contribute to the development of gastrointestinal symptoms, particularly diarrhoea, in humans. The purpose of conducting this literature review is to summarise the current understanding of: i) the human immune responses involved in the elimination of Campylobacter infection and ii) the resistance potential in Campylobacter against these immune responses. This review has highlighted that the intestinal epithelial cells are the preliminary cells which sense Campylobacter cells by means of their cell-surface and cytosolic receptors, activate various receptors-dependent signalling pathways, and recruit the innate immune cells to the site of inflammation. The innate immune system, adaptive immune system, and networking between these systems play a crucial role in bacterial clearance. Different cellular constituents of Campylobacter, mainly cell membrane lipooligosaccharides, capsule, and toxins, provide protection to Campylobacter against the human immune system mediated killing. This review has also identified gaps in knowledge, which are related to the activation of following during Campylobacter infection: i) cathelicidins, bactericidal permeability-increasing proteins, chemokines, and inflammasomes in intestinal epithelial cells; ii) siglec-7 receptors in dendritic cell; iii) acute phase proteins in serum; and iv) T-cell subsets in lymphoid nodules. This review evaluates the existing literature to improve the understanding of human immunity against Campylobacter infection and identify some of the knowledge gaps for future research.

Distinct features of dendritic cell-based immunotherapy as cancer vaccines

Dendritic cells (DCs) are the most professional antigen presenting cells that play important roles in connection between innate and adaptive immune responses. Numerous studies revealed that the functions of DCs are related with the capture and processing of antigen as well as the migration to lymphoid tissues for the presenting antigens to T cells. These unique features of DCs allow them to be considered as therapeutic vaccines that can induce immune responses and anti-tumor activity. Here, we discuss and understand the immunological basis of DCs and presume the possibilities of DC-based vaccines for the promising cancer therapy.

The Role of B Cells in Transplantation Rejection / 대한이식학회지

B cells play a role in graft rejection via several mechanisms. Specifically, B cells produce high-affinity antibodies to alloantigens including allogeneic major histocompatibility complex (MHC) with the help of follicular helper T cells. B cells also function as antigen-presenting cells for alloreactive T cells, resulting in the activation of alloreactive T cells. Conversely, the frequency of regulatory B cells increases under inflammatory conditions and suppresses the rejection process. Here, the differential roles of the major B cell subpopulations (B-1, follicular B, marginal zone B, and regulatory B cells) involved in transplantation rejection are discussed together with their interaction with T cells.

Immune Responses Induced by HSP60 DNA Vaccine against Toxoplasma gondii Infection in Kunming Mice

Toxoplasma gondii can infect all the vertebrates including human, and leads to serious toxoplasmosis and considerable veterinary problems. T. gondii heat shock protein 60 (HSP60) is associated with the activation of antigen presenting cells by inducing initial immune responses and releasing inflammatory cytokines. It might be a potential DNA vaccine candidate for this parasite. A pVAX-HSP60 DNA vaccine was constructed and immune responses was evaluated in Kunming mice in this study. Our data indicated that the innate and adaptive immune responses was elicited by successive immunizations with pVAX-HSP60 DNA, showing apparent increases of CD3e+CD4+ and CD3e+CD8a+ T cells in spleen tissues of the HSP60 DNA-immunized mice (24.70±1.23% and 10.90±0.89%, P < 0.05) and higher levels of specific antibodies in sera. Furthermore, the survival period of the immunized mice (10.53±4.78 day) were significantly prolonged during the acute T. gondii infection. Decrease of brain cysts was significant in the experimental group during the chronic infection (P < 0.01). Taken together, TgHSP60 DNA can be as a vaccine candidate to prevent the acute and chronic T. gondii infections.

Fundamental role of dendritic cells in inducing Th2 responses

A mysterious puzzle in immunology is how the immune system decides what types of immune response to initiate against various stimuli. Although much is known about control of T helper 1 (Th1) and Th17 responses, the mechanisms that initiate Th2 responses remain obscure. Antigen-presenting cells, particularly dendritic cells (DCs), are mandatory for the induction of a Th cell response. Numerous studies have documented the organizing role of DCs in this process. The present review summarizes the fundamental roles of DCs in inducing Th2 responses.

Blocking Two Signals of Immuno-Activated T Cells from Antigen Presenting Cells Can Prevent Chronic GVHD of Murine / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To explore the effects of blocking TCR-CD3 and B7-CD28 signals on immune function of mice with chronic GVHD by using TJU103 and CTLA4-Ig.</p><p><b>METHODS</b>On the basis of foregoing murine model of chronic GVHD, according to interference modes after infusion 6×10 spleen cells of donor mice, the recipients were divided into 5 groups: blank control, cGVHD, TJU103 interference, CTLA4-Ig interference and TJU103+CTLA4-Ig interference groups. The score of clinical manifestation and tissue histopathology were used to evaluate the effects of all the interferences on chronic GVHD.</p><p><b>RESULTS</b>TJU103 and CTLA4-Ig could not influence the formation of the mouse chimera. The analysis of Kaplan survival curve of mice with chronic GVHD showed that the CTLA4-Ig and TJU103+CTLA4-Ig reduced the incidence of chronic GVHD, the TJU103 could delay the occurrence of chronic GVHD, but all the interference factors could not change the severity of chronic GVHD.</p><p><b>CONCLUSION</b>TJU103 can delay the onset time of chronic GVHD, and the CTLA4-Ig can reduce the incidences of cGVHD, the combining use of TJU103 and CTLA4-Ig can significantly reduce the incidence of chronic GVHD, but can not change the severity of chronic GVHD.</p>

Dendritic Cell Dysfunction in Patients with End-stage Renal Disease

End-stage renal disease (ESRD) with immune disorder involves complex interactions between the innate and adaptive immune responses. ESRD is associated with various alterations in immune function such as a reduction in polymorphonuclear leukocyte bactericidal activity, a suppression of lymphocyte proliferative response to stimuli, and a malfunction of cell-mediated immunity at the molecular level. ESRD also increases patients' propensity for infections and malignancies as well as causing a diminished response to vaccination. Several factors influence the immunodeficiency in patients with ESRD, including uremic toxins, malnutrition, chronic inflammation, and the therapeutic dialysis modality. The alteration of T-cell function in ESRD has been considered to be a major factor underlying the impaired adaptive cellular immunity in these patients. However, cumulative evidence has suggested that the immune defect in ESRD can be caused by an Ag-presenting dendritic cell (DC) dysfunction in addition to a T-cell defect. It has been reported that ESRD has a deleterious effect on DCs both in terms of their number and function, although the precise mechanism by which DC function becomes altered in these patients is unclear. In this review, we discuss the effects of ESRD on the number and function of DCs and propose a possible molecular mechanism for DC dysfunction. We also address therapeutic approaches to improve immune function by optimally activating DCs in patients with ESRD.

Diclofenac Inhibits 27-hydroxycholesterol-induced Differentiation of Monocytic Cells into Mature Dendritic Cells

We investigated whether diclofenac could influence the development of antigen-presenting cells in an oxygenated cholesterol-rich environment by determining its effects on the 27-hydroxycholesterol (27OHChol)-induced differentiation of monocytic cells into mature dendritic cells (mDCs). Treatment of human THP-1 monocytic cells with diclofenac antagonized the effects of 27OHChol by attenuating dendrite formation and cell attachment and promoting endocytic function. Diclofenac inhibited the transcription and surface expression of the mDC markers of CD80, CD83, and CD88, and reduced the 27OHChol-induced elevation of surface levels of MHC class I and II molecules to the basal levels in a dose-dependent manner. It also reduced the expression of CD197, a molecule involved in DC homing and migration. These results indicate that diclofenac inhibits the differentiation of monocytic cells into mDCs, thereby potentially modulating adaptive immune responses in a milieu rich in cholesterol oxidation products.

T Cell's Sense of Self: a Role of Self-Recognition in Shaping Functional Competence of Naïve T Cells

Post-thymic naïve T cells constitute a key cellular arm of adaptive immunity, with a well-known characteristic of the specificity and robustness of responses to cognate foreign antigens which is presented as a form of antigen-derived peptides bound to major histocompatibility complex (MHC) molecules by antigen-presenting cells (APCs). In a steady state, however, these cells are resting, quiescent in their activity, but must keep full ranges of functional integrity to mount rapid and robust immunity to cope with various infectious pathogens at any time and space. Such unique property of resting naïve T cells is not acquired in a default manner but rather requires an active mechanism. Although our understanding of exactly how this process occurs and what factors are involved remains incomplete, a particular role of self-recognition by T cells has grown greatly in recent years. In this brief review, we discuss recent data on how the interaction of T cells with self-peptide MHC ligands regulates their functional responsiveness and propose that variable strength of self-reactivity imposes distinctly different levels of functional competence and heterogeneity.

The transcription factor Batf3 inhibits the differentiation of regulatory T cells in the periphery

Naive CD4 T cells activated by antigen-presenting cells (APCs) undergo terminal differentiation in the periphery. Multiple mechanisms determine their fates, that is, whether they differentiate into conventional T (Tconv) cells or regulatory T (Treg) cells. The key event during Treg generation is expression of the transcription factor Foxp3, which is the lineage-determining regulator for Treg differentiation and function. Here we show that the transcription factor Batf3 acts as a fate-decision factor with respect to Tconv versus Tregs by restraining Treg differentiation. Batf3 was preferentially expressed in effector CD4 T cells but not in Treg cells, and ectopic expression of Batf3 inhibited Foxp3 induction. Batf3-deficient CD4 T cells favorably differentiated into Treg cells in vitro and in colonic lamina propria. Batf3 KO mice also showed enhanced Treg function in gut-associated immune disease models (for example, ovalbumin tolerance and inflammatory bowel disease models). Batf3 bound to the CNS1 region of the Foxp3 locus and reduced expression of the gene. Thus, Batf3 is a transcriptional suppressor of Treg differentiation.

Dendritic Cell-based Immunotherapy for Rheumatoid Arthritis: from Bench to Bedside

Dendritic cells (DCs) are professional antigen presenting cells, and play an important role in the induction of antigen-specific adaptive immunity. However, some DC populations are involved in immune regulation and immune tolerance. These DC populations are believed to take part in the control of immune exaggeration and immune disorder, and maintain immune homeostasis in the body. Tolerogenic DCs (tolDCs) can be generated in vitro by genetic or pharmacological modification or by controlling the maturation stages of cytokine-derived DCs. These tolDCs have been investigated for the treatment of rheumatoid arthritis (RA) in experimental animal models. In the last decade, several in vitro and in vivo approaches have been translated into clinical trials. As of 2015, three tolDC trials for RA are on the list of ClinicalTrial.gov (www.clinicaltrials.gov). Other trials for RA are in progress and will be listed soon. In this review, we discuss the evolution of tolDC-based immunotherapy for RA and its limitations and future prospects.

Generation of Tolerogenic Dendritic Cells and Their Therapeutic Applications

Dendritic cells (DCs) are professional antigen-presenting cells (APCs) that bridge innate and adaptive immune responses, thereby leading to immune activation. DCs have been known to recognize pathogen-associated molecular patterns such as lipopolysaccharides (LPS) and nucleic acids via their pattern recognition receptors, which trigger signaling of their maturation and effector functions. Furthermore, DCs take up and process antigens as a form of peptide loaded on the major histocompatibility complex (MHC) and present them to T cells, which are responsible for the adaptive immune response. Conversely, DCs can also play a role in inducing immune suppression under specific circumstances. From this perspective, the role of DCs is related to tolerance rather than immunity. Immunologists refer to these special DCs as tolerogenic DCs (tolDCs). However, the definition of tolDCs is controversial, and there is limited information on their development and characteristics. In this review, we discuss the current concept of tolDCs, cutting-edge methods for generating tolDCs in vitro, and future applications of tolDCs, including clinical use.

TCF4-Targeting miR-124 is Differentially Expressed amongst Dendritic Cell Subsets

Dendritic cells (DCs) are professional antigen-presenting cells that sample their environment and present antigens to naive T lymphocytes for the subsequent antigen-specific immune responses. DCs exist in a range of distinct subpopulations including plasmacytoid DCs (pDCs) and classical DCs (cDCs), with the latter consisting of the cDC1 and cDC2 lineages. Although the roles of DC-specific transcription factors across the DC subsets have become understood, the posttranscriptional mechanisms that regulate DC development are yet to be elucidated. MicroRNAs (miRNAs) are pivotal posttranscriptional regulators of gene expression in a myriad of biological processes, but their contribution to the immune system is just beginning to surface. In this study, our in-house probe collection was screened to identify miRNAs possibly involved in DC development and function by targeting the transcripts of relevant mouse transcription factors. Examination of DC subsets from the culture of mouse bone marrow with Flt3 ligand identified high expression of miR-124 which was able to target the transcript of TCF4, a transcription factor critical for the development and homeostasis of pDCs. Further expression profiling of mouse DC subsets isolated from in vitro culture as well as via ex vivo purification demonstrated that miR-124 was outstandingly expressed in CD24+ cDC1 cells compared to in pDCs and CD172alpha+ cDC2 cells. These results imply that miR-124 is likely involved in the processes of DC subset development by posttranscriptional regulation of a transcription factor(s).

Application of Cytotoxic T-Lymphocytes for the Treatment of Cytomegalovirus Infection in Hematopoietic Stem Cell Transplantation / 中国实验血液学杂志

Human cytomegalovirus (HCMV) infection, a common complication, remains a major risk factor related with patient death after hematopoietic stem cell transplantation (HSCT). Cytotoxic T lymphocytes (CTL) which is crucial to control HCMV infection, can prevent or treat HCMV infection safely and effectively after adoptive infusion. Many studies have been focussed on exploring different methods for preparation of CTL. The method of using antigen presenting cells to stimulate peripheral blood mononuclear cells is simple to operate, easy to conduct large-scale clinical trials. Isolation of CTL from donor-derived PBMC by peptide-tetramer or INF-γ antibody requires a large volume of peripheral blood and high cost for preparation. Third-party CTL can provide an "off-the-shelf" product, but the problem of HLA-mismatch still would be solved. In addition, the clinical efficacy and safety of different methods also vary. This article reviews and compares the current methods to generate CTL and efficacy of the cells after infusions.

A Case of Neonatal Langerhans Cell Histiocytosis Presenting with Generalized Skin Involvement at Birth Evolving to Hepatic Involvement / 임상소아혈액종양

Langerhans cell histiocytosis (LCH) is a rare disease having an unknown etiology, but characterized by a disorder of antigen presenting cells and the mononuclear phagocytic system. Neonatal LCH, defined as LCH presenting within the first 4 weeks of life, accounts for less than 5-6% of the total LCH cases. Skin involvement of neonatal LCH tends to regress spontaneously, as has been shown in Hashimoto-Pritzker syndrome. We report a case of LCH that presented as whole body, polymorphic, generalized, erythematous, yellowish plaques at birth, with no evidence of other organ involvement. These skin lesions regressed spontaneously within 14 days. Two weeks later, however, the patient presented with hepatosplenomegaly, fever, hyperbilirubinemia, anemia and leukocytosis. LCH with liver involvement was shown on abdominal MRI findings, and the patient received systemic chemotherapy. Although neonatal LCH may initially only show skin manifestations, it should be followed up closely and periodically for other organ involvement.

A Case of Neonatal Langerhans Cell Histiocytosis Presenting with Generalized Skin Involvement at Birth Evolving to Hepatic Involvement / 임상소아혈액종양

Langerhans cell histiocytosis (LCH) is a rare disease having an unknown etiology, but characterized by a disorder of antigen presenting cells and the mononuclear phagocytic system. Neonatal LCH, defined as LCH presenting within the first 4 weeks of life, accounts for less than 5-6% of the total LCH cases. Skin involvement of neonatal LCH tends to regress spontaneously, as has been shown in Hashimoto-Pritzker syndrome. We report a case of LCH that presented as whole body, polymorphic, generalized, erythematous, yellowish plaques at birth, with no evidence of other organ involvement. These skin lesions regressed spontaneously within 14 days. Two weeks later, however, the patient presented with hepatosplenomegaly, fever, hyperbilirubinemia, anemia and leukocytosis. LCH with liver involvement was shown on abdominal MRI findings, and the patient received systemic chemotherapy. Although neonatal LCH may initially only show skin manifestations, it should be followed up closely and periodically for other organ involvement.

Desarrollo de una vacuna mejorada de la subunidad del virus de la diarrea viral bovina basada en la glicoproteína E2 fusionada con un anticuerpo de cadena única que se dirige a las células presentadoras de antígenos / Development of an enhanced bovine viral diarrhea virus subunit vaccine based on E2 glycoprotein fused to a single chain antibody which targets to antigen-presenting cells

Bovine viral diarrhea virus (BVDV) is an important cause of economic losses worldwide. E2 is an immunodominant protein and a promising candidate to develop subunit vaccines. To improve its immunogenicity, a truncated E2 (tE2) was fused to a single chain antibody named APCH, which targets to antigen-presenting cells. APCH-tE2 and tE2 proteins were expressed in the baculovirus system and their immunogenicity was firstly compared in guinea pigs. APCH-tE2 vaccine was the best one to evoke a humoral response, and for this reason, it was selected for a cattle vaccination experiment. All the bovines immunized with 1.5Ag of APCH-tE2 developed high levels of neutralizing antibodies against BVDV up to a year post-immunization, demonstrating its significant potential as a subunit vaccine. This novel vaccine is undergoing scale-up and was transferred to the private sector. Nowadays, it is being evaluated for registration as the first Argentinean subunit vaccine for cattle

El virus de la diarrea viral bovina (BVDV) es causante de importantes pérdidas económicas a nivel mundial. La proteína E2 es la inmunodominante del virus y es la candidata para desarrollar vacunas de subunidad. Para mejorar su inmunogenicidad, una versión truncada de la E2 (tE2) se fusionó a un anticuerpo de cadena simple (APCH), que se dirige a las células presentadoras de antígeno. Se expresaron las proteínas APCH-tE2 y tE2 en el sistema de baculovirus y su inmunogenicidad fue evaluada y comparada en cobayos; la proteína APCH-tE2 fue la que indujo la mejor respuesta humoral. Por dicha razón se la evaluó en bovinos utilizando 1,5µg de antígeno. Los animales presentaron altos títulos de anticuerpos neutralizantes contra BVDV hasta un año posinmunización. Esta nueva vacuna está en proceso de escalado y se transfirió al sector privado. Actualmente se está evaluando para su registro como la primera vacuna argentina de subunidad para bovinos

Functional disruption of human leukocyte antigen II in human embryonic stem cell

BACKGROUND: Theoretically human embryonic stem cells (hESCs) have the capacity to self-renew and differentiate into all human cell types. Therefore, the greatest promise of hESCs-based therapy is to replace the damaged tissues of patients suffering from traumatic or degenerative diseases by the exact same type of cells derived from hESCs. Allo-graft immune rejection is one of the obstacles for hESCs-based clinical applications. Human leukocyte antigen (HLA) II leads to CD4+ T cells-mediated allograft rejection. Hence, we focus on optimizing hESCs for clinic application through gene modification. RESULTS: Transcription activator-like effector nucleases (TALENs) were used to target MHC class II transactivator (CIITA) in hESCs efficiently. CIITA(-/-)hESCs did not show any difference in the differentiation potential and self-renewal capacity. Dendritic cells (DCs) derived from CIITA(-/-)hESCs expressed CD83 and CD86 but without the constitutive HLA II. Fibroblasts derived from CIITA(-/-)hESCs were powerless in IFN-γ inducible expression of HLA II. CONCLUSION: We generated HLA II defected hESCs via deleting CIITA, a master regulator of constitutive and IFN-γ inducible expression of HLA II genes. CIITA(-/-)hESCs can differentiate into tissue cells with non-HLA II expression. It's promising that CIITA(-/-)hESCs-derived cells could be used in cell therapy (e.g., T cells and DCs) and escape the attack of receptors' CD4+ T cells, which are the main effector cells of cellular immunity in allograft.