Dendritic cells: In the forefront of immunopathogenesis and vaccine development - A review

A review on the antagonist Ebola: A prophylactic approach

Ebola virus (EBOV), a member of Filoviridae virus family under the genus Ebolavirus, has emerged as a dangerous and potential threat to human health globally. It causes a severe and deadly hemorrhagic fever in humans and other mammals, called Ebola Virus Disease (EVD). In recent outbreaks of EVD, there has been loss of large numbers of individual’s life. Therefore, EBOV has attracted researchers and increased interests in developing new models for virus evolution, and therapies. The EBOV interacts with the immune system of the host which led to understand how the virus functions and effects immune system behaviour. This article presents an exhaustive review on Ebola research which includes EVD illness, symptoms, transmission patterns, patho-physiology conditions, development of antiviral agents and vaccines, resilient health system, dynamics and mathematical model of EBOV, challenges and prospects for future studies.

Deciphering the pathophysiology of irritable bowel syndrome and functional gastrointestinal disorders-an alternative model for pathogenesis: cytokine controlled transepithelial multi-feedback loop

A working theoretical model for irritable bowel syndrome (IBS) and other functional gastrointestinal disorders (FGIDs) does not exist, hampered by the lack of any clear cut invention that address all symptom and signs of the disease. Reports of cessation of symptom and signs of both major types of IBS have been published using a non-systemic, topically active agent-high potency polymerized cross-linked sucralfate (HPPCLS). The unique clinical effect of this non-systemic agent restricted to the luminal surface of the gut provides opportunity to elaborate on an alternative working model for the pathogenesis of IBS and FGIDs. While the chemical determinants of HPPCLS and the mucosal lining contribute to the clinical effects, the sequence of events resides in the functional interplay among elements within the mucosa itself. The proposed model assumes that failure of a pre-existing genomic-controlled surveillance of the epithelium localized to the luminal surface triggers primary and secondary immune activation of inflammation intent on restoring epithelial homeostasis. Delayed restoration of homeostasis results in all the symptoms, signs and likely molecular events that characterize IBS and FGIDs.

Dendritic cell vaccine against leukemia: advances and perspectives

As with many other types of malignancies, sustainable eradication of leukemia has been a challenge. This is related to the inevitable failure of conventional chemotherapeutic agents and radiation therapy to target the relatively quiescent leukemia stem cells, which are believed to have multidrug resistance, antiapoptotic capacity and enhanced DNA repair mechanisms allowing them to evade the immune system. Considering other therapeutic options that are minimally toxic to normal cells and effectively target not only the majority and more differentiated cancer cells, but also the rare residual leukemia cells, is of paramount importance. A number of immunotherapeutic options have been proposed to counter this challenge. One of the remarkable achievements in the field of immunotherapy has been the successful use of antigen presenting cells as vehicles of tumor/pathogenic antigens to the T-cell compartments. This review will focus on advances and perspectives of this arm of immunotherapy against leukemia.

Induction of IFNα or IL-12 depends on differentiation of THP-1 cells in dengue infections without and with antibody enhancement

Background

Appropriate induction of the early Th1 cytokine IL-12 is a critical defense directed against viral infection. We have previously shown that different viruses elicited either IL-12 or IFNα dependent Th1 reactions. Using dengue-2 virus, we sought to explore how dengue-2 induced IL-12 or IFNα expression by monocytic and its derived dendritic cells.

Methods

We employed human monocytic cell line, THP-1, to investigate whether differentiation of monocytic cells is involved in the switch between IFNα and IL-12 induction. Flow cytometry, RT-PCR and ELISA were respectively used to determine cell differentiation, IL-12 and IFNα mRNA expression and protein production.

Results

THP-1, expressing CD123, which is a plasmacytoid dendritic cell marker, but not CD14, CD11b or CD11c revealed IFNα mRNA expression while stimulated by dengue-2. In contrast, PMA-induced THP-1 differentiation toward monocytic cells expressed CD11b⁺, and CD14⁺, but not CD123, and revealed exclusively IL-12 expression while stimulated by dengue-2. Further studies showed that CD123⁺ expressing THP-1 cells elicited higher IFNα expression in dose and time dependent induction after infection, and PMA-induced monocytic differentiation of THP-1 cells revealed IL-12 expression. Antibody-dependent enhancement of DEN-2 infection significantly suppressed the DEN-2 induced IL-12 p40 expression in monocytic differentiated THP-1 cells.

Conclusions

Clarification and modulation of the early Th1 reaction in different monocytic cells may change or prevent complication from dengue infection.

Umbilical cord blood: current status and future directions

Once considered biological waste, umbilical cord blood (UCB) has become an accepted source of haematopoietic stem cells (HSCs). With initial success in the pediatric setting, UCB transplantation continues to gain favor in the adult patient population. Novel approaches to UCB transplantation include use of two units and a variety of graft manipulations. Additional uses for UCB are currently being explored and include applications in regenerative medicine and immunotherapy.

Probiotics: from bench to market

"Probiotics: From Bench to Market" was a one-day conference convened by the New York Academy of Sciences on June 11, 2010, with the goal of stimulating discussion of the physiological effects of probiotics on the gastrointestinal, nervous, and immune systems. The program included speakers from academia, industry, and government to give conference participants a full understanding of the state of the field of probiotics. The overall goal of the program was to increase communication and collaboration among these groups to advance probiotic research and probiotic contributions to public health. The conference was divided into three sessions and included both oral and visual presentations as well as panel discussions.

Effect of patulin on the interdigitating dendritic cells (IDCs) of rat thymus

Patulin is a common fungal contaminant of ripe apples used for the production of apple juice concentrates and it is also present in other fruits, vegetables and food products. Patulin is a secondary metabolite produced by species of the genera Penicillium, Aspergillus and Byssochlamys. Patulin has been reported to be mutagenic, carcinogenic and teratogenic. Antigen-presenting cells (APCs) are of prime importance in the innate immune response; they capture antigen in tissues and then migrate to the lymphoid organs to present the antigen to T lymphocytes. Thus, they are crucial for the initiation of immunity. Interdigitating dendritic cells (IDCs) are a subset of APCs that are present at the lymphatic organs. In the thymus, they act in positive and negative selection during T cell development. In the present study, patulin was administered orally to growing male rats aged 5-6 weeks. A dose of 0.1 mg kg(-1) bw day(-1) was given to rats for a period of 60 or 90 days daily. The effect of patulin on the IDCs of thymus was investigated by transmission electron microscopy (TEM), and the results were evaluated in terms of cell destruction. In the rats of the control group, it was observed that the IDCs had an indented nucleus, a clear cytoplasm and numerous membrane extensions. In the cytoplasm, a well-developed golgi complex, mitochondria, granular endoplasmic reticulum and a small number of lysosomal structures were observed. At day 60 of patulin-treated rat groups (P-60), loss of cristae in mitochondria and chromatin margination and lysis in the nucleus were found. It was observed that the IDCs had a perinuclear area of cytoplasm surrounded by a peripheral electron-lucent zone. In the cytoplasm of the 90-day patulin-treated rat group (P-90), a peripheral electron-lucent zone was also found, similar to the P-60 group. Additionally increase in vesicular and lysosomal structures, increase in apoptotic bodies and condensation of chromatin in the nucleus were noted. It was observed that patulin leads to apoptotic body formation and cell apoptosis in the IDCs of rat thymus especially in the P-90-treated groups.

Generation of canine dendritic cells from peripheral blood monocytes without using purified cytokines

Dendritic cells (DCs), which differentiate in vitro from peripheral blood monocytes (PBMOs) or bone marrow precursors, are a promising candidate for immunotherapy against cancer. The dog, which suffers common types of cancers along with humans, make an ideal large animal model for cancer studies. Monocyte-derived DCs in the dog have not been well characterized, however, since the appropriate condition for in vitro differentiation has not been established. To tackle this problem, we have developed a conditioned media by culturing T cells with immobilized anti-canine CD3 antibody, and sought to induce differentiation of DCs from PBMOs. When purified CD14+ PBMOs were cultured in the presence of 25% T cell conditioned medium (TCCM), the PBMOs increased size and had extended dendritic processes by day 12 of the culture. The cultured PBMOs were found to increase the expression of MHC class II and CD1a molecules, and significantly increased stimulatory activity for allogeneic T cells in the mixed leukocyte reaction. Moreover, the cells significantly increased their expression of IL-18 and IFN-gamma when stimulated with polyinosinic-polycytidylic acid (Poly (I:C)). The cells have a reduced phagocytic activity, which is a common defect in mature DCs. It follows from these results that TCCM does induce the differentiation of DCs from PBMOs.

Changes in the proteomic profile during differentiation and maturation of human monocyte-derived dendritic cells stimulated with granulocyte macrophage colony stimulating factor/interleukin-4 and lipopolysaccharide

Dendritic cells (DCs) are highly specialized antigen-presenting cells that play an essential role in the immune response. We used the proteomic approach based on two-dimensional gel electrophoresis and mass spectrometry to identify the protein changes that occur during differentiation of DCs from monocytes (Mo) stimulated with granulocyte macrophage colony stimulating factor/interleukin-4 (GM-CSF/IL-4) and during the maturation of immature DCs stimulated with lipopolysaccharide. Sixty-three differentially expressed proteins (+/- two-fold) were unambiguously identified with sequence coverage greater than 20%. They corresponded to only 36 different proteins, because 11 were present as 38 electrophoretic forms. Some proteins such as tropomyosin 4 and heat shock protein 71 presented differentially expressed electrophoretic forms, suggesting that many of the changes in protein expression that accompany differentiation and maturation of DCs occur in post-translationally modified proteins. The largest differences in expression were observed for actin (21-fold in Mo), Rho GDP-dissociation inhibitor 2 (20-fold in Mo), vimentin (eight-fold in immature DCs), lymphocyte-specific protein 1 (12-fold in mature DCs) and thioredoxin (14-fold in mature DCs). Several proteins are directly related to functional and morphological characteristics of DCs, such as cytoskeletal proteins (cytoskeleton rearrangement) and chaperones (antigen processing and presentation), but other proteins have not been assigned specific functions in DCs. Only a few proteins identified here were the same as those reported in proteomic studies of DCs, which used different stimuli to produce the cells (GM-CSF/IL-4 and tumor necrosis factor-alpha). These data suggest that the DC protein profile depends on the stimuli used for differentiation and especially for maturation.

IL-4 is more effective than IL-13 for in vitro differentiation of dendritic cells from peripheral blood mononuclear cells

Dendritic cells (DCs) are the most potent professional antigen-presenting cells which can activate T cells to induce the primary immune response. For clinical studies, DCs are often differentiated in vitro from peripheral blood mononuclear cells (PBMCs) through treatment with granulocyte macrophage colony-stimulating factor (GM-CSF) and IL-4. However, IL-13, a cytokine closely related to IL-4, has also been reported to induce differentiation equally or more efficiently when used with GM-CSF. For the present study, we compared the DC characteristics exhibited by iDCs and LPS-matured DCs differentiated from PBMCs using GM-CSF and IL-4 or IL-13. Physical characteristics examined include cellular morphology and surface phenotype. Functional traits investigated include FITC-dextran uptake, IL-10 and IL-12 production, allostimulation and cytokine production by stimulated T cells and antigen-specific T cell stimulation. Compared with IL-13-derived DCs, IL-4 treatment yielded more differentiated DCs, with extensive dendrites and higher expression of DC-SIGN, DEC-205, CD86 and HLA-DR. In addition, IL-4 DCs were more efficient at inducing allogeneic T cell proliferation and immature IL-4 DCs had higher endocytic activity at low FITC-dextran concentrations (1 microg ml(-1)). Although IL-13 was capable of generating DCs from PBMCs, it was not as effective as IL-4 in generating DC phenotype and functionality. Thus, the use of GM-CSF and IL-4 is the more efficient treatment for inducing DC differentiation from PBMCs.

The evolving field of biodefence: therapeutic developments and diagnostics

Bioweapons are a clear threat to both military and civilian populations. Here, the latest advances in the pursuit of inhibitors against biothreat threat toxins, current therapeutic strategies for treating biodefence related pathogens, and strategies for improving detection and exposure survivability are covered.

There are numerous lead therapeutics that have emerged from drug discovery efforts. However, many of these are toxic and/or fail to possess conventional drug-like properties. One clear advantage of small (non-peptidic) molecules is that they possess scaffolds that are inherently more likely to evolve into real therapeutics.

One of the major obstacles impeding the translation of these lead therapeutics into viable drugs is the lack of involvement of the pharmaceutical industry, which has been discovering leads and translating them into drugs for decades. The expertise of the pharmaceutical industry therefore needs to be more effectively engaged in developing drugs against biothreat agents.

New methods for rapidly detecting and diagnosing biothreat agents are also in development. The detection and diagnosis of biothreats is inherently linked with treatment. The means for detecting the release of bioweapons are being deployed, and new technologies are shortening the timeframe between initial sample collection and conclusive agent determination. However, the organization of this process is imperfect.

At present, a unifying entity that orchestrates the biodefence response is clearly needed to reduce the time-to-drug process and redundancies in drug development efforts. Such a central entity could formulate and implement plans to coordinate all participants, including academic institutions, government agencies and the private sector. This could accelerate the development of countermeasures against high probability biothreat agents.

The threat of bioterrorism and the potential use of biological weapons against both military and civilian populations has become a major concern for governments around the world. For example, in 2001 anthrax-tainted letters resulted in several deaths, caused widespread public panic and exerted a heavy economic toll. If such a small-scale act of bioterrorism could have such a huge impact, then the effects of a large-scale attack would be catastrophic. This review covers recent progress in developing therapeutic countermeasures against, and diagnostics for, such agents.

Gene-inducing program of human dendritic cells in response to BCG cell-wall skeleton (CWS), which reflects adjuvancy required for tumor immunotherapy

Adjuvants induce the expression of a number of genes in dendritic cells (DCs), which facilitate effective antigen-presentation and cytokine/chemokine liberation. It has been accepted that the toll-like receptor (TLR) family governs the adjuvant activity in DCs. An adjuvant with a long history is mycobacteria in an oil-in-water emulsion, namely Freund's complete adjuvant. Since the active center for the adjuvancy in mycobacteria is the cell-wall skeleton (CWS), we used the bacillus Calmette-Guerin cell-wall skeleton (BCG-CWS) to test DC maturation by GeneChip analysis. We identified the genes supporting an efficient DC response and output. Approximately 2000 genes were up-regulated by BCG-CWS stimulation. BCG-CWS-, peptidoglycan (PGN)- and lipopolysaccharide (LPS)-stimulation generally up-regulated some gene clusters including genes for inflammatory cytokines (TNF, IL1alpha, IL1beta, IL6, IL12 p40, IL23 p19, etc.), chemokines (CCL20, IL8, etc.), cell adhesion molecules (ICAM-1, etc.), apoptosis-related proteins (GADD45B, BCL2A1, etc.), metabolic enzymes (PTGS2, SOD2, etc.) and miscellaneous proteins (EHD1, TNFAIP6, etc.). LPS-stimulation, but not BCG-CWS- or PGN-stimulation, up-regulated the interferon-inducible antiviral proteins, including IFIT1, IFIT2, IFIT4, CXCL10, ISG15, OASL, IFITM1 and MX1. We also found that the BCG-CWS- or PGN-stimulation up-regulated CXCL5, MMP1, etc. We discussed their properties in association with TLRs and recently discovered TLR adapters.

Th1/Th2 cells in inflammatory disease states: therapeutic implications

Inflammation is initiated as a protective response by the host, but can often result in systemic pathology. Among cells of the immune system, T lymphocytes play a major role in the inflammatory response. T cell inflammation is characterised histologically by an infiltration of mononuclear cells. Key regulators of this response are a subset of T lymphocytes called T helper (Th) cells. These cells secrete soluble mediators called cytokines, which orchestrate the immune response. The appropriate regulation of Th cell immunity is critical in the control and prevention of diverse disease states. This review will focus on the role of Th cells in the inflammatory process involved in allergic disease, diabetes, infectious disease, rheumatoid arthritis, heart disease, multiple sclerosis and cancer. In the area of autoimmunity, in particular, a basic understanding of Th cells and cytokines has contributed to the development of clinically efficacious biological agents. This review also examines current and novel treatment strategies under investigation at present that regulate Th cell immunity, which may result in better treatments for immune-mediated diseases.