T Cell-Derived GM-CSF, Regulation of Expression and Function

Granulocyte-macrophage colony-stimulating factor (GM-CSF), also known as colony stimulating factor 2 (CSF2), was termed due to its ability to promote in vitro differentiation of granulocytic and macrophage colonies from bone marrow precursors and is therefore considered as a hematopoietic-cell growth factor. However, GM-CSF-null mice undergo normal hematopoiesis and only the maturation of alveolar macrophages is compromised. GM-CSF is produced by various types of cells, including activated T/B cells, monocytes/macrophages, neutrophils, fibroblasts, epithelial cells, endothelial cells, stromal cells and tumor cells.

An increasing body of evidences supports GM-CSF as a potent proinflammatory factor that is critically involved in inflammatory and autoimmune conditions and that the function of this cytokine varies depending on the origin of the cytokine and the status of the cells in vivo. CD4+ T cells are critical for immune response against microbial infection but also play essential roles in autoimmunity. Naïve CD4+ T cells can differentiate into various subsets of T helper (TH) cells including TH1, TH2 and TH17 cells.

Each subset of TH cells expresses unique cytokines and has distinct functions in immunity. Interestingly, GM-CSF is more or less expressed by all of these TH cells. In this review, we will focus on the recent discoveries concerning the function of CD4+ T cell-derived GM-CSF as well as the regulatory mechanism governing GM-CSF expression by CD4+ T cells.

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Cancer Treatment in the Checkpoint Inhibitor Era

Cross talk between antigen presenting cells, effector T cells and immune regulatory cells through co-stimulatory and inhibitory signals orchestrates the anti-tumor immune response that eventuates in either the effective tumor directed immune activity leading to the tumor removal or an immune suppressed tumor microenvironment leading to the tumor progression and metastasis.

The co-stimulatory signals have been shown to be mediated by CD28 and members of the tumor necrosis factor receptor (TNFR) family, such as CD40, OX-40, 4-1BB, CD30, and CD27, while the regulatory signals are generally mediated through cytotoxic T lymphocyte activator-4 (CTLA-4) and programmed death -1 (PD-1) receptors that share structural homology with the CD28 co-stimulatory class and also bind to the B7 family members. Despite the observed similarities in their structure and receptors, CTLA-4 and PD-1 show the main regulatory role and considered as checkpoints. Targeting these co-stimulatory or inhibitory receptors with either stimulating or blocking antibodies may lead to the enhanced immune response within tumor microenvironment and clinical benefits.

Successful treatment of tumors with primary resistance to conventional chemotherapy and radiation, such as melanoma in advanced and metastatic setting with CTLA-4 and PD-1 targeted monoclonal antibodies and the encouraging results of checkpoint inhibitors in the treatment of non-small cell lung cancer and renal cell carcinoma have led to more than 2000 ongoing clinical studies addressing safety and efficacy of these classes of monoclonal antibodies in a wide range of solid tumors and hematologic malignancies either alone or combined with other therapeutic options from conventional chemotherapy and radiation to other members of the checkpoint inhibitor family, small molecule kinase inhibitors and even cancer vaccines. These combination treatment modalities may demonstrate synergic anti-tumor effect beyond their specific therapeutic effects.

Cancer Treatment in the Checkpoint Inhibitor Era

Cross talk between antigen presenting cells, effector T cells and immune regulatory cells through co-stimulatory and inhibitory signals orchestrates the anti-tumor immune response that eventuates in either the effective tumor directed immune activity leading to the tumor removal or an immune suppressed tumor microenvironment leading to the tumor progression and metastasis.

The co-stimulatory signals have been shown to be mediated by CD28 and members of the tumor necrosis factor receptor (TNFR) family, such as CD40, OX-40, 4-1BB, CD30, and CD27, while the regulatory signals are generally mediated through cytotoxic T lymphocyte activator-4 (CTLA-4) and programmed death -1 (PD-1) receptors that share structural homology with the CD28 co-stimulatory class and also bind to the B7 family members. Despite the observed similarities in their structure and receptors, CTLA-4 and PD-1 show the main regulatory role and considered as checkpoints. Targeting these co-stimulatory or inhibitory receptors with either stimulating or blocking antibodies may lead to the enhanced immune response within tumor microenvironment and clinical benefits.

Successful treatment of tumors with primary resistance to conventional chemotherapy and radiation, such as melanoma in advanced and metastatic setting with CTLA-4 and PD-1 targeted monoclonal antibodies and the encouraging results of checkpoint inhibitors in the treatment of non-small cell lung cancer and renal cell carcinoma have led to more than 2000 ongoing clinical studies addressing safety and efficacy of these classes of monoclonal antibodies in a wide range of solid tumors and hematologic malignancies either alone or combined with other therapeutic options from conventional chemotherapy and radiation to other members of the checkpoint inhibitor family, small molecule kinase inhibitors and even cancer vaccines. These combination treatment modalities may demonstrate synergic anti-tumor effect beyond their specific therapeutic effects.

P-Selectin is a Key Molecule Underlying the Pathophysiology of Aspirin

Aspirin-exacerbated respiratory disease (AERD) is characterized by the triad of asthma, nasal polyposis, and hypersensitivity to aspirin and other cyclooxygenase (COX)-1 inhibitors. Aspirin intolerance is one of the risk factors for severe asthma, particularly in patients with persistent airflow limitation (PAFL).

 The overproduction of cysteinyl leukotriene (cysLT) is the biochemical hallmark of AERD. Urinary leukotriene levels are 3-4 fold higher in AERD patients than in ATA patients, which further increase after aspirin-induced reaction in AERD patients. Decreased levels of prostaglandin E2 (PGE2) were also a characteristic feature of AERD patients. Impaired E prostanoid 2 (EP2) expression and resistance to PGE2 were detected in nasal polyp fibroblasts from AERD patients. However, the mechanism underlying the development of AERD has not been clarified in detail.

In addition to their role in hemostasis, platelets have the capacity to mediate immune responses during inflammation and to facilitate granulocyte recruitment into airways. Platelet activation has been detected in several allergic diseases, including asthma. Platelets play an important role in asthma, which contributes to airway hyper reactivity (AHR), bronchoconstriction, airway inflammation and airway remodeling. Recently, Laidlaw and Boyce have demonstrated that platelet activity is strongly associated with the pathophysiology of AERD.

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Diabetes Mellitus and Periodontitis |Molecular Interrelationships

Diabetes mellitus (DM) and periodontitis are both chronic inflammatory diseases, which contribute significantly to morbidity and are a major health care burden. The interrelationship between DM and periodontitis has been studied for many years. It has been accepted that the supposed interrelationship between DM and periodontitis is a two-way relationship. In this sense, the presence of one condition tends to increases the risk and severity of the other, and vice versa. However, the mechanisms for this two-way relationship still remain unknown.

DM is a chronic metabolic disorder, involving impaired glucose homeostasis. DM poorly controlled is characterized by high blood glucose levels that result in an increased formation of protein glycosylation leading to amplified formation of so-called advanced glycation end products. AGEs are glucose products that have the ability to attract and stimulate inflammatory cells to produce inflammatory cytokines such as tumor necrosis factor alpha (TNF-α), Prostaglandin E2 (PGE2), and interleukin-1β (IL-1β) and matrix metalloproteinases (MMPs) that together with increased generation of reactive oxygen species  may raise the risk of periodontal attachment and/or alveolar bone loss and contribute to diabetic complications.

AGEs combined with pro-inflammatory cytokines can motivate fibroblast apoptosis and impair periodontal wound healing. It is known that, the expression of these pro-inflammatory mediators is regulated by the T helper cells. In addition, the polymorphonuclear neutrophils are important in the first line of defense in periodontal disease process, as periodontitis. However, exacerbate response may transpose this protective action of polymorphonuclear neutrophils into destroyers. Thus, the host immune-inflammatory responses would be protective or destructive.

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Cancer Cell Lines: MHC Class 1-Related Chain A and B Ligands Differently Expressed

In 1994, a new set off loci related to MHC class 1 genes called MHC class 1 chain-related genes (MIC) or Perth beta block transcript 11 were identified independently by Bahram et al. and Leelayuwat et al.in which five copies existed. The nomenclature was then standardized as MIC, which since then is in current use. Major Histocompatibility complex class 1chain related molecule is known to play an important role in tumor immune-surveillance.

MICA/B is encoded in the MHC (major histocompatibility complex) region, and they share structural and sequence similarity with MHC class I proteins (28-35%). MICA/B has α1-α2-α3 extracellular domains and short transmembrane tails similar to MHC class 1. MICA/B does not associate with β2-microglobulin or antigenic peptides like their counterpart MHC class 1. They are highly polymorphic, with close to 60 recognizable MICA and 25 MICB alleles. Although much is not known about the significance of their polymorphism, MICA alleles might vary in their affinity for NKG2D binding and thus affect the thresholds of recognition by NK cells and T lymphocytes.

The MIC molecules have been detected in broader range of tumorshematological malignances and various adenocarcinomas such as breast, lung, colon, kidney, ovary and prostate tumors, gliomas, neuroblastomas and melanomas. Previous studies show that MIC genes are widely and transcribed and therefore possibly translated and membrane bound with exception of the Central Nervous system.

In human, NKG2D recognizes two structurally distinct families of ligands namely (MIC) molecules and the UL 16 binding proteins (ULBPs) 1-5 molecules which is also known as RAET1: retinoic acid early transcript, originally identified through interaction with Cytomegalovirus UL 16 glycoproteins. MIC and ULBP both engage NKG2D, which then triggers cytokine production and cytotoxic activity seen in activated NK cell.

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Critical Role for Inflammatory Macrophages in Driving Antigen-dependent Th17 Cell Responses

Macrophages have a key role in regulating immune responses such as inflammation, wound healing, and maintenance of tissue homeostasis. Macrophages are characterized by remarkable plasticity and diversity. They rapidly respond to microenvironmental signals, for example, cytokines and acquire distinct phenotypes and functions. Key phenotypes have been characterized in vitro , as M1-activated proinflammatory/microbicidal macrophages induced by microbial products and IFNg, and, M2 antiinflammatory/ tissue healing/immunomodulatory macrophages induced by IL-4/IL-13/IL-10. These are, however, extremes on a continuum of the phenotypes found in vivo .

Critical Role for Inflammatory Macrophages

The nature and balance of macrophage activation-states is important and their dysregulation has been linked to inflammatory diseases, autoimmunity or, at the other extreme, cancer and chronic wounds. Macrophages are professional antigen-presenting cells (APCs) and recent evidence suggests the heterogeneous nature of macrophages impacts their role in CD4+ Tcell polarization.

CD4+ T helper (Th) cells orchestrate adaptive immune responses. Soluble and cell-contact dependent signals from APCs result in T cell differentiation into distinct functional phenotypes including Th1, Th2, Th17, and regulatory T (Treg) cells, characterised by cytokine output and transcription factor expression. Human M1 and M2 subsets differentially produce cytokines modulating T-cell polarization.

Potentially Pandemic Live Influenza Vaccines Based on Russian Master Donor Virus are Genetically Stable after Replication in Humans

Birds and Mammals are the main reservoir of newly emerging pandemic influenza viruses [1-3]. Global circulation of influenza A viruses in avian species poses a constant threat to human public health. Vaccination remains the main strategy against influenza. Over the last decade, the interest in the live attenuated cold-adapted reassortant influenza vaccine (LAIV) has increased dramatically. To a large degree, it is because World Health Organization (WHO) recognized the advantages of LAIV in the event of pandemic situation. For instance, needle–free administration, high vaccine virus yield, easy down– stream processing, cross–reactivity of immune responses etc. make LAIV very attractive preparation in the face of pandemic situation.

Genetic stability and the absence of transmission potency are the main properties of LAIVs, which guarantee their safety. Confirmation of genetic and phenotypic stability is one of key points of characterisation of LAIV, which is especially important in pandemic situation to guarantee its safety profile during large–scale immunization campaigns.

 In each of those studies, 38-40, 18-49 years old participants both sexes were randomly assigned to receive two doses of vaccine or placebo at a 3:1 vaccine:placebo ratio. Vaccine and placebo were administrated intranasally. The preclinical studies, as well as safety and immunogenicity of these three LAIVs for use in the pandemic situations were earlier well documented and published. In this paper, we presented the results of molecular genetics and virological studies conducted as a part of phase I clinical trials. In particular, shedding, transmission and genetic stability of H7N3, H5N2 and H2N2 LAIVs against pre–pandemic influenza viruses were studied.

The Effect of Oxidative Stress on Pulmonary Involvement in Patients with Systemic Sclerosis

Systemic sclerosis (SSc) is a connective tissue disease characterized by fibrosis of the skin, blood vessels, skeletal muscles, and visceral organs and associated with some immunological abnormalities and vascular injury. Collagen overproduction by activated stromal fibroblasts, autoantibody production and acral vasospasm known as Raynaud’s phenomenon are the hallmarks of the disease. There are two major subgroups: limited cutaneous SSc and diffuse cutaneous SSc. The kidneys, esophagus, heart, and lungs are the most frequent targets.

Under normal circumstances there is a balance between oxidant agents and antioxidant defense mechanisms, and if this balance is disturbed oxidative stress occurs. Reactive oxygen species (ROS) such as superoxide anion radicals (O2−) are known as oxidant agents. Malondialdehyde (MDA) as a lipid peroxidation end product is an indicator of oxidative stress Xanthine oxidase (XO) is an oxidant enzyme catalyzing oxidation of hypoxanthine to xanthine and xanthine to uric acid, and can produce O2− during these reactions. Superoxide dismutase (SOD) catalyzes the dismutation of O2− to hydrogen peroxide (H2O2), and catalase (CAT) and glutathione peroxidase (GSH-Px) are the enzymes that catalyze the reduction of H2O2 to water. SOD, CAT, and GSH-Px are known as endogenous antioxidant enzymes playing important role in antioxidant defense. Adenosine deaminase is a key enzyme in the degradation of adenine nucleotide .

Free radical mediated damage could be an important basis for the SSc pathogenesis. Oxidative stress is supposed to play a role on endothelial injury at earlier stages of the disease. Modifications of the vascular system leads to loss of the control of vascular tone. The oxygen free radical species can be generated during Raynaud’s phenomenon that causes hypoxic/ischemic episodes, with consequent lipid peroxidation and tissue damage. Free radicals are harmfull to cells, modifying cellular macromolecules including lipids, proteins, carbohydrates and nucleic acids. Variation in prooxidant or antioxidant genes may also be associated with SSc .

There is evidence of an association between oxidative stress and SSc from several studies. Lipid peroxidation products, which are markers of oxidative stress were found at highest levels in patients with interstitial lung disease and in patients with frequent ischemia/ reperfusion episodes. Inflammation can play a predominant role in the generation of reactive oxygen species. Tissue damage by respiratory burst of polymorphonuclear leucocytes can occur especially in lungs. The oxygen free radicals are supposed to contribute to the tissue damage occuring in diffuse lung diseases, a heterogenous group of diseases with pulmonary fibrosis of various degrees of severity. Pulmonary involvement (interstitial lung disease and pulmonary hypertension) and cardiac involvement are major causes of death in SSc. Therefore, the aim of this study was to to measure levels of oxidant and antioxidant enzymes in patients with Ssc, to evaluate possible contibution of oxidative stress to the pathogenesis of SSc and pulmonary involvement and its severity.

Allergy, Still Waiting to Explore: Recent Advancement in the Pathogenesis and Therapeutic Approaches of Allergy

Allergic diseases increased greatly in recent decades and are becoming one of the major world health problems of this century. Why there is a high prevalence of allergic diseases not only in western world but in Asia and other developing countries still needs further investigation. It is a new frontier to explore the pathogenesis of allergy and its therapeutic approaches. Journal of Allergy & Therapy is dedicated to allergic diseases and therapeutic researches from clinical trials and laboratory experiments, including various approaches adopted and new strategies in diagnosis, therapy and prevention of allergic diseases. I am pleased to write this editorial for Journal of Allergy & Therapy and confident that this journal will become a highly respected resource in allergic diseases research.

The term “allergy” was first used in 1906, which derives from the Greek words “allos” and “ergos” to describe the hypersensitivity reactions of immune system to certain substances such as dust, pollen or some kind of foods. All forms of hypersensitivity used to be classified as allergies and the meaning of the word changed over time, allergy now is restricted to type I hypersensitivities (immediate hypersensitivity), which are mainly characterized as immunoglobulin E (IgE) antibodies mediated allergic diseases, including hay fever, food allergies, atopic dermatitis, allergic asthma and anaphylaxis, etc. Generally, two categories, namely host and environmental factors are responsible for this allergic condition. The host risk factors include heredity, sex, race and age that may put the individuals into a predisposition, namely atopy, which is an exaggerated tendency to become sensitized.

 The exposure to environmental pollution, infectious diseases and allergens makes up the external causes. Reduced exposure to environmental pathogenic microorganisms in the early childhood, according to the “hygiene hypothesis”, results in insufficient stimulation of Th1 cells and leading to an overactive of Th2 cells polarization in immune system, which in turn facilitates allergic diseases. Other hypotheses from gut microbiota diversity, infant feeding, over exposure to allergens in occupation to the effects of pollution have been explored, while there is a complex interplay of environmental factors and host genetics that cannot be detached from each other in the immunopathogenesis of allergy, further efforts should be performed to elucidate the etiology of allergy.

T-type Calcium Channels during Neuroendocrine Differentiation

cells produce and release (neuro) hormones, neuropeptides or monoamines in the extracellular milieu using a regulated pathway in response to a specific stimulus. The NE system includes specific organs, where cells are organized into secreting tissues (adrenals or pituitary for instance) and a diffuse system, where endocrine cells are scattered in an apparently disorganized pattern among non-secretory cells. The observation of dispersed NE cells throughout the body derives from the seminal works of Heidenhain, Kulchitsky, Masson and Hamperl in the late 19th century and the early 20th century. Their studies demonstrated, from the ability of cells to be stained by silver salts (argent affinity or argyrophily), the existence of dispersed hormone-secreting cells in non-endocrine tissues.

Using histological techniques,Feyrter and Froelich identified the existence of many clear cells (Hellen Zellen) throughout the body and noticeably in the gut, leading to the concept of DNES. Miscellaneous sites were also identified in the prostate, where they are dispersed in the normal epithelium, representing only about 0.5 to 2 % of the total cell population. Anton Pearse then defined NE cells as cells sharing the common ability to uptake and decarboxylate amine precursors, to convert these precursors into biogenic amines and neurotransmitters. From this property, Pearse coined the term, APUD system (Amine Precursor Uptake and Decarboxylation). NE cells were all initially thought to originate only from neuroectoderm (neural crest) and were thus also termed para neurons. However, subsequent studies showed that some of them did not derive from the neural crest. These include pancreatic endocrine cells or gastrointestinal enterochromaffin cells, which originate from endodermal tissue.

NE cells are usually characterized by various functional, morphological and molecular features (for a review see. A NE cell is characterized in electron microscopy by the presence of electrodense secretory granules containing peptidergic and aminergic neurohormones. NE cells possess the capability to rapidly release their neurohormones or neurotransmitters in response to specific stimuli, such as other hormones. In this context, the acquisition of cell excitability, characterized by action potentials and voltage-dependent ion channels, is an important step towards the acquisition of a regulated secretory pathway. Morphologically, the acquisition of a NE phenotype is usually accompanied by the lengthening of neuritic extensions. NE cells therefore share many features with neurons, but do not have specialized nerve terminals or axons. From a molecular point of view, NE cells express specific proteins that may also be expressed by neurons or even by non-neuronal cells. Among these NE markers are the members of the granin family, chromogranin A and B (CgA and CgB), secre-togranin II, III and VII.

These acidic soluble proteins are stored with neuropeptides and neurotransmitters in dense-core vesicles. Other markers of NE differentiation are the enzymes Prohormone Convertases PC1/3 and PC2, which process various protein precursors, including granins, into functional hormones. Like granins and neuropeptides, Prohormone Convertases are stored in dense-core vesicles where they exert their proteolytic activity. These enzymes have therefore been considered as good markers of the NE phenotype or differentiation. These common markers, along with others (neuron-specific enolase (NSE), synaptophysin, S100), are used in pathology to identify NE tumours. 

Microsporidial Keratitis

Microsporidia are small eukaryotic, spore forming obligate intracellular parasites belonging to the phylum Microsporidia. They were first recognised 100 years ago from the silk worm Bombyx mori as an etiological agent of the pebrine disease-a destructive disease in these worms. Though initially believed to be early diverging eukaryotes, they are currently known to be closely related to fungi. These infectious pathogens can exhibit diverse clinical manifestations such as ocular, sinus, renal, intestinal, pulmonary, and muscular diseases. Ocular microsporidiosis can present as stromal keratitis, scleritis, keratoconjuntivitis and endophthalmitis. High index of suspicion is required for the diagnosis of ocular microsporidiosis.

Etiology

Microsporidia are small unicellular parasites and are considered as true eukaryotes because they have a nucleus with a nuclear envelope, an intracytoplasmic membrane system, and chromosome separation on mitotic spindles. Joseph et al. reviewed the disease and detected four genera that infect humans Encephalitozoon , Nosema , Pleistophora and Enterocytozoon. Seven genera (Enterocytozoon species, Brachiola species, Encephalitozoon species, Pleistophora species, Nosema species, Vittaforma species and Trachipleistophora species) as well as unclassified microsporidia (collectively referred to as Microsporidium ) have been found to be associated with human disease involving immunocompromised patients. Nosema sp. and Nosema like organisms of the nontaxonomic group Microsporidium are the parasites involved in ocular microsporidiosis in immunocompetent individuals whereas in immunocompromised individuals Encephalitozoon hellem or other Encephalitozoon -like organisms were involved.

Pathogenesis

Life cycle of these organisms is completed within the human host. There is no role of an intermediate host or a vector in transmitting the developmental stages of microsporidia. The spore is the infective and the resistant stage. In microsporidial keratitis spores are believed to enter the eye either by direct contact or trauma. The spore has a unique means of inoculation of the infective sporoplasm. It extrudes the sporoplasm via the everting and unwinding polar filament into the host cell. Further after invading the cell the sporoplast division takes place by binary fission forming schizont with 2-6 nuclei, which split into unicellular meronts. The meronts secrete a rigid capsule thus attaining its final size measuring about 2.5 × 1.5 microns. The meronts further differentiates into sporonts and spores. The cell finally ruptures to continue the cycle and further destruction of the host tissue eventually occurs. The spores of the genus Encephalitozoon reside in a parasitophorus vacuole which is a membrane bound vacuole. Members belonging to other genera complete their intracellular life cycle in direct contact with the cell cytosol.