No abstract available.
Fetal Blood* ; Humans* ; Oxygen* ; Phagocytes*

Fever has been recognized as a cardinal feature of disease since antiquity, but only recently has the pathophysiology of fever come to be understood. It became clear that the ultimate cause of fever is not a bacterial product (a so-called exogenous pyrogen) but a product of host inflammatory cells (i.e., an endogenous pyrogen). Many studies have demonstrated that mononuclear phagocytes are the principal source of endogenous pyrogen and that a variety of mononuclear cell products can mediate the febrile response. Cytokines are also important as mediators of the acute-phase response to infection and inflammation.
Acute-Phase Reaction ; Cytokines ; Fever* ; Inflammation ; Phagocytes

The clearance of apoptotic cells is an essential process for tissue homeostasis. To this end, cells undergoing apoptosis must display engulfment signals, such as ‘find-me' and ‘eat-me' signals. Engulfment signals are recognized by multiple types of phagocytic machinery in phagocytes, leading to prompt clearance of apoptotic cells. In addition, apoptotic cells and phagocytes release tolerogenic signals to reduce immune responses against apoptotic cell-derived self-antigens. Here we discuss recent advances in our knowledge of engulfment signals, the phagocytic machinery and the signal transduction pathways for apoptotic cell engulfment.
Apoptosis ; Autoantigens ; Homeostasis ; Phagocytes ; Signal Transduction

Neutrophils are the most abundant white blood cells in the peripheral blood and have long been recognized as the major phagocytes in acute infection by destroying extracellular pathogens. Although research on neutrophils hampered by intractability in the experiments, the newly discovered effector functions of neutrophils includes granular proteins, and cytokines, extracellular traps. With all effector mechanism neutrophils play a critical role in the pathogenesis of acute and chronic infection, autoimmunity and cancer.
Autoimmunity ; Cytokines ; Inflammation ; Leukocytes ; Neutrophils ; Phagocytes ; Proteins

Autophagy is a highly conserved intracellular degradation and energy-recycling mechanism that contributes to the maintenance of cellular homeostasis. Extensive researches over the past decades have defined the role of autophagy innate immune cells. In this review, we describe the current state of knowledge regarding the role of autophagy in neutrophil biology and a picture of molecular mechanism underlying autophagy in neutrophils. Neutrophils are professional phagocytes that comprise the first line of defense against pathogen. Autophagy machineries are highly conserved in neutrophils. Autophagy is not only involved in generalized function of neutrophils such as differentiation in bone marrow but also plays crucial role effector functions of neutrophils such as granule formation, degranulation, neutrophil extracellular traps release, cytokine production, bactericidal activity and controlling inflammation. This review outlines the current understanding of autophagy in neutrophils and provides insight towards identification of novel therapeutics targeting autophagy in neutrophils.
Autophagy ; Biology ; Bone Marrow ; Extracellular Traps ; Homeostasis ; Inflammation ; Neutrophils ; Phagocytes

Extracellular vesicles (EVs) are membrane-derived vesicles that mediate intercellular communications. As professional phagocytes, neutrophils also produce EVs in response to various inflammatory stimuli during inflammatory processes. Neutrophil-derived EVs can be categorized into 2 subtypes according to the mechanism of generation. Neutrophil-derived trails (NDTRs) are generated from migrating neutrophils. The uropods of neutrophils are elongated by adhesion to endothelial cells, and small parts of the uropods are detached, leaving submicrometer-sized NDTRs. Neutrophil-derived microvesicles (NDMVs) are generated from neutrophils which arrived at the inflammatory foci. Membrane blebbing occurs in response to various stimuli at the inflammatory foci, and small parts of the blebs are detached from the neutrophils, leaving NDMVs. These 2 subtypes of neutrophil-derived EVs share common features such as membrane components, receptors, and ligands. However, there are substantial differences between these 2 neutrophil-derived EVs. NDTRs exert pro-inflammatory functions by guiding subsequent immune cells through the inflammatory foci. On the other hand, NDMVs exert anti-inflammatory functions by limiting the excessive immune responses of nearby cells. This review outlines the current understanding of the different subtypes of neutrophil-derived EVs and provides insights into the clinical relevance of neutrophil-derived EVs.
Blister ; Endothelial Cells ; Extracellular Vesicles* ; Hand ; Ligands ; Membranes ; Neutrophils* ; Phagocytes

Johne's disease is a condition that refers to chronic granulomatous enteritis in ruminants. It is believed that survival and replication of Mycobacterium (M.) paratuberculosis in mononuclear phagocytes plays an important role in the pathogenesis of Johne's disease. However, it is not clear how M. paratuberculosis survives for long time periods in mononuclear phagocytes, nor is it clear which factors trigger multiplication of these bacilli and result in the development of Johne's disease. Investigating the intracellular fate of M. paratuberculosis is challenging because of its very slow growth (more than two months to form visible colonies on media). Existing animal models also have limitations. Despite those obstacles, there has been progress in understanding the intracellular survival tactics of M. paratuberculosis and the host response against them. In this review, we compare known aspects of the intracellular survival tactics of M. paratuberculosis with those of other mycobacterial species, and consider possible mycobactericidal mechanisms of mononuclear phagocytes.
Animals ; Leukocytes, Mononuclear/*microbiology ; Mycobacterium avium subsp. paratuberculosis/*physiology ; Phagocytes/*microbiology

We present a case of perforating granuloma annulare which appeared as multiple small papular lesions with central umbilication on the dorsum of both foot and sides of foot, The patient was a 12 year-old female child who had slightly tender lesions of one month's duration. Histologic study showed perforation of the epiderrnis and release of the abnormal necrobiotic material transepiderrnally. The epidermal perforation communicated with area of granuloma annulare in the dermis that consist of necrobiotic collagen surrounded by palisading mononucler phagocytes in the dermis. All the lesions resolved spontaneously with a slight hyperpigmentation in 4 months. She also had erythematous tender nodules, which diagnosed as erythema nodosum, on both shins. The lesions responded to potassium iodide 1.0g for 2 weeks.
Child ; Collagen ; Dermis ; Erythema Nodosum ; Female ; Foot ; Granuloma Annulare* ; Granuloma* ; Humans ; Hyperpigmentation ; Phagocytes ; Potassium Iodide

The immune system is comprised of cells and molecules whose collective and coordinated response to the introduction of foreign substance is referred to as the immune response. Defense against microbes is mediated by the early reaction (innate immunity) and the late response (adaptive immunity). Innate immunity consists of the epithelial barrier, phagocytes, complement and natural killer cells. Adaptive immunity, a more complex defense reaction, consists of activation of later-developed lymphocytes that, when stimulated by exposure to infectious agents, increase in magnitude and defensive capabilities with each successive exposure. In this review we discuss recent advances in important primary immune deficiency disorders of innate immunity (chronic granulomatous disease, leukocyte adhesion deficiency) and adaptive immunity (severe combined immune deficiency, Wiskott-Aldrich syndrome).
Adaptive Immunity ; Complement System Proteins ; Immune System ; Immunity, Innate ; Killer Cells, Natural ; Leukocytes ; Lymphocytes ; Phagocytes

Neutrophils are professional phagocytes that conduct effectors functions in the innate immune systems. They are differentiated in the bone marrow (BM) and terminally differentiated neutrophils are then released into systemic circulation. Neutrophils migrate into inflammatory foci through extravasation, reverse transmigration, and chemotaxis. As neutrophils arrive at a target site, they actively participate in eliminating pathogens. They phagocytose bacteria, and eliminate them through the generation of reactive oxygen species (ROS), release of protease-enriched granules, and formation of neutrophil extracellular traps (NETs). Since neutrophils are equipped with toxic arsenals, the activation of neutrophils is tightly controlled. Priming is the process of unlocking safety mechanisms before complete activation of neutrophils. Since the first discovery of neutrophils, they were considered as a homogeneous population with an inflammatory phenotype. However, heterogenous populations of neutrophils were discovered under physiological and pathological conditions. This review outlines the normal differentiation of neutrophils in the BM, and discusses the current understandings of neutrophil heterogeneity.
Bacteria ; Bone Marrow ; Chemotaxis ; Extracellular Traps ; Immune System ; Neutrophils* ; Phagocytes ; Phenotype ; Population Characteristics* ; Reactive Oxygen Species