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Surfactant Protein A
Surfactant protein A is an innate immune system collectin. It is water-soluble and has collagen-like domains similar to SP-D. It is part of the innate immune system and is used to opsonize bacterial cells in the alveoli marking them for phagocytosis by alveolar macrophages. SP-A may also play a role in negative feedback limiting the secretion of pulmonary surfactant. SP-A is not required for pulmonary surfactant to function but does confer immune effects to the organism. During parturition The role of surfactant protein A (SP-A) in childbirth is indicated in studies with mice. Mice which gestate for 19 days typically show signs of SP-A in amniotic fluid at around 16 days. If SP-A is injected into the uterus at 15 days, mice typically deliver early. Inversely, an SP-A inhibitor injection causes notable delays in birth. The presence of surfactant protein A seemed to trigger an inflammatory response in the uterus of the mice, but later studies found an anti-inflammatory response in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SFTPA1
Surfactant protein A1 (SP-A1), also known as Pulmonary surfactant-associated protein A1 (PSP-A) is a protein that in humans is encoded by the ''SFTPA1'' gene. Summary SP-A1 is primarily synthesised in type II alveolar cells in the lung, as part of a complex of lipids and proteins known as pulmonary surfactant. The function of this complex is to reduce surface tension in the alveoli and prevent their collapse during expiration. The protein component of surfactant helps in the modulation of the innate immune response, and inflammatory processes. SP-A1 is a member of a subfamily of C-type lectins called collectins. Together with SP-A2, they are the most abundant proteins of pulmonary surfactant. SP-A1 binds to the carbohydrates found in the surface of several microorganisms and helps in the defense against respiratory pathogens. Surfactant homeostasis is critical for breathing (and thus survival) in the prematurely born infant, but also for maintaining lung health, and normal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SFTPA2B
Surfactant protein A2 (SP-A2), also known as Pulmonary surfactant-associated protein A2 (PSP-A2) is a protein that in humans is encoded by the SFTPA2 gene. Summary The protein encoded by this gene (SP-A2) is primarily synthesized in lung alveolar type II cells, as part of a complex of lipids and proteins known as pulmonary surfactant. The function of this complex is to reduce surface tension in the alveolus and prevent collapse during expiration. The protein component of surfactant helps in the modulation of the innate immune response, and inflammatory processes. SP-A2 is a member of a subfamily of C-type lectins called collectins. Together with (surfactant protein A1 ) SP-A1, they are the most abundant proteins of pulmonary surfactant. SP-A2 binds to the carbohydrates found in the surface of several microorganisms and helps in the defense against respiratory pathogens. Surfactant homeostasis is critical for breathing (and thus survival) in the prematurely born infant, bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Innate Immune System
The innate, or nonspecific, immune system is one of the two main immunity strategies (the other being the adaptive immune system) in vertebrates. The innate immune system is an older evolutionary defense strategy, relatively speaking, and is the dominant immune system response found in plants, fungi, insects, and primitive multicellular organisms (see Beyond vertebrates).. The major functions of the innate immune system are to: * recruit immune cells to infection sites by producing chemical factors, including chemical mediators called cytokines * activate the complement cascade to identify bacteria, activate cells, and promote clearance of antibody complexes or dead cells * identify and remove foreign substances present in organs, tissues, blood and lymph, by specialized white blood cells * activate the adaptive immune system through antigen presentation * act as a physical and chemical barrier to infectious agents; via physical measures such as skin and chemical measures such a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Collectin
Collectins (collagen-containing C-type lectins) are a part of the innate immune system. They form a family of collagenous Ca2+-dependent defense lectins, which are found in animals. Collectins are soluble pattern recognition receptors (PRRs). Their function is to bind to oligosaccharide structure or lipids that are on the surface of microorganisms. Like other PRRs they bind pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs) of oligosaccharide origin. Binding of collectins to microorganisms may trigger elimination of microorganisms by aggregation, complement activation, opsonization, activation of phagocytosis, or inhibition of microbial growth. Other functions of collectins are modulation of inflammatory, allergic responses, adaptive immune system and clearance of apoptotic cells. Structure Functionally collectins are trimers. Monomeric subunit consists of four parts: * a cysteine-rich domain at the N-terminus * a collagen-like domain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SP-D
Surfactant protein D, also known as SP-D, is a lung surfactant protein part of the collagenous family of proteins called collectin. In humans, SP-D is encoded by the ''SFTPD'' gene and is part of the innate immune system. Each SP-D subunit is composed of an N-terminal domain, a collagenous region, a nucleating neck region, and a C-terminal lectin domain. Three of these subunits assemble to form a homotrimer, which further assemble into a tetrameric complex. Interactions Surfactant protein D has been shown to interact with DMBT1, and hemagglutinin of influenza A virus. Post-translational modification of SP-D i.e. S-nitrosylation switches its function. See also * pulmonary surfactant Pulmonary surfactant is a surface-active complex of phospholipids and proteins formed by type II alveolar cells. The proteins and lipids that make up the surfactant have both hydrophilic and hydrophobic In chemistry, hydrophobicity is t ... References Further reading * * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulmonary Alveolus
A pulmonary alveolus (plural: alveoli, from Latin ''alveolus'', "little cavity"), also known as an air sac or air space, is one of millions of hollow, distensible cup-shaped cavities in the lungs where oxygen is exchanged for carbon dioxide. Alveoli make up the functional tissue of the mammalian lungs known as the lung parenchyma, which takes up 90 percent of the total lung volume. Alveoli are first located in the respiratory bronchioles that mark the beginning of the respiratory zone. They are located sparsely in these bronchioles, line the walls of the alveolar ducts, and are more numerous in the blind-ended alveolar sacs. The acini are the basic units of respiration, with gas exchange taking place in all the alveoli present. The alveolar membrane is the gas exchange surface, surrounded by a network of capillaries. Across the membrane oxygen is diffused into the capillaries and carbon dioxide released from the capillaries into the alveoli to be breathed out. Alveoli are pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phagocytosis
Phagocytosis () is the process by which a cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs phagocytosis is called a phagocyte. In a multicellular organism's immune system, phagocytosis is a major mechanism used to remove pathogens and cell debris. The ingested material is then digested in the phagosome. Bacteria, dead tissue cells, and small mineral particles are all examples of objects that may be phagocytized. Some protozoa use phagocytosis as means to obtain nutrients. History Phagocytosis was first noted by Canadian physician William Osler (1876), and later studied and named by Élie Metchnikoff (1880, 1883). In immune system Phagocytosis is one main mechanisms of the innate immune defense. It is one of the first processes responding to infection, and is also one of the initiating branches of an adaptive immune response. Although mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrophages
Macrophages (abbreviated as M φ, MΦ or MP) ( el, large eaters, from Greek ''μακρός'' (') = large, ''φαγεῖν'' (') = to eat) are a type of white blood cell of the immune system that engulfs and digests pathogens, such as cancer cells, microbes, cellular debris, and foreign substances, which do not have proteins that are specific to healthy body cells on their surface. The process is called phagocytosis, which acts to defend the host against infection and injury. These large phagocytes are found in essentially all tissues, where they patrol for potential pathogens by amoeboid movement. They take various forms (with various names) throughout the body (e.g., histiocytes, Kupffer cells, alveolar macrophages, microglia, and others), but all are part of the mononuclear phagocyte system. Besides phagocytosis, they play a critical role in nonspecific defense (innate immunity) and also help initiate specific defense mechanisms (adaptive immunity) by recruiting other immun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulmonary Surfactant
Pulmonary surfactant is a surface-active complex of phospholipids and proteins formed by type II alveolar cells. The proteins and lipids that make up the surfactant have both hydrophilic and hydrophobic In chemistry, hydrophobicity is the physical property of a molecule that is seemingly repelled from a mass of water (known as a hydrophobe). In contrast, hydrophiles are attracted to water. Hydrophobic molecules tend to be nonpolar and, t ... regions. By adsorption, adsorbing to the air-water Interface (chemistry), interface of pulmonary alveolus, alveoli, with hydrophilic head groups in the water and the hydrophobic tails facing towards the air, the main lipid component of surfactant, dipalmitoylphosphatidylcholine (DPPC), reduces surface tension. As a medication, Pulmonary surfactant (medication), pulmonary surfactant is on the WHO Model List of Essential Medicines, the most important medications needed in a basic health system. Function * To increase pulmonary com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SFTPA2
Surfactant protein A2 (SP-A2), also known as Pulmonary surfactant-associated protein A2 (PSP-A2) is a protein that in humans is encoded by the SFTPA2 gene. Summary The protein encoded by this gene (SP-A2) is primarily synthesized in lung alveolar type II cells, as part of a complex of lipids and proteins known as pulmonary surfactant. The function of this complex is to reduce surface tension in the alveolus and prevent collapse during expiration. The protein component of surfactant helps in the modulation of the innate immune response, and inflammatory processes. SP-A2 is a member of a subfamily of C-type lectins called collectins. Together with (surfactant protein A1 ) SP-A1, they are the most abundant proteins of pulmonary surfactant. SP-A2 binds to the carbohydrates found in the surface of several microorganisms and helps in the defense against respiratory pathogens. Surfactant homeostasis is critical for breathing (and thus survival) in the prematurely born infant, bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
