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Langerin
Langerin (CD207) is a type II transmembrane protein which is encoded by the ''CD207'' gene in humans. It was discovered by scientists Sem Saeland and Jenny Valladeau as a main part of Birbeck granules. Langerin is C-type lectin receptor on Langerhans cells (LCs) and in mice also on dermal interstitial CD103+ dendritic cells (DC) and on resident CD8+ DC in lymph nodes. Structure Langerin consists of a relatively short intracellular domain and an extracellular domain which consists of a neck-region and a carbohydrate recognition domain (CRD). The intracellular part contains a proline-rich domain (PRD). The neck region consists of alpha-helixes and mediates a formation of langerin homotrimers via a coiled-coil interaction. The homotrimers formation increases avidity and specificity of the antigen. The CRD of langerin is similar to CRDs of other C-type lectins. It contains an EPN motif – a Glu-Pro-Asn rich region. The CRD is divided into two lobes by 2 anti-parallel beta-sheet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Langerhans Cell
A Langerhans cell (LC) is a tissue-resident macrophage of the skin. These cells contain organelles called Birbeck granules. They are present in all layers of the epidermis and are most prominent in the stratum spinosum. They also occur in the papillary dermis, particularly around blood vessels, as well as in the mucosa of the mouth, foreskin, and vaginal epithelium. They can be found in other tissues, such as lymph nodes, particularly in association with the condition Langerhans cell histiocytosis (LCH). Function In skin infections, the local Langerhans cells take up and process microbial antigens to become fully functional antigen-presenting cells. Generally, tissue-resident macrophages are involved in immune homeostasis and the uptake of apoptotic bodies. However, Langerhans cells can also take on a dendritic cell-like phenotype and migrate to lymph nodes to interact with naive T-cells. Langerhans cells derive from primitive erythro-myeloid progenitors that arise in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mannan-binding Lectin
Mannose-binding lectin (MBL), also called mannan-binding lectin or mannan-binding protein (MBP), is a lectin that is instrumental in innate immunity as an opsonin and via the lectin pathway. Structure MBL has an oligomeric structure (400-700 kDa), built of subunits that contain three presumably identical peptide chains of about 30 kDa each. Although MBL can form several oligomeric forms, there are indications that dimers and trimers are biologically inactive as an opsonin and at least a tetramer form is needed for activation of complement. Genes and polymorphisms Human MBL2 gene is located on chromosome 10q11.2-q21. Mice have two homologous genes, but in human the first of them was lost. A low level expression of an MBL1 pseudogene 1 (MBL1P1) was detected in liver. The pseudogene encodes a truncated 51-amino acid protein that is homologous to the MBLA isoform in rodents and some primates. Structural mutations in exon 1 of the human MBL2 gene, at codon 52 (Arg to Cys, allele D), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmembrane Protein
A transmembrane protein (TP) is a type of integral membrane protein that spans the entirety of the cell membrane. Many transmembrane proteins function as gateways to permit the transport of specific substances across the membrane. They frequently undergo significant conformational changes to move a substance through the membrane. They are usually highly hydrophobic and aggregate and precipitate in water. They require detergents or nonpolar solvents for extraction, although some of them (beta-barrels) can be also extracted using denaturing agents. The peptide sequence that spans the membrane, or the transmembrane segment, is largely hydrophobic and can be visualized using the hydropathy plot. Depending on the number of transmembrane segments, transmembrane proteins can be classified as single-span (or bitopic) or multi-span (polytopic). Some other integral membrane proteins are called monotopic, meaning that they are also permanently attached to the membrane, but do not pass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DC-SIGN
DC-SIGN (Dendritic Cell-Specific Intercellular adhesion molecule-3-Grabbing Non-integrin) also known as CD209 ( Cluster of Differentiation 209) is a protein which in humans is encoded by the ''CD209'' gene. DC-SIGN is a C-type lectin receptor present on the surface of both macrophages and dendritic cells. DC-SIGN on macrophages recognises and binds with high affinity to high-mannose type N-glycans, a class of PAMPs (pathogen associated molecular patterns) commonly found on viruses, bacteria and fungi. This binding interaction activates phagocytosis. On myeloid and pre-plasmacytoid dendritic cells DC-SIGN mediates dendritic cell rolling interactions with blood endothelium and activation of CD4+ T cells, as well as recognition of pathogen haptens. Function DC-SIGN is a C-type lectin and has a high affinity for the ICAM3 molecule. It binds various microorganisms by recognizing high-mannose-containing glycoproteins on their surface, and can function as a co-receptor for several ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-Acetylglucosamine
''N''-Acetylglucosamine (GlcNAc) is an amide derivative of the monosaccharide glucose. It is a secondary amide between glucosamine and acetic acid. It is significant in several biological systems. It is part of a biopolymer in the bacterial cell wall, which is built from alternating units of GlcNAc and ''N''-acetylmuramic acid (MurNAc), cross-linked with oligopeptides at the lactic acid residue of MurNAc. This layered structure is called peptidoglycan (formerly called murein). GlcNAc is the monomeric unit of the polymer chitin, which forms the exoskeletons of arthropods like insects and crustaceans. It is the main component of the radulas of mollusks, the beaks of cephalopods, and a major component of the cell walls of most fungi. Polymerized with glucuronic acid, it forms hyaluronan. GlcNAc has been reported to be an inhibitor of elastase release from human polymorphonuclear leukocytes (range 8–17% inhibition), however this is much weaker than the inhibition seen wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fucose
Fucose is a hexose deoxy sugar with the chemical formula C6H12O5. It is found on ''N''-linked glycans on the mammalian, insect and plant cell surface. Fucose is the fundamental sub-unit of the seaweed polysaccharide fucoidan. The α(1→3) linked core of fucose is a suspected carbohydrate antigen for IgE-mediated allergy. Two structural features distinguish fucose from other six-carbon sugars present in mammals: the lack of a hydroxyl group on the carbon at the 6-position (C-6) (thereby making it a deoxy sugar) and the L -configuration. It is equivalent to 6-deoxy--galactose. In the fucose-containing glycan structures, fucosylated glycans, fucose can exist as a terminal modification or serve as an attachment point for adding other sugars. In human ''N''-linked glycans, fucose is most commonly linked α-1,6 to the reducing terminal β-''N''-acetylglucosamine. However, fucose at the non-reducing termini linked α-1,2 to galactose forms the H antigen, the substructure of the A an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mannose
Mannose is a sugar monomer of the aldohexose series of carbohydrates. It is a C-2 epimer of glucose. Mannose is important in human metabolism, especially in the glycosylation of certain proteins. Several congenital disorders of glycosylation are associated with mutations in enzymes involved in mannose metabolism. Mannose is not an essential nutrient; it can be produced in the human body from glucose, or converted into glucose. Mannose provides 2–5 kcal/g. It is partially excreted in the urine. Etymology The root of both "mannose" and "mannitol" is manna, which the Bible describes as the food supplied to the Israelites during their journey in the region of Sinai. Several trees and shrubs can produce a substance called manna, such as the "manna tree" ('' Fraxinus ornus'') from whose secretions mannitol was originally isolated. Structure Mannose commonly exists as two different-sized rings, the pyranose (six-membered) form and the furanose (five-membered) form. Eac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conventional Dendritic Cell
Dendritic cells (DCs) are antigen-presenting cells (also known as ''accessory cells'') of the mammalian immune system. Their main function is to process antigen material and present it on the cell surface to the T cells of the immune system. They act as messengers between the innate and the adaptive immune systems. Dendritic cells are present in those tissues that are in contact with the external environment, such as the skin (where there is a specialized dendritic cell type called the Langerhans cell) and the inner lining of the nose, lungs, stomach and intestines. They can also be found in an immature state in the blood. Once activated, they migrate to the lymph nodes where they interact with T cells and B cells to initiate and shape the adaptive immune response. At certain development stages they grow branched projections, the ''dendrites'' that give the cell its name (δένδρον or déndron being Greek for 'tree'). While similar in appearance, these are structures disti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrophage
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 immune ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Immune Cells
White blood cells, also called leukocytes or leucocytes, are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and derived from multipotent cells in the bone marrow known as hematopoietic stem cells. Leukocytes are found throughout the body, including the blood and lymphatic system. All white blood cells have nuclei, which distinguishes them from the other blood cells, the anucleated red blood cells (RBCs) and platelets. The different white blood cells are usually classified by cell lineage (myeloid cells or lymphoid cells). White blood cells are part of the body's immune system. They help the body fight infection and other diseases. Types of white blood cells are granulocytes (neutrophils, eosinophils, and basophils), and agranulocytes (monocytes, and lymphocytes (T cells and B cells)). Myeloid cells (myelocytes) include neutrophils, eosinophils, mast cells, basoph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oral Mucosa
The oral mucosa is the mucous membrane lining the inside of the mouth. It comprises stratified squamous epithelium, termed "oral epithelium", and an underlying connective tissue termed ''lamina propria''. The oral cavity has sometimes been described as a mirror that reflects the health of the individual. Changes indicative of disease are seen as alterations in the oral mucosa lining the mouth, which can reveal systemic conditions, such as diabetes or vitamin deficiency, or the local effects of chronic tobacco or alcohol use. The oral mucosa tends to heal faster and with less scar formation compared to the skin. The underlying mechanism remains unknown, but research suggests that extracellular vesicles might be involved. Classification Oral mucosa can be divided into three main categories based on function and histology: *Lining mucosa, nonkeratinized stratified squamous epithelium, found almost everywhere else in the oral cavity, including the: **Alveolar mucosa, the lining betwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vaginal Mucosa
In mammals, the vagina is the elastic, muscular part of the female genital tract. In humans, it extends from the vestibule to the cervix. The outer vaginal opening is normally partly covered by a thin layer of mucosal tissue called the hymen. At the deep end, the cervix (neck of the uterus) bulges into the vagina. The vagina allows for sexual intercourse and birth. It also channels menstrual flow, which occurs in humans and closely related primates as part of the menstrual cycle. Although research on the vagina is especially lacking for different animals, its location, structure and size are documented as varying among species. Female mammals usually have two external openings in the vulva; these are the urethral opening for the urinary tract and the vaginal opening for the genital tract. This is different from male mammals, who usually have a single urethral opening for both urination and reproduction. The vaginal opening is much larger than the nearby urethral opening, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
