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Addressin
Mucosal vascular addressin cell adhesion molecule 1 (MAdCAM-1) is a protein that in humans is encoded by the ''MADCAM1'' gene. The protein encoded by this gene is an endothelium, endothelial cell adhesion molecule that interacts preferentially with the leukocyte beta7 integrin LPAM-1 (ITGA7, alpha4 / ITGB7, beta7), L-selectin, and VLA-4 (alpha4 / CD29, beta1) on myeloid cells to direct leukocytes into mucosal and inflamed tissues. It is a member of the immunoglobulin superfamily and is similar to ICAM-1 and VCAM-1. Nomenclature Addressin is a lesser-used term to describe the group of adhesion molecules that are involved with lymphocyte homing, commonly found at High endothelial venules, high-endothelial venules (HEVs) where lymphocytes exit the blood and enter the lymph node. Addressins are the ligands to the homing receptors of lymphocytes. The task of these ligands and their receptors is to determine which tissue the lymphocyte will enter next. They carry carbohydrates in or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High Endothelial Venules
High endothelial venules (HEV) are specialized post-capillary venous swellings characterized by plump endothelial cells as opposed to the usual thinner endothelial cells found in regular venules. HEVs enable lymphocytes circulating in the blood to directly enter a lymph node (by crossing through the HEV). Table 14-1 In humans, HEVs are found in all secondary lymphoid organs (with the exception of spleen, where blood exits through open arterioles and enters the red pulp), including hundreds of lymph nodes dispersed in the body, tonsils and adenoids in the pharynx, Peyer's patches (PIs) in the small intestine, appendix, and small aggregates of gut-associated lymphoid tissue, lymphoid tissue in the stomach and large intestine. In contrast to the endothelial cells from other vessels, the high endothelial cells of HEVs have a distinctive appearance, consisting of a cuboidal morphology (biology), morphology and with various receptors to interact with leukocytes (express specialized ligand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homing Receptor
Lymphocyte homing receptors are cell adhesion molecules expressed on lymphocyte cell membranes that recognize addressins on target tissues. ''Lymphocyte homing'' refers to adhesion of the circulating lymphocytes in blood to specialized endothelial cells within lymphoid organs. These diverse tissue-specific adhesion molecules on lymphocytes (''homing receptors'') and on endothelial cells (''vascular addressins'') contribute to the development of specialized immune responses. Free lymphocytes constantly recirculate in blood after their re-entry from lymphoid tissue, via lymphatic vessel, lymphatic and thoracic ducts. This happens so that the full repertoire of antigenic specificities of lymphocytes is continuously represented throughout the body. Homing happens in tissue-specific manner—e.g. B lymphocytes migrate better to mucosa-associated lymphoid tissue (Peyer's patches), and T lymphocytes preferentially to the peripheral lymph nodes. The process of lymphocyte homing is deliberat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CD34
CD34 is a transmembrane phosphoglycoprotein protein encoded by the CD34 gene in humans, mice, rats and other species. CD34 derives its name from the cluster of differentiation protocol that identifies cell surface antigens. CD34 was first described on hematopoietic stem cells independently by Civin et al. and Tindle et al. as a cell surface glycoprotein and functions as a cell-cell adhesion factor. It may also mediate the attachment of hematopoietic stem cells to bone marrow extracellular matrix or directly to stromal cells. Clinically, it is associated with the selection and enrichment of hematopoietic stem cells for bone marrow transplants. Due to these historical and clinical associations, CD34 expression is almost ubiquitously related to hematopoietic cells; however, it is actually found on many other cell types as well. Function The CD34 protein is a member of a family of single-pass transmembrane sialomucin proteins that show expression on early haematopoietic and vascul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoclonal Antibody
A monoclonal antibody (mAb, more rarely called moAb) is an antibody produced from a cell Lineage made by cloning a unique white blood cell. All subsequent antibodies derived this way trace back to a unique parent cell. Monoclonal antibodies can have monovalent affinity, binding only to the same epitope (the part of an antigen that is recognized by the antibody). In contrast, polyclonal antibodies bind to multiple epitopes and are usually made by several different antibody-secreting plasma cell lineages. Bispecific monoclonal antibodies can also be engineered, by increasing the therapeutic targets of one monoclonal antibody to two epitopes. It is possible to produce monoclonal antibodies that specifically bind to virtually any suitable substance; they can then serve to detect or purify it. This capability has become an investigative tool in biochemistry, molecular biology, and medicine. Monoclonal antibodies are being used on a clinical level for both the diagnosis and therapy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lymphotoxin
Lymphotoxin is a member of the tumor necrosis factor (TNF) superfamily of cytokines, whose members are responsible for regulating the growth and function of lymphocytes and are expressed by a wide variety of cells in the body. Lymphotoxin plays a critical role in developing and preserving the framework of lymphoid organs and of gastrointestinal immune responses, as well as in the activation signaling of both the innate and adaptive immune responses. Lymphotoxin alpha (LT-α, previously known as TNF-beta) and lymphotoxin beta (LT-β), the two forms of lymphotoxin, each have distinctive structural characteristics and perform specific functions. Structure and function Each LT-α/LT-β subunit is a trimer and assembles into homotrimers or heterotrimers. LT-α binds with LT-β to form membrane-bound heterotrimers LT-α1-β2 and LT-α2-β1, which are commonly referred to as lymphotoxin beta. LT-α1-β2 is the most prevalent form of lymphotoxin beta. LT-α also forms a homotrimer, LT ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GLYCAM1
Glycosylation-dependent cell adhesion molecule-1 (GLYCAM1) is a proteoglycan ligand expressed on cells of the high endothelial venules in lymphoid tissues. It is the ligand for the receptor L-selectin L-selectin, also known as CD62L, is a cell adhesion molecule found on the cell surface of leukocytes, and the blastocyst. It is coded for in the human by the ''SELL'' gene. L-selectin belongs to the selectin family of proteins, which recognize s ... allowing for naive lymphocytes to exit the bloodstream into lymphoid tissues. GLYCAM1 binds to L-selectin by presenting one or more O-linked carbohydrates to the lectin domain of the leukocyte cell surface selectin. Data suggests that GLYCAM1 is a hormone-regulated milk protein that is part of the milk mucin complex. GlyCAM-1 is expressed exclusively on high endothelial venules. It is unclear how GlyCAM-1 is attached to the membrane as it lacks a transmembrane region. External links * References {{immunology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EMedicine
eMedicine is an online clinical medical knowledge base founded in 1996 by doctors Scott Plantz and Jonathan Adler, and computer engineer Jeffrey Berezin. The eMedicine website consists of approximately 6,800 medical topic review articles, each of which is associated with a clinical subspecialty "textbook". The knowledge base includes over 25,000 clinically multimedia files. Each article is authored by board certified specialists in the subspecialty to which the article belongs and undergoes three levels of physician peer-review, plus review by a Doctor of Pharmacy. The article's authors are identified with their current faculty appointments. Each article is updated yearly, or more frequently as changes in practice occur, and the date is published on the article. eMedicine.com was sold to WebMD in January, 2006 and is available as the Medscape Reference. History Plantz, Adler and Berezin evolved the concept for eMedicine.com in 1996 and deployed the initial site via Boston Med ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lymphocyte
A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include natural killer cells (which function in cell-mediated, cytotoxic innate immunity), T cells (for cell-mediated, cytotoxic adaptive immunity), and B cells (for humoral, antibody-driven adaptive immunity). They are the main type of cell found in lymph, which prompted the name "lymphocyte". Lymphocytes make up between 18% and 42% of circulating white blood cells. Types The three major types of lymphocyte are T cells, B cells and natural killer (NK) cells. Lymphocytes can be identified by their large nucleus. T cells and B cells T cells (thymus cells) and B cells ( bone marrow- or bursa-derived cells) are the major cellular components of the adaptive immune response. T cells are involved in cell-mediated immunity, whereas B cells are primarily responsible for humoral immunity (relating to antibodies). The function of T cells and B cells is to recognize sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ligand
In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electron pairs, often through Lewis bases. The nature of metal–ligand bonding can range from covalent to ionic. Furthermore, the metal–ligand bond order can range from one to three. Ligands are viewed as Lewis bases, although rare cases are known to involve Lewis acidic "ligands". Metals and metalloids are bound to ligands in almost all circumstances, although gaseous "naked" metal ions can be generated in a high vacuum. Ligands in a complex dictate the reactivity of the central atom, including ligand substitution rates, the reactivity of the ligands themselves, and redox. Ligand selection requires critical consideration in many practical areas, including bioinorganic and medicinal chemistry, homogeneous catalysis, and environmental chemi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VCAM-1
Vascular cell adhesion protein 1 also known as vascular cell adhesion molecule 1 (VCAM-1) or cluster of differentiation 106 (CD106) is a protein that in humans is encoded by the ''VCAM1'' gene. VCAM-1 functions as a cell adhesion molecule. Structure VCAM-1 is a member of the immunoglobulin superfamily, the superfamily of proteins including antibodies and T-cell receptors. The VCAM-1 gene contains six or seven immunoglobulin domains, and is expressed on both large and small blood vessels only after the endothelial cells are stimulated by cytokines. It is alternatively spliced into two known RNA transcripts that encode different isoforms in humans. The gene product is a cell surface sialoglycoprotein, a type I membrane protein that is a member of the Ig superfamily. Function The VCAM-1 protein mediates the adhesion of lymphocytes, monocytes, eosinophils, and basophils to vascular endothelium. It also functions in leukocyte-endothelial cell signal transduction, and it may play ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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