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Panel Reactive Antibody
A panel-reactive antibody (PRA) is a group of antibodies in a test serum that are reactive against any of several known specific antigens in a panel of test leukocytes or purified HLA antigens from cells. It is an immunologic metric routinely performed by clinical laboratories on the blood of people awaiting organ transplantation. Traditionally serum is exposed to panel lymphocytes and to an extent other leukocytes in a complement dependent cytotoxicity test. From the extent and pattern of cytotoxicity an estimation of what percentage of the possible donor population the patient has antibodies against is calculated. The PRA score is expressed as a percentage representing the proportion of the population to which the person being tested will react via pre-existing antibodies against human cell surface antigens, which include human leukocyte antigen, HLA] and other polymorphic antigen systems. It is a test of the degree of alloimmunity in a graft recipient and thus a test that quan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antibodies
An antibody (Ab) or immunoglobulin (Ig) is a large, Y-shaped protein belonging to the immunoglobulin superfamily which is used by the immune system to identify and neutralize antigens such as bacteria and viruses, including those that cause disease. Each individual antibody recognizes one or more specific antigens, and antigens of virtually any size and chemical composition can be recognized. Antigen literally means "antibody generator", as it is the presence of an antigen that drives the formation of an antigen-specific antibody. Each of the branching chains comprising the "Y" of an antibody contains a paratope that specifically binds to one particular epitope on an antigen, allowing the two molecules to bind together with precision. Using this mechanism, antibodies can effectively "tag" the antigen (or a microbe or an infected cell bearing such an antigen) for attack by cells of the immune system, or can neutralize it directly (for example, by blocking a part of a viru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alloimmunity
Alloimmunity (sometimes called isoimmunity) is an immune response to nonself antigens from members of the same species, which are called alloantigens or isoantigens. Two major types of alloantigens are blood group antigens and histocompatibility antigens. In alloimmunity, the body creates antibodies (called alloantibodies) against the alloantigens, attacking transfused blood, allotransplanted tissue, and even the fetus in some cases. Alloimmune (isoimmune) response results in graft rejection, which is manifested as deterioration or complete loss of graft function. In contrast, autoimmunity is an immune response to the self's own antigens. (The ''allo-'' prefix means "other", whereas the ''auto-'' prefix means "self".) Alloimmunization (isoimmunization) is the process of becoming alloimmune, that is, developing the relevant antibodies for the first time. Alloimmunity is caused by the difference between products of highly polymorphic genes, primarily genes of the major histocomp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intravenous Immunoglobulin
Immunoglobulin therapy is the use of a mixture of antibodies (normal human immunoglobulin) to treat several health conditions. These conditions include primary immunodeficiency, immune thrombocytopenic purpura, chronic inflammatory demyelinating polyneuropathy, Kawasaki disease, certain cases of HIV/AIDS and measles, Guillain–Barré syndrome, and certain other infections when a more specific immunoglobulin is not available. Depending on the formulation it can be given by injection into muscle, a intravenous, vein, or subcutaneous injection, under the skin. The effects last a few weeks. Common side effects include pain at the site of injection, muscle pain, and allergic reactions. Other severe side effects include kidney problems, anaphylaxis, blood clots, and red blood cell breakdown. Use is not recommended in people with some types of IgA deficiency. Use appears to be relatively safe during pregnancy. Human immunoglobulin is made from human blood plasma. It contains antibo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma Exchange
Plasmapheresis (from the Greek πλάσμα, ''plasma'', something molded, and ἀφαίρεσις ''aphairesis'', taking away) is the removal, treatment, and return or exchange of blood plasma or components thereof from and to the blood circulation. It is thus an extracorporeal therapy, a medical procedure performed outside the body. Three general types of plasmapheresis can be distinguished: * ''Autologous'', removing blood plasma, treating it in some way, and returning it to the same person, as a therapy. * ''Exchange'', a patient's blood plasma is removed, while blood products are given in replacement. This type is called plasma exchange (PE, PLEX, or PEX) or plasma exchange therapy (PET). The removed plasma is discarded and the patient receives replacement donor plasma, albumin, or a combination of albumin and saline (usually 70% albumin and 30% saline). * ''Donation'', removing blood plasma, separating its components, and returning some of them to the same person, while hol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exogenous Antigen
In immunology, an antigen (Ag) is a molecule, moiety, foreign particulate matter, or an allergen, such as pollen, that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune response. Antigens can be proteins, peptides (amino acid chains), polysaccharides (chains of simple sugars), lipids, or nucleic acids. Antigens exist on normal cells, cancer cells, parasites, viruses, fungi, and bacteria. Antigens are recognized by antigen receptors, including antibodies and T-cell receptors. Diverse antigen receptors are made by cells of the immune system so that each cell has a specificity for a single antigen. Upon exposure to an antigen, only the lymphocytes that recognize that antigen are activated and expanded, a process known as clonal selection. In most cases, antibodies are ''antigen-specific'', meaning that an antibody can only react to and bind one specific antigen; in some instances, however, antibodies may cross-react to bi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorochrome
A fluorophore (or fluorochrome, similarly to a chromophore) is a fluorescent chemical compound that can re-emit light upon light excitation. Fluorophores typically contain several combined aromatic groups, or planar or cyclic molecules with several π bonds. Fluorophores are sometimes used alone, as a tracer in fluids, as a dye for staining of certain structures, as a substrate of enzymes, or as a probe or indicator (when its fluorescence is affected by environmental aspects such as polarity or ions). More generally they are covalently bonded to macromolecules, serving as a markers (or dyes, or tags, or reporters) for affine or bioactive reagents (antibodies, peptides, nucleic acids). Fluorophores are notably used to stain tissues, cells, or materials in a variety of analytical methods, such as fluorescent imaging and spectroscopy. Fluorescein, via its amine-reactive isothiocyanate derivative fluorescein isothiocyanate (FITC), has been one of the most popular fluorophores. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latex
Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latices are found in nature, but synthetic latices are common as well. In nature, latex is found as a wikt:milky, milky fluid, which is present in 10% of all flowering plants (angiosperms) and in some Mushroom, mushrooms (especially species of ''Lactarius''). It is a complex emulsion that coagulation, coagulates on exposure to air, consisting of proteins, alkaloids, starches, sugars, Vegetable oil, oils, tannins, resins, and Natural gum, gums. It is usually exuded after tissue injury. In most plants, latex is white, but some have yellow, orange, or scarlet latex. Since the 17th century, latex has been used as a term for the fluid substance in plants, deriving from the Latin word for "liquid". It serves mainly as Antipredator adaptation, defense against Herbivore, herbivores and Fungivore, fungivores.Taskirawati, I. and Tuno, N., 2016Fungal defense against mycophagy in milk caps ''Science Report Kanazaw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transplant Rejection
Transplant rejection occurs when transplanted tissue is rejected by the recipient's immune system, which destroys the transplanted tissue. Transplant rejection can be lessened by determining the molecular similitude between donor and recipient and by use of immunosuppressant drugs after transplant. Types Transplant rejection can be classified into three types: hyperacute, acute, and chronic. These types are differentiated by how quickly the recipient's immune system is activated and the specific aspect or aspects of immunity involved. Hyperacute rejection Hyperacute rejection is a form of rejection that manifests itself in the minutes to hours following transplantation. It is caused by the presence of pre-existing antibodies in the recipient that recognize antigens in the donor organ. These antigens are located on the endothelial lining of blood vessels within the transplanted organ and, once antibodies bind, will lead to the rapid activation of the complement system. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Risk Assessment
Risk assessment is a process for identifying hazards, potential (future) events which may negatively impact on individuals, assets, and/or the environment because of those hazards, their likelihood and consequences, and actions which can mitigate these effects. The output from such a process may also be called a risk assessment. Hazard analysis forms the first stage of a risk assessment process. Judgments "on the tolerability of the risk on the basis of a risk analysis" (i.e. risk evaluation) also form part of the process. The results of a risk assessment process may be expressed in a quantitative or qualitative fashion. Risk assessment forms a key part of a broader risk management strategy to help reduce any potential risk-related consequences. Categories Individual risk assessment Risk assessments can be undertaken in individual cases, including in patient and physician interactions. In the narrow sense chemical risk assessment is the assessment of a health risk in response ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Complement System
The complement system, also known as complement cascade, is a part of the humoral, innate immune system and enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and attack the pathogen's cell membrane. Despite being part of the innate immune system, the complement system can be recruited and brought into action by antibodies generated by the adaptive immune system. The complement system consists of a number of small, inactive, liver synthesized protein precursors circulating in the blood. When stimulated by one of several triggers, proteases in the system cleave specific proteins to release cytokines and initiate an amplifying cascade of further cleavages. The end result of this ''complement activation'' or ''complement fixation'' cascade is stimulation of phagocytes to clear foreign and damaged material, inflammation to attract additional phagocytes, and activation of the cell-killi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antigen
In immunology, an antigen (Ag) is a molecule, moiety, foreign particulate matter, or an allergen, such as pollen, that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune response. Antigens can be proteins, peptides (amino acid chains), polysaccharides (chains of simple sugars), lipids, or nucleic acids. Antigens exist on normal cells, cancer cells, parasites, viruses, fungus, fungi, and bacteria. Antigens are recognized by antigen receptors, including antibodies and T-cell receptors. Diverse antigen receptors are made by cells of the immune system so that each cell has a specificity for a single antigen. Upon exposure to an antigen, only the lymphocytes that recognize that antigen are activated and expanded, a process known as clonal selection. In most cases, antibodies are ''antigen-specific'', meaning that an antibody can only react to and bind one specific antigen; in some instances, however, antibodies may cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lymphocytes
A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include T cells (for cell-mediated and cytotoxic adaptive immunity), B cells (for humoral, antibody-driven adaptive immunity), and innate lymphoid cells (ILCs; "innate T cell-like" cells involved in mucosal immunity and homeostasis), of which natural killer cells are an important subtype (which functions in cell-mediated, cytotoxic innate immunity). They are the main type of cell found in lymph, which prompted the name "lymphocyte" (with ''cyte'' meaning cell). 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. They can also be classified as small lymphocytes and large lymphocytes based on their size and appearance. Lymphocytes can be identified by their large nucleus. T cells and B cells T cells (thymus cells) and B cells ( bone marrow- or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
