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Heterophile
Heterophile antibodies are antibodies induced by external antigens ( heterophile antigens). Some cross-react with self-antigens. For example, in rheumatic fever, antibodies against group A streptococcal cell walls can also react with (and thus damage) human heart tissues. These are considered heterophile antibodies. In clinical diagnosis, the heterophile antibody test specifically refers to a rapid test for antibodies produced against the Epstein-Barr virus (EBV), the causative agent of infectious mononucleosis. Heterophile antibodies can cause significant interference in any immunoassay.An immunoassay is a biochemical test, frequently used in medical diagnostic testing, that measures the presence or concentration of a macromolecule in a solution through the use of an antibody or immunoglobulin. The presence of a heterophile antibody is characterized by broad reactivity with antibodies of other animal species (which are often the source of the assay antibodies). Such antibo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infectious Mononucleosis
Infectious mononucleosis (IM, mono), also known as glandular fever, is an infection usually caused by the Epstein–Barr virus (EBV). Most people are infected by the virus as children, when the disease produces few or no symptoms. In young adults, the disease often results in fever, sore throat, enlarged lymph nodes in the neck, and tiredness. Most people recover in two to four weeks; however, feeling tired may last for months. The liver or spleen may also become swollen, and in less than one percent of cases splenic rupture may occur. While usually caused by the Epstein–Barr virus, also known as human herpesvirus 4, which is a member of the herpesvirus family, a few other viruses may also cause the disease. It is primarily spread through saliva but can rarely be spread through semen or blood. Spread may occur by objects such as drinking glasses or toothbrushes or through a cough or sneeze. Those who are infected can spread the disease weeks before symptoms develop. Mono is p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monospot Test
The mononuclear spot test or monospot test, a form of the heterophile antibody test, is a rapid test for infectious mononucleosis due to Epstein–Barr virus (EBV). It is an improvement on the Paul–Bunnell test. The test is specific for heterophile antibodies produced by the human immune system in response to EBV infection. Commercially available test kits are 70–92% sensitive and 96–100% specific, with a lower sensitivity in the first two weeks after clinical symptoms begin. The United States Center for Disease Control deems the monospot test not to be very useful. Medical uses It is indicated as a confirmatory test when a physician suspects EBV, typically in the presence of clinical features such as fever, malaise, pharyngitis, tender lymphadenopathy (especially posterior cervical; often called "tender glands") and splenomegaly.Davidson's Principles & Practices of Medicine 20th ed In the case of delayed or absent seroconversion, an immunofluorescence test could be use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterophile Antigen
Heterophile antigens are antigens of similar nature, if not identical, that are present in different tissues in different biological species, classes, or kingdoms. Usually different species have different antigen sets, but the hetereophile antigen is shared by different species. Other heterophile antigens are responsible for some diagnostic serological tests such as: * Weil-Felix reaction for typhus fever * Paul Bunnell test for infectious mononucleosis *Cold agglutinin test in primary atypical pneumonia Chemically, heterophile antigens are composed of lipoprotein-polysaccharide complexes. There is a possibility of there being identical chemical groupings in the structure of mucopolysaccharids and lipids. Example: Forssman antigen The Forssman antigen is a glycolipid heterophil protein and a type of heterogenetic antigen found in certain animals like dogs, horses, cats, turtles and sheep, and enteric organisms such as pneumococci. In sheep, it is found on erythrocytes but n ... ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterophile Antigen
Heterophile antigens are antigens of similar nature, if not identical, that are present in different tissues in different biological species, classes, or kingdoms. Usually different species have different antigen sets, but the hetereophile antigen is shared by different species. Other heterophile antigens are responsible for some diagnostic serological tests such as: * Weil-Felix reaction for typhus fever * Paul Bunnell test for infectious mononucleosis *Cold agglutinin test in primary atypical pneumonia Chemically, heterophile antigens are composed of lipoprotein-polysaccharide complexes. There is a possibility of there being identical chemical groupings in the structure of mucopolysaccharids and lipids. Example: Forssman antigen The Forssman antigen is a glycolipid heterophil protein and a type of heterogenetic antigen found in certain animals like dogs, horses, cats, turtles and sheep, and enteric organisms such as pneumococci. In sheep, it is found on erythrocytes but n ... ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cross-reactivity
Cross-reactivity, in a general sense, is the reactivity of an observed agent which initiates reactions outside the main reaction expected. This has implications for any kind of test or assay, including diagnostic tests in medicine, and can be a cause of false positives. In immunology, the definition of cross-reactivity refers specifically to the reaction of the immune system to antigens. There can be cross-reactivity between the immune system and the antigens of two different pathogens, or between one pathogen and proteins on non-pathogens, which in some cases can be the cause of allergies. In medical testing In medical tests, including rapid diagnostic tests, cross-reactivity can be either confounding or helpful, depending on the instance. An example of confounding that yields a false positive error is in a latex fixation test when agglutination occurs with another antigen rather than the antigen of interest. An example of helpful cross-reactivity is in heterophile antibo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antibody
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the pathogen, called an antigen. Each tip of the "Y" of an antibody contains a paratope (analogous to a lock) that is specific for one particular epitope (analogous to a key) on an antigen, allowing these two structures to bind together with precision. Using this binding mechanism, an antibody can ''tag'' a microbe or an infected cell for attack by other parts of the immune system, or can neutralize it directly (for example, by blocking a part of a virus that is essential for its invasion). To allow the immune system to recognize millions of different antigens, the antigen-binding sites at both tips of the antibody come in an equally wide variety. In contrast, the remainder of the antibody is relatively constant. It only occurs in a few varia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antigen
In immunology, an antigen (Ag) is a molecule or molecular structure or any foreign particulate matter or a pollen grain that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune response. The term ''antigen'' originally referred to a substance that is an antibody generator. Antigens can be proteins, peptides (amino acid chains), polysaccharides (chains of monosaccharides/simple sugars), lipids, or nucleic acids. 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, an antibody can only react to and bind one specific antigen; in some instances, however, antibodies may cross-react and bind more than one antigen. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Self-antigen
Immune tolerance, or immunological tolerance, or immunotolerance, is a state of unresponsiveness of the immune system to substances or tissue that would otherwise have the capacity to elicit an immune response in a given organism. It is induced by prior exposure to that specific antigen and contrasts with conventional immune-mediated elimination of foreign antigens (see Immune response). Tolerance is classified into central tolerance or peripheral tolerance depending on where the state is originally induced—in the thymus and bone marrow (central) or in other tissues and lymph nodes (peripheral). The mechanisms by which these forms of tolerance are established are distinct, but the resulting effect is similar. Immune tolerance is important for normal physiology. Central tolerance is the main way the immune system learns to discriminate self from non-self. Peripheral tolerance is key to preventing over-reactivity of the immune system to various environmental entities (allergens, g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rheumatic Fever
Rheumatic fever (RF) is an inflammatory disease that can involve the heart, joints, skin, and brain. The disease typically develops two to four weeks after a streptococcal throat infection. Signs and symptoms include fever, multiple painful joints, involuntary muscle movements, and occasionally a characteristic non-itchy rash known as erythema marginatum. The heart is involved in about half of the cases. Damage to the heart valves, known as rheumatic heart disease (RHD), usually occurs after repeated attacks but can sometimes occur after one. The damaged valves may result in heart failure, atrial fibrillation and infection of the valves. Rheumatic fever may occur following an infection of the throat by the bacterium ''Streptococcus pyogenes''. If the infection is left untreated, rheumatic fever occurs in up to three percent of people. The underlying mechanism is believed to involve the production of antibodies against a person's own tissues. Due to their genetics, some peo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Group A Streptococcus
Lancefield grouping is a system of classification that classifies catalase-negative Gram-positive cocci based on the carbohydrate composition of bacterial antigens found on their cell walls. The system, created by Rebecca Lancefield, was historically used to organize the various members of the family Streptococcaceae, which includes the genera ''Lactococcus'' and ''Streptococcus'', but now is largely superfluous due to explosive growth in the number of streptococcal species identified since the 1970s. However, it has retained some clinical usefulness even after the taxonomic changes, and as of 2018, Lancefield designations are still often used to communicate medical microbiological test results. Enterococcus, formerly known as Group D Streptococcus, were classified as members of the genus Streptococcus until 1984 and were included in the original Lancefield grouping. Many - but not all - species of streptococcus are beta-hemolytic. Notably, Enterococci and ''Streptococcus bovis' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Immunoassay
An immunoassay (IA) is a biochemical test that measures the presence or concentration of a macromolecule or a small molecule in a solution through the use of an antibody (usually) or an antigen (sometimes). The molecule detected by the immunoassay is often referred to as an "analyte" and is in many cases a protein, although it may be other kinds of molecules, of different sizes and types, as long as the proper antibodies that have the required properties for the assay are developed. Analytes in biological liquids such as serum or urine are frequently measured using immunoassays for medical and research purposes. Immunoassays come in many different formats and variations. Immunoassays may be run in multiple steps with reagents being added and washed away or separated at different points in the assay. Multi-step assays are often called separation immunoassays or heterogeneous immunoassays. Some immunoassays can be carried out simply by mixing the reagents and sample and making a p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
