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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
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] |
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] |
Tissue (biology)
In biology, tissue is a biological organizational level between cells and a complete organ. A tissue is an ensemble of similar cells and their extracellular matrix from the same origin that together carry out a specific function. Organs are then formed by the functional grouping together of multiple tissues. The English word "tissue" derives from the French word "tissu", the past participle of the verb tisser, "to weave". The study of tissues is known as histology or, in connection with disease, as histopathology. Xavier Bichat is considered as the "Father of Histology". Plant histology is studied in both plant anatomy and physiology. The classical tools for studying tissues are the paraffin block in which tissue is embedded and then sectioned, the histological stain, and the optical microscope. Developments in electron microscopy, immunofluorescence, and the use of frozen tissue-sections have enhanced the detail that can be observed in tissues. With these tools, the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weil–Felix Test
The Weil–Felix test is an agglutination test for the diagnosis of rickettsial infections. It was first described in 1916. By virtue of its long history and of its simplicity, it has been one of the most widely employed tests for rickettsia on a global scale, despite being superseded in many settings by more sensitive and specific diagnostic tests. The Weil-Felix antibody was recently found to target rickettsia LPS O-antigen. History and basis for test The basis of the test is the presence of antigenic cross-reactivity between ''Rickettsia'' spp. and certain serotypes of non-motile ''Proteus'' spp., a phenomenon first published by Edmund Weil and Arthur Felix in 1916. Weil-Felix is a nonspecific agglutination test which detects anti-rickettsial antibodies in patient’s serum. Weil-Felix test is based on cross-reactions which occur between antibodies produced in acute rickettsial infections with antigens of OX (OX 19, OX 2, and OXK) strains of Proteus species. Dilution of pat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Typhus
Typhus, also known as typhus fever, is a group of infectious diseases that include epidemic typhus, scrub typhus, and murine typhus. Common symptoms include fever, headache, and a rash. Typically these begin one to two weeks after exposure. The diseases are caused by specific types of bacterial infection. Epidemic typhus is due to ''Rickettsia prowazekii'' spread by body lice, scrub typhus is due to ''Orientia tsutsugamushi'' spread by chiggers, and murine typhus is due to ''Rickettsia typhi'' spread by fleas. Vaccines have been developed, but none are commercially available. Prevention is achieved by reducing exposure to the organisms that spread the disease. Treatment is with the antibiotic doxycycline. Epidemic typhus generally occurs in outbreaks when poor sanitary conditions and crowding are present. While once common, it is now rare. Scrub typhus occurs in Southeast Asia, Japan, and northern Australia. Murine typhus occurs in tropical and subtropical areas of the worl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterophile Antibody 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] |
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] |
Cold Sensitive Antibodies
Cold sensitive antibodies (CSA) are antibodies sensitive to cold temperature. Some cold sensitive antibodies are pathological and can lead to blood disorder. These pathological cold sensitive antibodies include cold agglutinins, Donath–Landsteiner antibodies, and cryoglobulins which are the culprits of cold agglutinin disease, paroxysmal cold hemoglobinuria in the process of Donath–Landsteiner hemolytic anemia, and vasculitis, respectively. Cold agglutinin antibodies Cold agglutinins are antibodies, typically immunoglobulin M (IgM), that are acquainted with and then binding the antigens on red blood cells, typically antigens "I" or "i" on the RBC surface, in the environment in which the temperatures are lower than normal core body temperature and, thus, ends up leading to agglutinations of the red blood cells and hemolysis reaction occurring outside the vessels (extra-vessels), resulting in anemia without hemoglobinuria in ordinary cases. Cold agglutinins can cause two pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mucopolysaccharides
Glycosaminoglycans (GAGs) or mucopolysaccharides are long, linear polysaccharides consisting of repeating disaccharide units (i.e. two-sugar units). The repeating two-sugar unit consists of a uronic sugar and an amino sugar, except in the case of the sulfated glycosaminoglycan keratan, where, in place of the uronic sugar there is a galactose unit. GAGs are found in vertebrates, invertebrates and bacteria. Because GAGs are highly polar molecules and attract water; the body uses them as lubricants or shock absorbers. Mucopolysaccharidoses are a group of metabolic disorders in which abnormal accumulations of glycosaminoglycans occur due to enzyme deficiencies. Production Glycosaminoglycans vary greatly in molecular mass, disaccharide structure, and sulfation. This is because GAG synthesis is not template driven, as are proteins or nucleic acids, but constantly altered by processing enzymes. GAGs are classified into four groups, based on their core disaccharide structures. He ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipid
Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include storing energy, signaling, and acting as structural components of cell membranes. Lipids have applications in the cosmetic and food industries, and in nanotechnology. Lipids may be broadly defined as hydrophobic or amphiphilic small molecules; the amphiphilic nature of some lipids allows them to form structures such as vesicles, multilamellar/unilamellar liposomes, or membranes in an aqueous environment. Biological lipids originate entirely or in part from two distinct types of biochemical subunits or "building-blocks": ketoacyl and isoprene groups. Using this approach, lipids may be divided into eight categories: fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, saccharolipids, and polyketides (derived from condensati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 not on tissue and organs, unlike hamsters and guinea pigs whose organ cells do carry the antigen. The Forssman antigen is distinct from the Paul-Bunnell antigen, antibodies to which are diagnostic of glandular fever (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 adult ...). Both antigens are present on the red blood cells of horse and sheep but guinea pig kidney cells have only the Forssman antigen. A serum positive for glandular fever therefore agglutinates horse or sheep red blood cells after absorption with guinea pig k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
