An antibody (Ab) is the secreted form of a B cell receptor; the term immunoglobulin (Ig) can refer to either the membrane-bound form or the secreted form of the B cell receptor, but they are, broadly speaking, the same protein, and so the terms are often treated as synonymous. Antibodies are large, Y-shaped proteins belonging to the immunoglobulin superfamily which are used by the immune system to identify and neutralize foreign objects such as bacteria and viruses, including those that cause disease. Antibodies can recognize virtually any size antigen with diverse chemical compositions from molecules. Each antibody recognizes one or more specific antigens. This term literally means "antibody generator", as it is the presence of an antigen that drives the formation of an antigen-specific antibody. Each tip of 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" a microbe or an infected cell for attack by other parts of the immune system, or can neutralize it directly.
Immunoglobulin G (IgG) is a type of antibody. Representing approximately 75% of serum antibodies in humans, IgG is the most common type of antibody found in blood circulation. IgG molecules are created and released by plasma B cells. Each IgG antibody has two paratopes.
Immunoglobulin E (IgE) is a type of antibody that has been found only in mammals. IgE is synthesised by plasma cells. Monomers of IgE consist of two heavy chains and two light chains, with the ε chain containing four Ig-like constant domains (Cε1–Cε4). IgE is thought to be an important part of the immune response against infection by certain parasitic worms, including Schistosoma mansoni, Trichinella spiralis, and Fasciola hepatica. IgE is also utilized during immune defense against certain protozoan parasites such as Plasmodium falciparum. IgE may have evolved as a defense to protect against venoms.
Immunoglobulin M (IgM) is the largest of several isotypes of antibodies that are produced by vertebrates. IgM is the first antibody to appear in the response to initial exposure to an antigen; causing it to also be called an acute phase antibody. In humans and other mammals that have been studied, plasmablasts in the spleen are the main source of specific IgM production.
Cryoglobulinemia is a medical condition in which the blood contains large amounts of pathological cold sensitive antibodies called cryoglobulins – proteins that become insoluble at reduced temperatures. This should be contrasted with cold agglutinins, which cause agglutination of red blood cells.
The immunoglobulin heavy chain (IgH) is the large polypeptide subunit of an antibody (immunoglobulin). In human genome, the IgH gene loci are on chromosome 14.
Theralizumab is an immunomodulatory drug developed by Thomas Hünig of the University of Würzburg. It was withdrawn from development after inducing severe inflammatory reactions as well as chronic organ failure in the first-in-human study by Parexel in London in March 2006. The developing company, TeGenero Immuno Therapeutics, went bankrupt later that year. The commercial rights were then acquired by a Russian startup, TheraMAB. The drug was renamed TAB08. Phase I and II clinical trials have been completed for arthritis and clinical trials have been initiated for cancer.
The complement component 1q is a protein complex involved in the complement system, which is part of the innate immune system. C1q together with C1r and C1s form the C1 complex.
The immunoglobulin light chain is the small polypeptide subunit of an antibody (immunoglobulin).
The word allotype comes from two Greek roots, allo meaning 'other or differing from the norm' and typos meaning 'mark'. In immunology, allotype is an immunoglobulin variation that can be found among antibody classes and is manifested by heterogeneity of immunoglobulins present in a single vertebrate species. The structure of immunoglobulin polypeptide chain is dictated and controlled by number of genes encoded in the germ line. However, these genes, as it was discovered by serologic and chemical methods, could be highly polymorphic. This polymorphism is subsequently projected to the overall amino acid structure of antibody chains. Polymorphic epitopes can be present on immunoglobulin constant regions on both heavy and light chains, differing between individuals or ethnic groups and in some cases may pose as immunogenic determinants. Exposure of individuals to a non-self allotype might elicit an anti- allotype response and became cause of problems for example in a patient after transfusion of blood or in a pregnant woman. However, it is important to mention that not all variations in immunoglobulin amino acid sequence pose as a determinant responsible for immune response. Some of these allotypic determinants may be present at places that are not well exposed and therefore can be hardly serologically discriminated. In other cases, variation in one isotype can be compensated by the presence of this determinant on another antibody isotype in one individual. This means that divergent allotype of heavy chain of IgG antibody may be balanced by presence of this allotype on heavy chain of for example IgA antibody and therefore is called isoallotypic variant. Especially large number of polymorphisms were discovered in IgG antibody subclasses. Which were practically used in forensic medicine and in paternity testing, before replaced by modern day DNA fingerprinting.
In immunology, antibodies are classified into several types called isotypes or classes. The variable (V) regions near the tip of the antibody can differ from molecule to molecule in countless ways, allowing it to specifically target an antigen . In contrast, the constant (C) regions only occur in a few variants, which define the antibody's class. Antibodies of different classes activate distinct effector mechanisms in response to an antigen . They appear at different stages of an immune response, differ in structural features, and in their location around the body.
Protein L was first isolated from the surface of bacterial species Peptostreptococcus magnus and was found to bind immunoglobulins through L chain interaction, from which the name was suggested. It consists of 719 amino acid residues. The molecular weight of protein L purified from the cell walls of Peptostreptoccus magnus was first estimated as 95kD by SDS-PAGE in the presence of reducing agent 2-mercaptoethanol, while the molecular weight was determined to 76kD by gel chromatography in the presence of 6 M guanidine HCl. Protein L does not contain any interchain disulfide loops, nor does it consist of disulfide-linked subunits. It is an acidic molecule with a pI of 4.0. Unlike protein A and protein G, which bind to the Fc region of immunoglobulins (antibodies), protein L binds antibodies through light chain interactions. Since no part of the heavy chain is involved in the binding interaction, Protein L binds a wider range of antibody classes than protein A or G. Protein L binds to representatives of all antibody classes, including IgG, IgM, IgA, IgE and IgD. Single chain variable fragments (scFv) and Fab fragments also bind to protein L.
Tanox was a biopharmaceutical company based in Houston, Texas. The company was founded by two biomedical research scientists, Nancy T. Chang and Tse Wen Chang in March 1986 with $250,000, which was a large part of their family savings at that time. Both Changs grew up and received college education in chemistry in National Tsing Hua University in Taiwan and obtained Ph.D. degrees from Harvard University. For postdoctoral training, Tse Wen shifted to immunology and did research with Herman N. Eisen at the Center for Cancer Research, M.I.T. The two Changs successively became research managers and worked with a range of monoclonal antibody projects in Centocor, Inc. based in Malvern, Pennsylvania, from 1981 to 1985. The Changs were recruited by Baylor College of Medicine toward the end of 1985 and offered faculty positions in the Division of Molecular Virology. Soon after their arrival, they were encouraged by a high-ranking Baylor official and local business leaders to start a biotech venture in Houston. This was in a period of time when the economy of Houston was in slump as the result of the collapse of the oil industry.
A myeloma protein is an abnormal antibody (immunoglobulin) or a fragment thereof, such as an immunoglobulin light chain, that is produced in excess by an abnormal monoclonal proliferation of plasma cells, typically in multiple myeloma or Monoclonal gammopathy of undetermined significance. Other terms for such a protein are monoclonal protein, M protein, M component, M spike, spike protein, or paraprotein. This proliferation of the myeloma protein has several deleterious effects on the body, including impaired immune function, abnormally high blood viscosity, and kidney damage.
Ig mu chain C region is a protein that in humans is encoded by the IGHM gene.
IgG deficiency is a form of dysgammaglobulinemia where the proportional levels of the IgG isotype are reduced relative to other immunoglobulin isotypes.
In hematology, plasma cell dyscrasias are a spectrum of progressively more severe monoclonal gammopathies in which a clone or multiple clones of pre-malignant or malignant plasma cells over-produce and secrete into the blood stream a myeloma protein, i.e. an abnormal monoclonal antibody or portion thereof. The exception to this rule is the disorder termed non-secretory multiple myeloma; this disorder is a form of plasma cell dyscrasia in which no myeloma protein is detected in serum or urine of individuals who have clear evidence of an increase in clonal bone marrow plasma cells and/or evidence of clonal plasma cell-mediated tissue injury. Here, a clone of plasma cells refers to group of plasma cells that are abnormal in that they have an identical genetic identity and therefore are descendants of a single genetically distinct ancestor cell.
Complement-dependent cytotoxicity (CDC) is an effector function of IgG and IgM antibodies. When they are bound to surface antigen on target cell, the classical complement pathway is triggered by bonding protein C1q to these antibodies, resulting in formation of a membrane attack complex (MAC) and target cell lysis.
Recombinant antibodies are antibody fragments produced by using recombinant antibody coding genes. They mostly consist of a heavy and light chain of the variable region of immunoglobulin. Recombinant antibodies have many advantages in both medical and research applications, which make them a popular subject of exploration and new production against specific targets. The most commonly used form is the single chain variable fragment (scFv), which has shown the most promising traits exploitable in human medicine and research. In contrast to monoclonal antibodies produced by hybridoma technology, which may lose the capacity to produce the desired antibody over time or the antibody may undergo unwanted changes, which affect its functionality, recombinant antibodies produced in phage display maintain high standard of specificity and low immunogenicity.
Monoclonal gammopathy of renal significance (MGRS) are a group of kidney disorders that present with kidney damage due to nephrotoxic monoclonal immunoglobulins secreted by clonal plasma cells or B cells. By definition, people with MGRS do not meet criteria for multiple myeloma or other hematologic malignancies. The term MGRS was introduced in 2012 by the International Kidney and Monoclonal Gammopathy Research Group (IKMG). MGRS is associated with monoclonal gammopathy of undetermined significance (MGUS). People with MGUS have a monoclonal gammopathy but does not meet the criteria for the clonal burden nor the presence of end organ damage seen in hematologic malignancies. In a population based study based on the NHANES III health survey; 6% of patients with MGUS were subsequently classified as having MGRS. The prevalence and incidence of MGRS in the general population or in specific populations is not known but it is more prevalent in those over the age of 50 as there is a monoclonal protein (M-protein) present in 3% of those 50 and years older and 5% of those 70 years and older, placing those 50 and older at increased risk of MGRS.
