Anti-body
| of these articles treats anti-bodies from scientific view. For the feature of the same name see anti-body (film). |
Anti-bodies are proteins (proteins) from the class of the Globuline, which are formed in vertebrate animals, lively by certain penetrated foreign matter, as Antigens to be designated. They serve the protection against these foreign matter. As antigens almost exclusively macromolecules work or at particles bound molecules, for example Lipopolysaccharide at the surface of bacteria. A certain antigen induces usually the education only onecertain, suitable anti-body, which is bound specifically only to this foreign matter.
The specific connection of anti-bodies to the antigens forms a substantial part of the defense against the penetrated foreign matter. With pathogens (Pathogenen) as foreign matter the education can and connection from anti-bodies to the immunity lead. Anti-bodies are thus central of components of the immune system of higher vertebrate animals and one designation therefore the anti-bodies than Immunglobuline (industrial union).
Anti-bodies become from a class of white blood cells (leukocytes), i.e. to Effektorzellen differentiated B-cells (= plasma cells), sezerniert (seperately). They seem to the fabric in the blood and in the extracellular liquid . They “recognize” usually not entire structure of the antigen, but only one part of the same, the so-called antigens determinant (that Epitop).
Table of contents |
structure of anti-bodies
anti-bodies as B-cell-receptors
diaphragm-constant anti-bodies (when designates B-cell-receptors (BCR)) can activate B-cells, if they are transverseinterlaced by antigens. The B-cell takes thereupon up, the antigen digests and presents the immune complex by Endocytose proteolytically over MHC class IIMolecules of fragments of it (Peptide with 8-12 amino acids) on their cell surface. If the presented fragments are then recognized of a CD4 T-cell (T-Helferzellen) as strange, this T-cell stimulates the B-cell, which further maturing processes (somatic hypermutation, class change) as well as the transformation of the B-cell to the antikörpersezernierenden plasma cell or to MEMORY the B-cell releases. These maturing processes take place within germ centers in the secondary lymphatic organs (spleen, lymph node) and under the term of the germ center reaction are summarized.
impactsfrom sezernierten anti-bodies
Sezernierte anti-bodies work by different mechanisms:
- The simplest is the neutralization of antigens. Because the anti-body binds the antigen is blocked, this and cannot unfold for example its toxic effect any longer, or other reciprocal effects of the antigenwith body cells are prevented.
- A further is the Opsonisierung (“lecker make”), the cladding of pathogens and foreign particles with anti-bodies. If an anti-body binds for example to an antigen that on the surface of a bacterium is, it “marks” thereby that at the same timeBacterium, because the constant region of the anti-body, which bound to its antigen, are recognized by Phagozyten, which can take up and digest the bacterium as Fresszellen.
- A third impact is that antique opera activate the complement system.
- Anti-body, those to body-own cellsbind, can numerical control cells activate, which kill these cells then. This process is called also “Antibody dependency cell mediated cytotoxicity” (ADCC).
gives different classes (ISO types) of
anti-bodies in the body five different groups (classes) of anti-bodies, whereby that industrial unionfor Immunglobulin stands. The different ISO types occur in different Kompartimenten of the body and have different tasks:
IgA
- becomes on all mucous membranes of the respiratory system, the eyes, the gastro-intestinal tract, the Urogenitaltrakts as well asover special glands around the nipple of mothers sekretiert approximately and protects there against Pathogenen (also the newborn child). Sekretiertes IgA occurs in the form of Homo Dimeren; the two portions are connected by “Joining Peptide”.
IgD
- it becomesthe receptor (BCR) on, naive (antigen-inexperienced) B-cells mature through differential splices IgM/IgD Prä mRNA together with IgM as B-cell diaphragm-constantly coexprimiert.
- IgD is only in small quantities in sezernierter form in blood and Lymphe available, unknown to function.
IgE
- IgEobtain the protection from parasites, like e.g. Worms. It is bound by fiber plastic receptors on mast cells. For this reason almost all IgE is diaphragm-bound, in the blood is practically missing it. With antigen contact it is transverseinterlaced, which for the payment of histamines, Granzymen etc. by the mast cells and Granulozyten leads. These kill the exciter. In addition the latters work strongly container-extending, which facilitates an approaching of other immune cells. In addition it works muskelkontraktierend, which facilitates the elimination of the exciters over lung and intestine.
- IgEis just as involved to the allergischen Sofortreaktion.
IgM
- is formed immediately after the contact with antigens and indicates the acute infection phase of an illness.
- e.g. Anti HBs IgM = against hepatitis B virus arranged anti-bodies thatIgM class (indication of the active hepatitis B-illness)
- IgM is a Pentamer (Multimer) from five subunits. Also these subunits are connected by the Joining of Peptide.
IgG
- is only formed in a retarded defense phase (3 weeks) andremains for a long time. A gone through infection indicates.
- e.g. Anti HBs IgG = against hepatitis B-virus arranged anti-bodies of the IgG class (indication of one taken place having hepatitis B - illness or inoculation)
- it gives diseases with an innate or acquired lackat anti-bodies, see lack of anti-body.
- If the body forms anti-bodies against own body components, one speaks autoanti-bodies so mentioned of an autoimmune illness.
- In addition IgG is transported actively over the blood and the Plazenta (barrier) into the Fötus and ensures there also nachgeburtlichfor a first protection from infections.
use of anti-bodies in the medicine
from animals won anti-bodies (anti-serums) are used as therapeutic agent for most diverse purposes. An important example is the use as passive vaccine.
In addition become monoclonal anti-bodies since newest used in the medicine therapeutically. Main field of application is the Hämatologie and Onkologie, besides they become also in the treatment of autoimmune illnesses (e.g. with multiple Sklerose) like the Rheumatoiden Arthritis (RA) assigned. Here these anti-bodies recognizeper inflammatorische Zytokine such as IL-1 or TNF A. Thus anti-body represents a medicine class, which is for the first time able to intervene specifically in the inflammatory procedures.
Anti-bodies can be also used for it certain materials in the body to make. In addition one hangsto the anti-body a weakly radioactive substance. If one the anti-body now ausrichted to hang itself to a certain material by changing the antigen binding place accordingly, one can determine by radiographs, where the radioactive substance is exactly. Thiscan for example be used to make Geschwülste in the body.
In former times was the constant part of the anti-bodies still murin (from the mouse), which could lead to repulsion reactions by the immune system. In order to go around this problem, recently so-called become humanisierte anti-bodies uses. Conventional monoclonal anti-bodies contain protein components of the mouse, which possibly repels the human immune system as strange beside the variable region obtaining specificity against human antigens still. With the help of molecular-biological procedures therefore the murinen parts become thatconstant sections far away and by identically constructed constant parts of human anti-bodies replaces. The constant sections of the anti-bodies do not play a role for the specific connection of the monoclonal anti-body. The monoclonal anti-body developed in such a way is designated as „humanisierter monoclonal anti-body " and becomes ofImmune system of humans no longer push off. Humanisierte anti-bodies are made in a culture of hamster Ovarialzellen, why their production is also more expensive very many more complex and therefore than production in micro organisms.
use of anti-bodies in biology
One makes the high specificity, with which anti-bodies recognize their antigen, in biology too uses oneself, in order to make the antigen, in the very most cases a protein, visible. One proceeds as follows: First the antigen must, against that thatAnti-body to be arranged is to be selected and produced. This can be achieved in different ways, for example, as a Peptid is synthesized in vitro or the protein as a whole rekombinant in bacteria is manufactured. The protein an animal becomes subsequently,injected, whose forms immune system then anti-bodies against the protein. This procedure is called “Immunisierung”. As anti-body producers mice and rabbits, in addition, goats, sheep and horses are particularly used. The Immunisierung is repeated several times. After a few weeks the animal one becomesBlood test taken, which is examined for existing anti-bodies against the antigen. If it is positive, the antigen can be made visible with the anti-body (see anti-body colouring).
Applications methodically:
see also
- radio immune therapy : With this therapy an ionizing radiation is coupled to an anti-body.
literature
- Stefan peg, Petra tubing brook, Andreas Schmiedl: Rekombinante anti-body: Tools against cancer, infections and autoimmune illnesses?Biology in our time34 (6), S. 372-379 (2004), ISSN 0045-205X
