immunology Immunology is a branch of medicineImmunology for Medical Students, Roderick Nairn, Matthew Helbert, Mosby, 2007 and biology that covers the medical study of immune systems in humans, animals, plants and sapient species. In such we can see the ...

, an idiotope is the unique set of

antigenic determinants An epitope, also known as antigenic determinant, is the part of an antigen that is recognized by the immune system, specifically by antibodies, B cells, or T cells. The epitope is the specific piece of the antigen to which an antibody binds. The p ...

(epitopes) of the variable portion of an

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 ...

. In some cases it can be the actual

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 respons ...

-binding site, and in some cases it may comprise variable region sequences outside of the antigen-binding site on the antibody itself. Thus each antibody would have multiple idiotopes; and the set of these individual idiotopes is termed the ''idiotype'' of the antibody. Idiotopes contrast with allotopes, which are non-varying structures on the Fc receptor. If a separate antibody is produced that has specific binding capabilities to an idiotope of the previously described antibody, it is said to be an "anti-idiotypic antibody". If such is the case, the anti-idiotypic antibodies will be able to bind to the

B lymphocyte B cells, also known as B lymphocytes, are a type of white blood cell of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system. B cells produce antibody molecules which may be either secreted or ...

receptor for the original antigen and inhibit the

immune response An immune response is a reaction which occurs within an organism for the purpose of defending against foreign invaders. These invaders include a wide variety of different microorganisms including viruses, bacteria, parasites, and fungi which could ...

to that antigen. This type of regulation was proposed by Danish immunologist

Niels Jerne Niels is a male given name, equivalent to Nicholas, which is common in Denmark, Belgium, Norway (formerly) and the Netherlands. The Norwegian and Swedish variant is Nils. The name is a developed short form of Nicholas or Greek Nicolaos after Saint ...

in 1974. He termed it the "Network Hypothesis". This type of B lymphocyte regulation may be partially responsible for preventing an immune response from getting out of control, which would elicit damage to host tissue or even cause an autoimmune diseased state. Because of the resemblance of anti-idiotypic antibodies to the original antigen,

vaccine A vaccine is a biological preparation that provides active acquired immunity to a particular infectious or malignant disease. The safety and effectiveness of vaccines has been widely studied and verified.

studies have been performed. These types of vaccines are called "idiotypic vaccines". An anti-idiotypic

monoclonal antibody A monoclonal antibody (mAb, more rarely called moAb) is an antibody produced from a cell Lineage made by cloning a unique white blood cell. All subsequent antibodies derived this way trace back to a unique parent cell. Monoclonal antibodies ...

was generated to possess an "internal image of

cocaine Cocaine (from , from , ultimately from Quechua: ''kúka'') is a central nervous system (CNS) stimulant mainly used recreationally for its euphoric effects. It is primarily obtained from the leaves of two Coca species native to South Ameri ...

". The anti-idiotypic antibody bound to the human

dopamine transporter The dopamine transporter (also dopamine active transporter, DAT, SLC6A3) is a membrane-spanning protein that pumps the neurotransmitter dopamine out of the synaptic cleft back into cytosol. In the cytosol, other transporters sequester the dop ...

with mimicry of the cocaine molecule and completely inhibited cocaine binding. None are produced commercially to date.

References

{{reflist Antibodies