Immunostimulating complex

Aluminium salts are currently the only widely used adjuvants in human vaccines (65). Developments in the understanding of the structure, composition, and preparation of immunostimulating complexes (ISCOMs) have been reviewed and compared. 

Quil A is used as a free form or incorporated into ISCOMs (Immunostimulating complexes). The ISCOM is a cage-like 30-40 nm particle formed through hydrophobic interactions between amphipathic antigens and the complexes formed by Quillaja saponins (0.5 % of Quil A), cholesterol (0.1.%) and phospholipids (0.1.%) [43, 53]. ISCOMs are... 

It is marketed as, and has been described to be, a potent adjuvant which has found widespread use in veterinary vaccines against, for example, foot and mouth disease, rabies, and in a number of experimental vaccines and in preclinical trials. Unfortunately its hemolytic activity and local counter reactions make it unsuitable for human vaccines [5]. Furthermore, Quil A is used for production of ISCOMs (immunostimulating complexes, typically composed of 0.5 % Quillaja saponins, 0.1% cholesterol, 0.1% phospholipid and antigen dissolved in PBS). Although side effects of Quil A were almost absent when incorporated into ISCOM, this form of vaccine is only used for veterinary vaccines and has not been approved for humans. Quil A is still a heterogeneous mixture, consisting of up to 23 different individual saponins detectable by HPLC [8]. Later, it was observed that not all saponins were active as adjuvants. A saponin termed QS III was purified from of a methanol extract of Quillaja bark by several chromatographic steps, it has, however, not been tested for adjuvant activity [12]. 

Barr IG, Mitchell GF (1996) ISCOMs (immunostimulating complexes) The first decade. Immunol Cell Biol 74 8-25... 

Morein B, Lovgren K, Hoglund S, Sundquist B (1987) The ISCOM an immunostimulating complex. Immmunol Today 8 333-338,... 

An immunostimulating complex formed from a semipurified quillaia saponin fraction by a protein antigen has proven usefiil as a protective vaccine for equine influenza virus also the subject of HIV research in humans. ... 

Saponins have additionally been reported to exhibit adjuvant-active properties. An open cage-like immunostimulating complex of cholesterol, lipid, immunogen, and saponins from bark of Quillaja saponaria MOL. (soap bark tree) has found successful application as an active adjuvant for vaccinatiMi [16]. 

Bacillus Calmette-Guerin (BCG) and its active component, muramyl dipeptide, have been shown to have aspecific immunostimulant activity. It is mainly used for the local treatment of bladder cancer. It binds to fibronectine in the bladder epithelium. Hypersensitivity reactions and immune complex disease are its major adverse reactions. 

A number of agents can suppress the immune system. However, there has been considerable interest in developing pharmacologic methods to modify or even stimulate immune function in specific situations. In particular, agents that have a positive immunomodulating effect could be beneficial to patients with compromised immune function (such as AIDS or certain cancers) or chronic infections.19,41 Development of immunostimulants, however, is understandably a complex and potentially dangerous proposition. Excessive or incorrect immune activation could trigger myriad problems that resemble autoimmune diseases. Likewise, it may be difficult to selectively stimulate certain aspects of the immune system to treat a specific... 

Immunotoxic chemicals can interfere with the body s ability to ward off disease, can induce and exacerbate allergic responses, and contribute to autoimmune diseases. The complexity of the immune system and its interaction with other body systems makes it particularly vulnerable to attack by xenobiotics. Studies that have been carried out, however, have demonstrated that a wide variety of chemicals are immunotoxic and that chemical mixtures such as those contained in air polluted with the products of combustion, industrial emissions, and tobacco smoke is immunotoxic. Such polluted air can induce immunostimulative responses and bring on allergic reactions in previously sensitized individuals. 

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