Immune system immunopotentiation

In an attempt to restore normal immune system function or to activate the immune system, immunopotentiators often are used. The best example of immunopotentiation of the immune system is the practice of immunizations. Active immunization with a vaccine or toxoid induces the host s immune system to confer protection against a pathogen (e.g., hepatitis A, hepatitis B, diphtheria toxoid, etc.). This process requires the uptake of the immunogenic epitope by ABCs, followed by presentation to CD4+ T-lymphocytes, and the subsequent development of either a cellular or humoral immune response. 

A common method to enhance the humoral response to weak immunogens is the admixture of the immunogens with so-called adjuvants. These adjuvants are immunopotentiators which activate one or more sectors of the immune system resulting in an enhanced immune response. A rigid classification of adjuvants or a unifying concept of the mechanism of their action is, therefore, impossible (Dresser,... 

Thus, saponins are apparently able to stimulate or suppress the immune system by two different mechanisms. In one mechanism, saponins interact with cell membrane components to alter cell permeability, membrane-associated enzymes, cell-surface receptors, and other components, and thus result in a nonspecific stimulation (or suppression) of phagocytosis, phagocytic chemiluminescence, and other functions of phagocytic lymphocytes. These effects can take place in vivo or in vitro. In the other mechanism, formation of imines (Schiff bases) by carbonyl-containing saponins can provide a co-stimulatory signal necessary for specific immunopotentiation of T cells that leads to a CMI response. This second mechanism, which is known as an adjuvant effect, takes place only in vivo, and is discussed in more detail in subsequent sections of this article. From previous work [62,73], it is expected that, for saponins with appropriate structures, both mechanisms would take place. Perhaps, the best-known case where both mechanisms can take place is that of the saponins derived from Q. saponaria Molina, which are next discussed in more detail. 

One way that selenium appears to act is as a non-specific stimulant of immune competent tissues and cells contributing to its anti-inflammatory, immunopotentiation and carcinostatic attributes. Additional data suggests other effects of Se upon cells of the immune system perhaps independent of GSHPx activity such as ubiquinone biosynthesis, (Coenz3one Q 10) which in turn affects host-defense mechanisms (Frost, 1975). A third possibility to explain the effects attributed to Se above is to propose that increases in levels of the selenium dependent enzyme glutathione peroxidase and perhaps other specific selenium-dependent functions in lymphocytes and macrophages is the reason for immunoenhancement. This subject has been addressed by Schauzer (1979) and is amplified here by the author. 

Its biodegradability and low toxicity in humans have aided the recent increased interest in chitosan as an immunopotentiating agent. In vivo studies have demonstrated that chitosan powder and solution formulations are able to enhance the systemic and mucosal immune responses after nasal vaccine delivery [19, 22, 76],... 

Khan, M. Z. I., Opdebeeck, J. P., and Tucker, I. G., 1994, Immunopotentiation and delivery systems for antigens for single-step immunization Recent trends and progress, Pharm. Res. 11 241. 

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