Immune system immunosuppression

Immunoglobulin. Immunoprotein glycoprotein of animal origin with known antibody activity, or protein related by chemical structure, which may or may not have antibody activity. Divided into five classes IgM, IgG, IgA, IgD, and IgE on the basis of structure and biological activity. Immunostimulant. Stimulating various functions or activities of the immune system. Immunosuppressant. An agent capable of suppressing immune responses. 

Drugs that act on the immune system immunosuppressive and immunostimulatory drugs... 

Drugs that Act on the Immune System Immunosuppressive and Immunostimulatory... 

Many different types of immunosuppressants can be used to prevent or control rejection. Most of them, including steroids, suppress the entire immune system (Merck 2003). Antilymphocyte globulin, antithymocyte globulin, and monoclonal antibodies suppress only specific parts of the immune system. Immunosuppressants must be taken for an indefinite period. High doses are usually necessary for the first few weeks, and after that smaller doses can usually prevent rejection (Stark et al. 2002 Villard 2006). 

Secondary immunodeficiencies (9) are much more common than primary ones and frequently occur as a result of immaturity of the immune system in premature infants, immunosuppressive therapy, or surgery and trauma. Illnesses, particularly when prolonged and serious, have been associated with secondary immunodeficiencies, some of which may be reversible. Acquked immune deficiency syndrome (AIDS) (10—12) may be considered a secondary immunodeficiency disease caused by the human immunodeficiency vimses HIV-1 or HIV-2. Hitherto unknown, the disease began to spread in the United States during the latter part of the 1970s. The agent responsible for this infection has been isolated and identified as a retrovims. 

Immunosuppressive agents (immunosuppressants) are drugs that attenuate immune reactions. An application is indicated in case our immune system reacts inadequately leading to serious diseases or normal immune reactions are unwanted, e.g., following transplantations. 

Varizella zoster vitus (VZV) is a highly contagious herpesvirus causing chickenpox upon primary infection. After recovery, the vims stays dormant in nerve roots. Weakening of the immune system, e.g. in people over the age of 60 or under immunosuppressive therapy, can lead to reactivation of VZV. This recurrence causes shingles (herpes zoster), a painful rash that develops in a well-defined band corresponding to the area enervated by the affected nerve cells. 

Tolerance is the process that allows organ-specific antigens to be accepted as self.2,6 This would mean that the immune system would cease to respond to the allograft, and immunosuppressive medications would not be necessary. Immune tolerance has not been accomplished successfully in humans.2,6... 

There is clear evidence linking defects of the immune system to the development of NMSC. For example, it is observed that patients receiving chronic immunosuppressant therapy for organ transplantation have a 50% risk of developing SCC within 20 years of transplantation, and 30% of these cancers are highly aggressive.21 Additionally, patients with human immunodeficiency virus (HIV) infection are predisposed to melanoma.18 Data also support the idea that UV radiation... 

The discovery of the peripheral CB2 receptor, which localizes in cells of the immune system, is very likely linked to the well-known immunosuppression of marijuana smokers. 

Recently, it has been shown that inhalation of MWNTs caused suppression of the systemic immunity without resulting in significant lung inflammation or tissue damage [82,83]. Inhaled MWNTs in fact modified the functionality of spleen cells in exposed mice [82]. Notably, the activity of cyclooxygenase (COX) enzymes in spleen was affected as a response to a cytokine (TGF(5) released from the lungs. This cytokine activated the COX pathway in the spleen, triggering T-cell dysfunction and systemic immunosuppression [83]. 

The third example considered the interaction of life-history traits (survival rates, fecundity, immunogenicity) with an environmental factor specific to parasites, namely the host immune system. Here phenotypic diversity in response to environmental conditions (host immunity) is not so readily apparent. To observe phenotypic diversity, different parasite lines need to be compared in their kinetics of infection and, to show immune-dependence, these must be complemented by control experiments in immunosuppressed hosts. Experiments seeking to select on this diversity... 

The immunosuppressant compound170 FK-506, similar in effect to cyclosporin A, the leading drug for use in immune system suppression to prevent rejection of transplanted organs171, has been labelled at carbon atoms 10, 16, 18, 21a, 24 and 26 by fermentative biosynthesis using sodium [l-14C]propionate as a precursor172. The same 13C-labelled positions were derived from [l-13C]propionate. FK-506 producing culture Streptomyces tsukubaenis no 9993 has been utilized in this biosynthesis (120 h incubation at 29 °C). 

A variety of medical conditions exist that are caused or exacerbated by the immune system itself. These are usually treated by administering immunosuppressive agents. Examples include ... 

The majority of early publications that can be reasonably identified as comprising immunotoxicology reported altered resistance to infection in animals exposed to various environmental or industrial chemicals. Authors logically concluded that xenobiotic exposure suppressed immune function since the immune system is ultimately responsible for this resistance to infection. Subsequent studies demonstrated that suppression of various cellular and functional endpoints accompanied or preceded increased sensitivity to infection, and that administration of known immunosuppressants likewise decreased host resistance. The human health implications of these studies, that chemical exposure reduced resistance to infection, drove the initial focus of many immunotoxicologists on functional suppression, and provided the theoretical and practical underpinnings of immunotoxicity testing. 

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