Immune system interferons

Cancer now afflicts one out of four adults. One of the more promising therapies for certain kinds of cancers involves the use of interferon, a protein that occurs in minute quantities in the body where it is an essential part of the body s immune system. Interferon can be produced outside the body in cultures of transformed lymphoblastoid cells. A few years ago, it was possible to culture these human cells on scales up to a few hundred milliliters. Chemical engineers have now developed reactors for the aseptic culture of human cells on a scale 100,000 times larger, making it possible to produce human interferon in practical useful quantities. 

Virus infection stimulates the production of protective glycoproteins (interferons) which act (1) directly on uninfected cells to induce enzymes that degrade viral RNA (2) indirectly by stimulating the immune system. Interferons will also modify cell regulatory mechanisms and inhibit neoplastic... 

The pathway is negatively regulated by protein tyrosine phosphatases and by feedback inhibition through STAT-mediated expression of suppressors of cytokine signaling (SOCs). Agonists for cytokine receptors are currently used to stimulate red blood cell maturation in anemia (erythropoietin) and to stimulate the immune system (interferons). The cascade nature of the cytokine pathway lends itself to future agents that specifically target components of the pathway. 

Immunomodulators are a group of mostly stimulatory effectors which act on cells of the immune system (e.g. cytokines, interferons). 

The key end result of TLR signalling is the induction of cytokines. Cytokines are proteins produced during an immune response that allow the maturation, activation and differentiation of effector cells in the immune system. The activation of NFkB and AP-1 by the MyD88 and the TREF dependent pathways leads to the production of proinflammatory cytokines such as IL-6, TNF-a and various chemokines. This pathway can also activate IRF-7 via TLR-7and TLR-9 allowing Type-I interferons to be produced. 

Type II interferons. These are acid-labile and are also known as immune (IFN-y) interferons because they are produced by T-lymphocytes (see Chapter 14) in the eellular immune system in response to specific anhgens. 

Neutrophils, lymphocytes, and monocytes are attracted to the area, and monocytes are converted to macrophages.18,19 The macrophages then stimulate additional prostaglandin production. Phagocytic cells and other players in the immune system release cytokines, including interleukins, interferon, and tumor necrosis factor. 

The categories of a, (3, and y interferons exist the a interferons are used in the treatment of cancer. Interferon enhances the immune system s attack on cancer cells, can decrease new... 

The term cytokine was first introduced in the mid 1970s. It was applied to polypeptide growth factors controlling the differentiation and regulation of cells of the immune system. The interferons and interleukins represented the major polypeptide families classified as cytokines at that time. Additional classification terms were also introduced, including lymphokines (cytokines such as IL-2 and IFN-y, produced by lymphocytes) and monokines (cytokines such as TNF-a, produced by monocytes). However, classification on the basis of producing cell types also proved inappropriate, as most cytokines are produced by a range of cell types (e.g. both lymphocytes and monocytes produce IFN-a). 

Interferons alpha and beta have major effects on the immune system, such as increasing the expression of MHC-I and MHC-II. Interferon-a is elevated in patients with idiopathic lupus and it is believed to be involved in its pathogenesis [105] therefore, it is not surprising that therapy with these interferons can lead to autoimmunity. 

The presence of a certain number of amino acids is significant for the restitution of the immune system s cells, interferon synthesis process and other factors realization of the immune defense system. The decrease of full-form protein consumption is one of the causes of secondary immune-deficiency states. The significance of ascorbic acid presence for the immune system is supported by the fact that its concentration in the neutrophil granulocytes is 150 times higher than in the blood serum. The significance of retinol s and carotenoids role is supported in the cases of cell differentiation, where DNA synthesis increase, and proliferation decrease thus stabilizing the organism when under infection. 

Interferons—Family of immune system signal proteins that interfere with the ability of viruses to infect cells. Interferons have been genetically engineered to provide treatments by weakening immune response in autoimmune disease such as multiple sclerosis, or by strengthening immune response in diseases like hepatitis C. 

Interferons are natural proteins produced by the cells of the immune system in response to challenges by foreign agents such as viruses, parasites and tumor cells. Interferons assist the immune response by inhibiting viral replication within host cells. There are three major classes of interferons, interferon type I, interferon type II and interferon type III. They bind to a differen cell surface receptor complexes. The type I interferons in humans are IFN-o , IFN-jS and IFN- >. IFN-y is human interferon type II. All classes of interferon are important in fighting RNA virus infections and endogenous interferons are secreted when abnormally large amounts of dsRNA are found in a cell. 

Immunomodulators affect the functioning of the immune system. Immune functions may be promoted as well as suppressed by these agents. In this section interferon alpha, BCG, immunocyanin and aldesleukine and the monoclonal antibodies, alem-tuzumab, bevacizumab, cetuximab, trastuzumab, rit-uximab and ibritumomab tiuxetan will be briefly discussed. 

The effects of interferons on the human immune system are highly variable. IFN-p tends to suppress certain aspects of immune function, whereas IFN-a can inhibit immune cell proliferation IFN-y, on the other hand, displays immune-enhancing properties. All three types of interferon have been studied preclinically and even clinically. 

Cytokine is a general term used for a diverse assortment of water-soluble protein molecules that mediate interactions between the various cells of the innate and adaptive immune systems. Over 100 human cytokines are currently under study and more than 300,000 research papers have been published in this area over the past 10-15 years. The interferons, discussed in section 6.2.1, are a subset of the cytokines, as are the interleukins, discussed in section 6.1.3. The nomenclature used to describe cytokines is somewhat confusing and varying subclasses of cytokines are recognized ... 

Just as interferons and interleukins are a subset of the class of molecules known as cytokines, in turn, cytokines are a subset of a larger family of proteins known as growth factors (see figure 6.3). Although not all growth factors are involved in regulation of the immune system, they are nevertheless protein messenger molecules that influence cell... 

Cytokines are proteins that serve as signal molecules in cell-cell communication, and as such, perform a central and very diverse function in growth and differentiation of an organism. Representatives of cytokines control proliferation, differentiation and function of cells of the immune system and of cells of the blood-forming system. Furthermore, they are involved in processes of inflammation and in the neuronal, hema-poetic and embryonal development of the organism. Known cytokines include the interleukins (IL), erythropoietin, growth hormone, interferons (INF) and tumor necrosis factor (TNF) (see Table 8.1). A review of cytokines and cytokine receptors is to be found in HiU and Treisman, (1995) Taniguchi et al., (1995) and Moutoussamy et al., (1998). 

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