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introduction to the immune system and immunotherapyThe immune system has many components
The human immune system is made up of several different systems that work together to protect the body against foreign matter, organisms or aberrant cells of the body. These systems can be differentiated according to their specificity and the cell types involved. There are three types of immunity:(1) non-specific innate immunity, (2) humoral immunity and (3) cellular immunity. The last two types are known as part of adaptive immunity and considered "specific" because they rely on the recognition of foreign molecules by B and T cells produced by the body and adapt with exposure. This is why once you get a cold, you will not get sick from the same cold virus again. Furthermore, your body mounts a much faster response the second time you are infected and prevents symptoms from appearing.
Immune system disorders and treatment through immunotherapy
The immune system's ability to recognise foreign molecules can sometimes go awry. For example, signalling pathways may not function properly or the immune system may fail to recognize the body's own parts and attack them as though they were foreign. This is called autoimmunity and results in diseases of the immune system. Key examples include type 1 diabetes (T1D), which affects the β cells in the pancreas; multiple sclerosis, which affects motor neurons; and systemic lupus erythematosus, a systemic autoimmune disease in which the host generates antibodies against chromatin and proteins in the cell's replication machinery. One way of reducing the severity of these aberrant immune reactions or to cure these diseases is through direct modulation of the immune system through immunotherapy. The following sections will discuss both the immune system and immunotherapy.
Social importance of immune diseases
Despite the rarer occurrence of these diseases in comparison to infectious diseases in any given population, new research has shown that many diseases have secondary autoimmune consequences. For example, HIV infection is associated with the production of autoantibodies, which leads to the destruction of immune cells as well as other host components. In addition, treatment during highly active antiretroviral therapy (HAART) can lead to complications in which autoimmune diseases appear. This is not to say, however, that autoimmune diseases themselves are unimportant: quite the contrary. Diseases such as type 1 diabetes, rheumatoid arthritis and systemic lupus erythematosus can have a profound impact on an individual's quality of life and, if not caught in time or treated, can lead to very serious complications, including death[5,6,7]. Consequently, the study of autoimmune diseases and immunotherapy is important to the improvement of health in all countries, regardless of their wealth.
Transgenic plants as a promising production system for immunotherapy
Human use of plants as sources of medicinal compounds is not a new occurrence. What is new, however, is that genetic techniques in the 21st century have allowed researchers to turn plants into "bioreactors" in which the desired genes and vectors are added to obtain the desired protein products. But this view that transgenic plant systems are "unnatural" is entirely unfounded. Current research has shown that transgenic plant systems are safe and efficient. For example, protein extraction techniques have been shown to be very specific so that even in transgenic tobacco systems, nicotine is not isolated along with the protein of interest[7,8]. Furthermore, scale-up costs of transgenic plant systems are minimal while the short reproduction cycle of these plants allow multiple harvests within a year.
references1) Sherwood L. Human physiology: From cells to systems. Belmont: Wadsworth Publishing Company; 1997; p.374-415.
2) Janeway C , Travers P, Walport M, Shlomchik M. Immunobiology: The immune system in health and disease. New York: Garland Science Publishing; 2005, p. 557-612.
3) Ansari A A. Autoimmunity, anergy, lentiviral immunity and disease. Autoimmun Rev 2004, 3: 530-40.
4) French MA, Price P, Stone SF. Immune restoration disease after antiretroviral therapy. AIDS 2004, 18: 1615-27.
5) WHO. Diabetes mellitus factsheet. http://www.who.int/mediacentre/factsheets/fs138/en/, accessed Mar 24, 2006.
6) Hewlett S, Cockshott Z, Byron M, Kitchen K, Tipler S, Pope D, Hehir M. Patients' perceptions of fatigue in rheumatoid arthritis: Overwhelming, uncontrollable, ignored. Arthritis & Rheumatism 2005, 53: 697?702.
7) Desai UA, Sur G, Daunert S, Babbitt R, Li Q. Expression and affinity purification of recombinant proteins from plants. Protein Expr Purif 2002, 25: 195-202.
8) Ko K, Wei X, Crooks PA, Koprowski H. Elimination of alkaloids from plant-derived human monoclonal antibody. J Immunol Methods 2004, 286: 79-85.
9) Schillberg S, Twyman RM, Fischer R. Opportunities for recombinant antigen and antibody expression in transgenic plants--technology assessment. Vaccine 2004, 23: 1764-1769.