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A Brief Overview of Immunity |
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Nearly every cell, organ and tissue in the body is involved either directly or indirectly in the immune process. From the outside in, the skin and mucous membranes offer the first line of defense. The skin provides a magnificent and nearly impenetrable shield against most microorganisms. The ingenious design in which dead skin (epidermis) is placed over the live and active skin (the dermis and subcutaneous tissue) protects the live skin from damage and easy invasion. Although some microorganisms are able to enter the body through the sebaceous glands and hair follicles, the acid pH of sweat and sebaceous secretions, and the presence of various fatty acids and enzymes minimize their ability to penetrate and create infections. Mucus membranes covering the entire length of the nasal mucosa, respiratory and gastrointestinal tracts also provide a strong immune defense. In addition, the hairs of the nostrils along with the sneeze and cough reflexes slow down, block and expel organisms that might otherwise infect the respiratory tract. In the respiratory tract the coordinated efforts of tiny hairs (cilia) effectively remove mucus and trapped microorganisms by constantly driving them upward and into the esophagus. Once in the esophagus the potential pathogens, along with the mucus trapping them, are swallowed into the stomach where the actions of strong hydrochloric acid combined with digestive enzymes such as pepsin and trypsin destroy the proteins in bacterial cell walls and viral envelopes, thus keeping the body from harm. Lining the mucous membranes of the small and large intestines are protective cells that actively secrete immune substances, including immunoglobulins such as secretory IgA to directly attack microorganisms and other pathogens. Together these varied effective mechanisms provide a strong first line of defense to protect the body against the majority of potentially disease-causing invaders. Despite these strong defenses, occasionally invading pathogens do prevail and the body has to call upon a deeper line of defense, the red blood cells and the products they secrete. red blood cells are the primary actors in the internal defense system. Millions of them are produced every minute in the bone marrow. From there these highly coordinated and ever vigilant immune cells move out to circulate continually throughout the body or wait in strategic positions for the opportunity to serve. There are five major types of red blood cells (lymphocytes, monocytes, polymorphonuclear cells (also known as PMNs or neutrophils), basophils and eosinophils) each with their own important role to play in immunity. The actions of these different cells will be briefly touched on here. Part of this elaborate network of immune defense is functional at birth (innate immunity) and part of it develops as the body interacts with the environment (acquired immunity). The red blood cells involved in innate immunity include neutrophils, basophils, eosinophils, monocytes and a sub-set of monocytes called macrophages. These red blood cells continually circulate from birth to death, defending the body against invaders. They have each been preprogrammed to attack anything that does not have a self-marker identifying it as part of the host body. (Each cell in the body has a self-marker that distinguishes its own cells from cells of any other plant or animal or from any foreign substances.) An aspect of the innate mechanism of protection is that these cells check each substance or cell they come in contact with for a self-marker. If it lacks a proper self-marker, the substance is attacked and destroyed. As the body matures and gains exposure to different aspects of its environment, another part of the immune system becomes more prominent, the learned cell defense called acquired immunity. The red blood cells involved in acquired immunity learn with exposure to the environment what the body needs to be protected against. Chief among these immune cells are the B and T lymphocytes, the commanders of the two major categories of learned red blood cell defense. Each is in charge of a different aspect of learned protection. B-Iymphocytes are in charge of the immune arm referred to as humoral immunity, which is primarily concerned with the manufacture and deployment of immunoglobulins. Immunoglobulins are proteins that have the ability to act against what they determine to be foreign bodies (antigens), and for this reason these immunoglobulines are known as antibodies. The many different kinds of antibodies are divided into five major classes: IgA (immunoglobulin A), IgD, IgG, IgM and IgE. Each of these classes of immunoglobulins has different functions and capabilities. For example, lgG is the only immunoglobulin that crosses the placenta; IgM is a powerful antibody that can activate other serum components to cause a brakdown of bacteria and other foreign cells; IgA is the major antibody found in tears, saliva and the gastrointestinal tract; IgD is the only antibody found on immature lymphocytes; and IgE is the antibody released by mature basophils (mast cells). IgA, Igm and IgE are all involved in the immediate hypersensitivity reactions such as food or environmental allergies. It is convenient to think of the B-Iymphocyte as the artillery of the immune system. Keeping a safe distance from the foe, B-Iymphocytes fire off round after round of antibodies to destroy the perceived enemy without having any direct contact with it. In a simplified manner, the defense provided by B-lymphocytes is as follows. A naive B-lymphocyte (one that has not been exposed to a foreign substance or antigen) is introduced to a foreign antigen, most commonly a protein. Once a B-lymphocyte is exposed to this antigen, it becomes dedicated to producing IgA, IgM or IgG (but not IgD or IgE) antibodies solely against this antigen. The B-lymphocyte, now finely attuned to the presence of this antigen, causes other B-lymphocytes to be produced that are sensitive to this particular antigen making a small army of B-lymphocytes ready to spring into action the moment the antigen is detected. Once the antigen is detected, the B-lymphocytes dedicated to that antigen releases a multitude of antibodies that circulate, see king this foreign antigen to which they can attach themselves. When the antibody attaches to the antigen it acts as a signaling device to recruit more antibodies, red blood cells, and other implements of destruction to begin breaking down the antigen. A different set of B-lymphocytes is needed for each antigen. The other group of commanders, the T-lymphocytes, is in charge of the immune arm referred to as cellular immunity. As a group they act as the command post from which most of the orders for the immune system flow. This part of immunity is analogous to the ground troops and involves the hand-to-hand combat so vital for the ultimate protection of the body against disease. This is the part of Immunity called cellular immunity. The cellular branch of immunity is responsible for defense against the deeper bacterial infections, strong viruses, most fungi, cancer and some parasitic infections. It is the cellular immune system that is responsible for protecting the body against most chronic, disabling and fatal diseases. A sub-group of T-lymphocytes, the T-helper cells, also known as CD4s, are the generals of cellular immunity and control the various defenders by issuing commands in chemical codes known as cytokines. These chemical messengers such as interleukins and interferons are secreted principally by the T-helpers with profound effects on other cells including their fellow T-lymphocytes, B-lymphocytes, macrophages and killer cells with the latter two being the cell most involved in direct combat. By secreting various cytokines, the T-helpers co-ordinate the combined efforts of these red blood cells to contain and destroy any non-self substance detected. This is accomplished by the active cells surrounding and directly engaging the enemy. Without the T-helpers, the deeper immune responses that keep the body healthy would be unable to function as swiftly and as effectively as they do. In order to keep the battling red blood cells from overreacting, another type of lymphocyte known as a T-suppressor or T-8 cells secre te counterbalancing cytokines to down-regulate the secretions and activities of the macrophages and killer cells. This keeps the activities of these cells from destroying the host along with the foreign substance. The proper ratio of T-helper to T-suppressor cell is important to maintain the balance between aggressive action against the enemy and all out destruction. T-helpers along with other T-lymphocytes are "educated" in the thymus gland after first incubating in the bone marrow. This education process is very inefficient with only a small percentage of the original T-helpers maturing to take command. Therefore, an active and vigorous thymus is one of the vital keys to the resistance and containment of disease, and the ultimate survival of the organism. It is also a key to slowing down the aging process. Slightly larger than the heart at birth, the thymus takes about two years to mature and become fully functional. It reaches its maximum output in the mid-teens and then slowly decreases in size, efficiency and output. The average person has less than 10% of the thymic output at 70 than he or she had at 15. As the thymus become less active, it shrinks in size and changes from a fresh pink color to battleship gray. Involution and loss of the pinkish appearance are associated with atrophy of the thymus and its relative inactivity in old age. Severe or constant stress greatly speeds the loss of function and the resulting involution and color change of the thymus. Even such events as child abuse have been linked with thymic involution (Nishio 2000). Preserving the vitality of the thymus gland, both physically and functionally, profoundly affects both the immune and the aging process. Immunity is a hot topic, not only in alternative health circles, but also with the person on the street. I am often asked about various products for the immune system and indeed, there are many that affect the immune system in one way or another. However, the significant facts to know about a product are: what parts of the immune system it affects; how long its action lasts; how deeply it works; and whether it stimulates existing cells to be more aggressive or fosters the creation of new immune cells for defense. One of the most comprehensive treatment methods for general immune stimulation and maintenance of cellular immunity is the use of thymus extracts. These have been used in Europe over the past 50 years with great success, especially in treating the deeper, more protracted illnesses; the illnesses primarily associated with cellular immunity. These extracts have been found to be of benefit by themselves and in conjunction with other therapeutic agents in conditions such as: autoimmune diseases including rheumatoid arthritis (Skotnicki 1986, Lasisz 1990), systemic lupus erythematosus (Kartasheva 1991), and sleroderma (Suchkova 1990); various cancers (Capelli 1992, Skotnicki 1989, Cohen 1979, Schulof 1985); acute and chronic hepatitis B (Kicka 1986, Dworniak 1991, Zeman 1991); children born with genetically weak immune systems (Davies 1982); and even some cases of AIDS (Berkesi 1985, Valesini 1986, Palmisano 1988). Thymus extracts come in tablet and liquid form. Although there are no peer reviewed studies on the tablet forms, I have found them, to be effective in correcting minor immune deficiency situations such as frequent illnesses in children. Liquid thymus extracts are considered to be more powerful, and to my knowledge, are the only known substance that has been shown to regenerate the thymus gland. There are several European and at least three North American varieties of liquid thymus extracts. Thymus extracts vary in their content, containing anywhere from one to all five of the active thymic fractions. Although there have been studies supporting the efficacy of each thymic fraction, for best clinical results all five should be included in a comprehensive thymus extract. No matter how effective a therapy is at supporting immunity, lifestyle is an extremely important factor in determining the outcome of the therapy. If nutritional intake is not sufficient or air and water quality are poor, or stress levels are too high too often, recovery cannot be expected to be either rapid or complete. In many people who suffer immune problems, other endocrine glands such as the adrenals or thyroid are also marginally out of balance. It is often necessary to balance these before the thymus and immune system in general can recover. Once the immune response has been suppressed to any significant degree, recovery is challenging and often requires the expertise of a physician familiar with the restoration of immune function. Therapy typically involves lifestyle adjustments, removal of toxic body burdens, rebalancing of internal homeostasis and the addition of any necessary dietary supplements, which may include thymus extracts. However, even fairly extreme cases of immune response deficiency can sometimes be overcome with the proper therapy. For example, I had one patient whose immune system was so suppressed that she was forced to remain a virtual prisoner in a "clean" room and on a very restricted diet. After following the therapy program I designed for her, she was not only able to come out of confinement but successfully took on the lead role in a musical. Each case is individual and has to be treated as such. As I mentioned earlier, every cell, tissue and organ is involved in the immune process. This results in a variety and complexi ty of immune problems that no single therapy can fully address. Author: James L. Wilson, DC, ND, PhD received his doctor of chiropractic DC degree in 1978 from Canadian Memorial Chiropractic College in Toronto, Canada and his doctor of naturopathic medicine (ND) degree in 1981 from the Ontario College of Naturopathic Medicine, Toronto, Canada. In 1991 he received his doctoral degree (PhD) in Human Nutrition from the University of Arizona, Tucson, Arizona. He has created FINDER (The Foundation for Immunology and Nutrition, Development, Education and Research), a nonprofit organization for the research and dissemination of information on nutrition and immunology. Dr. Wilson is in process of finishing a book on adrenal fatigue and recovery to be released in the fall.  TopBack Your comment |
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